Skip to main content

Full text of "Popular science monthly"

See other formats

5 o 5 

$ o t 


Popular Science 


Volume 91 
July-December, 1917 

Modern Publishing Company 

225 West 39th Street 
New York 

This volume contains 

960 pages 
1306 articles 
2082 pictures 


Copyright, 1917, by 

All rights reserved 

Popular Science Monthly 

Volume 91 — July-December, 1917 


Ancestors of the Bird and Airplane 3 

The Strength of Human Wings 32 

Fighting from Balloons 50 

Fighting in the Air 76 

America's Biggest Flying Machine 200 

U. S. Dirigible D.N. I 225 

"Pillows" as Airplane Targets 327 

A Fire-Chief's Airplane 385 

The Ideal Aerial Bomb 386 

Will the Dinners of the First Trans-Oceanic Flight 

Be Hot? 425 

A Life-Preserver for Aeronauts 439 

The Charge of the Lightest Brigade 530 

The Airplane to the Rescue of Storm-Tossed 

Mariners 538 

The Zeppelins Are Coming! Hug the Ground. . . 540 

Protecting the Airplane with a Fire-Proof Coating 542 

Air Scouts Learn to Sketch Battlefields 545 

The New Blimp Type of Dirigible 546 

Italy's Huge Bombing Triplane 688 

Catapulting Seaplanes from U-Boats 696 

Directing the Big Gun Fire from Airplanes 701 

New Gun-Tunnel Airplane 709 

Testing the Fighting Aviator. 711 

A New Map-Holder for the Aviator 728 

Sixty Miles an Hour Is the Climbing Speed of Fly- 
ing-Machines 744 

Making a Safe Landing at Night from an Air- 
plane 752 

Fishing in the Air 803 

A Biplane Which Crashed Through a Roof 838 

Sixteen Airplanes Against One Destroyer 850 

The Sun, an Enemy to Airplanes 857 

Testing Airplane Engines at Factory 861 

Dummy Airplane Targets 866 

Commuting by Airplane 879 

Our Aviation Problems 894 

Aviators Now Can Carry Their Telephones Under 

Their Hats. 907 

Testing Airplanes in a Man-Made Storm 910 


Guinea Pigs Were Once Cultivated Like Chickens 

for Food > 27 

Making the Cow's Tail Behave with a Trolley 

Restrainer 27 

A New Corn-Husking Machine 60 

A Garden in Which Weeds Are Not Only Tolerated 

but Cultivated 61 

To Make Your Lawn Attractive You Must Edge It 

Evenly 89 

An Adjustable Rake for the "Land Patriots" .... 90 

Silo Roof Opens Like Umbrella. 106 

Take Good Care of the Eggs This Year 167 

Growing Mustard and Water Cress on Blankets. . 204 

Plowing and Pulverizing the Soil in One Operation 205 

Soya Beans, a Substitute for Meat 206 

Studying the Effects of Calf-Foods by Means of 

Photographic Records 253 

The "Pretty Maids" of a Chinese Window Garden 269 

The Stationary Fruit Net 273 

To Prevent a Colt from Becoming Tangled in 

Halter Rope 288 

An Old Cake Tin Makes a Good Watering Pan for 

the Poultry Yard 300 

A Plumbing System for the Farm Residence 305 

Watering Plants Drop by Drop 354 

Subduing the Cow's Tail 388 

The Latest Tree-Trimming Ladder 407 

A Tin-Pan Orchestra to Scare the Birds Away 430 

A Stylish New Coat for the Baby Lamb 507 

The By-Products of the Grapefruit Obtained from 

the Culls 555 

A Little Bit of Egypt on a California Ostrich Farm 570 

Let the Birds Save a Billion Dollars a Year 588 

Sowing Tree Seed in the Snow 588 

Gold-Plated Teeth for the Sheep Is Common in 

Scotland 591 

Keep Livestock Away from Railroad Tracks .... 644 
A Spading Machine Which Makes Patriotic Gar- 
dening Worth While 685 

A Pig Carries His Own Pen 698 

A Portable Alfalfa Mill 698 

A Homemade Plow 706 

Providing a Treat for the Birds in' Cold Weather. . 728 

Grooming the Horse with a Vacuum- Cleaner Mitten 746 

This Is the Way They Plow in Porto Rico. . . .... 750 

Hatching Chickens in Glass Globe by Electricity . 806 
The War Gardens of Railroad Employees and Sta- 
tion Agents 893 

His Majesty, the Turkey 902 

Cattle-Guard Made of Cactus 905 

Raising Terrapins on the Farm 906 

Consider the Rat 916 


The Door to This Siberian Home Is Located on the 

Roof 101 

Circular Farm Garage Built with Silo Forms 187 

Roadtown — The Commuter's Utopia 188 

Unique Shelter for Garden Entrance 292 

Making a Durable Playhouse for the Children 300 

How Sound-Proof Rooms Were Built 329 

Star Spangled Banner in Brick 382 

Like a Spider in His Web 561 

This Store Sets a New Style in Exterior Decoration 671 

Trees in the Forest One Week — Houses the Next. . 735 

A Folding Staircase for the Fire Escape 839 

House Numbers in Concrete 875 

A Miniature Hotel with Two Thousand Rooms . . . 878 

A Chimney with Windows 892 


How the Sun Looks in the Arctic Circle 164 

What's on the Moon? . 256 

A Laboratory Two Miles in the Air 401 

How Old Is the Earth? 747 

A Parsec — The Greatest Unit of Measurement. . . 807 

Chained to Our Earth I 835 


A Suitcase Laboratory for the Laundryman 7 

Whiskey from Jam and Potatoes 72 

Mixing a Durable Water Color Aluminum Paint. . 300 
Manufacturing Prussian Blue from American 

Product 303 

The Chemical Wealth of Some of Our Lakes 407 

The Hottest Heat 414 

Buttons Are Now Made as a By-Product of Beer . . 517 

Getting Sulphur Without Liberating the Fumes ... 671 

Indigo from Michigan 702 

Powder Gases Wash Away Steel Guns . 754 

Making Money Out of a Nuisance. The Industrial 

Rise of Acetylene Ash 848 

Oleomargarine Glorified 877 

Sausage Made from Cottonseed 909 


Making Paving Machinery from Odds and End*. . 597 


Why a Sidewalk Was Built on the Top of a Storm- 
Sewer Tunnel 746 

Building a Park Around the Debris of a Burned- 
Down Schoolhouse 722 

Two Billion Paving Bricks a Year 855 

Measuring the Flow of Rivers 867 


Electrified Street Directions 33 

An Effective Burglar Alarm 49 

Cooling a Room with Cold Water 62 

An Electric Machine for Cutting Uniforms 71 

Newspapers in the Sky 104 

A Telephone Attachment Which Performs the Ser- 
vices of a Watch Dog . . . . 105 

Seal Your Letters by Electricity 114 

Applying Insulation to Splices Made in Electric 

Wires 147 

A Simple and Easily Made Electric Battery Motor 147 

Rebuilding Worn-Out Dry Battery Cells. 148 

Method of Insulating Secondary "Pies" in Trans- 
formers 1 49 

Steadying Voltage of Dynamo Driven by Gasoline 

Engine 150 

Increasing the Voltage of a Dry Battery 150 

Keyless Lamp Socket for Switching Electric Cur- 
rents , 151 

The Effect of Electricity and Music on the Human 

Organism 152 

A Rain Alarm Made of a Broken Electric Globe . . 152 
Protect Yourself Against Highwaymen with an 

Electrified Cane 191 

An Electric, Self- Winding Clock 222 

A Light for Luring Fish 233 

The First Life-Long Flashlight 240 

A Flashlight Attached to Your Razor 251 

An Electric Cord for the Sash Curtain 280 

Simple Oscillograph to Record Current Alternations 284 
Reversing Rheostat for Controlling a Small Motor 309 

A Drip-Pan Alarm for the Ice-Box Drain. 311 

The Electric Stevedore 328 

Telephoning from a Trolley-Car 353 

The Ben Franklins of Today 363 

The Electric Manicurist 400 

Increasing England's Crops by Electricity 421 

The Price of This Kiss Was Death 432 

A Method for Recharging Dry Cells 442 

His Lighting Bill Is Twenty-five Cents a Month. . 536 
"Do It Electrically" Also Applies to the Barber. . 538 
Using Resistance in Field Wiring on Automobile 

Dynamo 606 

Connecting a Spot Light in an Automobile Dynamo 

Circuit 613 

Electric Lamp Attached to a Spoon for Tongue 

Depresser 618 

This Electric Heating Faucet Has No Switch or Coils 668 
An Electric Wire in the Street Ignites a Balloon. . 670 
Using an Electric Heater to Dry the Glue on En- 
velopes 672 

Announcing the Election Returns by Telephone . . 740 
Making Telephones and Phonographs Clearer.... 745 
Click! Click! Go These Electrically Operated 

Scissors 748 

Telegraphing by Typewriter 756 

Automatic Cut-Outs for Charging Storage Cells . . 789 

A Practical Electric Vacuum Cleaner 791 

Making an Electric Furnace for the Laboratory . . 792 
Testing Electric Wires for High Tension Currents . 797 
Resistance in Circuit to Make Double Tone Auto- 
mobile Horn 797 

Making a Selenium Cell for the Laboratory 799 

A New Way of Oiling Machinery by Electiicity. . 825 

Illuminated Muffs 881 

Combining an Electric-Elevator with the Shoe- 
Shining Chair 888 

Applying the Principle of the Phonograph to the 

Telegraph Sounder 889 

Reducing Packing Costs in Handling Telephone Sets 908 
A Telephone Conversation May Be Almost "Pri- 
vate" Nowadays 913 

Telephone Conversation Made Easy by a New De- 
vice 919 

Charging Storage Batteries with Direct Current . . 947 

Simple Method of Making Storage Cells 947 

Auto-Transformer in Headlight Circuit on a Mag- 
neto 952 


Making a Good Outdoor Ground to a Pipe 952 

Finding the Combined Value in Parallel Resistances 959 
Heating a Soldering Iron with an Electric Arc. . . . 960 


Save Your Bottles. A Shortage of Jars and Cans 

Is Threatened 37 

Not Even the Space Underneath This Desk Is 

Wasted 37 

A Machine for Ironing Stockings 49 

Household Appliances 52-53 

A Tea-Making Machine 66 

Using Your Player Piano as a Vacuum Cleaner. . . 72 
Changing the Apartment Telephone into a Pay- 
When- You-Call System 86 

Alarm Which Tells You When Your Bathtub Has 

Been Filled to Whatever Depth You Desire ... 87 
Combining a Strainer with the Bung of a Barrel . . 90 
Making the Kitchen Range One Hundred Per Cent 

Efficient Ill 

A Clever Bottle-Opener 1 90 

Co-operative Kitchens to Solve the "High Cost" 

Problems 198 

Children May Write on" These Walls Without Fear 

of Punishment 204 

An Electric Fan Runs Without Electricity 217 

Household Appliances 238-239 

Keeping Out Flies When You Open the Door. . . . 260 
Household Bookless Bookkeeping on the Poker- 
Chip Principle 267 

Put Your Flowers Outdoors on this Adjustable 

Window Shelf 271 

Hanging Backing Cloth for Wall Paper 283 

A Double Deck Revolving Clothes Hanger for a 

Yard 287 

Iceless Refrigerator Using Evaporation for Cooling 289 
Sterilization Is the Essential Factor in Canning 

Vegetables 290 

The Burlap Cooler 351 

Scrub Your Walls by Machinery 360 

Housekeeping Made Easy 372 -3 

An Approved Smoker's Kit 410 

A New Attachment to Hold the Trousers in Place 420 

A Handy Clothes Closet for Your Vacation 424 

The Clam-Shell as a Decoration 43 5 

That Bit of Butter Left on Your Plate— What 

Becomes of It? 519 

This Vacuum Cleaner Is Used Like an Ordinary 

Broom 519 

Housekeeping Made Easy 552-553 

Fountain Spot-Remover Works Like a Scrubbing 

Brush 568 

An Owl with Eyes of Scissors and Backbone of Paste 576 
You Can Roll This Can Without Spilling the Gar- 
bage , 593 

A Wooden Lighthouse Candlestick and How It Is 

Made. 600 

Sending the' Wash to the Laundry Through a Glass- 
Lined Chute 664 

The Full Dinner Pail 669 

An Accommodating Gas Stove 670 

What to Do with That Dripping Umbrella 671 

Keeping Your Neckties Smooth 672 

New Can-Opener Which Does Not Destroy the Can 679 

Housekeeping Made Easy 694-695 

A Necktie Rack 702 

Cook Over the Gas Lamp 72 I 

Making a Window Seat Out of the Radiator 725 

Dry Your Fruits and Vegetables at Home 736 

Carry Your House Key in Its Own Bag ........ 736 

The Kitchen Cabinet Up-to-Date 742 

The Temperature Alarm 747 

Keeping the Shampooing Soap Suds Out of Your 

Eyes 804 

Storing Needles and Thread in the Handles of 

Scissors 828 

Solving Kitchen Problems Electrically 830 

Abolishing the Garbage Can 833 

Rocking the Baby Fore and Aft ... 842 

New Shoe-Polishing Kit 857 

Improved Office Appliances 870 

Electric Fish-Sealer 873 

Baby's Wheeled Dressing Table 877 

Housekeeping Made Easy 890-91 

A Pelican in Your Wardrobe to Hold Your Coat. . 904 
Want to Go to the Attic? Just Pull Down the Stairs 912 



This Typewriter Prints in Every Type and Lan- 
guage 5 

Is Your Typist a Rapid Operator? This Machine 

Will Time Her 25 

Big Steel Guns and How They Are Made . '. 38 

Typewriting in Code 59 

Mechanical Appliances 74-75 

A Cushioning Drawbridge Gate 80 

A Safety Coat for Workmen 96 

The Last Word in Fountain Pen Efficiency — An 

Eraser Attachment 97 

Removing Iron Rivets with a Pneumatic Hammer 97 
With the Warm Weather Come Improvements in 

Ice-Cream Making 1 00 

Safety Nets of Rope for Skyscraper Workers .... 114 

Largest Indoor Waterfall 166 

A Street Cleaner Built Like a Carpet Sweeper .... 203 

Mechanical Appliances 210-21 1 

A Coal Mine in His Cellar 215 

Repairing Flag Pole Without Steeplejack 216 

Canning Beans by Machinery 221 

A Portable Elevated Saw 228 

A New Addressing Machine 234 

A Conveyor for Loading Coal 237 

A Self-Propelling Sprinkler 240 

A Mechanical Bank Teller 245 

The Needle Bath in Shell Making 248 

A Portable Nail Distributor 249 

T he Evaporation of Water Drives This Remarkable 

Clock 254 

One Horsepower Will Run All the Watches in the 

World ...261 

A Small Sand Spreader Is Useful All the Year 

Round 263 

Panning for Gold in Central and South America . . 264 

The Compressed-Air Orchestra 265 

The Efficient Garbage Collector 397 

Mechanical Kinks 398-9 

A Machine for Reclaiming Scrap Material 410 

Three Roadmaking Machines in One 421 

A Time-Saver for the Repairman 425 

Standardizing the Die-Sinker 440 

Gear Wheels Made of Cotton 517 

Steam Jets Which Save Thousands of Dollars in 

Large Power Plants 523 

Do It with Tools and Machinery 534-535 

Stamping Two Thousand Letters an Hour 537 

A Substitute for Forms in Concrete Roofs and 

Floors 543 

An Iron Worker's Steel Glove 544 

How One Furnace Can Save a Big Slice of the 

Country's Coal Bills 564 

We Burn Coal Lavishly, but We Have Plenty to 

Burn 567 

Making a Fortune Out of Cement Factory Dust . . 569 

Blowing Stumps Away with Air 576 

Welding Ten Miles of Pipe for a Skating Rink .... 584 
Drilling with This Electric Drill Is Like Shooting a 

Pistol 593 

Let This Automatic Device Feed Your Envelopes . 595 
The Overdriven Nail and the High Cost of Living. 543 
Potted Plants as a Part of a Plumber's Equipment 548 
Perfect Bread Slicing Machine for the Commis- 
sariat ; 645 

Fastening Motors to Ceilings Without Scaffolding 673 
Weighing Your Coal by the Ounce or the Pound. . 686 

A Device for Handling Rugs 699 

A Simplified Gasoline Engine 704 

Stamping Oranges 705 

Extinguishing Flames of a Gas Well 708 

Mechanical Appliances 718-719 

The Most Ornamental Smokestack in the World. 734 

How the Cellar Shut-Off Nozzle Originated 740 

This Furnace Practically Takes Care of Itself. . . . 742 

Any Boy Can Build a Concrete Wall 745 

Whirling Concrete Poles into Shape 749 

Fire Doors That Close Themselves 750 

Sorting Letteis with Gravity Chutes 752 

A Valveless Pump for Gearset Grease 753 

Cutting Sheet Metal with a New Machine 757 

Handling Cotton Bales with an Over-Head Trolley 757 

The Giant Crane of the Austrian Navy 758 

A Jeweler's Ruse 760 

A New Siphon That Starts Itself Without Suction 

or Pumping 832 

Turning Valves on Their Seats Automatically. . . . 859 

Furnace Burns Soft Coal and Cleans Its Own 

Radiator 867 

Largest Direct-Current Power Plant 868 

Improved Mechanical Appliances 871 

Running the Oven by the Hot-Air Furnace 879 

Making Flour from Pigskin 882 

Barking Wood by Machinery 885 

A Dipper Dredge That Served as a Qrydock 893 

Two Locomotives to the Aid of a Shivering Manu- 
facturing Plant 899 

Doing the Work of Three Hands with Two, on a 

Soldering Job 900 

Which Way Will the Tree Fall? 901 

New Looms for Old — A Wartime Necessity 904 

A Collapsible Concrete Form Which Works on the 

Principle of an Umbrella 905 

The Smallest Bandsaw 907 

Another Biggest Thing in the World— This Time a 

Riveting Machine 9| 3 

Hot Water in an Instant 920 


Be Thou Wary of the Bubbling Cup 86 

The Hospital Toothbrush — It Has a Removable 

Pad 95 

The Private Hairbrush — The Bristles Can Be 

Locked Up 95 

The U. S. Armies Prepare to Fight Germs 106 

That Wad of Dental Cotton— Was It Sterilized? . . 107 

An Ice Helmet to Relieve the Fever Patient 115 

Separating Russian Prisoners from Vermin 119 

Chiropodists for the Army 164 

A Holder and Sterilizer for the Toothbrush 205 

Gigantic Models of Mouths 221 

A Single First-Aid Dressing 235 

How Policemen Revive You When You Faint. . . . 237 
The Feet and Legs of American Citizens Are Un- 
sound . 263 

Closing Up a Wound Without Using a Surgeon's 

Needle 269 

Feeding Germs on a Special Diet 270 

Inducing Artificial Respiration with a Vacuum. . . 350 

A Device for Supporting the Arch 385 

The Dental Hygienist 387 

A Spring-Motor for the Human Jaw 408 

A Treatment for Distemper in Dogs 434 

If You Lisp or Stammei Use a Mirror or Candle. . 484 
A Self-inflicted Tug-of-War to Increase Your 

Height 484 

Combination Knife and Fork for the Wounded. . . 485 

Choosing the Air for Our "Castles" 503 

A Crutch Built on the Principle of the Rocking 

Chair " 523 

The Army Medical Museum's Giant Skull 551 

The Massaging Chair 564 

A Huge Barber-Shop Sterilizer on Wheels 583 

This Death's Head Poison Bottle Will Prevent 

Fatal Mistakes 594 

Bomb Exits for America's First Portable Hospital 596 

Fat People Are Unpatriotic 645 

Medical Men in the Army 685 

Open Your Mouth and Let the Doctor Flashlight 

Its Interior. . 687 

Preventing Typhoid 706 

Testing the Fighting Aviator 711 

The Best Night Light for the Sick Room 729 

A Medical Battery No Bigger Than an Ordinary 

Flashlight 731 

How About ThatThird Cup of Coffee for Breakfast? 734 
Train Your Skin So That It Will Not Be Sensitive 744 

Artificial Lungs for New Born Babies 807 

It Bathes, Massages, and Dries Us 832 

The Old Indian Priests Had No Easy Time of It. . 837 

Toe Spring for Enlarged Joints and Bunions 838 

A Disappearing Crutch 854 

Curing Wounds with Sugar 867 

Fracture Setting Machine 875 

Employing Destructive Gases in the Warfare 

Against the Sleeping Sickness 888 

Using Brine Baths as a Cure for Shell Shock 899 

Examining Recruits for Tuberculosis 909 

Treating the Wounds of the War by Electricity. . 918 

How the Fighters Will Be Fed 6 


The Poison Gases that Kill Men in Trench Warfare 24 

Big Steel Guns and How They Are Made 38 

A New Caterpillar Truck 57 

A Submarine's Trip on Land 58 

Fire-Crackers to Ward Off Submarines 59 

Our Unsinkable Cargo Fleet 63 

An Inverted Periscope Used Under Water 68 

The Shoe Hospital of the Allies 61 

California's Conception of a "Tank" 67 

Millions Spent for Shells 70 

A Signal Gun 71 

Conserving Wheat with Alfalfa 72 

An Electric Rammer 80 

Motor-Boats for Submarine Chasers 82 

Dummy Guns Train England's Gunners for the Sea 94 
To Save Money During War Time Why Not All 

Dress Alike 1 00 

The U. S. Armies Prepare to Fight Germs 106 

Protecting the British Fleets with Chain-Nets. ... 112 

Separating Russian Prisoners from Vermin 119 

Drag-Bombing Submarines with Airplanes 163 

Handling a Submarine 1 68 

The Time Fuse and How It Works 192 

Antiseptic, Anaesthetic Bayonet 216 

A New French Word "Camouflage" 217 

The Onerous Task of Rejecting Recruits 218-219 

The New French "37" 220 

A Great Map of Warring Europe 222 

An Automobile-Mounted Machine-Gun 226 

How the Germans Mutilated Their Boats 230 

The Largest American Flag .' 245 

A New Method of Foiling Bomb-Droppers 247 

Applying the Idea of the Needle Bath in Shell- 1 

Making. 248 

An Army Tool-Shield 266 

Figures That Give An Idea of the Task of Trans- 
porting Our Armies 27 1 

Why Not the Land Torpedo? 323 

A Target Which Answers 349 

A Visor for the Helmet 350 

The Marines Sleep on Their Life-Prese. vers 354 

Hurling Barbed Wire at the Enemy 355 

The Primer of the Giant Shell 36 1 

The Biggest Red Cross Flag 369 

Details Involved in Making Shrapnel 369 

Target Practice with Coast Defense Guns 369 

Moving a Piano Across the Sahara 378 

Desert Sandshoes 379 

The Mother of the Submarine 380 

Italian Soldiers Paint Their Faces 382 

Rifle-Firing Kinks Taught West Pointers 383 

Body Armor for the Soldier 389 

Newspaper Torches 390 

Testing the Hearing of a Soldier. 392 

Revolver Machine Gun 393 

How the U-Boats Get Through the Nets . 395 

Khaki Has Been Used Since 1848 401 

All Around a Battleship 402 

The War Dress of the New Guinea Soldiers 406 

Demolishing Cottages with a Battering Ram 409 

The Detonator Head 419 

A Million Dollars a Year to Paint Our Navy 424 

Thrusting Spears for Cavalry 430 

Military Marching for Beginners 475 

Is This the Machine-Gun of the Future? 483 

Three Million Pairs of Shoes Ordered for the Army 507 
Firing Shells Charged with Gasoline Which Ignites 

on Impact 507 

Will the Shell Burst When It Is Fired? 513 

The New Enfield Rifle 518 

A Shock Absorber for the Soldier's Kit 521 

Statistically, What Is Your Chance of Being Killed 

in This War? 532 

The Camouflage Soldier 533 

Saving the Food Cargo of a Torpedoed Ship 540 

Forty-Three Bombs in a Freight Car of Scrap 

Iron . 542 

The "Red Cross" for the Soldiers; the "Red Star" 

for Their Steeds 544 

The Carrier Pigeon Still Holds Its Own as Trusted 

Messenger 554 

Shoot or Stab This Dummy, and an Explosion 

Occurs 555 

Megaphoning the Reveille 568 

Fighting a Gas Attack in the Trenches 580 

Moving Targets to Quicken the Eye and Steady the 

Aim 585 

What You Will Need When You Go to Training ** 

Camps 596 

Gun-Buoy for Repelling Submarines 643 

A Merry-Go-Round for the German Soldiers .... 644 

A Leopard Ship of the Sea 645 

A Versatile "Helmet 646 

Cowards in the Armv Are Rare 646 

Fighting at Night with Searchlight Torpedoes. . . . 680 

What's Wrong with the Submarine? 682 

Medical Men in the Army 685 

Packing Chocolate in Sausage-Links 685 

Shells with Scissors Attachments That Cut Wire 

Entanglements 686 

Portable Army Bread-Mixer 689 

Catapulting Seaplanes from U-Boats 696 

Identification Rings for Soldiers 699 

A Shoe-Repairing Truck for the Army 700 

Guarding Venice 706 

The New Service Flag 707 

Assembling Torpedos 717 

A Temporary Tombstone for the Unexploded Shell 721 

Paper Uniforms for German Soldiers 728 

A Bullet That Flies Like a Comet 729 

The Machine-Gun Principle Applied to the Revolver 730 

Eliminating the Periscope from the Submarine. . . 731 

Men Who Ought to Make Good Rifle Shots 732 

Business Is Booming in War Horses and Mules. . . 736 

Three Shots with a Single Shell 739 

Will a Projectile Fly True? 743 

A French "75" Anti-Airplane Gun with a Camou- 
flage Dressing 744 

How a Fighting Dummy Teaches Men to Use the 

Bayonet 824 

Steel Castings for Modern Dreadnoughts 827 

Reaching the Soldiers, Wounded Far Up in the 

Mountains 839 

The Unsinkable Submarine 840 

The Possibilities of a 60-Inch Gun 844 

Testing Shells for Hardness 847 

The French "Horizon Blue" Is the Best Color for 

Uniforms . . 848 

What Defective Ammunition Means 849 

New Motor Truck Kitchen 851 

Blinding the Enemy with Searchlights 859 

A Bomb in a Piano 865 

Dummy Airplane Targets 866 

A German Military Obstacle 869 

The Latest Sea Camouflage 876 

Protecting Battleships with Compressed Air 886 

German Trenches as Comfortable as Houses 889 

England's Great Under-Sea Walls of Bombs 915 


A Hint to Motorists — Keep Your Radiator Clean 7 

Differentiator Motor Vehicles 30 

Automobiles, Motor-Trucks and Accessories. . . .34-35 

Measuring Motor-Truck Loads Automatically. ... 36 

The Youngest Manufacturer of Automobiles 48 

A Solution to Tire Troubles 58 

Auto Engine Cooler on Steam Ejector Plan 62 

Transforming an Auto Roadster into a One-Ton 

Truck 73 

A Ten-Ton Motor-Truck on Eight Wheels 88 

A New Type of Transmission Employs Cork Inserts 1 00 

The Problem of the Automobile Top :••.••• '02 

A Community Garage Comprises Fifty Buildings 

on One Lot Ill 

Making the Acetylene Light as Brilliant as the 

Electric Lamp 120 

Combined Ice-Box, Pantry and Trunk for Autos. . 165 
Testing a Car's Power to Pull Itself Out When 

Stuck 167 

A First Assistant to the Motorcycle Cop 169 

The Automobilist's Mechanical Cost Keeper 186 

A Folding Crib in the Automobile and Summer 

Camp 191 

A Funnel Will Fill Up Your Automobile Tank 

Without Spilling the Gasoline 193 

Automobiles, Motor-Trucks and Accessories. . . 194-195 

Convenient Automobile Doors 224 

Automobile Run on Alcohol 229 

The Cost of French Army Cars 233 

A Keyless Lock for Your Ford 236 

Auto Engine Cooler Operates on Steam Ejector 

Plan 246 


One Inventor's Idea for Lengthening the Life of a 

Rubber Tire • 255 

Making a Trolley-Car of the Motor-Truck 261 

Device to Remove Automobile Bodies Without 

Scratching 262 

The Newest Child's "Pushmobile" 263 

An Easily Adjusted Tire That Locks Itself on the 

Wheel 268 

A Motor-Truck for Ice Cream Delivery 272 

Tipping Truck for a Large Cylindrical Oil Tank. . 282 

Miniature Automobiles and Their Race Meets. . . . 283 

Effects of Oil and Grease on Rubber Tires 288 

Repairing a Worn Plunger in an Automobile Oil- 
Pump 293 

A Tractor Trailer Made for an Old Automobile. . 295 
Inflation and Weight Governs the Resiliency of 

Tires ....296 

Constituency of Rubber for Side Walls of a Tire. . 302 

Salvaging Motor Wrecks with an Equipment Car 324 

Motor Truck Carries Thirty-Eight Soldiers 326 

Live Steam or Vapor to Save Gasoline 351 

A Lock which Makes the Ford Car Thief-Proof. . . 353 

Automobile Accessories 357 

Men Whom the Automobile Has Made Rich . .358-359 

The Gasoline Automobile as a Locomotive 360 

The Air-Propelled Unicycle 370 

Loading Coal Baskets from a Motor Truck 379 

Cleaning the Air Fed to Automobile Cylinders. . 383 

The Biggest Automobile Spring 384 

What Six Gallons of Gasoline Can Do 409 

A Dust-Proof Cover to Keep the Automobile Lug- 
gage Clean 417 

A Tire Pressure Gage No Bigger Than a Pencil. . 421 

Storing Automobile Fenders 424 

A Garage Built with the Contour of a Cathedral. . 431 

An Anti-Kick Device for the Ford 435 

Caring of Inner Tubes to Prevent Chafing 455 

Dust Proofing the Automobile Priming Cup 455 

Rim Cuts in Tires 470 

Automobiles, Motor-Trucks and Accessories . . .508-51 1 

Turning a Car in Its Own Length 512 

This Truck Loader Will Lift One Ton Ten Inches 

Per Second 517 

Your Motor Is Known by the Piston Rings It Has 522 
The Small Caterpillar Tractor Rings the Death 

Knell of the Industrial Railroad 532 

The Rising Price of Automobiles 543 

Inspecting a Six-Mile Tunnel by Automobile 544 

A Motor Truck Line I 540 Miles Long 548 

Advertising by Motor-Truck 549 

Photographing the Jolts of an Automobile 550 

Loading Trucks Without Disturbing Sidewalk 

Traffic 554 

A Car-Lifting Brake 560 

Improved Electric Gearshift for Autos 567 

Buying a "Used Car" 573 

This Tire Pump Gets Power from the Engine 

Crankshaft 585 

A Harrow-Like Brake for Mountain-Climbing 

Automobiles 590 

The Common Rotary-Valve Gasoline Engine Is a 

New Departure 600 

Testing for Trouble That Causes Poor Auto Lights 610 

How to Relieve Your Auto Brakes 617 

Electrically Operated Turntables for Automobiles . 669 
Automobiles, Motor-Trucks and Accessories .... 674-7 

It Has Both a -Pneumatic and a Solid Tire 681 

Preventing the Ford Engine from Overheating. . . . 687 

Touring in a Motor-Truck 697 

Transporting a Precious Mirror 703 

An Automobile Safety Device 705 

Kerosene-Driven Farm Tractor 720 

Hauling a Seven-Ton Truck Out of the Mud 735 

Changing a Roadster Into a Five-Passenger Car. . 737 

Getting More Mileage Out of Gasoline 738 

A Simple Cylinder Re-Boring Machine 748 

A New Way of Cushioning the Front Spring Action 

of an Automobile 828 

Three-Purpose Electric Drill 828 

The Automobile Driver Must Know What to Do in 

. Case of Accident 83 1 

Bell Gives Warning When Automobile Backs Up. . 834 

A Powerful Motor Sprinkler 849 

New Motor Truck Kitchen 85 I 

Automobile Accessories 852-53 

Mirrors to Avoid Auto Accidents 855 

Burning Distillate in Your Auto Engine 864 


Keeping Auto Engine at Right Temperature 866 

Turning the Headlights Electromagnetically 919 

Forty-Five Miles an Hour on This Motorcycle Sleigh 920 
An Automobile Steering Wheel for a Bob-Sled. . . 928 


The Grave-Digger Beetle 25 

How Scientists Capture Mosquitoes Alive for Ex- 
periment and Study 26 

Japanese Mosquitoes for Bird Food 68 

Counting the Drops in a Fog 91 

Mountains Float 1 08 

The Common Housefly Is the Most Unpopular of 

Insects 110 

The Misunderstood Shark 196 

Teaching the Proper Care of Forests by Object 

Lessons 1 99 

It Is Beautiful Because It Is So Ugly. 201 

Teaching Children Natural History with Animal 

Pictures Made of Sand 201 

Mysterious Ice Mines 207 

Poison Ivy and How to Avoid It 207 

The Curious Ways of Egypt's Holy Beetle 252 

What Monterey Did with a Whale 255 

Everybody Knows the Squash Bug 264 

Coaxing Music from a Pile of Rocks 267 

Imitating Nature with a Miniature Volcano 286 

An Irish Thrush Rings for His Food 288 

Potash from California Sea Kelp 325 

Operating upon Trees 346 

Unwashed Sponges Are Dirty 351 

Penitentiary Roof Garden 390 

Feeding London's Zoo Animals 400 

The Night Song of the Tree Cricket 406 

Faces in Walnut 407 

Why Pheasants Need Foster Mothers 410 

Growing Umbrella Handles ,. 420 

How a Cyclone Bent a Flagpole 433 

Why Does a Cat Have a Tail? 438 

This Bird's Nest Is a Two-Room Apartment 525 

If You Had No More Teeth Than an Elephant You 

Couldn't Be a Soldier 572 

Teaching the Truth About the Misunderstood 

Snake 579 

Rivers That Flow in Two Different Directions .... 678 

Why Do Salmon Go Annually Out to Sea? 681 

A Thirty-Five Acre Island of Mud Near Memphis 721 

The Robber Crab 730 

Orchids That Grow on Telegraph Wires 731 

How Plants Accommodate Themselves to the Cli- 
mate f 737 

San Salvador's Terrible Quake 741 

A Lizard That Squirts Blood from Its Eyes 805 

Palm Spiings 805 

Snow Honeycombs and "Penitents" 805 

How Did One Egg Get Inside of the Other? 826 

The Cut Branch Did Not Die 836 

Exploded Beliefs about the Arctic 839 

You Can Hold a Dozen of These Coconuts in One 

Hand. . 848 

The Eccentricities of the Sleeping Horse 851 

Can a Frozen Fish Be Restored 873 

Mvsterious Sound That Baffles Science 881 

Eat Your Dates with an Easy Mind 918 


A Photographic Trick— Try It the Night of the 

Fourth 7 

Making "Night Scenes" for the Motion Picture. . . 24 

Wireless in the Talking Movies 33 

Making Motion Pictures at Home. 54 

Taking Motion Pictures on the Road in a Queer 

Vehicle 61 

An Attachment Which Will Lock Your Camera to 

the Tripod in an Instant 120 

Dinner Served in Gondolas on a Champagne River 220 

Camera Handled Like a Pistol 241 

Directing a Motion Picture Show from the Mana- 
ger's Office 254 

Taking Snap Shot Action Pictures at Night 280 

A Solution for Reclaiming Over Exposed Blue 

Prints 287 

Leveling a Motion Picture Camera Tripod 292 

A Quick Action Electric Switch for Photographers 307 

Taking the Glare Out of Motion Pictures 324 


Taking Photographs with a Concealed Camera. . . 327 

Airplane Camera Takes 750 Exposures 328 

A Motion-Picture Projector Which Can Be Carried 

in a Suitcase 423 

The Original Motion Picture Film 484 

Taking Pictures a Thousand Feet Under Water . . 577 

Moving Pictures That Really Talk 578 

Aim and Pull the Trigger to Photograph an Enemy 

from the Air 586 

Making It Easy to See the "Movies" 599 

Finger-Print Camera for Modern Sherlock Holmes. 678 
Making Pictures and Projecting Them with the 

Same Machine 722 

Harnessing a Fighting Lion for the Films 739 

A Moving-Picture Show, the Martian Might See . 856 

A Motion-Picture Camera on One Leg 878 

How the Lion and the Lamb Lie DownTogether in 

the Motion Pictures 884 

Hang That Book from Your Shoulders 892 

Incandescent Lamps May Now Be Used to Project 

Motion Pictures 893 


The Flag Equipment of an American Battleship. . 8-9 

An Airplane View of Salonika 10 

How New York Firemen Save Lives II 

Testing the Senses 12-13 

Primitive Man's Art and Handicraft 14 

Odd Specimens of Tattooing 15 

Selecting Fit Men for Our Navy 16-17 

The Latest Styles for Automobile Bodies 18 

Killing the Dry Frog in the Opera Singer's Throat 19 

Gas Masks Used in Peacetime 20-2 1 

Importance of the Hoe, Spade and Pitchfork in 

War 22-23 

Bayonet Practice for Our Recruits I 70 

Why the Hindenburg Line Seemed So I mpregnable I 7 1 

Sculpture of Fat and Sugar 1 72-1 73 

The Chimney Sweeps of Paris I 74 

Novel Methods of Recruiting 175 

The Importance of Rope on a Battleship 176-177 

Making the American Flag 1 78-1 79 

A Waterspout . . 180 

Keeping the Animals Cool in the Zoo 181 

Soldiers' Art Exhibit in Paris 182 

President Wilson's Message Reaches the Germans 183 
Prisoners and Wounded Alike Must Have Pleasure 184 

Queer Trees and Near Trees — All Are Useful 185 

In the Grottoes Under the Battlefields 330 

Trench Farms of the Philippines 331 

The Eagle Builds Remote from Man 332 

Bungalows on a Roof 333 

And the Inventors Never Cracked a Smile 334 

France's Tank Contribution to the War 335 

They Earn Their Living with Their Senses. . .336-337 

Natural Figures in Wood 338 

Profit in Raising Skunks 339 

New Eagles of the Western Front 340 

Armor Appears on the Airplane 341 

Making an Army Hat 342-343 

Wood Carving by Machinery 344 

New Fashions in Gas Masks 345 

Army Refiigerating Devices 486 

Trained Horses for the New York Mounted Police 487 

Making Anti-Submarine Nets 488-489 

What It Means to Feed and Clothe the Armies of 

the Allies 490-491 

The Sahara Viewed from an Airplane 492 

Specimens of Indian Art 493 

Food — -Food Everywhere and Not a Bit to Eat . . . 494 

French Forces Using Liquid Fire 495 

Dolling Up Your Fo*d \ .496-497 

Big Guns Used by the Coast Artillery 498-499 

Various Stages in the Development of a Wasp . 500-502 

Posing on Flying Rings 648-9 

Queer Ways of Making a Living 650-1 

The Way of the Slacker Is Hard 652-3 

Baths Without Bath-tubs and Milk Without Dairies 654 

Cliff Dwellers Near Santa Fe 655 

Russia's Modern Joans of Arc 656 

A Sharp Shooter Wearing a New Water Jacket . . . 657 

Odd Uses of the Talking Machine 658-9 

Exploits of Tanks and Airplanes 660-1 

Who's Who and What's What in the Army 662-3 

Making Serums for Uncle Sam's Army 808-09 

X-Ray Photographs 810-1 1 


Women Working on French Dirigible 812-13 

Performing Dogs i 814 

The Allies Big Repair Tents 815 

Comfort Kits for Our Soldiers 816-17 

Avoiding a Broken Head in Boxing 818-19 

Fresh Air for New York's Anemic Children. . . . 820-21 
Making Rifles and Bullets for Our Soldier Boys . .822-23 


Cutting Clippings from Magazines with a Pin. ... 121 

Solid Board Fence with Artistic Upper Edge 121 

Rustic Furniture Made of Poles and Logs 121 

Using a Drop of Water for Lens in Photomi- 
crography 123 

An Effective Fireproofing for Children's Clothing. 125 
Collecting Ants in a Sponge and Drowning 1 hem . 125 
Exterminating Moles and Gophers by Asphyxiation 1 25 
Exhibiting Specimens of Flowers in Single Blos- 
soms 1 26 

A Tracing Cloth Repair That Does Not Affect 

Transparency 1 26 

Differences in Curing Time of Parts Makes Poor 

Tire Repair 126 

Porcupine Removes Window Pane to Gain Admit- 
tance 1 26 

Round Belt Guide on a Washing Machine Wheel. 127 

A Vine Covered Tepee for the Garden 127 

A Shaft-Polisher Made Like a Lemon Squeezer. . 127 
Building an Artistic Bird-House for the Garden .... 1 28 
A Printing Process for Imitating Hard Woods. ... 129 
An Improvised Stage for a Country Fairy-Play. . 131 
An Experiment in Optics Using Heated Graphite 132 
Small Hand Drill Made from a Cheap Watch .... 132 

A Snap-Fastener for the Cupboard Door 132 

Awnings for the Veranda and How They Are Made 133 
Fastening an Oar-Lock to Keep It from Falling Out 134 

A Boomerang Flyer 135 

How to Cut Roses So That the Plants Are Not 

Injured 136 

Sheet Metal Working Simply Explained 137 

A Pin Inverted in a Cork to Make an Oil Dropper 138 
An Automatic Watering Tank for Poultry Yards. 138 
A Trough for Thoroughly Washing Film Negatives 138 
Safety Guard Placed on an Emery- Wheel Dresser 139 
A Nest-Box Trap for Catching the English Sparrow 1 39 
Look Over Stored Tires Before Applying Them to 

Rims 139 

An Easily Made Garage from a Metal Tank 140 

A Cheap and Effective Method of Bracing a Roof 140 
Small Closet in Door Frame Stile for Milk Bottle. 140 

Winning an Athlete's Laurels 141 

Sticky fly Paper Used to Keep Insects Away from 

Poultry 145 

Saving Concrete in Setting Posts in Holes 145 

Waterproofing Blue Prints and Drawings for Rough 

Handling 1 45 

A Coating Which Gives the Appearance of Stone to 

Wood 146 

A Special Ladder for Use in Boiler Shops. 146 

Three Plates and Three Color Screens Used in New 

Color Photography I 46 

Making a Push Cart Oil Sprinkler for Dusty Drives 28 I 
Never-Slip Calks Used on Lawn-Mower Wheels. . 281 

Three Methods for Finding a Chosen Card 281 

End Mills Made of Broken and Worn Twisted Drills 282 
Fastening Nails So They May Be Quickly With- 
drawn 282 

Waterproofing for Concrete Walls and Floors 282 

An Open Shelter for the Yard or Flat Roof 290 

A Self-Acting Fountain for the Home Conservatory 291 
Preserving Unpainted Surfaces Caused by Wear . . 293 
A Substitute for a Shoe Horn in an Emergency . . . 293 

A Tool for Accurately Lining Shop Shafting 294 

A Turned Down or Pistol Grip Handle for a Rake . 294 
A Cement Wash for Applying to a Damp Wall . . . 296 
A Porch Swing Made from Your Favorite Rocker . 296 

Sheet Metal Working Simply Explained 301 

Folding Camp Fireplace Made of Angle Iron. .... 302 

Garden Seat with Checkerboard in Its Top 302 

Making an Electric Searchlight for a Motor-Boat. 307 

Running Bell- Wires Through Walls 442 

A Binder for Water Colors 446 

Window Tappers Which Tap Intermittently 454 

Bath Water Supply for an Army Camp. 456 

The Right Meaning of the Term Reaming 456 

Sending Small Coin by Mail 456 



Painting the Automobile. . . 457 

A Bubbling Fountain with Icing Reservoir 461 

A Hat Hook Made of a Lead Pencil 461 

Nails Which May Be Quickly Withdrawn 461 

A Wire Stretcher for Repairing a Fence 461 

Keeping Rope Strands from Unraveling 462 

Saving Chemicals in Developing Motion-Picture 

Films 462 

A Shoe Lace Tie That Will Stay Tied 462 

A Driver to Turn Studs in Aluminum Castings. . 463 

A Lasting Paint for Heated Surfaces 463 

Keeping Vise Jaws Open with a Spring 464 

Making Fly Traps for Packing Houses 464 

Short Cuts in Sign Painting 465 

Preparing Demar Varnish 466 

Rubber Plugs in Handsaw Handle 466 

Using Ball of Soap to Recover Screw 466 

Sheet Metal Working Simply Explained 467 

Clothes-Hangers Used for Handles in Barrel Covers 468 

Pocket-Knife Cigar Cutter 468 

Typewriter Soldiers 468 

Knock-Down Canvas Boat 469 

Passing Cigarette Smoke Under Handkerchief . . . 470 

An Outboard Motor 471 

Making and Using a Casting Rod 472 

Burning Glass Made of Watch Crystals 474 

Burning a Lump of Sugar 474 

Burning Out Designs in a Piece of Paper 479 

Knockdown Walls to Make a Portable Summer 

House 480 

Using a Bicycle Pump for a Water Rheostat 601 

A Flexible Spline Used for a Draughtsman Curve. 602 
New Type of Acid Proof Brush for Soldering Flux 606 

The Underwriter's Knot for Flexible Cords 610 

Testing for Trouble That Cause* Poor Automobile 

Lights 610 

Making a Practical Vacuum Cleaner 611 

Blackboard an Adjunct to the Amateur's Shop. . . 614 

An Interesting Thermo-Magnetic Motor 614 

An Undercoating for Copper to Hold Paint 614 

Stropping a Razor on the Fleshy Part of the Hand 615 
Warming Army Tents with Improvised Stoves. . . 615 

Making a Campfire Tent with an Awning 616 

Preserving Flowers in Natural Colors with Wax. . 616 

How to Relinc Your Automobile Brakes 617 

Cord Cutter Made from a Safety Razor Blade. ... 618 
Temporary Repair on a Broken Lubricator Filling 

Glass 618 

Sheet Metal Working Simply Explained 619 

Ingredients That Make the Best Kind of Glue . . . 620 
An Inexpensive Cesspool Made of a Barrel and Cask 620 
Pedal-Operated Brake for a Belt Driven Motorcycle 62 I 
Making a Soldering Iron Heater of Pipe and Fittings- 621 
A Durable Paint for Surfaces Exposed to the 

Weather 621 

Clip for Carrying Pipe in the Vest Pocket 622 

A Silvering Process for Glass Instruments and 

Mirrors 622 

Holding the T-Square on the Drawing-Board 622 

Range Finder to Locate Landmarks and Signal Fires 623 
A Convenient Pivoted Card File for the Desk. . . . 624 

Three Methods for Finding a Chosen Card 625 

Piping Automobile Engine Exhaust Gas from 

Garage 626 

Edging Flower Beds with Bottles 626 

Repairing a Broken Test Tube or Beaker 626 

Making and Using a Casting Rod 627 

Making a Cabin Tent Out of Ordinary Sheeting. . 629 
Holding Papers on a Movable Sloping Desk-Top. . 630 

Keeping Oil from V-Belt of a Motorcycle 630 

Building a Model Airplane Kite 631 

Repairing a Broken Link in a Motorcycle Roller 

Chain 632 

Grouping Sheet Music Into Books and Binding 

Them . 632 

A Teeter Swing for Public or Private Playground. 633 

An Experiment with Sulphate of Soda 633 

Cutting Brass Tubing Rapidly on a Buzz Saw. . . . 634 

A Wood Lift Built in Like a Dumb- Waiter 634 

Improving Piano Tone by Makinfr Air Humid. . 635 
Simple Camera Attachment for Photographic 

Enlarging 635 

Bracing for an Iron Pipe Fence Post 636 

Attaching Linoleum to a Cement Floor 636 

Casing for Carrying Tube Cements Without Damage 636 

A Silver Plating Bath and How to Use It 636 

A Simple Toy Motor Run with Dry Sand 638 


Wigwam Made of a Tripod 639 

A Siphon Made of Gas Pipe and Fittings 640 

Making a Miter Box for Cutting Trestle Legs. . . . 640 

Replacing Tongue in a Fancy Brass Hook 640 

A Window Ventilator Which Eliminates Drafts. . 761 
Flaps Used on Inner Tubes to Prevent Pinches. . . 761 

Keeping Insects Away from Lunch Boxes 762 

The Construction of an Automatic Centering Tool 762 
Caution in Turning Corners to Prevent Tire Injury 762 
Making a Cigar Stand on the Top or Side of a Hat 762 

Smoke Your Own Fish 763 

Simple Ejector for Removing Water from an Ash 

Pit 765 

Automobile Footboard Used as a Roller Board. . . 765 
A New Way to Make a Hydraulic Test for Steam 

Boilers 765 

Some Common Abrasives 766 

Half-Soling Rubber Overshoes to Give Longer Wear 768 

Simple Designs for Sheet Metal Working 769 

Table Leg Sliders Made of Shotgun Shell Wads . . . 770 

Blue Print Drying Rack to Hang Over Sink 770 

Simple Die Casting for the Home Shop 771 

Expansion Shield for Screws Made of Sheet Lead . . 77 1 

Painting on Cemented or Concrete Surfaces 771 

Two-Speed and Reverse Countershaft for a Small 

Lathe 773 

The Damage Caused by Running Tires Deflated. . 773 
A Jack to Keep Automobile Weight from Tires. . . 774 
Camera Focusing Screen for Fine Detail Work. . . 774 
Lathe Centers Used as a Clamp for Gluing a Box. . 774 
Applying a Change-Speed Device to an Automobile 

Clutch 775 

Softening Carbon with Steam in the Automobile 

Engine . . 7 76 

Testing Gasoline Engine Compression 776 

Preventing Hinge Rods from Loosening on an 

Automobile Hood 777 

The Proper Camber for Front Wheels 777 

Making a Re- Winder for a Motion Picture Film . . 778 

A Hard Finish for a Lunch Counter Top 778 

A Storage House for Potatoes 779 

A Paste Lubricant for Starting Screws and Nails. . 781 
To Keep the Ends of Rafters from Spreading .... 782 
Making a Substantial Cardboard Pulley for Belts . 782 
An Insulator and Fire Protector for a Stovepipe. . 782 
A Solution for Electro-Plating with Aluminum . . . 782 
A Lead Pencil Sharpener with Dust Collector Box . 783 
A Stain for Giving Wood a Brilliant Rose Color . . 783 

Repairing a Fast-Pin Hinge Riveting 783 

Drawing Perspective Views 783 

Removing the Point of a Broken Center Drill .... 784 
Safe Method of Joining Airplane Sections or Wings 784 
A Closet Rod Which Will Accommodate Several 

Suit Hangers 784 

Repairing a Broken Link in a Motorcycle Chain . 784 

Etching Photographs on the Surface of Glass 784 

A Modest Home at a Modest Price 785 

Grouping Sheet Music Into Books 786 

Testing for Trouble That Causes Poor Automobile 

Lights . . 796 

Chemical Flasks Made from Electric Light Bulbs. 921 
A Concrete Mixer Made Out of an Old Mower. . . 921 
Comic Photograph Made with Film Negatives. . . 922 
Protection Curtain for a Mechanic's Work Bench . 922 

Testing the Strength of Norway Iron 922 

Coating for Window Glass to Keep Off the Frost . . 923 

Instruction Marker for Photographic Plate 923 

Drill Holder for the Tailstock of a Lathe 923 

Some Useful Hints for the Owner of a Phonograph 923 
The Balanced Aquarium for the Proper Care of Fish 924 

V-Block with Clamps for Small Drill Press 924 

Making a Sprinkler Hose Nozzle for the Boiler Room 925 

Making a Gage for an Oil Storage Tank 926 

Finishing a Book Trough in Natural Wood 926 

An Individual Strap-Hanger for a Crowded Car. . 927 
A Garage Air-Compressor Made from Automobile 

Engine 927 

An Emergency Repair on a Leaking Water Pipe. . 927 

Door Catch Made of a Spring Shoe Tree 928 

Reshaping Artists' Paint Tubes for Refilling 928 

Tearing a Pack of Cards in Half with Ease 928 

Construction of a Bob-Sled 929 

Boring Mill Tool-Holder for Saving Expensive Steel 932 

An Improvement on an old Card Trick 932 

Newspaper as a Substitute for Chalk Talk Board . . 932 

Treadle for an Automobile Foot Accelerator 932 

Coal Is Dear. Learn How to Burn It 933 



Hand Bob-Sleds Made of Barrel Staves 934 

Making Butt Mortises with an Ordinary Rabbet 

Plane 934 

Making a Talking Machine Stylus from a Tooth- 
pick 934 

Making a Whistling Weather Vane for the Barn . . 934 

Windng a Coil Spring Evenly 934 

Cutting Rafters for Gothic Roof Barn Construction 935 
Fruit Jar Rubber Ring to Repair Bicycle Tire 

Puncture 935 

The Proper Care of a Soldier's Wardrobe 935 

Improving the Qualities of Cheap Lead Pencils... 936 

A Barrel Stave Iceboat 937 

A Homemade Sight Feed Oil Indicator for an Auto- 
mobile 938 

A Simple Method of Fastening Umbrella Handles 938 

Simple Designs for Sheet Metal Working. . 939 

Garden Hose Used as a Form for Cement Pipe. . . 941 

Eliminating Noise from Shift Levers 941 

Repairing a Scratch on an Automobile 941 

How to Straighten a Warped Drawing Board. . . . 942 
Making a High Gloss Finish on a Matt Surface 

Picture 942 

Protecting Drawings on Drawing Board 942 

Setting a Lathe Quickly for Taper Turning 942 

Teeth of a Hack-Saw Blade Used for Spacing on 

Section Liner , 946 

How to Make a Secure Joint in Copper Tubing. . . 948 
Things to Know About Lubricants for Machinery . 948 
Constructing a Thermostat to Regulate Furnace 953 
A Coating to Make a Battery-Box Acid Proof .... 954 
Heating Sheet Hard Rubber to Cut Round Disks . . 959 
Lighting the Dash-Board of an Auto from the Side 

Light 960 

Sheet Asbestos to Make a Packing for Steam Chests 960 


"Silent Music" — Recreation for the Bedridden. . . 28 
Curious Circuit for Audion on a Wireless Set. ... 151 

Conversion of Kilometers to Nautical Miles 151 

An Experimental Wireless Aerial Made of Zither 

Strings 151 

To Prevent the Ears Perspiring When Wearing 

Telephones 152 

Mounting Tinfoil on Glass Condenser Plates 152 

How Germany's Secret Service Wireless Stations 

Are Being Weeded Out 1 53 

A Crystal Detector Holder for Wireless Apparatus 155 
Effect of the Moon and Season on Wireless in the 

Tropics 1 55 

A Trussed Aerial Spreader for Long Wires 1 56 

Position of Wireless Waves Passing Over Land. . . 156 
Cloudy Days Best for Wireless Wave Signals .... 1 56 
Improving the Tone of a Test Buzzer Used on Wire- 
less Detector 1 56 

Simple Construction of a Rotary Gap Disk 1 56 

Simple Solutions of Wireless Problems 157 

Magnetic Brake for a Wireless Rotary Gap 160 

Adjusting the Detector of a Receiving Set 160 

How theJGovernment Seals Unofficial Stations . . 208 
A Simple Arc Lamp Using a Thermostat Control . . 308 

Slow Acting or Sluggish Relays 308 

An Ingenious Wiring System for Two Inductive 

Transformers 310 

A Variable Condenser for a Receiving Set 310 

An Amplifying Electrostatic Radio Receiver 311 

Treating Cardboard Tubes for Tuners 311 

Strong Wireless Signals in Winter Time 312 

A Testing Set That Does Not Use a Battery .... 312 
How the Radio Inspectors Trapped a Disorderly 

Amateur 313 

How to Make a Kick-Back Preventer for Wireless 

Apparatus 314 

A Use for Discarded Cylindrical Food Boxes 314 

Variable Primary Coil Using a Switch Instead of a 

Slider 314 

America's New Semi- Wireless System for Telephon- 
ing from Captive Balloons 315 

A Polarity-Changer for Reversing Lighting Battery 

Current 315 

Dormitory Beds Furnish the Essential for Antennas 3 1 6 

An Insulation for Secondary Terminals 316 

Wireless Work in Wartime 317 

A Simple Fixed Adjustment Detector 320 , 

An Audion Battery Made of Medicine Vials 441 

An Easily Adjusted Detector-Stand 441 


Wireless Signals Transmitted by Telephone 442 

Fighting the Big Guns with Wireless 443 

Supplanting the School Bell with Wireless 445 

How to Make a Variable Condenser for Five Cents 446 

Wireless Work in Wartime 447 

An Inexpensive and Quickly Made Detector 450 

Relieving the Strains on Aerials 450 

Sustained Wave Telegraphy Between the United 

States and Germany 451 

Double Set of Receivers for Visitors 453 

A High Voltage Lead-in Insulator Tube 453 

Loading Coil in Series with the Secondary 453 

A Ticker Interrupter Made from a Buzzer 454 

A Simple and Attractive Loading Coil 601 

Transmitting Wireless Messages Underground 

Without Aerial 602 

Sending Wireless Messages Under Fire 603 

Construction of a Rotating Arm for a Rotary Gap 606 

Wireless Work in Wartime 607 

A Grid Placed in the Wings of an Airplane 614 

I ncreasing the Efficiency of the One-I nch Spark Coil 787 

Wireless Work in Wartime 793 

A Strong Guy- Wire Anchor for Aerial Poles 797 

A Magnetic Telegraph Key for the Wireless Operator 798 
Ballast Weights for Antenna to Prevent Aerial from 

Overturning 800 

The Marconi Company Sues the Government .... 913 

Detecting Defective Insulators 914 

The Human Morse Code 950 

An Inexpensive Multi-Point Loading Coil 953 

Water Glass Gage for a Lead-in Insulator 954 

Wireless Work in Wartime 955 

An Easily Constructed High Tension Insulator. . . 959 


This Railroad Crossing Cleans Itself and Eliminates 

Jolts 5 

Attacking Mail-Car Robbers with Deadly Fumes. 27 
Owens Valley, California, Has a Freight-Car Hotel 87 

Can the Railway Train Be Made Noiseless? 92 

Flushing Streets with Water Pipes on Trolley Cars 107 

Street Railway Smoking Car 214 

The Largest Traveling Kitchen 224 

The Biggest Locomotive 251 

A Refrigerator Car That Really Works 394 

The Most Powerful Locomotive in the World .... 396 

Street Cars Pull Each Other Up , . 41 I 

A Sanitary Dining Car 418 

Solving the Car Shortage Problem 422 

Lest the Engineer Forget 436 

Canning the Baby in a Super Sleeper 513 

How Print Butter Is Shipped to the Retailer 519 

Flagman's Shelter House Built Like a Mosque. . . 551 
Safeguarding Our Bridge and Railroad Crossings . . 565 
Putting Driving Wheels Under the Locomotive 

Tender 570 

A Lift Deck for Automobile Freight Cars 592 

A Lumberman's Camp Which Can Be Moved from 

Place to Place on Rails 598 

Special Cars for Persons Carrying Parcels 708 

Loading Cattle on Trains in a New Way 723 

Diminutive Electric Locomotives 738 

How a Railroad Steam-Shovel Traveled Through 

New York City 747 

An Iron "Flag" for Protecting the Railroad Car 

Inspector Against Injury. 755 

Keeping the Trains from Being Blown Off the 

Tracks 824 

A One-Man Rail Grinder 825 

A Labor-Saving Dump Car 884 


Why You Can't Compare Ships in Tons 29 

A New Life-Boat 60 

Salvaging in Armor 93 

Motor Attachment Which Prevents the Rowboat 

Propeller from Being Injured 96 

The Latest Salvaging Device — An Electromagnet . 113 
An Electric Eye Watches the Smoke Screen During 

a Battle 115 

Practical Motor-Boating 116 

A Two-Million-Dollar Hospital Ship 206 

A Ship with Six Hulls 209 

The U.S.S. "Recruit" 212 

New Type of Life Boat 223 



The Unbeaten "Constitution" 242 

The Largest Model of a Ship Under a Roof 252 

Disguised Submarines 265 

Giant Mushroom Anchors for Holding Buoys .... 265 

Practical Motor-Boating 275 

Toy Compressed Air Boats 297 

A Paddle- Wheel Canoe 393 

A New Life-Saving Platform 408 

Practical Motor-Boating 426 

Making the River Drive a Ferry Boat •. . . 432 

The Graveyard of Ships That Passed in the Night . 520 
The Life-Preserver Is More Important Than Meals 

Aboard Ship 521 

Boats That Travel on Land and Water 525 

She Launches Seaplanes and She's Unsinkable .... 529 

A Houseboat of Marble 538 

Even a Battleship Would Sink If It Were Not 

Cleaned 554 

Shall We Build Concrete Ships? 556 

She Was Torpedoed but Her Cargo Plugged the Hole 569 

Signaling Storms to Mariners 582 

A Leopard Ship of the Sea 645 

What's Wrong with the Submarine 682 

Cast-Steel Ships 690 

A Bungalow Takes a Sail Across San Francisco Bay 751 

A Thriving Fishing Village That Floats 760 

Raising Sunken Ships with Collapsible Air Bags . . 829 
Boat Carries Engine in Its Fin 872 


Dickory, Dickory, Dock, the Mouse Ran Up the — 

Clock 29 

A Refrigerator Basket for the Picnic Outing 31 

A Many-Sided Bathing Cap 69 

This Board Will Help You Learn to Swim 85 

A Vast Fortune Is Chewed Up Every Year 103 

Land Skates with Brakes and Pneumatic Tires ... 109 
Rafting the Rapids on the Rio Grande in Jamaica 1 10 

A Rein-Spur 190 

Scraping a Baseball Bat 214 

An Automatic Bait-Casting Fishing Rod 226 

The Speed of a Baseball 227 

This Spoon Hook Won't Tangle 240 

Conquering Your Cramps Under Water 250 

With an Axe and Two Springboards He Chops His 

Way Up a 120-Foot Tree 253 

A Hook and Bait Carrier ( 326 

Shooting Snapping Turtles 368 

A New Game of Pocket Billiards 388 

Anchoring the Fisherman to the Fishing Pier 392 

An Amusement Park in a Vacant Lot 412 

Hitching a Fishing Line to a Kite 412 

Detecting the Undertow Before It Catches the 

Swimmer 43 I 

Pulling and Pushing to Make the Swing Go 524 

Lowering the Life-Boats by Means of Gear- 
Operated Davits 533 

Put These Webbed Gloves on and Swim Like a Duck 532 
Maltreating a Water Bottle to Test Its Strength. . 536 
Making a Mule Push and Pull at the Same Time . 586 
A Water-Cooling and Purifying Pipe for the Fastid- 
ious Smoker 590 

The Suitcase Talking-Machine 644 

The American Boy's Wagon 670 

Looping the Loop in a Rocking Chair 673 

Fishing for Herring with a Windmill 724 

Making the Swimming Pool Attractive 725 

Playing Patriotic Tunes on the Air-Brake 737 

Making Comfortable Quarters for the Pet Snake . . 829 

Eskimos of Alaska Held a Reindeer Fair 837 

The Pull-Motor 842 

Watch-Case Revolver 843 

Mechanical Toys 862-63 

A Christmas Tree Stand 874 

A Jungle in a School- Yard 880 

The Home-Made Ice Sleds of the Chinese Boys. .881 

A Toy Gun for the Pacifists 883 

Novel Color Mixer for Teaching Color Effects ... 888 
A Billiard Table That Folds Up When Not in Use . 909 

A Mouse Spins Cotton Thread 912 

Winning an Athlete's Laurels 943 


The Largest Straw Hat in the World Is Yours If It 

Fits 24 


Is Curled Hair Becoming Stylish in Japan? 26 

These Magnifying Glasses Are Worn Like Spec- 
tacles ...;.. 29 

Making a Second "Self" for Dressmaking Purposes 48 

Ingenious Toys Made by Soldiers 57 

A Hair-Drying Frame 61 

A German Medal Commemorating the Sinking of 

the Lusitania 66 

. A Safety Chain for Your Pocketbook 69 

Platinum Is Too Useful to Be Used as Jewelry. . . 69 
A Twelve-Year-Old Inventor's Combination Um- 
brella and Rain-Cape 91 

The Straw Hat for Storms 95 

Giving Convicts a Real Chance 98 

This Really Happens More Often Than You'd 

Think 101 

Five Hundred Indian Languages 165 

Mechanical Hair-Parter 165 

A Tight Cord Fastener 166 

Foiling the Pickpocket and Protecting Your Watch 167 

Use Your Natural Arm If a Craftsman 187 

A Helmet for Smoke-Filled Rooms 1 99 

A Chinese Composing Room 202 

Wire Hood for Protection Against Mosquitoes .... 202 

Teaching the Blind How to Write on Straight Lines 208 

Deadening Noise by Pasting Tar Paper on Floors 228 

A Pencil with Nine Good Points 228 

A Novel Change Receptacle 233 

An Open- Air Barber Shop '. 235 

Wild Goats Live on the Roof 236 

Cold Water Pipes to Cool a Room 246 

Another Improvement on the Policeman's "Billy" 247 

A Fortune from Old Razor Blades 248 

Fifty-five Packages of Chewing Gum for Everybody 249 

Wave Your Cane Flag 249 

An Accommodating Church — It Goes Wherever 

It Is Wanted 260 

If Your Parrot Thirsts, Give Him a Drink 260 

A Buttonhole Watch 261 

An Automatic Revolver No Bigger Than Your 

Watch 262 

The Rate at Which Food Prices Have Advanced . . 265 

The Dumb Turk. He Smokes Cigarettes 268 

The Outdoor Trap for the Anti-Fly Campaign . . 271 

Holding the Whetstone Where It Is Needed 273 

Going to College to Learn Wood Graining 274 

The "Swat the Fly" Campaign Is On 274 

Collecting Old Newspapers 280 

A Paper-Disk Flipper 329 

A Kitchen on Wheels 348 

Washing for Gold in the Guianas 349 

Risking Lives in Government Surveys 352 

Cardboard Covers for School Desks 352 

Eat More Fruit and Drink Less Water 353 

Using a Dozen Different Inks Without Mistake. . 354 

Making Mud-Highways 362 

Food for the Taking 374 

The Broomstick Periscope 378 

Why Are Skirts So Short? 378 

The Biggest Bible 384 

An Encounter Between Fire and Ice 389 

A Heel Which Wears Straight 394 

The Candle Industry Still Flourishes 397 

Float Made of Raisins 397 

Self-Operated Cradle 400 

A Fire Hose with Ten Nozzles 408 

A Waving Flag for Your Buttonhole 409 

This Device Won't Let Your Hat Blow Off 411 

Measuring the Wear on Roads 413 

Goats' Milk Saves Babies' Lives 416 

A "Safety First" Device for the Bill Folder 417 

Experts Punch the Time Clock for Slow Stevedores 418 

A Shrewd Marketwoman Made of Figs 418 

What's Become of the Breweries? 423 

A New Clock Scheme for the Daylight Saving Plan 432 

The Umbrella Hat 484 

From Soup to Nuts . 514 

Work the Typewriter Standing or Sitting. 516 

Each Salesman Has His Own Telephone in This 

Grocery 516 

A Pencil-Pen Without Wood, Rubber or Graphic 520 

Two Ties in One . •. 522 

It Holds and Presses Your Tie at the Same Time. . 522 

In Japan the Barber Cleans His Patron's Ears. . . 524 
It Takes About 150 Pounds Pressure to Break an 

Egg 525 

What Makes a Man a Criminal 526 



Let Cheese Be Your Meat Substitute 531 

How You Light Your Cigar in Italy 537 

The More You Pay for Your Clothes, the More 

They Suffer on the Clothes Line 569 

And These Are Not Leather? 571 

Where Violin and Tennis Strings Come From . . 581 
A Convenient Device for Keeping Your Razor 

Blades Clean 584 

A New Zinc Product Which Is a Substitute for Tin- 

foil . . 585 

To Keep Out Burglars Leave Your Key in the Door 591 

The Over-All Has Entered the Fashion Sheets 591 

Is This the Secret of Curious Finger Prints?. . . . 594 
The Ivory Pie-Crust Trimmers of New England. . 595 

Pack Your Water-Proof in Your Bog 596 

The Mechanical Cigarette-Filler. '. . 646 

His Drum Is Made of Human Skin and His Trum- 
pet of a Thighbone 647 

The Favorite Pocket-Knife of the Jackie* 647 

A Machine That Moistens the Indoor Air 664 

Filtering the Snores Out of Sleep 665 

A Space-Saving Display Fixture 668 

How to Store Flour to Prevent It from Molding. . 672 
Efficiency as Applied to an Ink-Bottle Holder. . . . 678 

Fuel from Waste Paper 679 

A Fountain Ink-Eradicator 679 

You Can't Spill Ink When Pouring from This Bottle 681 

Lucky and Unlucky Telephone Numbers 687 

Holding Crowds at Store Windows 693 

Dolls That Proclaim the Fashions 693 

A Novel Tobacco Pouch 700 

Dogs I nstead of Horses 702 

A Pad and Pencil Attached 703 

A Xylometer 704 

A Time-Saving Measuring Board 707 

Transforming the Bow Leg 710 


Flushing Sidewalks Without Disturbing Cars 710 

A Self-Filling Pipe 717 

Iron Signs Give Good Advice to Tourists 724 

Showing House Numbers on Street Signs at Corners 725 

Leather from the Sea 726 

Why Anthracite Coal Lands Differ in Price 731 

This Kerosene Lamp Has a Horizontal Wick 751 

"Woodman, Spare That Tree," 755 

A Device for Keeping Bananas Clean 804 

The War Price on Monkeys 804 

A Badge Which Tells the Story of Your Life 807 

The Largest Ball of Twine 824 

The Most Expensive Coat in All the World 834 

How the "Ship of the Desert" Is Anchored When 

the Caravan Rests . 831 

Is This the Secret of the Earth's Magnetism 843 

Rice for Face Powder 854 

A New Method of Learning to Play the Violin. . . 860 

Protecting Your Shoes from Mud 861 

A Palace of Corn 874 

Wealth in Scrap Piles 883 

Wearing Spikes on Your Feet to Prevent Slipping 

on Ice 889 

The "Complex Dinner" Container for Long Trips. 900 
Pull Out a Cigarette and a Lighted Match with 

One Motion 901 

We Boycott the Chinese but Not His Hair 904 

To Open a Stubborn Knife-Blade, Throw It from 

You 907 

Arrowhead Lamp Posts Mark the Arrowhead Trail 908 
Filtering Out the Harsh Tones from a Phonograph 91 I 
We Use Eighteen Times as Much Light as Did 

Our Great-Grandfathers 914 

Matches? Take One at a Time, Please 914 

Sharpening Your Pencil Without Soiling Your 

Fingers 918 

Rear Admiral Fiske, Naval Strategist 


"Permit me to express my admiration for the POPULAR SCIENCE 
MONTHLY in its present form. You are doing a splendid thing 
in making science really popular. The whole structure of modern 
civilization is built on physical science and its application to the 
mechanic arts; and the more successfully and widely we can utilize 
physical science, the higher a civilization we shall have. Your maga- 
zine is making a generous and powerful contribution to this end." 


(X. cfvQoJu. 

The First Successful Fliers of Man and Nature 

B E 

rm rm Till mi mi 

— " i j — ^^ — ^ — 

-"^ — 

ttitt 1 




* •ft 









. / 






^tt'/j ! 







■ i ' 

J, ..«*" .. •" • ■' ', 


$ : 

- *$ 

1 B P 






KMv* '-^9s r " ''-* >*? 

».""'■ skSP"*"' 


■ .- 







_ .— — «S 

1 **•*>- 

3 H 

About seven million years ago the first bird began to fly. Flight was merely gliding, and clumsy 
gliding at that, which developed from the about-to-be birds instinctively spreading their limbs 
when falling from trees or jumping up in exuberance of spirits. Notice how closely the lines and 
movements of the first living flier resemble those of the pioneer motor-driven flier behind it 


3 a 

Popular Science Monthly 

Vol. 91 
No. 1 

239 Fourth Avenue, New York City 

July, 1917 


A Bird with Four Wings 

When Nature decided to evolve a bird out of a reptile she 
molded a four-winged flyer curiously like the first flying machine 

By Maurice Krosby 

BIRDS came later than fishes and 
reptiles in the evolution of life. But 
what manner of creature was it that 
linked fish with bird? What was the first 

bird that ever fl( 

Fossil re- 

mains and imprints have so far 
given only scant information 
as to how the feathered de- 
scendants of the fish or the rep- 
tile gradually came into posses- 
sion of the power of flight. 
Intermediate links in the develop- 
ment have left but few and faint 
traces, and this is due, at least in 
part, to the extreme remoteness 
of the transition period durin 
which birds became birds from 
whatever they were before. The 
change was so radical that it re- 
quired millions of years by Na- 
ture's slow methods. 

Fortunately a single natural 
document has come down through 
the ages which goes far toward explaining 
the mechanics that made the elongated 
swimming fish or crawling reptile fit for 
sustaining, propelling and balancing it- 
self in the air, and this document, as it 
happens, also establishes a most curious 
and interesting parallel between Nature's 
experiments in flying and those funda- 
mental experiments by Professor Langley 
of the Smithsonian Institution in Washing- 
ton to which the inauguration of the air- 
plane era in flight is due, more than to any 
other one cause. The document referred 
to is a true document; for it was found 
printed by natural forces on the rocks of 
the Solinghofen quarry in Germany. Here, 
in a formation not less than seven million 
years old, one of the ancestors of the 

This is Nature's 
first attempt at 
creating a flyer 

modern bird, a strange feathered reptile, 
had been imprisoned, caught unawares per- 
haps in one of the every-day upheavals of 
that formative age when mountain ranges, 
continents and oceans were still 
in the making. Its skeleton, its 
outlines and its feathers are 
here preserved, stamped in un- 
mistakabledistinctnessin stone, 
which is now hard but which 
must have been plastic as clay 
when the fluttering creature was 
seized in deadly embrace. More 
than twice as old as any of the 
prehistoric monsters reconstructed 
from their bones in our museums 
of natural history, the fossil im- 
print of the Tetrapteryx, as this 
creature has been named (mean- 
ing "four-winger"), represents an 
indisputable and descriptive rec- 
ord of perhaps the earliest feath- 
ered flyer. 

The Tetrapteryx record was discovered 
fifty-five years ago, but science has only re- 
cently undertaken to interpret it mechani- 
cally. William C. Beebe, while curator of 
birds at the New York Zoological Park, 
demonstrated that several species of modern 
birds, and especially the white-winged dove, 
show very marked traces of just such wings 
on the legs, called pelvic wings, as the Tet- 
rapteryx record reveals. On the very young 
dove, at the time when its body is still bare 
but for the sprouting flight feathers of wings 
and tail, twelve flight feathers and six 
coverts begin to grow from the outer and 
upper edge of the leg, extending in two 
rows from the knee almost to the base of the 
tail. While the growth of these tell-tale 
feathers is soon arrested and is covered up 

Popular Science Monthly 

in the surrounding plumage, so that the 
grown bird shows only traces, the fact 
that the young of the species pass rapidly 
through the same evolution that is repre- 
sented in the succession of 
innumerable generations of 
their ancestry, almost 
clinches the conclusion that 
birds are descended from a 
type equipped with wings on all 
four limbs, as the Tetrapteryx, 
and that Nature has learned 
gradually to replace four small 
and imperfect wings, weakly mus- 
cled, by two larger and stronger 
wings under perfect control. 

Frederic A. Lucas, Director of 
the American Museum of Natural 
History, called attention last year 
in the American Museum Journal 
to the great force of the evidence 
which has thus been collected to 
prove how Nature learned to ac- 
complish flight, the in- 
terest centering in birds, 
on account of their con- 
siderable weight, rather 
than in bats and insects 

The ancestor-bird, faithfully re- 
produced from the record, and the 
ancestor-airplane are presented in 
illustration herewith, side by side. 
The dimensions of the bird have 
been relatively exaggerated to fa- 
cilitate the comparison, and the re- 
semblance in structure is striking. 
Langley's "aerodrome" repeatedly 
flew over the Potomac in 1895, 
sustaining its own weight in the air 
for more than one minute at a time 
by the action of its two pairs of 
planes or wings and two 
rotary propellers, of five 
to six feetdiameter, driven 
from a diminutive steam 
engine developing one to 
one and one-half horsepower. The 
necessity for placing the power 
equipment and the propellers 
amidships called for an elongated 
body for the machine as a whole, 
so that the weight might be evenly 
supported by planes at the rear 
as well as in front. This con- 
structive difficulty has been over- 
come in modern airplanes, but it 
was decisive for Langley's machine, with 
its small power, in the same degree and 
almost for the same reasons as for the 

As the wings in- 
creased in power 
the rear wing 
decreased in size 


Gradually the 
tail shortened 
and the feath- 
ers lengthened 

The fan-shaped 
tail of the bird 
of to-day is a 
kind of a rudder 

original, four-winged bird. The latter 
came from a race whose fore and hind 
limbs were spaced well apart, whose legs 
were relatively heavy and whose arm mus- 
cles were weak. Its struc- 
ture had to be modified by 
hereditary influences before 
it would balance at all in 
the air, hung from the arm 
sockets alone, as birds do. Mean- 
while Nature did practically as 
Langley did. She adopted the 
compromise solution of upholding 
the rear weight by large feathery 
extensions from the legs and tail, 
and it may be noticed that the 
fantastic feather tail of the Tet- 
rapteryx was built up around a 
tail-like appendage and was not 
all feathers under muscular con- 
trol like that of the modern bird. 
Nature evidently found it impos- 
sible to change the bony structure 
in less than millions of 
S||y years, working from the 
basis of a reptile with 
only growth and heredity 
as the tools at command, but she 
could make feathers grow in the 
place of horny scales, which are 
made of almost the same material, 
by a comparatively brief 

To transform Langley's ma- 
chine into the modern airplane 
was a task much simplified by 
the advent of the compact and 
powerful gasoline engine, small 
enough to be moved forward in 
line with the support from planes 
arranged on the biplane or mono- 
plane principle and 
' strong enough to pull 
the machine safely, in 
most cases, through dis- 
turbing eddies of the 

This decided change in the 
machine took the place of all the 
transformations in bone dimen- 
sions, balance and muscle 
strength by which the Tetrap- 
teryx became a bird after start- 
ing out in the world with an ana- 
tomical construction very much 
like an animated parachute or 
gliding machine. But the mechanical flyer 
is still an infant compared with Nature's 
eon-old product. 

Popular Science Monthly 

This Typewriter Prints in Every Type 
and Language 

THE multiplex typewriter, shown on 
the right, can type in all the languages 
and in hundreds of different styles of type. 
Naturally, it is radically different from the 
usual machine. Instead of having fifty 
different type blocks all mounted on sep- 
arate steel bars, it uses one plate on which 
all the characters of one style are cast. 
This plate is removably attached to the 
machine. By sliding it off and sliding on 
another plate having a different set of 
characters, the typewriter is converted 

Two different plates, in fact, can be 
carried in the machine at one time. These 
plates are curved and can be adjusted into 

t-cur Except icra I 
Blanket Groups 

For $12 pair, all - wool 
plaid blanket, silk bound, 


Third Gallery, 

Hew Building 

Four Exceptional 
Blanket Groups 

For $5.50 
pair, white 
blanket with 
pink and 
blue bor- 
ders, silk 
binding ; 
mixed wool 
and cotton 
filling on 
warp; 70 x 
82 inches. 
For $6.50 same quality, 76 x 84 

For $12 pair, all - wool 

plaid blanket, silk bound, 

72 x 84 inches. 

Third Gallery, New Building. 

A typewriter which prints any- 
kind of type. Samples of its 
work appear on the left 

guists, to physicians and to all 
who have to use unusual charac- 
ters, this typewriter is invaluable 
to the advertising man. An ad- 
vertising manager of a large de- 
partment store, for instance, can 
send his advertisement to the 
newspapers all written in the cor- 
rect style and size of type. 

The advertising manager can send his copy to the 
printer looking just as he wants it to look in type 

a slot in the circular type-carrier after the 
carrier has been withdrawn from the 
machine. The type-carrier fits into the 
center of the machine. When a 
key is pressed, an automatic 
spring mechanism turns the 
carrier until the corn 
sponding characteron th< 
plate faces the front. At 
the same time, a hammer 
at the back is released to 
knock the writing paper 
against the ribbon and 
the character. The ac- 
tual impression of 
the character is thus 
made on the same 
principle as in other 

Besides being of This crossing provides 
especial value to lin- the tracks and 

This Railroad Crossing 

Cleans Itself and 

Eliminates Jolts 

WHEREVER a road crosses railway 
tracks, this light weight steel cross- 
ing belongs. 

It will fit any standard-gage 
track, it can be put down or 
taken up by one workman 
in thirty minutes, or in 
case of repair work it can 
be adjusted to a skeleton 
track in ten minutes with 
sufficient security to 
allow teams, automo- 
biles and other heavy 
traffic to pass safely. 
Its surface is such 
that mud, snow, 
gravel, sleet or ice 
cannot get a purchase, 
yet its knobs prevent 
level space between horses from slipping, 

sloping surface to the road It eliminates jolting. 

How Our Fighters Will Be Fed 

Nothing is left to guesswork. Menus 
are planned by chemists and physicians 

Above: The 
daily Army 
ration of the 
garrison or 
camp. Other 
articles in 
quantities of 
equal food 
value may be 
if desire 

UNCLE SAM has written generous 
menus for his fighting men on land 
and on sea and if the regulations 
which he has prescribed are followed his 
soldiers and sailors need never go hungry. 
He provides approximately twenty-eight 
cents a day to buy food for each one of his 
soldiers and a like allowance is made for 
his sailors. To the housekeeper who has 
to contend with war-time prices of food- 
stuffs, this sum seems entirely inadequate, 
but it must be remembered that Uncle Sam 
buys his supplies in ton lots and not by 
the pound. 

There is no guesswork in either the 
army or the navy when it comes to deter- 
mining just how much food a man shall be 
given. All this has been figured out and 
the person charged with the responsibility 
of supplying the food merely follows certain 

The fixed allowance or portion of food 
furnished a soldier or sailor each day is 
called a ration. It consists of specified 
components or substitutive articles. There 
may be an over-issue of any ration com- 
ponent, provided there is an under-issue 

It costs the 
only about 
cents a day 
per man to 
provide such 
looking meals 
as this on 
the left for 
the men of 
our Navy 

or equal value of other components; but 
the total cost of a man's rations at the end 
of a month must not exceed the average 
of the daily allowances for that period. 

In garrison or permanent camp, a sol- 
dier's allowance of food consists of the 
following components and quantities, or 
specified quantities of substitutes: Beef, 
20 oz. ; flour, 18 oz. ; baking powder, .08 oz. ; 
beans, 2.4 oz.; potatoes, 20 oz. ; prunes, 
1.28 oz.; coffee, 1.12 oz.; sugar, 3.2 oz.; 
evaporated milk, .5 oz.; vinegar, .16 gill; 
salt, .64 oz.; black pepper, .04 oz.; cin- 
namon, .014 oz. ; lard, .64 oz. ; butter, .5 oz. ; 
syrup, .32 gill ; and flavoring extract, .014 oz. 
A number of substitutive articles are pro- 
vided for each of the ration components. 
For instance, instead of the 20 ounces of 
beef, a like quantity of mutton may be 
supplied or 12 ounces of bacon, 16 of canned 
meat, 14 of dried fish or other meat sub- 
stitutes. Instead of the bean component, 
1. 16 ounces of either rice or hominy may 
be supplied. Prescribed quantities of dried 
apples or peaches or of jam and preserves 
may be substituted ' for the prunes. The 
reserve ration is less varied. 

Popular Science Monthly 

A Photographic Trick— Try It 
the Night of the Fourth 

THE young man in 
the accompanying 
illustration, pictured as 
looking so calmly and 
critically at us from 
behind one of the rings 
of Saturn or some other 
astronomical wonder, 
is really standing out 
in his own back yard, 
in Hornell, New York, 
and posing for his pho- 
tograph while whirling 
a sparkler, such as 
children delight in for 
the safe and sane 
Fourth of July cele- 

A four by five camera 
was used with a poly- 
chrome plate. The 
photograph was taken 
by the light of the 
sparkler, and the dark 
spot over the right shoulder is the 
which held and whirled it. 

the suitcase laboratory illustrated, with 
which valuable information is quickly 
obtained as to the purity of chemicals. 
This "pocket edi- 
tion" laboratory en- 
ables the laundryman 
to test all his materials 
as he buys them. Thus 
he is able to assure 
himself that everything 
used in his establish- 
ment is of a sort that 
will not damage or 
harm the goods en- 
trusted to him. In 
other words, he sub- 
mits all his purchases 
to a chemical analysis, 
without going to the 
expense of hiring a 
chemist to do the same 
thing for him. 

When closed , the lab- 
oratory resembles a 
suitcase. It becomes a 
laboratory by raising 
the handle side and 
lowering the side which forms the lid. The 
lowered side forms a table. 

a photograph by the light 
ng sparkler which he holds 


A Suitcase Laboratory for the 
Use of the Laundryman 

THE Mellon Institute of Industrial 
Research has been studying the laun- 
dry business scientifically. It wants to 
help the laundrymen guard against bad 
laundrv materials. The result has been 

The suitcase labor- 
atory which is used 
by laundrymen for 
testing the materi- 
als they use and the 
hardness of water 

A Hint to Motorists — Keep Your 
Radiator Clean 

TO assure the efficient operation and 
long life of your automobile, it is 
essential that the radiator be kept clean. 
Every radiator has been designed for the 
purpose of dissipating some of the heat 
from the engine to prevent it from over- 
heating. The radiator can only accomplish 
this when the radiator cells are cleared of 
mud so that the comparatively cool 
^^^^ air can circulate through it. Yet 
^M 8L many are the cars which are 

^ PPtt allowed to clog up with 

mud and dirt until it al- 
most takes a hammer 
to knock it out. A 
good antidote is a 
powerful stream of 
water from a hose; 
or where this may 
not be convenient, a 
stiff brush or a broom 
will assist in solving 
the cleaning problem. 
Care in this respect 
will be repaid in good 

The Flag Equipment of an American Battleship 

The complete flag equipment of an American battleship. About 250 flags are carried. 
Each flag is carefully rolled and packed away in a waterproof bag to await future use 

Consists of 250 Flags of Various Kinds Costing $2,500 

Measuring and basting up flags on the floor. The method is laborious but it 
is the only one possible. The President's flag is pictured in the background 

An Airplane Spies on Greece 



New York Firemen Have Strenuous Training 

It looks easy, but would you care to try it? 
The only safe way to strike a life net is with 
feet and hands extended. This method has to 
be mastered by the probationary firemen 

Above: Climbing by 
means of a scaling ladder, 
and sliding down a rope, 
using a safety brake appli- 
ance. At left: The correct 
position to assume when 
jumping into a life net 

Holding the net in the 
right way. Note the posi- 
tion of the hands. They 
are held neck high and the 
palms are turned toward 
the men to be in the best 
position to resist the pull 


Tests Which Scientists Use to Show Why We Can 

The eye is a kind of pho- 
tographic camera. You don't 
always want a bright light 
when you photograph, and 
neither does the eye when it 
sees. A camera has a dia- 
phragm which can be opened 
more or less to regulate the 
amount of light admitted; 
the eye has an iris which does 
the same automatically. But 
the eye can be fooled. In the 
picture the observer is look- 
ing through a lens at an 
object. When the object is 
moved farther away and the 
lens removed the iris opens 
to see better, and yet the 
intensity of the light has 
not changed and the widen- 
ing of the iris is unnecessary 

Photos by Jacques Boye 

The "olfactometer" which de- 
termines the density of vapor at 
which the first perception of 
smell is possible. By its use 
we learn that there are many 
odors which we do not perceive 

At left: An interesting test to 
prove to the human brain that 
the muscles can lift a greater 
load than seems possible. The 
load is increased very gradually 



Not Always Believe Our Own Eyes and Ears 





1 1 

Another trick played on the 
eye is shown in the illustra- 
tion at the left. A man looks 
through a lens at an object 
placed a short distance from 
it. The object is then moved 
farther away and the lens is 
removed. The brain realizes 
that the distance has been 
increased and here again 
the iris of the eye widens, 
even though the intensity 
of light was not altered 

Acuteness of hearing is determined by varying the 
volume of sound let into the ear through an opening 
in a tube. For some people the full volume of sound 
may be audible through a tiny section of the opening 
while others get it only through the fully opened tube 


Your sensitiveness to tempera- 
ture may be tested by placing 
your hands in two jars of water 
of different temperature. If the 
hands are crossed as in the 
picture above, it will be almost 
impossible to tell by the sense 
of feeling which hand is in the 
hot water and which in cold 

Photos by Jacques Boyer 

The Oldest Man-made Things in the World 


*** * 

The oldest known sculp- 
ture represents a seated 
man clasping an oval- 
shaped vase. It is prob- 
ably 7,000 years old and 
bears witness to primi- 
tive man's conception of 
beauty and manly grace 

The finger imprint in the circle preserves to us the 
oldest evidence of man, estimated at 250,000 years 

At left above is the earliest known painting of a Christian subject on canvas — the Saints 
Raphael, Michael and Gabriel. At right above are two baby shirts, the oldest known shirts 


Improving on Man's "Natural Finish" 

Picking the Best in Brain and Brawn 

A detachment of bluejackets, members of an artillery division, going through a field 
drill on board a man-of-war. Sham battles are carried on in deadly earnest 


and Training Them for the Navy 

Taking the chest measurement of a recruit. 
He is a fine specimen, with a chest expansion 
of four inches. At right: The recruit picks 
out skeins of yarn that harmonize in color, 
to determine whether or not he is color blind 

A bluejacket squad prac- 
ticing overhead firing with 
the ordinary service rifle. 
Their targets are a fleet of 
imaginary enemy airplanes 

The wireless telegraph room 
and equipment of a modern 
battleship. The operator 

performs a service which is 
second in importance to none 


Making Motor-Car Bodies to Order 

There are styles 
in automobile 
bodies just 
there are in mi- 
lady's gowns. 
Here the pattern 
plotters are 
shown at work 

Wives of million- 
aires have car 
bodies built to 
order, with inte- 
rior linings that 
can be changed 
whenever desired 
to match a gown 

Above: Setting up the 
body after the various 
parts have been cut to 
order. The next opera- 
tion is to glue the 
parts securely together 

Fitting the aluminum 
overcoat on the skele- 
ton body of white ash. 
The fit must be made 
absolutely perfect to with- 
stand the vibration 

Putting the fin- 
ishing touches 
on a limousine 
body. None but 
an expert is 
trusted with this 
important task 

A body, with its aluminum over- 
coat, turned upside down for 
a part of the fitting operation 

Special workmen attaching the 
trimming and upholstery 
to a modern high-priced car 


Killing the Dry Frog in the Opera Singer's Throat 

Contrary to your first impression the figures in the first picture are not fortune- 
tellers but opera singers playing cards in an inhalation room. They are 
breathing the prepared air which is said to be beneficial to the throat. From 
right to left are Pasquale Amato and A. de Segurola. In oval: Taking 
the nasal douche. The singers are A. de Segurola and Pasquale Amato 


The European Trenches Are Not the Only 

Gas masks a new development? Hardly. 
They have been used for years in American 
industries. At the left a girl is shown 
putting caps on bottles of disinfectants 

Foreign cotton has to be disinfected 
to kill the boll weevil. Here it is 
treated with hydrocyanic gas, pumped 
at a pressure of 1,000 pounds a square 
inch. A whiff of the gas is fatal 

Handling barrels of chloride of lime 
which gives off an irritating dust pow- 
der and chlorine gas, the destructive 
gas used in trench warfare. The 
men are well protected by their masks 


Places Where Gas Masks Are Necessary 

A gas mask worn by the photographer 
enables him to take a picture of the 
man who is shown at left below repairing 
a leak in an ammonia tank. Dur- 
ing the time the photograph was taken 
choking fumes of ammonia were escap- 
ing in great volume from the tank, which 
is situated in a cold storage plant 

Photo? © Kadel and Herbi 

Repairing the ammonia tank, a task made 
safer through the use of the gas mask. The 
cylinder below the mask contains chemi- 
cals which absorb all of the poisonous fumes 
and allow only pure air to reach the lungs 

A chemist experimenting with a dangerous 
combination of chemicals which give off poi- 
sonous fumes. With the gas mask pro- 
tecting his nostrils, he is able to approach 
close enough to his work to watch it intently 


How the Stay-at-Homes Can Provide the Sinews 

America turns to the soil 
in earnest. Even women 
are responding to the call 
for active service. Mrs. 
Ruth Litt, the wealthy 
suffragist, has turned over 
her 135-acre farm for cul- 
tivation, the work to be 
done entirely by women. 
The photograph below 
shows Mrs. Litt, Mrs. 
Grace Homer, Mrs. 
George Baxter, Jr., and 
Mrs. Charles Gould at work 


Three hundred acres of land in East Potomac Park, Washington, were given over entirely 
to the Boy Scouts Brigades by the Government to be cultivated as a vegetable garden 


of War for America and Our European Allies 

Picture continued from 
opposite page. Citizens 
of Nyack, New York, 
leave their rifles at home 
temporarily and go forth 
to wage war against the 
soil with farmer's imple- 
ments. The men are 
shown preparing the 
ground for garden products 

A Chicago girl do- 
ing her farm bit to 
back up the na- 
tion's fighters. With 
six other girls she 
was transferred 
from her employer's 
office to his farm 

The Rockland 
County Patriotic 
Society on their 
way to charge a 
ten-acre plot and 
convert it into 
vegetable garden. 
They believe that 
the spade is as 
valuable as the rifle 



Popular Science Monthly 

Getting ready for a "hold-up" picture. The blackness of 
night is genuine but the lights are brought from the studio 

The Poison Gases That Kill 
Men in Trench Warfare 

WE do not know defi- 
nitely the composition 
of the gases used in trench 
fighting. From the appear- 
ance, odor and effects on 
the men it is believed that 
a mixture of chlorine and 
bromine is employed with 
the possible addition of sul- 
phur fumes or formaldehyde 
gas. Germany produces 
chlorine and bromine in large 
quantities. These gases at- 
tack the eyes, the lining of 
the mouth, throat and nose. 
One part of bromine or 
chlorine in one thousand 
parts of air produces almost 
instant death. The gases 
first cause a violent cough, 
followed by spitting of blood. 

Making "Night Scenes" for the 
Motion Pictures 

THE Limited is held up! Light from a 
switchman's lamp or from the high- 

waymen's bull's-eye illuminates the harrow 
ing scene. Or so it appears on the screen 
at the motion picture theater. As a matter 
of fact the light is supplied by a semi- 
circle of flaming arcs such as are 
used in the ordinary studio for 
"close-up" photographs. The 
only necessary feature which the 
studio cannot supply is 
the darkness. In order 
to get the realistic impres- 
sion which marks the 
success of a picture, a night 
scene such as the one described 
must be taken in the genuine 
blackness of night. 

The accompanying illustration 
shows the director of such a motion 
picture lining up his characters and 
adjusting the lights preliminary to 
taking the picture. The arcs are fed 
from the dynamo of the car. The 
light is very brilliant and is exceed- 
ingly hard on the eyes since it 
has to be flashed directly 
into the faces of the actors. 
For this reason such night 
scenes are not as popular 
with the performers as with 
the spectators. 

The Largest Straw Hat in the World Is 
Yours If It Fits 

IN the display window of a large hat 
manufacturing company in New York 

city the hat in the photograph below was 
recently placed on view, bearing the pla- 
card, "The Largest Hat in the World. If 
you can wear it it is yours." Immediately 
one of the editorial family of the 
Popular Science Monthly be- 
came interested. Perhaps he 
needed a new straw hat. He was 
too modest, however, to 
take the company at its 
word and step right in 
and claim the hat by 
right of head dimensions. 

Not so the editor's mascot — 

the office boy. He was not 

absolutely sure that the hat would 

fit but he was unwilling to let 

it pass without a trial. Boldly he 

went inside and tried it on, finding 

to his surprise that it covered not 

only his head but his shoulders and 

a goodly portion of all the rest of 

him. Thus convinced against his 

will, he nevertheless, 

proved his ability to 

wear the hat long enough 

to pose for a photograph 

in it, or under it, though 

it required both hands 

the largest straw hat in the world for the task. 

Popular Science Monthly 

How Fast Is Your Typist? This Inge- 
nious Machine Will Time Her 

INVENTORS have tried for years to put 
a counter on the typewriter to estimate 
the speed of the typist, but the efforts have 
always been confined to a count of the 
words written. A recently patented device, 
called a cyclometer, counts every 
stroke which the typist makes 
on the keyboard. It is 
fastened to the escapement 
wheel of the typewriter. 
This wheel does not move 
when the carriage is 
shoved backward and 

One firm employing 
fifty typists found that 
its work was below nor- 
mal by cyclometer cou nt 
and later that it had 
some very rapid typists 
and; some very slow ones. 
The rate of pay had always 
been based on the number 
of years of service, and 
many of the slow ones were 
being paid for the work 
done by the rapid operators. 
This of course was quickly adjusted 

The timing device records not 
only the number of words written 
but the number of strokes made 

The Grave-Digger Beetle — Nature's 
Sanitary Policeman 

WHEN an animal dies in a garden or 
in the woods and decomposition be- 
gins, carrion bugs come from far and near. 
A dead bird, a mouse or a harmless snake 
wantonly killed by some wanderer pro- 
vides a banquet for hundreds of insects. 
Among these the "grave-diggers" are found, 
embracing forty-three species, twelve of 

The beetles dig the earth away from under the dead body 
so that it sinks into its grave. Then they cover it over 


which are found in Europe, the rest in 

You can identify these beetles by the 
two jagged yellowish-red or reddish trans- 
verse bands upon their black wing-covers. 
Their scientific name (Necrophorus) means 
no more than "buriers of the dead." As 
undertakers, the insects have legs 
especially adapted for digging. 
A grave-digger beetle has 
a most extraordinary sense 
of smell. He can detect 
the peculiar odor of de- 
composition a long dis- 
tance away and flies to 
the dead thing as 
straight as an arrow. 
His remarkably keen 
nose is situated in his 
club-like feelers. 
As a rule several grave- 
diggers are found near a 
dead body. They crawl 
under it and scratch the 
supporting earth away, so 
that the body soon lies in a 
hollow. Gradually the body 
is lowered until it sinks below 
the surface. Then it is 
covered with earth. The female lays her 
eggs around the interred form, thus insur- 
ing for the newly hatched larvae a plentiful 
food supply. 

It is interesting to note that these grave- 
diggers can produce a curious creaking 
noise, by rubbing the fifth abdominal ring, 
which has two longitudinal projecting bars, 
on the under edge of both wing-covers. 
This noise is only made when the bug 
is attacked; it has therefore been con- 
sidered an expedient to frighten away 
Nature further fortifies the 
beetle with a general musk- 
like odor and by a particu- 
larly strong smelling juice 
which it exudes like a skunk 
if touched. This odor serves 
as a protection from human 
beings, especially, as it is 
peculiarly unpleasant and 
penetrating. If the beetle is 
handled it requires several 
washings to remove the odor 
from the fingers. 

The grave-diggers are 
among the most useful of 
beetles. They have been 
designated Nature's sanitary 
police. — Dr. E. Bade. 

its enemies. 

26 Popular Science Monthly 

How Scientists Capture Mosquitoes When making a catch, the trap end 
Alive for Experiment and Study of the . tube . is Placed over the resting 

mosquito, which in attempting to escape 

is necessary to do 
something else with a 
mosquito besides swat- 
ting it out of existence. 
In order to study the 
best methods of annihi- 
lating it, scientists, 
health officials and en- 
tomologists find it neces- 
sary to classify the 
insect, dissect it and 
experiment with it. For 
these purposes it is nec- 
essary to collect the mos- 
quitoes without crushing 

A collecting tube of any 
size may be used, but 
the one most approved 
is a glass or celluloid 
tube about five inches 
long and one inch in 

selects the only way out, 
toward the light. This 
leads through the glass 
cone into the large col- 
lecting tube. The aver- 
age time required for a 
catch is about three 
seconds. When the col- 
lection is made for lab- 
oratory use, not more 
than ten specimens 
should be taken in the 
tube at one time, lest 
the captives injure one 

Above is shown a collector 
using the mosquito trap to 
catch live specimens. At 
left is the tube, natural size 

A Japanese Invents a 
Curling Iron 

Japanese residing 
in Seattle, Washington, 
has invented a curling 
iron, which is designed 
to make the hair-curling 
operation not only easier 
but more expeditiously 
performed. With it the 
hair may be curled and 
the iron taken out without the usual un- 
wrapping process. This is supposed to 
leave the curl in better form. 

By pressing a kind of button the curl- 
ing is done almost automatically. By 
another pressure the parts are unlocked 
so that they can be slipped out separately. 
Another advantage which Mr. Tanaka 
claims for his curling iron is that only one 
hand is required for the operation. 

diameter. When in use one end of this 
tube is closed with a cork stopper and 
the other with a specially designed trap, 
the invention of Dr. T. H. D. Griffiths, 
of the Public Health Service, of New 
Orleans, La. 

The trap consists of a cork stopper to fit 
the tube. Into this a one-half inch 
central opening is bored to accom 
modate a small somewhat taper- 
ing glass tube, the outer end of 
which is one-half inch in diam- 
eter, diminishing to three- 
eighths inch in diameter at the 
opposite, or inner end. 

This curling iron 
is in two parts 
so that it can be 
slipped out of 
the curl in sep- 
arate sections 

Sliding nut to 
rotate worm gear 


Popular Science Monthly 


Attacking Mail-Car Robbers with 
Deadly Fumes 

IT would be a sad 
gang of robbers 
who tried to break 
into the railway car 
invented by George 
W. Meyers, of the 
United States Army. 
They would be 
greeted with clouds 
of poisonous gas 

Meyers' robber- 
proof car works 
with extreme sim- 
plicity. Two tanks, 
In which fumes of 
cyanide of potas- 
sium are stored 
under pressure, are 
fitted inside of the 
car at each end. 
These are connected 
with a perforated pipe which extends all 
around the door of the car, just, in back 
of the outer framework. Should the train 
be held up, the locomotive engineer would 
telephone the guards within the car, who 
would immediately open the valves of the 
tank. The fumes would stream out through 
the pipe perforations and into the robbers' 
faces. The door being gas-tight, the deadly 
gas could not penetrate into the car. 

The overhead trolley system and the fastener 
keep the cow's tail from annoying the milker 

Making the Cow's Tail Behave with 
a Trolley Restrainer 

and Joseph O. 
Venden, of Guler, 
Washington, have 
come to the rescue 
of the legion of tail- 
flogged milkers,with 
a device which 
makes the cow's tail 

Briefly, the de- 
vice consists of a 
clamp, which holds 
the ' tail and an 
overhead trolley 
system which per- 
mits the holder to 
be moved from one 
cow to another. As 
the drawing shows, 
a rod is attached 
to the wire track 
in such a way that it can be readily moved 
and held in a rigid vertical position at the 
same time. At its lower end it is joined to 
the tail fastener by a flexible cord. The 
inventors do not take the trouble to de- 
scribe their fastener,, but it is evidently 
designed so that a strong spring grasps 
the tail. 

•» A -Tank of Cyanide of Potassium 
fumes, under pressure 

The deadly fumes are turned on from their tanks 
through the perforated pipe around the door 

Guinea Pigs Were Once Raised 
Like Chickens for Food 

THE cavy (guinea pig) is typically 
a pet animal, and has no other 
excuse for existence than the pleasure he 
gives those who appreciate his good 
qualities. . . . But it is to the undeniable 
edibility of the cavy that we owe the 
existence of the cheerful little squeaker of 

"The Incas of Peru long ago domesticated 
the wild ancestor of the modern animals 
— a small, tailless, unicolored member of 
the genus Cavix, the exact identity of 
which is a matter of some doubt. These 
creatures were allowed to run freely about 
the homes of their owners, whose object 
in breeding them undoubtedly was for 
their food value. 

"The time which must undoubtedly 
have elapsed since this domestication was 
first begun is evident from the entirely 
changed color of the present-day cavy." 
{Pets, by Lee S. Crandall. Henry Holt 
& Co., New York.) . 


Silent Music"— A Hospital Recreation 

A wireless system conveys the melodies to those who 
want to hear without disturbing those who don't 

Suffrage reports by- 
wireless. The contri- 
vance on the left is 
the receiving set with 
a few feet of "aerial" 

Below: The telephone 
sending station. By- 
throwing a switch a 
voice transmitter is 
cut into the system 
to allow the 
operator to 
announce the 
record titles 

A CHICAGO concern has come forward 
with a "silent music" contrivance 
that is designed to furnish recreation 
to inmates of hospitals. With this system 
installed in a hospital, a continuous and 
noiseless program of music can be fur- 
nished. Each patient may decide for him- 
self or herself whether or not to listen, 
and if the decision is against such recrea- 
tion, the patient is not disturbed in any 

Briefly stated, the mechanism consists 
of a phonograph attached to a telephone 
transmitter, which in turn is hooked up to 
an electrical wiring system that reaches 
each private room and each bed in the 
wards. At each wall outlet a watch-case 
telephone receiver is wired in. The patient 
desiring to hear the musical program simply 
lifts this receiver to his ear. 

The sending station equipment is located 
at the office or in any convenient room, 
and consists, as stated, of an ordinary 
phonograph, electrically driven, holding 
the turntable, which carries any disk 
record. Attached to this machine is a 
special music transmitter, consisting of a 
combination of a telephone transmitter 
with a vibrating diaphragm and needle. 
The needle, following the groove of the 
record, energizes the diaphragm of the 
transmitter, which in turn energizes the 
telephone attached thereto. 

Beside the transmitting apparatus is a 
control box, containing electrical resist- 

ances, which energize the transmitting 
apparatus properly, and binding posts for 
all connections. 

By throwing a switch, a voice transmitter 
is cut into the system. This enables the 
operator to announce the names of the 
records about to be played, to give baseball 
scores, recitations, war news, and whatever 
other items may be of interest to his tele- 
phone clientele. 

Except when this voice transmitter is 
being used, there is no noise of any descrip- 
tion connected with the sending apparatus 
beyond a light scratching of the needle, 
for no tone arm or horn is used. 

When installing this system in hospitals 
in the course of erection, the wiring is 
made to connect the sending station equip- 
ment with outlet jacks at the bedsides. 
These outlets are all connected in multiple 
on a single pair of wires, carried along with 
the regular telephone or signal system. 


Popular Science Monthly 


Dickory, Dickory, Dock, the Mouse 
Ran up the — Clock 

WHERE are the creepy spiders, the 
mechanical beetles, and the spring- 
operated bugs which used to be the delight 
of the office boys and the terror of the 
stenographers? And surely the mouse has 
lost none of its effectiveness as a scream- 

A Frenchman has devised a magic wand 
with a celluloid mouse attached which is 
capable of great activity. It is worked by 
the action of a concealed magnet, so that 
the mouse appears to run up or down the 
wand in a mysterious way. The wand is 
a square tube of light wood covered with 
silk. The celluloid mouse has 
a small piece of iron on the 
bottom which is attracted by 
the magnet. When the wand 
is turned up a small lead weight 
on an endless cord falls and 
draws along the magnet which, 
in turn, takes the mouse with 
it. When the rod is tipped 
the mouse climbs up real- 

In the photograph the silk 
covering of the wand is broken 
away to show the interior 


-wi[[k tubecovered 

The celluloid mouse 
runs up the rod by 
magnetic attraction 

These Magnifying Glasses Are Worn 
Like Spectacles 

THE field of usefulness of the 
binocular magnifier, shown in 
the illustration on the right, in- 
cludes the scientific laboratory, the 
medical office or hospital, and 
the workrooms of botan- 
ists, metal workers, watch- 
makers, etc. An elastic 
headband fastens it on so 
that both hands are free. 
The eye-pieces of vul- 
canite are fitted with 
lenses in such a way 
that the fields of view 
are brought within 
small divergent angles. 

A small incandescent lamp 
fitted with a reflector and 
condensing lens may be fast- 
ened over the top, current 
being supplied from a bat- 
tery carried in the pocket. 

Both eyes are used with this 
glass, so that the object exam- 
ined is seen in natural perspective 

Why You Can't Compare Ships 
According to Tonnage 

THE different uses of tonnage terms 
when speaking of ships are causes 
of confusion to the lay mind. For ex- 
ample, steamship companies in order to 
impress upon the traveling 
public the size, and conse- 
quent relative safety of their 
craft, will advertise the sail- 
ing of a certain steamer of 
twenty-thousand tons, mean- 
ing, of course, gross tons. 
The company's agent, in en- 
tering her at the custom house, 
will take great precaution to 
certify that she is of only 7,340 
tons, when paying tonnage taxes. 
He then is referring to her net 
tonnage, and in fact that stand- 
ard is used only when paying 
dues or taxes. 

Displacement tonnage is al- 
most exclusively applied to war- 
ships as they do not carry 
cargoes. Strange to say, the 
tonnage of a battleship varies 
almost hourly, as coal or other 
weighty objects are used or taken 
on board. The tonnage of war- 
ships is, however, fixed ; they are 
referred to in terms of the fixed 
A statement that a ten-thousand ton 
battleship sank a ten-thousand ton mer- 
chant ship does not mean that the ships 
were of equal size. The merchant 
ship would be much the larger owing 
to the different meanings of the 
term "ton," as applied to the two 
types of vessels. It is absolutely 
impossible to give rules for 
the relations of these terms, 
as the conditions vary 
too greatly. Generally 
speaking, the gross ton- 
nage of a ship is from 
fifty to one hundred per 
cent greater than the 
net tonnage. Tons dis- 
placement are always in 
excess of tons gross ; dead- 
weight tonnage is on an 
average from thirty to fifty 
per cent greater than gross 
tonnage. — Capt. C. A. 
McAllister, Engineer-in- 
Chief, U. S. Coast Guard. 

Differentials for Motor Vehicles 

Comparisons which illustrate the merits of various types 
By Marius C. Krarup 

HP 1 

left pick-up plate 
Left ratchet 



IHE Bailey is the name of a new 
differential gear for motor vehicles. 
It transmits power to both driving- 
wheels when these can rotate at the 
same speed, but only to one wheel when 
the other runs faster. The power 
is divided at the rate at which 
the wheels can utilize it for trac- 
tion if the wheels have the same 
speed but one is inclined to slip. 
Traction from 
one of the 
wheels is thus 
sacrificed on all 
curves, wheth- 
er the going 
is good or not, 
in order to con- 
centrate power 
and traction on 
one of the 
wheels when 
traction from 
the other is lost 
for lack of fric- 
tion with the 

road surface from slippery mud or snow. 
The casing is rotated by a bevel gear or 
worm drive, as usual. To the casing are 
secured two heavy pawls, of which one 
holds the left and the other the right 
wheelshaft by engaging notched disks fixed 
upon the ends of the shafts. The pawls 
are pressed against ball-pivots by coil 
springs. Their seats in the disks are 
shaped so as to make the engagement 
hold in either direction of movement, for 
backward as well as forward driving; but 
if one of the disks is forced around by the 
road contact of its wheel faster than the 
casing and the pawl are rotated by the 
power, this movement is permitted by 
means of a cam plate that lifts the pawl 
out of its seat. This action seems to be as 
follows : The pair of cam plates is mounted 
on a sleeve as a rigid unit that turns 
around with' the casing, and opposite to 
each pawl one of the plates has a semi- 
circular recess that limits sideways turning 
of the pawl on its ball pivot, while the 
other plate here has a straight-line contour 
passing obliquely under the active end of 
the pawl but coming to a point directly 




A differential which concentrates power on one 
wheel when the other has lost traction on a bad road 

before it This gives the lifting action. 
When both pawls drive, they stand at 
right angles transversely, balanced one 
against the other, but when one of the 
disks, actuated from 
the road, begins to 
push its pawl, the 
latter begins to turn 
a little on its 
pivot, allowing 
the disk the 
same small 
thereby the 
relatively im- 
movable cam 
plate gets a 
higher point of 
support under 
the pawl, rais- 
ing it and per- 
mitting the 
disk further 


A compari- 
son with other differentials illustrates 
the merits of each. In the ordinary 
balance gear differential of the type still 
used in a majority of motor vehicles 
the four small bevel pinions revolve 
on the plan of freely balancing the pres- 
sures on all teeth engaged. The engine 
power turns the casing which carries with 
it the two pivot pins on which two of the 
pinions are mounted. The two wheel- 
shaft pinions, each in mesh with both of 
the power-transmitting pinions, can con- 
form with the turning of the casing by 
revolving, taking the wheelshafts with 
them. If one wheelshaft resists as much 
as the other, one side of the actuating 
pinions is resisted as much as the other, 
and these pinions remain balanced and un- 
moved in relation to their pins. The 
teeth engaged become mere lugs gripping 
the wheelshaft pinions and forcing them 
to follow, by revolving. But, the moment 
one wheelshaft resists more than the other, 
from any cause whatsoever, the pressure 
on the teeth on one side of the actuating 
pinions becomes greater than that on the 
other side. These pinions are no longer 


Popular Science Monthly 

balanced. They begin to revolve on their 
pins, toward the low-pressure side. The 
high-pressure side of them no longer carries 
its wheelshaft pinion around unyieldingly. 
It lags till pressures are equalized, the 
wheelshaft with the higher resistance turn- 
ing more slowly and the other wheelshaft 
more rapidly in the same proportion. The 
total of power utilized remains unchanged, 
except that a portion of it is spent in over- 
coming the friction of the revolving pinions. 

As friction adds tooth 
pressure on both sides, it 
may be purposely increased 

Links and 

An eccentric can drive 
a link in and out but 
cannot be rotated by- 
turning the link around 


turned on. Suppose, further, that one 
wheelshaft resists very little and does not 
equalize tooth pressures until it is revolved 
eight times as fast as the other. Then the 
differential works four times as much as 
before and the value of the friction rises 
rapidly, perhaps from 2 to 8. The power is 
consumed. By arranging the friction on a 
less drastic scale, however, one can have a 
shaft which offers a rather small resistance 
under small differential action, yet equals 
the resistance of the other shaft 
as soon as its rotary velocity 
becomes only two or three 
times as high, after which 
no greater difference in 
shaft speed can be pro- 
duced. The power is 
then divided somewhat 
on this plan: 2 for the 
slow shaft, 1 for the 
small friction identified 
with its side of the dif- 
ferential action, 4 for 
the friction of the rapid 
shaft and I for driving 
it. If the wheel of the 
rapid shaft has no trac- 

It is built strong enough to resist the 
stresses that arise in its operation 

tion, there is still a net 
power of 2 for driving. 

to modify the action of the differential. 
For example, if the power delivered to the 
casing has a numerical value of 8 and the 
resistance of each shaft against rotation at 
a certain velocity is 4, no friction in the 
differential arises. But when road contact 
interferes and one of the shafts produces in- 
creased resistance at this velocity but only 
4 at a velocity 33^ per cent higher, while 
the other shaft produces 4 at a 
velocity 33^ per cent lower, 
such as may be the case when 
a vehicle is made to turn or 
a fairly sharp curve, one shaft 
is turned twice as fast as the 
other and a certain friction is 
produced. In the ordinary 
differential this friction i 
negligible; but suppose it i 
made to have a value of 2 
then there is only a 
power of 6 available 
and there is less 
than 4 for each 
wheelshaft. The < 
vehicle speed is 
reduced or more 
power must be 

A L 

The refrigerator-basket is the picnic party's 
ice-box. In it all perishable food is preserved 

A Refrigerator Basket for the 
Picnic Outing 

LL the luxuries of home are now at 
the disposal of the vacationist starting 
off for a picnic at the beach or in the 
woods. The increasing vogue of automo- 
bile touring trips has also created a demand 
for portable creature comforts. A refriger- 
ator basket is a refrigerator in minia- 
ture, which keeps the butter hard, 
the meat fresh and the 
milk sweet. It consists 
of a rust-proof metal 
food container with a 
smaller ice compartment 
partitioned off at one 
end. Around this shell 
is a layer of insulating 
material to keep the 
cold air in and the warm 
air out. Externally the 
carrier is a reed basket 
with convenient handles 
and straps to bind the 
lids down. Separate lids 
are provided for the 
two compartments. 

The Strength of Human Wings 

One hundred and twenty-two people can 
stand on the wings of a big biplane 

IF the men who lost their lives in the early 
years of the flying machine's develop- 
ment could come back to life and gaze 
upon the picture which accompanies this 
article, they would first gasp in astonish- 
ment and then they would approve en- 
thusiastically the construction which made 
it possible for sixty people to crowd upon 
one.Thalf.of-a huge biplane's wings without 
breaking, them. For, let it never be for- 
gotten/ that some of the early martyrs who 
dropped to a terrible" x death from great 
heights, went to their doom because the 
builders.. of;, their machines had no concep- 
tion of .the structural * strength required to 
buffet turbulent winds at high speed. 
. Study, the pictured well. Note that the 
wing section. of a biplane here depicted is 
supported from a. heavy wooden frame and 
not . from the.' floor. The wirig section is 
held" only, on one side and extends freely 
from that side into the air. Judging from 
their size, the wings are , those of any 

enormous flying yacht. Although the sup- 
porting surfaces of this yacht could evi- 
dently sustain the weight of some one 
hundred and twenty-six passengers, they 
have not, of course, that amount of lifting 
power. The crew of the vessel probably 
amounts to four. Hence, the weight for 
one hundred and twenty-two people is 
available for the boat body, rudders, 
engines, propellers and supplies, something 
like over eight and one-half tons. More- 
over, the human freight here pictured 
clearly does notoverstrain the wings. 

The picture is an object lesson in reserve 
strength. The stoutest storm-sails of an 
old-fashioned sailing ship were never sub- 
jected to such strains as those which must 
be endured by that fabric of linen, wires, 
and lattice-work of which the wings of a 
modern flying-machine are composed. A 
sail needs strength to resist mere tearing 
alone. A flying-machine's wings must in 
addition be so rigid that they will keep its 
shape in the worst hurricane. Only the 
pilot of an airplane knows how his wings 
are strained when he drops at a steep 
angle from a height of five thousand 
feet in a swift downward glide for 
home. It must bend no more than 
if it were made of cast iron. To 
this stiffness the modern 
airplane owes its superior 

Testing the wings of the great 
biplane by crowding upon it 
a maximum human load 

Popular Science Monthly 


Lost in New York? Consult an Electri- 
fied Street Directory 

THE man from Oshkosh or Paducah 
can easily find his way around New 
York city if he happens to stop at one 
of the thirteen hotels there which have in- 
stalled the electric directory. 
He can'find the location 
any building, street, or 
carline by pushing an 
electric button on 
the keyboard, for 
the location he is 
seeking will be il- 
luminated by a little 
six-volt incandes- 
cent lamp. 

The directory 
board is sixteen 
square feet in area 
and the map is di- 
vided into fifty-six 
sections for the city 
of greater New York. 
The current for the 
board is furnished 
by storage batteries. 

When the right button is pushed the 
desired location flashes into view 

Taking Records of Sounds by Wireless 
for Talking Motion Pictures 

THE problem of making talking motion 
pictures has been attacked by many 
inventors, but no more ingenious sugges- 
tion than that of Mr. William B. Vansize 
has been brought, out. According to Mr. 
Vansize's plan, each actor is equipped with 
a tiny wireless telephone transmitter, and 
his speech is sent through the ether by 
"radio" to a receiving station which is 


The wiring diagram of the apparatus which is worn by the actor. 
An oscillating vacuum tube supplies high-frequency current 

connected with the phonograph. The receiv- 
ing station may be located some distance 
from the actors and camera, so that as 
the people move about the stage their 
distances from the radio receiver will re- 
main relatively unchanged and their words 
will always be heard at about the same 

An oscillating vac- 
uum tube will supply 
the necessary high fre- 
quency current, and 
the batteries used 
to run it may be 
made of very small 
size. A ground con- 
nection is secured 
through contacts 
placed on the soles 
of the actor's shoes 
and arranged to 
touch a metal plate 
on the stage; the 
diminutive aerial re- 
quired may be con- 
structed of a few 
thin wires projecting 
upward a foot or 
two above the actor's head, or may merely 
be a sheet of thin metal foil fastened across 
his shoulders under his coat. The micro- 
phone transmitter which his voice operates 
need not be visible, for it has long been 
known that the vibrations of one's chest 
are amply strong enough to operate a tele- 
phone transmitter held over the lungs. 

The wireless waves sent out by each 
actor's radio telephone transmitter pass 
over the space separating the stage from 
the receiving station, which may be several 
thousand feet away, and there affect 
a very sensitive wireless detector. 
This instrument converts the 
speech waves into telephone 
currents, which are carried 
back to the recording phono- 
graph by a wire telephone 
line. The sound-recording in- 
strument may be either a 
magnetically controlled wax 
cylinder phonograph or a 
"telegraphone," which latter 
uses a thin steel wire instead 
of a soft cylinder or disk, and 
makes its sound records mag- 
netically. Whatever type of 
recorder is used, it is mechani- 
cally connected with the mov- 
ing picturf camera. 

The Newest Automobile Conveniences 

A new shock 
absorber which 
takes up shocks 
before they 
reach the car 
springs and the 
body of the car 

The man who is pressed for time has his car fitted 
up with a disappearing desk and typewriter 

\ Break in 

A plate or truss 
which provides 
a temporary re- 
pair for a broken 
spring. It sup- 
ports the break 

A spring cushion 
tire to eliminate 
blowouts. The 
inner tube is a 
series of heart- 
shaped springs 

A convenient 
luggage carrier 
strapped to the 
rear of the front 
seat. It is about 
three feet long 

An automatic lift which enables the autoist to "get out and get under" without lying on his back. 
The car is run on to the lift under its own power. The lift is both demountable and portable 


Labor-Savin g Automobile Attachments 

Two trucks, one backing up while the other went ahead, moved this house seven miles across 
country in a few hours. By old methods of house moving the job would have taken weeks 

An attachment by which a Ford 
is converted into a six to twelve 
horse - power stationary engine 

Lifting a 1000-pound wheel to 
the hub of a motor-truck with a 
strong portable ^s> crane 

A small transformer, wired as 
shown, gives steady-burning 
electric lights on a Ford car 

Pressed down with the foot a 
slot - block locks the gearshift 
lever, thus' foiling thieves 


Measuring Motor-Truck 
Loads Automatically 

A dial registers the readings from all 
four wheels as the load is distributed 

OVERLOADING of motor trucks 
would be entirely eliminated if all such 
trucks were fit-ted with the novel load- 
measuring device shown in the accompany- 
ing illustrations. The apparatus makes use 
of the relative motion between the axles and 
springs of a vehicle as loads are applied. The 
varying deflection of springs for loads of dif- 
ferent weights is allowed for by calibrating 
the dial scale on which the loads are read. 

The device differs from most others of its 
kind in that the weight carried on each 
wheel is recorded on the dial as the load is 
distributed, and not only that on the rear 
wheels. The proportions of weight over 
the truck body must be the same as when 
the device was calibrated or else the read- 
ing will not be a true. one. This makes it 
possible for the load to be properly dis- 
tributed over each wheel. 

The readings are obtained 
through the use of four verti- 
cal racks, each carried rigidly 
on a strap round each axle 
near the ends, the rack re- 
volving a spur gear mounted 
on the frame and driving a 
longitudinal shaft inside the 
frame channel through a 

Detail, of the rack which 
revolves the spur-gear 
mounted on the frame 


Overloading is one of the greatest dangers 
which the motor-truck owner fears. It is 
a question of correct weight distribution 

bevel-gear unit. The revolution of the 
shaft is transmitted to the reading dial 
placed on the dashboard of the truck in 
sight of the driver by means of a flexible 

As the load is put on the truck, that 
portion supported by each wheel forces the 
spring carrying that wheel down and causes 
the spur gear on the frame to revolve about 
the rack nearest that spring, simultaneously 
turning the 'corresponding longitudinal 
shaft and the flexible shaft registering the 
relative motion between the 
spring and the axle on the 
reading dial. The weights 
carried on the other three 
wheels are registered in a 
similar manner. 

The registering dial is a 
clever piece of mechanism 
which consists of a cylindri- 
cal casing with a central 
fixed stud carrying loosely 
four gears of like diameter 












The readings are obtained through four vertical racks, each carried rigidly on a strap round 
each axle near the ends and each revolving a spur gear driving a shaft through a bevel-gear unit 


Popular Science Monthly 

Register for 
left rear 

spaced along its length on 
telescoping journals. 
Each journal carries a 
hub to which are attached 
curved radial arms or 
spiders of similar contour 
but of varying sizes. At 
their outer ends each set 
of spiders carries a con- 
centric ring in the same 
plane and these together 
constitute the face of the 
registering dial. 

These rings are moved to 
the left or right of an 
assumed zero load line drawn 
from the center stud to the 
circumference of the casing 
by means of spur gears on 
the end of each' flexible 
shaft which extends through 
the back of the casing. The 
spur gears are within the 
casing and are arranged as Register tor 
planets around the central ,eft * rorTt 
stud and in mesh with the 
corresponding gears carried 
on it. This gearing is so 
arranged that the movement 
of the rings clockwise in 
reference to the zero line 
refers to the loads carried on the two right 
wheels of the truck, looking toward the 
front, and the counter clockwise turning of 
the alternate rings refers to the loads on the 
left wheels. Calibrations on each ring 
enable the load on the corresponding wheel 
to be read directly in multiples of ioo 
pounds or fractions of tons as desired. 

With the dial mechanism remaining the 
same, the movement of the registering 
rings may be accom- 
plished in two other 
ways in one of which 
a piston attached to 
the vehicle frame 
works in a cylinder 
substituted in place of 
the vertical rack on 
the axle to force a 
fluid to a second cylin- 
der having a piston 
whose rod carries a 
rack turning the end 
of the flexible shaft 
leading to the measur- 
ing dial. The latter 
cylinder may be pro- 
vided with a small 


fluid well with a screw-in 
piston by means of which 
the compression of the 
fluid may be varied for 
calibration purposes. 

Still another method 
employs a steel tape 
attached to the top of 
the axle near each wheel 
and carried over a roller 
on the vehicle frame and 
thence to a take-up wheel 
with a spring coiled 
around its axle and its outer 
end made fast to the frame. 

Not Even the Space Under 
This Desk Is Wasted 

of Brookline, Massa- 
chusetts, has patented a 
filing rack which utilizes the 

R e 9' 5 t er ^? r space under the desk beyond 
riqrvt front .1 u~c*.u~u tu~ 

Register for 
right rear 

The load carried on each 
wheel is given on the dial. 
Above: How the revolution 
of the shaft is transmitted 

A sliding letter rack utilizes the waste space 
under the desk. This is locked into place 

the reach of the knees. The 
rack slides forward when 
the letters are being filed; 
then a push by the hand 
sends it back out of the way. 
The desk is thus as comfort- 
able as before, while expen- 
sive floor space otherwise wasted is made 
use of. 

The rack consists of a platform which 
is supported upon waxed strips for guides. 
The platform can always be reached by 
the foot and drawn forward when wanted. 
A light chain on the platform is attached 
to the rear of the desk so that th« rack can- 
not be pushed too far forward and the letter 
files be spilled. 

Two bars are provided in 
front, which when brought 
together and locked, prevent 
the files from being removed. 
The most popular 
office desk of the pres- 
ent day is the flat-top 
style. Under it there 
is an unusual amount 
of space which could 
easily be utilized to 
advantage by the in- 
stallation of such a 
cabinet or rack as 
the one described. 
The material or books 
are kept free from 

Our Big Guns and How They Are Made 

It is the most powerful thing on earth, is a great gun, but 
its actual firing life is not as long as the life of a butterfly 

Illustrations by Kadel and Herbert 

IT is not easy to understand what the 
power of a gun really is — its penetrat- 
ing and destructive power. What we 
call a 15-inch gun — which means one whose 
muzzle or hollow part is 15 inches in diam- 
eter — will hurl a shell right through a plate 
or wall of the hardest steel 12 inches thick 
seven miles from the muzzle. The power 
of the very largest land guns ever made — 
the German howitzers or 16.5-inch guns — 
is such that one of their missiles cracks open 
a steel and concrete fort as if it were a nut. 

"Built-up" and Wire- wound Guns 
and What They Are 
There are two classes of guns — naval 
guns and army or land guns. Because they 
can be manipulated more easily than those 
of a ship, land guns are the heavier. 
From eight to ten miles is the greatest 
distance that a gunner can cover success- 
fully at sea. The largest naval gun is the 
15-inch English gun on the famous super- 
dreadnought, and the largest land gun is 
the German howitzer. Of the two the 
naval gun fires a shell weighing over half 
a ton, while the other fires a projectile a 
ton in weight. But the new giant 16-inch 

guns of the United States defending the 
Panama Canal and New York at Sandy 
Hook shoot projectiles weighing 2,370 
pounds, which is over a ton. These im- 
mense steel guns can sink a ship before it 
has really come into sight on the horizon, 
the location of the battleship having been 
determined by airplane or tower. 

How are these huge pieces made? The 
first step is the making of the pig iron from 
iron ore in large furnaces like towers, 
called blast furnaces. Then the pig iron 
is melted with other steel in large steel 
furnaces called "open hearth," until it is 
freed of its impurities and converted into 
steel. - 

The melted steel, thin as water, is run 
from these furnaces into big iron molds 
where it is allowed to cool into large solid 
cylindrical or corrugated blocks. After 
cooling these are reheated and reduced in 
size by pounding them with big steam ham- 
mers and squeezing them in rolls until at 
last the steel is pressed into a long barrel- 
like mass, the embryo of a real gun. This 
long skeleton of the inside of a gun must 
be bored out from one end to the other on 
immense lathes, some over 

The man is leaning against his completed work — an immense steel gun — the 
most powerful product of his skill. The various hoops that go to make up 
such a weapon are easily picked out — large steel bands which are put on 
one after another as described in the article. It is impossible to determine 
whether this is a built-up or wire-wound gun. The breech is clearly shown 

Stages in the Making of a Big Gun 

At the top, a glimpse of 
one of the big gun-heat- 
ing furnaces. The huge 
steel ingots or blocks 
are heated before they 
are worked or forged to 
a smaller size, just as a 
blacksmith forges down a 
tool. Big cranes handle 
these heavy steel pieces 
by means of some of the 
mechanism shown and 
insert them into a furnace 
or draw them out with 
the utmost ease. These 
heating or soaking fur- 
naces, as they are called, 
are fired by gas, oil or 
.oal. Steel, to be worked 
or kneaded like bread, 
must be at a white heat 



Popular Science Monthly 

90 feet long. Heavy as the mass is, 
a huge lathe turns it around as 
easily as a body turns a spool. 
After the inside has been rifled 
or scored to form an inside surface 
that gives the shell a twist before 
it leaves the muzzle and causes it 
to fly straight, the lower or muzzle 
end of the gun is made larger. 
This may be accomplished in one 
of two ways. Either additional 
shorter steel tubes are placed over 
the main inner tube, or the main 
tube is wound with wire and 
finished with an outer tube. The 
wire-wound guns are usually the 
heavier and are used on board ship. 

Why the Wire-Wound Gun Is 
So Strong 

The gun bound with wire is 
really stronger than the one built 
of bands or rings of steel, one on 
another; for the wire reinforces the 
gun tube so that it will safely with- 
stand the tremendous strain which 
is constantly put on it when it is 
fired — said to be as much as seven- 
teen tons pressure on each square 
inch. This means a pressure on 
every little space inside the gun 
as big as a domino of over 38,000 
pounds. No wonder that a gun 

The upper portion of a blast furnace in which pig iron 
is made — the first step in making steel. These men 
are dumping iron ore, coke and limestone into the 
large hopper. The materials are allowed to fall at 
intervals into the inside of the furnace where the 
intense blasts of hot air cause them to melt, mix and 
fuse together until they are tapped out at the bottom 

This is a steel ingot. It is the large block of steel resulting from pouring the hot liquid steel into 
a large mold and allowing it to cool. After it is cold the ingot is taken, in the manner here shown, 
to the large forge shop for conversion into a big gun. This block weighs something over 111 tons 

Charging the Furnaces with Iron Ore 


A Great Modern Gun-Shop Where the Giant 

The immense machine shop of one of the largest American steel companies making big naval 
and army guns. The sides of this vast building are lined with machine after machine and 
lathe after lathe for cutting off and reducing to accurate sire sections of steel for various 
purposes. Extremely accurate and skilled work is done here by experienced mechanics. 


Tubes of Guns Are Machined by Lathes 

In the near foreground of the picture above can be seen the barrel of a big gun that is 
being bored or cut out hollow on its inside by a big lathe. Some of these lathes are very long, 
in the section of the picture on page 42 one of the guns in a crude shape is beina carried by a 
big electric traveling crane to a large lathe where the first paring or cutting is to be done 



Popular Science Monthly 

The red hot steel about to be plunged into 
the oil tank for what is known as its "heat 
treatment." The tank extends down into 
the ground. The plunging of the hot steel 
into the oil suddenly cools it and hardens it 
and refines its grain or texture. After this 
it must be heated up again to temper it 

must be strong and that its life is short! 

In the case of a "built-up" gun, as it is 
called when made of hoops or bands of 
steel, the outer tubes or rings are shrunk 
or sweated on — that is, they are heated 
so that they expand or swell a little, as all 
steel does when heated, and then while 
hot they are fitted over the inner part 
and allowed to cool and shrink, or contract. 
In so doing they fit very tightly on to the 
main tube. In making a wire-wound gun, 
the wire is wound or coiled around and 
around until more than one hundred miles 
of it has been wrapped around the big 
cannon. A 12-inch gun requires 117 miles 
of wire weighing about thirteen and one- 
half tons. Although the strength of the 
wire is such that it gives great resisting 
force to pressures exerted sideways, it does 
not bestow strength lengthwise. Therefore 
an extra thickness of metal must be put 
on the muzzle of the gun where the vibra- 
tion caused by the shell leaving the gun 
is the greatest. 

The breech or back end of a gun is a 
very important part. Here the shell is 
inserted in a specially built chamber. 
After the shell is in place, the breech is 
closed by the shutting of a very complicated 
and strong door. It is fastened or fitted 
in the gun by extremely strong screws so 
that the charge will not burst the gun 
open at the back when it is fired. 

Sometimes a shell explodes in the barrel 
of the gun. In a wire-wound gun the 
wire tends to prevent a grave disaster; it 
hinders the steel tubes from bursting into 
many pieces and flying in every direction. 
The solid gun is wholly built of tubes, 
while in the wire-wound gun there may 
be one or two tubes over which the wire 
is wound with the jacket tubes shrunk 
over the wire. A bush for the breech-ring 
is screwed into the rear end, which is also 
reinforced by a breech-ring outside. 

Heat Treatment and What It Means 

With all these precautions to make a 
big gun strong enough to withstand pres- 
sure, the result would not be successful 
except for the extreme care in making the 
steel and its "heat treatment." Steel in 
its crude state, or when originally cooled 
from its molten or liquid condition, is one 
mass of crystals relatively large and in- 
timately knit together. But when these 
crystals are large the steel is not as strong 
as when they are small and fine. The 
object of heat treatment is to render all 

Forging a Great Gun 

One of the tremendously powerful "mechanical blacksmiths" or hydraulic presses which work 
down to smaller sizes the white hot large steel blocks or ingots. Gradually they are thus converted 
into long cylindrical pieces, the embryo or starting point of the gun itself. These immense 
presses are worked by levers which cause the ram in the center to obey the will of the operator. 
Cranes and mechanical apparatus, as shown, can turn this red hot block over'and over at will 


Cooling the Steel Under Pressure 

Steel, when it cools, contracts to such an extent that a hollow space is always left in the center 
of the upper part of a large body of metal. The extent of this cavity, or " pipe," is greatly 
reduced under pressure so that this natural contraction is taken up or prevented and a 
solid block obtained. The picture represents what is known as a fit-id compression plant 
or press in which hot steel can be allowed to cool under a constantly increased pressure 


Popular Science Monthly 




^^ i ^SSHMpii 



>* " -fevf-s L 



>a^ k 

- u 

Ll 1 


* IN j 



WffPffi ! 




HmP**^^^ ^^" 

^_0^f^^ ,..-■""" 

\ j 

^« X 

Making the first cuttings from a large round forged steel block which is to become part of a big 
gun. The work is being done on a large lathe in the machine shop plant. Another steel 
ingot or block can be seen just at the edge of the picture. Powerful cutting tools are necessary 

the crystals fine or to "refine the grain" as 
it is called. To do this the steel gun in 
one stage of its manufacture is heated 
until red hot throughout. In this condition 
it is suddenly cooled by lifting it high in 
the air and lowering it with a big electric 
crane down into a big tank of oil. It is 
thus suddenly cooled and the crystals 
made very small. 

But the gun in this condition is so 
hard that it has to be tempered or annealed. 
This is done by heating up the steel again 
to a lower temperature and cooling it 
slowly. This operation greatly toughens 
and strengthens the steel. 

There is something wonderful and also 
mysterious about the flight of very heavy 
shells and the energy that makes them go. 
It is, of course, the charge of powder in 
the back end of the gun that does the work. 
An electric spark explodes the charge, 
which is usually a nitro-glycerine com- 
pound. If gunpowder increased in the 
requisite quantity, the gun itself might 
burst before the shell was driven out; 
modern smokeless powder burns more 

gradually. You can light a cigar with it, so 
slowly does it burn. The principle of the 
phenomenon is that the explosive is, when 
ignited, at once changed to a gas which, 
confined in a tiny steel chamber, must 
find its way out. As it does, the shell is 
forced out by the only opening left. 

The life of a big gun is surprisingly short. 
The powerful explosive, such as cordite 
for example, creates an intense heat on 
the walls of the cannon. This gradually 
melts at each shot a little of the inner 
surface, constantly wearing away a thin 
layer of the steel. It is sometimes called 
the erosion of a gun. This erosion, or 
wearing away, is so persistent and gradual 
that the very big guns can be fired only 
a limited number of times. It is said the 
actual life — that is the sum total of the 
time consumed in the firing of the shots 
as long as a gun lasts — is really in some 
cases not more than a second or two. After 
that a new steel lining is put in. 

Many things have been tried to reduce 
erosion, for the cost of one large gun runs 
into many thousands of dollars. 


Popular Science Monthly 

Two thin coatings of 
plaster of Paris are 
washed lightly over 
snugly fitting jerseys 

The cast comes off in 
sections and is then 
filled in on the inside 
with papier mache 

wash of plaster of Paris is applied to the 
outside. When this is partially dried 
another coating is applied. After this 
second coating has dried a little, the tapes 
connecting the two portions of the jersey 
are untied, and the two parts, front and 
back, are taken off separately and allowed 
to dry thoroughly. The shape is then 
filled in on the inside with papier mache. 
It requires only about an hour to make the 
form, which is less than is often required 
by the modiste for one fitting of a fashion- 
able expensive garment. 

Casts of the arms may also be 
made and attached to the form, 
so that the figure is complete. 
The mold may be used on any 
lay-figure standard or it may 
be set on a table or stand of 
convenient height. The 
only objection to it is that 
it is not adjustable. If 
the stout woman makes 
up her mind to reduce 
and accomplishes her pur- 
pose she will have to 
order a new dress-mold in 
consequence. Similarly, 
the too-slender woman 
should not use her dress- 
mold after she has been 
through a building-up course 
of treatment, until she has 
had its lines altered. 

Making a Second "Self" for 
Dressmaking Purposes 

FITTING is the hardest and most 
tedious part of dressmaking. Many a 
woman could make her own clothes and 
save a good percentage of her pin-money if 
she were sure that the garments would have 
the proper "set." There are various kinds 
of dress forms on the market to meet this 
need. One of them, recently invented by 
Wayne T. Sachs, of Los Angeles, Cal., is 
cast on the lines of the 
living figure to be 

To make it, two 
jerseys are fitted 
snugly over the 
body. The outer 
one is made in 
two sections 
connected by 
strips of tape. 
After the jer- 
seys are ad- 
justed, a thin 

The little automobile is 
but it is capable of 

The Youngest Manufacturer 
of Automobiles 

ALTHOUGH only twelve years old, 
Clarence Suttcliffe, of Aurora, 111., has 
constructed a real automobile which makes 
record time for its size. His materials were 
obtained mostly from scrap heaps. His 
one purchase was a one-quarter-horse- 
power gasoline engine. 

The machine is belt-driven and will make 
a speed of fourteen miles an hour. 
In the absence of a clutch, the 
young manufac- 
turer shuts off 
the engine by 
means of a foot- 
lever. When 
rounding cor- 
ners he presses 
down on the 
lever; this 
shuts off the 

a single-passenger model, spark. lUecar 

accommodating a trailer is called "G-3." 

Popular Science Monthly 

The Laundry Keeps Pace with the 
Fashions. It Irons Stockings 

THIS is the day of conspicuous and 
elaborate hosiery. The laundering of 
stockings and socks has had to keep up with 
the fashion. Formerly it was necessary 
only to smooth out the wrinkles, regardless 
of any "shine" that might 
be imparted by the iron. 
In home laundries the 
queen of the washtubs 
often considered it un- 
necessary to iron the 
hosiery at all. 

Now, however, a fine 
stocking can be laundered 
in such a way that it will 
look exactly as it did when 
new. A stocking ironer 
has been invented which 
employs forms over which 
the wet stockings are 
drawn after they have 
been washed «nd rinsed. 
The steam heat is turned 
on and the stockings are 
dried and ironed at the 
same time from the heat inside the forms. 
In this way the original shape and luster of 
the stocking is retained and any embroid- 
ered design is brought out in relief. 

The ironer is intended principally for 
use in large laundries having steam power, 
although it can be adapted for the home 
laundry. The forms are of all shapes and 
sizes. They prevent shrinking of all-wool 
stockings, also. 

Forms on which 
stockings may 
be dried and 
ironed like new 
at the same time 
by steam heat 

Raising the window pushes in the 
button, closing the alarm circuit 

An Alarming Alarm for the Burglar. 
He Could Never Turn It Off 

AN entirely new burglar alarm which 
prevents a burglar from opening your 
window stealthily at night has been 
patented by William Connoly, of New 
York. Once the window is started upward, 
the noise of the alarm 
will upset the nerves of 
the burglar himself. 

The alarm is extremely 
simple. An automatically 
locking push-button fits 
into the window frame 
just above the lower win- 
dow. A flat-head bolt is 
screwed in back of this 
push-button and makes 
contact with the iron 
mounting in which it 
slides. The bolt and the 
button are normally 
pushed in their outer- 
most position by a spring 
inside the mounting. 

Should Mr. Burglar 
jimmy the window, the 
button is pushed in as the window is being 
raised. Immediately the head of the bolt 
passes a contact finger. The bell circuit is 
thus closed through the bolt and the finger. 
Thereupon the righteously indignant land- 
lord reaches for his gun. The iron finger 
prevents the button from being brought 
back. So if the burglar supposes he can 
turn off the alarm before anyone inside 
hears it, he will be horribly disillusioned. 

Only a person familiar with this alarm 
can turn it off. The flat head of the bolt 
contains a slight notch. By turning the 
button in a certain position, the notch will 
come opposite the finger, and the bolt-head 
can slide through. Simple though this is, 
the burglar would never think of 
doing it; neither would he have 
time enough to do it if it 
should flash across his mind; 
for there is nothing faint- 
hearted about the 
alarm. Its evident 
intention is to arouse 
not only the mem- 
bers of the house- 
hold but the police- 
man on the beat and 
all the neighbors on 
the block or in the 

Fighting the Big Guns from Balloons 

The sausage balloon is provided with a 
wind bag which keeps the balloon nose 
to the breeze. Steadying cones are also 
fastened to the rope, kite-tail fashion 

THERE never was a time in the 
history of fighting when a general 
did not envy the birds. If he could 
only hover over his enemy and see for 
himself what was going on ! Since he 
could not do that, he used such makeshifts 
as he could devise. But the first real spy- 
ing on the enemy came when the balloon 
was invented. 

Someone asked Benjamin Franklin what 
he thought of it. "It is a newly born child," 
he replied. That was non-committal; also 
prophetic. At all events, the French 
revolutionists, daring adventurers in war 
as well as in politics, adopted the balloon 
at once as a superior substitute for the 
old watch tower. They held it captive 
by a rope, quite in the best Twentieth 
Century way, and used it very effectively 
in battles to drive home revolutionary 
truths. Their "aerostiers" even dropped 
their messages on long streamers of paper 
weighted with lead. 

When the dirigible and the.airplane came, 
it was popularly assumed that the observa- 
tion balloon was to become as extinct as 
the dodo. Indeed, in the early days of 
the present war, observation balloons were 
never mentioned in the despatches as were 
the dirigibles and the airplanes. But as 
the war developed, as weapons changed 
their character and became even medieval, 
as all Europe was converted into one huge 
fortress, as warfare changed into a con- 
tinuous siege, as guns of unprecedented 
size and power were brought into action, 
lo and behold, the old captive balloon came 
into its own again with a vengeance! It 
came back with other discarded and ancient 
weapons — with steel helmets, and with 

Why the observation balloon still 
plays a part in war despite the 
airplane and the dirigible 

By Carl Dienstbach 

hand grenades thrown from trenches. 
Battles of to-day are won by the 
most terrible of systematic artillery 
bombardments. The captive bal- 
loon, connected as it is with a bat- 
tery by a telephone wire running 
through the holding cable, renders it pos- 
sible to correct the range instantly, and 
therein lies its advantage over a constantly 
moving airplane. The balloon is at a 
disadvantage because of its distance from 
the enemy — a distance dictated by con- 
siderations of safety. But that disadvan- 
tage is compensated for by supplementary 
information gathered by .the airplane. 
An active enemy rarely permits an ob- 
servation balloon to stay aloft for even an 
hour. But as a rule the balloons are so 
far behind their own lines that they may 
stay up for a whole day. During the re- 
cent engagements around Arras, Sir Doug- 
las Haig reported that he had shot down 
every German balloon over a front of per- 
haps twenty-five miles. Such wholesale 
destruction of observation balloons is pos- 
ble only under exceptional circumstances. 
Ordinarily the ranges are too great. But 
artillery is not the only dread of the bal- 
loon. Small, wasp-like airplanes darting in 
and out with bewildering rapidity, throw 
firebrands on the thin bladder filled with 
gas, which explodes even more easily than 
•dynamite. Threatened either by bursting 
shells, or by these firebrands, the obser- 
vation officers in the baskets of the bal- 
loons, must jump for their lives. 

The peculiar sausage-like captive bal- 
loons which are now used by all armies, 
were invented in 1894 by two German army 
officers. In Germany they are known as 
"kite balloons." A kite balloon consists of 
an elongated gas bag with an arrangement 
by which the wind, caught in internal air 
compartments by check-valves, distends 
and stiffens the balloon against itself. A 
regulation kite bridle is used. The balloon 
is provided with a fin, consisting of an 
appended air bag, like a modern kite, and 
even with a regular wire-tail consisting of a 
rope having a series of steadying cones. 


War-Time Uses of the Old -Fashioned Balloon 

Film Serv. 

In the oval: An officer in the basket of a sausage balloon. Telephone receivers are 
strapped to the officer's head. The wires run down through the rope to the ground. 
By means of the telephone he communicates to the battery the effect of each shot. 
Upper right hand picture: The man who is sent aloft often in the observation balloon 
becomes a far more daring parachute artist than any man who ever risked his neck at 
a county fair. The parachute was intended to serve as a safety device. In the 
whole history of aerial navigation, it never saved a single life in a cross-country 
journey. War, alone, justifies its existence. The war parachute is of the ordinary 
type made familiar by the county fair as seen in the bottom picture. Half an hour 
after an officer has dropped to the ground to save his life, he is up again in a new balloon 


Housekeeping Made Easy 

A beater attach- 
ment on the ordi- 
nary potato masher 
which adds greatly 
to its usefulness 

With these sealed water 
jars, butter, meats and 
other perishable food- 
stuffs can be kept fresh 
and sweet without ice 

With one revolution of the 
crank a seed is removed 
from a cherry without 
losing any of the juice. 
The seed is dropped 
through an opening in the 
bottom of the tray into a 
separate dish from that 
which receives the pulp 

Here the brush of the dish 
washer is in use. There is 
a soap compartment just 
above the bristles. The 
hot water passes down 
through the soap to the 
brush and plate surface 

Kettle made in aluminum having 
a double bail with handle so ar- 
ranged that it is self-tilting. 
The contents may be poured out 
or liquids drained off of vege- 
tables without removing the lid 

The usual difficulty of directing 
the breeze from an ordinary 
electric fan in the larger sizes is 
easily obviated by the ball joint 
in the stand. The fan may be 
set and clamped at any angle 


A permanent fix- 
ture for holding 
windows open for 
ventilation and pre- 
venting them from 
being opened fur- 
ther by intruders 


A dish washing device 
which has a small opening 
like a nozzle through which 
clear hot water may be 
thrown on the dishes by 
means of a thumb-operat- 
ed valve. A brush at one 
end completes the clean- 
ing process expeditiously 

Housekeeping Made Easy 

A crate for shipping dogs 
in safety and comfort with- 
out danger to the express- 
man and porters who must 
handle it on the journey. 

A circular cloth with draw 
string through six brass 
rings makes a convenient 
bag for odds and ends 

Food is put into the 
dog-crate shown at 
the left, through a 
small door in front 

A shelved wire mesh 
rack for con- 
veniently keeping 
the different vege- 
tables separate and 
where air can circu- 
late through them 
to prevent decay 

A hat protector made like 
an envelope. It may be 
carried in the pocket or 
handbag as a "prepared- 
ness" measure to be used 
in case of sudden rain 

.Supporting frame 
A light detachable fan for 
a sewing machine flywheel 


A neat appearing and 
sanitary dog kennel made 
from a barrel. There is a 
shaded resting place un- 
der the frame support 

A hanging or counter dis- 
play stand for grocers and 
fruiterers. It permits free 
air circulation on all sides 

A deodorizer of ornamen- 
tal design for hanging on a 
wall of the sick room or 
to counteract the musti- 
ness of a room that is to 
be kept cldted a long time 

This motion picture camera 
is smaller and lighter than the 
professional machine and re- 
quires no tripod. It is aimed 
from the shoulder through an 
open finder. The substitu- 
tion of a motor-drive for the 
hand crank makes it possible 
to follow the movements of an 
object. Current is supplied 
from batteries in the pocket 

Home-Made Paper Motion Pictures 

A safe and sane method by which you can make 
the pictures and exhibit them to your friends 

By Max Fleischer 

be entirely familiar with his machine and 
its dependent devices. Thousands of feet 
of highly combustible film must be driven 
directly across the path of the blazing 
arc-lamp's concentrated rays. The speed 
of the film itself is all that keeps it from 
being instantly consumed. Failure of the 
drop-shutter, as the film slows down, would 
result in a blaze. The operator must be 
specially trained. As a rule, theater pro- 
jection machines are quite safe — that is, 
safe in the hands of an experienced operator. 
In view of all the knowledge and ex- 
perience required to go from A to Z in 
the production and projection of motion 
pictures, considerable credit is due Mr. 
Hartwell W. Webb of New York, inventor 
of the home projector and camera, for his 
success in simplifying and reducing the cost 
of the process. In addition to making 
its operation safe, he has practically suc- 
ceeded in leveling the complete apparatus 
to the home basis of the phonograph. 

Mr. Webb has produced not only a 

motion picture camera which is almost as 

simple in operation as the kodak, but also a 

projector which requires little more 

knowledge to operate than the 

magic lantern. All fire 

danger has been eliminated 

by the perfection of a paper 

film. Incidentally, he has 

found the paper film to 

be far more durable and 

economical than the 


His camera, which 

WHY is the phonograph in every 
home, but not the motion picture? 
Chiefly, because celluloid films are 
highly inflammable, because rooms must 
be darkened, because screens must be set 
up, in a word because elaborate prepara- 
tions must be made. The making of 
motion pictures is hardly within the pos- 
sibilities of the average amateur. In pro- 
fessional motion picture photography, ex- 
tremely accurate mechanisms are employed 
at almost every step. Perfect results 
depend on the accuracy, judgment and 
experience of experts. 

The expert camera man is not called 
upon to develop his film. Developing 
processes are often as unfamiliar 
to the photographer, as pho 
tography is to the de- 
veloper. Fixing and 
drying the film is a 
separate branch of 
the process. Print- 
ing of positive film 
from the negative 
pequires the at- 
tention of skilled 
mechanics who 
may be entirely 
ignorant of cam- 
era work or 

Projection of the 
completed film is a 
mystery to almost th 
entire productive force; 
for some knowledge of 
electricity and arc-light- 
ing is necessary. The 
operator must be alert 
and cautious. He must 

End section of spring 
belt reduced, forms a 
threaded engagement 

Interior of the camera. The feed 
magazine will accommodate 100 
feet of film which is advanced 
by means of a single claw drive 


A spring belt, reduced 
at one end to fit the 
opposite end of the 
belt, makes a threaded 
flexible engagement 

Popular Science Monthly 

weighs about fifteen pounds, is considerably 
smaller than the professional machine and 
is operated by a small electric motor. A 
cell of dry batteries carried in the operator's 
pocket supplies the necessary current. The 

Developing the film in 
the form of a coil re- 
duces the quantity of 
solution required. 
About three quarts 
of solution will de- 
velop 500 feet of film 

Below: Method of 
coiling the film over a 
wood core for immer- 
sion. A frilled cellu- 
loid strip is used as a 
separator between the 
layers of coiled film 

separating strip 

camera can be 
loaded in day- 
light . No 
tripod is nec- 

The amateur 
who has de- 
veloped his 
own films will 
require no ad- 
ditional knowledge for developing the paper 
motion-picture film. The film is wound 
around a wood core together with a 
celluloid strip frilled on the edges. 
The frill acts as a separator be- 
tween the layers of the film and 
at the same time allows the de- 
veloping solution free access to 
every part of the surface. The 
film is rinsed, fixed and washed 
in the usual manner. It is dried 
on a collapsible wooden drum. 
An important feature of Mr. 
Webb's process is the produc- 
tion of the positive film. The 
paper negative film is not trans- 
parent; therefore a positive film 
cannot be made by contact. 
Even if it were possible to do so, 
it would not prove practical for 
the amateur, because motion 
picture film printing by contact 
is necessarily done by machinery 
and entails the additional ex- 
pense of another length of film. 
A much simpler method has 


been perfected in which the negative is 
chemically converted to a positive with 
remarkable results. One solution removes 
the silver nitrate from the negative ; another 
bleaches the shaded and dark portions 
leaving the film 
blank. On exposure 
to light, the color 
values are reversed, 
the most delicate 
tones and gradua- 
tions being retained 
in the color rever- 

By converting the 
negative into a posi- 
tive, it is evident 
that only one fin- 
ished positive film 
can be obtained from 
each negative. For 
quantity require- 
ments, a number of experiments have been 
made with the half tone or engraving proc- 
ess as a printing medium. In this process, 
the positive film is reproduced on a sensi- 
tized copper surface and etched with nitric 
acid to produce printing plates. In this 
manner an unlimited number of positive 
prints could be produced for circulation 
purposes, paper and ink being the only 
material required for the work. As the 
initial outlay for the half tone plates would 
be large, this method would prove practical 
only for quantities running into the 

At left : The screen on which the 
picture is thrown is in a shadow box 

At right : The projec- 
tion principle of the 
cabinet explained. 
The reflecting mirror 
is disposed at an angle 
of 45° under the lid 


thousands. One hun- 
dred feet of film could 
then be sold for a little 
more than the cost of 
the paper, or rented 
for much less. 

Two types of pro- 
jectors have be< 
made. One model is 
intended for use in 
schools and churches, 
while the other is suit- 
able for home use. The 
operating principle of 
both types is the This form of 
same; there is a 
difference only in 
the range of focus. 

The home model 
is built into a cab- 
inet, resembling 
that of a phonograph. In fact, 
phonograph cabinets with slight 
interior alterations are at present 
being utilized to assemble the 
home projector. 

Paper film being opaque, it 
must be reflected, rather than 
projected on the screen. In 
carrying out this principle, the 
projection machine is placed in 
the lower part of the cabinet 
with its lens directed upwards 
towards the lid. Fixed directly 
over the projector is a brace 
containing a ring of nitrogen 
lamps and reflectors which are 
arranged to throw their concen- 
trated light on a spot over which 
the paper film passes. Since the 
nitrogen lamp is very cool, there 
is no danger of burning the film. 
The picture is reflected upwards 

Popular Science Monthly 

to a mirror disposed at an angle of 45 de- 
grees and thence to the screen attached 
to the lid of the cabinet. 

A small motor drives the pro- 
jector mechanism, elec- 
tric current being sup- 
plied to the motor and 
the ring of lamps from 
any convenient lamp 

In addition to the 
I animated pictorial rec- 
1 ord that can be pre- 
served of family and 
of friends and of in- 
teresting incidents 
of sentimental 
value, Mr. Webb 
proposes to estab- 
lish a circulating 
library which will 
furnish by mail, at nominal 
cost, films of current interest 
occurring the world over. Judg- 
ing from the popularity of the 
motion picture theatre, there is 
every reason to believe that the 
home picture cabinet will prove 
as popular as the music cabinet. 
It can be made to harmonize 
with the surrounding furniture, 
and is as ornamental as the pho- 
nograph cabinet, with which it is 
identical in appearance except for 
the screen on which the pictures 
are projected. This screen is 
collapsible when not in use. It 
is set in an ornamental frame 
which serves as a shadow box, 
so that the pictures may be 
shown in broad daylight as suc- 
cessfully as they can at night or 
in a darkened room. 


Light cays Paper film 

Light rays to film 

Popular Science Monthly 


The track-laying caterpillar motor-truck is 
vehicle, with the track-layer as the 

A New Type of Caterpillar Motor-Truck. 
It Can't Stick in the Mud 

THE novel commercial vehicle shown in 
the accompanying illustration differs 
from other 
forms of cater- 
pillar tractors 
in that it has 
one caterpillar 
o r track-lay- 
ing unit in the 
rear and two 
wheels in front. 
It is substan- 
tially a three- 
wheeled vehi- 
cle with the 
track-layer as 
the third 
wheel. It has 
a much greater 
speed than a. 
conventional track-laying tractor. Fifteen 
miles an hour is within its capabilities. 

It is especially intended for hauling 
trailers over rough country roads, but it can 
run over improved state highways by 
reason of the rubber tires on its front 

The front, wheels are of steel with wide 
steel tires. The rubber tires are fitted in 
the center of the steel tire. 

When running over good roads the front 
wheels are supported 
on the rubber tires, 
but when soft roads 
are encountered they 
sink into the ground. 
The wide steel tires 
then support the trac- 
tor and prevent it 
from being mired. 

If any of the trailers 
should stick in the 
mud, a rope around 
the winch on the 
track-laying unit is 
employed to extricate 
them. Although this 
truck is equipped with 
the caterpillar unit it 
would not be possible 
for it to negotiate 
shell craters and deep 
trenches as readily as 
its predecessor, the 
British tank. Hence 
it is not designed for 
war service. 

third wheel 

The long-handled brushes and brooms 
were converted into individualities by 
black and white paint and shoe buttons for 
eyes. They required some clever carving too 

The Convalescent Soldiers Are 
Ingenious Toy Makers 

THE war has indirectly been the cause of 
driving many erstwhile clerks and 
mechanics but 
now soldiers 
into the ranks 
of the toy 
makers. The 
invalid soldier 
finds not only 
for his en- 
forced idle 
hours but a 
certain amount 
of recreation 
as well in de- 
vising original 

In order to 
make a really 
successful toy, one must needs have a more 
or less intimate-knowledge of child-nature. 
The men who made the designs shown in 
the accompanying photographs must have 
had in mind a picture of some toddler leav- 
ing all the expensive toys that Santa Claus 
had left around the Christmas tree and 
going persistently back to mother's old 
dust-brush or broom. 

The articles pictured, the work of maimed 
or blind soldiers, were exhibited at the 
Lyons Fair. Black 
and white paint and 
large shoe-buttons for 
eyes converted the 
long-handled brushes 
and brooms into in- 
dividualities, while 
clever carving in con- 
junction with paint 
and shoe-buttons and 
wooden wheels made 
stands for other types 
of brushes, which im- 
mediately became 
fierce and wonderful 
animals with accom- 
modating holes in 
their noses for strings. 
But the toys do not 
lose their utilitarian 
quality permanently. 
When they are no 
longer needed as play- 
things they may be re- 
turned to their hooks 
in the kitchen. 


Popular Science Monthly 

According to chemists' reports the solu- 
tion does not injure the inner tube in the 
least, but is, on the other hand, a preserva- 
tive of rubber. Under-inflation is the 
cause of the majority of tire troubles. With 
the new solution the proper air pressure 
is maintained at all times in the inner 

A small quantity of the 
solution is forced into the 
tire. When the wheel re- 
volves, the fluid spreads 
in a thin film over the 
pores of the inner lining 

A Solution Which Promises to 
Solve Some Tire Troubles 

A SOLUTION which is injected into the 
inner tube of an automobile tire 
through the stem is said to keep the tire at 
normal inflation and to make it practically 
puncture proof. The solution lies in a 
fluid state at the bottom of the tire, occupy- 
ing only six per cent of inner space, except 
when the car is in motion, when centrifugal 
force carries it around the tire in a thin film, 
thereby sealing all porous places that cause 
slow leaks. The fifty or eighty-pound pres- 
sure forces the solution into 
every infinitesimal open 
ing where air leaks 
out, and at once 
seals it. 

On Land a Submarine Travels at 
Tortoise Speed 

O her great surprise, the U. S. Sub- 
marine H-3, of the Pacific division, 
woke up one day to find herself 
high and dry on the sands of 
Samoa Beach, California. It was 
not exactly the proper place for 
a perfectly respectable subma- 
rine, and plans were immediately 
devised to launch her. The best 
launching place was Humbolt 
Bay, nearly a mile distant, where 
the land goes down rather ab- 
ruptly from the shore. So the subma- 
rine was jacked up and laid upon a wire 
cradle formed between two huge logs. The 
cradle and its burden, wheeled upon small 
logs as rollers, were then moved slowly 
forward by hauling on a block and tackle. 
This is the first authentic report of a 
bona-fide submarine taking an overland 

As a land animal, however, the sub- 
marine is not very spry — she makes about 
one hundred and fifty feet in an hour. 
Under water she travels at from six to eight 
miles an hour. Hereafter she will prob- 
ably be more careful about 
keeping away from shore 
and out of the path 
of breakers and 

When the U. S. Submarine H-3 became beached, she had to be jacked up on a massive log cradle 
and pulled on four sets of huge rollers to a suitable launching place nearly a mile distant 

Popular Science Monthly 


Typewriting in Code on a Specially 
Constructed Machine 

THE war has brought forth many devices 
for communication in code; and many 
different codes are used in the different 
departments, as well as among individuals. 
The invention of a typewriter which will 
print in code follows as a natural con- 
sequence, for time and speed cannot be 
sacrificed continually, even in the interest 
of secrecy and safety. 

The code typewriter is a complete type- 
writer, standard keyboard, with nothing in 
its appearance to indicate that it is not an 
ordinary typewriter. On this machine a 
stenographer may produce the cipher 
writing with the same speed as though he 
were writing in English. It is the inven- 
tion of Edward Hebern, of Oakland, Cal. 

All the characters of a standard keyboard 
may be represented, in the cipher of letters. 
In placing figures and other characters not 
letters into cipher the shift key is not 
operated, but in order to translate them out 
of the cipher it is necessary to hold down 
the shift key in copying the cipher letters 
that represent figures and other characters. 

For the receiver of a cipher message to 
ascertain what letters represent other 
characters than letters, he simply copies the 
whole of the message. The parts repre- 
sented by figures remain in cipher. He 
then sets the shift key and recopies those 
portions; the result will be that the figures 
or other characters will be printed. 

An unlimited number of different codes 
may be used. A change of code is effected 
without changing the position 
of the letters on either the 
keyboard or type. The 
code is changed by means 
of a small aluminum de 
vice called the "code 
bar," weighing about 
one ounce. It is 
simply withdrawn 
from a slideway and 
another bar, set in a 
different code, is in- 
serted. The code bar 
contains twenty -six 
graduated letter 
blocks. By unscrew- 
ing a thumbscrew 
and moving the let- 
ter blocks to a differ- 
ent position a change 
is made. 

The code is changed by means of a small 
code bar having twenty -six letter blocks 

A bunch of fire-crackers to scare away the 
malicious spirits of storms and submarines 

Fire-Crackers: A Chinese Protection 
Against Submarines 

THE Chinese are superstitious. They 
are constantly trying to slaughter the 
myriads of malicious spirits and sprites that 
are supposed to flutter everywhere, even 
under the bed or between the cracks of a 

Fortunately, it is a comparatively simple 
matter to put a couple of thousand sprites 
out of the way in one fell swoop. 
All you need do is to explode a 
fire-cracker. The evil spirit 
and malicious sprite 
can't stand noise. It 
irritates them to dis- 
traction. If loud 
enough it kills them. 
Conseq uen tly, 
when a Chinese crew 
makes ready to hoist 
anchor the first cere- 
mony is to unpack 
the fire-crackers and 
slaughter the evil 
spirits with a five- 
minute bombard- 
ment. Nowadays 
great quantities of 
fireworks are carried. 



The new life-guard boat 
which can not capsize. 
The man lying down is 
looking through the glass 
bottom to locate bodies 

A Life-Boat That Cannot 
Capsize or Sink 

ANEW life-boat built 
along the lines of a big 
surf board, has proved so 
satisfactory that it has been 
officially adopted by the city 
of Long Beach, California. 

The boat, sixteen feet long, 
forty inches wide and four- 
teen inches deep, is non- 
capsizable and self-draining, 
and is the invention of 
A. M. Nelsen of Long Beach. 
It has many advantages over 
the skiffs now used by the 
municipal life-guard squad 
of that city. It can be put 
through the heaviest surf 
without waiting for a calm. 
It has air tanks on both 
sides, at the ends, and down 
and has a glass bottom through 
bodies that may have sunk 
may be located. With one 
man paddling, and the other 
stretched at full length peer- 
ing through the glass bottom, 
a body can be located in 
twenty feet of water and 
brought to the surface by 
means of grappling hooks or 
by diving after it. 

The boat is propelled with 
double-bladed paddles by two 
guards. It can make a speed 
of six miles an hour, and will 
support twenty people. 

Popular Science Monthly 

A New Machine Husks a« Bushel of 
Corn a Minute in the Field 

NEW type of corn husker which 
promises to relieve the farmer of the 
tedious and disagreeable work of husking 
corn in the damp fields has just been 
completed by W. H. Tschantz, of Ohio. 
The apparatus is driven by a gas en- 
gine and not only husks the corn but 
deposits the clean ears in a wagon bin by 
means of an elevator forming a part 
of the device and binds up the 
husks and silks in bundles 
like wheat, eliminating all litter 
and loss. 

The apparatus consists of 
a small four-wheeled wagon 
on one end of which are 
mounted the gas engine and 
a suction blower, with the 
husker and binder at the other. 
In operation the wagon is 
drawn from shock to shock by 
horse or mule power. The un- 
husked corn is deposited on 
one side of the binder. The 
shock is first torn into small 
bundles and thrown on the 
feed board, which carries the 
bundles up to a series of hori- 
zontal rollers. Most of the 
husk is removed while passing 
through these rollers, and the 
ears are dropped on to a pair 
of rollers beneath the husking 
rolls. Here the silk is removed, 
after which the clean ear drops 
through a trough into the base 
of the elevator, which deposits 
them in a wagon or other 
waiting receptacle. 

The buoyant air tanks are 
at both sides, at the ends, 
and down the middle. 
Above: Launching the 
boat in a heavy surf 



Path of silk from bottom 
trough to binder 

Binder side' 
The bundles of corn are thrown on the feed board which 
carries them to a series of rollers which remove the husks 

Popular Science Monthly 


Millions of shoes worn to all degrees of disrepair, waiting to be sorted, patched and soaked in 
oil. Scraps of leather are passed through an ingenious cutter and converted into boot-laces 

The "Shoe Hospital" of the Allies. 
Not an Inch of Leather Is Wasted 

IN a recent issue of The New Republic, 
W. M. Meredith makes the following 
reference to the shoe-repair shops of the 
Allied Armies. 

"Entering another shop we find huge 
stacks of worn-out boots in every degree of 
disrepair. These are first sorted out like 
patients in a hospital, according to their 
various injuries. Those requiring new 
soles go in one direction, those which must 
have new toes or sides 
are passed on in another. 
Here the boots are re- 
fitted completely, and 
finally go into a bath of 
hot oil where they are 
thoroughly soaked. If 
any British soldier of 
the three million or so in 
France expresses a wish 
to have a certain pair of 
boots returned to him 
that fit him with com- 
fort, he is certain of 
getting that same pair 
back." Think of that 
in connection with our 
photograph above! 

The hair-drying frame is of wire net- 
ting with an adjustable head band 

Not the Latest Style in Hats — Just 
a Hair-Drying Frame 

THE artist who made the "human 
interest" drawing of the hair-drying 
frame illustrated below is evidently a 
bachelor who has spent all his days in an 
Eden where there were no Eves to go about 
periodically in low-necked kimonos and 
wildly flowing tresses during the process of 
drying and airing the hair after a shampoo. 
However, he has shown the frame clearly. 
It is made of wire netting, and buckles 
around the head with an 
adjustable band. The 
hair is drawn up tight to 
the crown of the head 
after the last rinsing and 
a perfunctory drying. 
Then the frame is ad- 
justed and buckled 
around the head, and 
the hair is spread over 
it in all directions, so 
that the air can circulate 
through it thoroughly. 
To the professional hair- 
dresser, with an electric 
fan for the drying, such 
a frame should prove 

62 Popular Science Monthly 

A Drawbridge Gate Which Will 
Stop Any Automobile 

still further absorbed as the spring is further 
compressed. Before the car has gone a half 
dozen feet forward, all of its "push" will 
have been completely destroyed without 
producing any undue strains on the gate. 
The method could be relied upon to stop 
anything short of a railroad train! 

A runaway car striking 
against this gate would 
be stopped by the cush- 
ioning of the huge gate- 
springs in the cylinder 

DESPITE even the 
massive iron gates 
that swing across a road 
when a drawbridge is 
opened, automobiles 
break through occa- 
sionally and plunge 
into the river below. 
Such accidents occur 
when the brakes jam. 
Here was an op- 
portunity for an in- 
ventor. It was seized 
by Jacob Harsen, a 
highway engineer of 
New York, who has 
invented a cushion 
lock for gates. Four 
huge "locomotive" 
springs are mounted 
inside of four cylin- 
ders at the ends of the 
swinging gates on each side. 
The cylinder plungers, which 
work against these springs, 
form one piece with the gate 
coupling, which is locked by 
the gateman when the draw- 
bridge is about to be closed. 
When the automobile strikes 
the gate at high speed, the 
huge springs are slightly com- 
pressed ; then the gate "gives" 
away gradually. The energy 
of the automobile's impact is 

Gate locked in normal 

Detail of the cushioning spring. The cylin- 
der plungers which work against these springs 
form one piece with the gate coupling 

The Wooden Hand Rammer — 
A Survival of the Fittest 

URING the last five years 
the electric chain rammer 
has disappeared from the tur- 
rets of modern warships. A 
short circuit on one of the 
battleships almost led to 
disastrous consequences. 
In other cases a tempora- 
ry breakdown spoiled the 
turret's chances in record 
firing. Gradually the old 
hand rammer, which 
in principle has changed 
little since Nelson's 
men rammed the 
round shot home in 
the muzzle loaders, 
has won back its 
supremacy. The 
turret of a Dread- 
nought is filled with 
other electrical de- 
vices, but the 
wooden rammer is 
the one bit of equip- 
ment that has sur- 
vived from the days 
of wooden ships, so 
far as the turret is 

Spring in all cylinders 

The electric chain rammer was placed directly in the 
rear of and parallel to the bore of the turret gun 

Our Unsinkable Torpedo-Proof Cargo Fleet 

The boats will be patterned after the ordinary 
its hull divided^ into a dozen or more tight 

By Joseph Brinker /- 

UNSINKABLE? Yes, practically. 
That's the kind of ships it is 
now proposed to build for Uncle 
Sam's fleet of freighters to thwart the 
torpedoes of the German submarines. 
Of course no vessel afloat or to be 
launched in the near future will be 
unsinkable if a sufficient number of 
torpedoes are exploded against her 
sides. Even the latest battleship is not 
immune. But Uncle Sam's new boats 
will have no unprotected portions of 
the hulls, and it will take at least two 
and perhaps three well-aimed torpedoes 
to sink one of them. 

The new type will be fully armed. 
It will be of steel construction and 
patterned after the present-day oil- 
tanker which is practically immune 
against 'single torpedo attacks except 
in the way of the engine and boiler 
rooms. If struck there she is done for 
and settles by the stern, with no power 
to proceed. The new boats will have 
fuel-oil tanks extending clear around 
the ship from main deck to main deck, 
from the front of the boiler space to 
the rear of the engine room. If a 
torpedo strikes her there and blows a 
hole in her outer skin, the inside of the 
tank will act as a new hull to keep her 
afloat until the submarine rises to view 
her prey. Then because of her arma- 
ment, the ship has a chance to de- 
stroy the submarine. None of the oil 
tankers have been sunk so far in the 
war by one torpedo, unless hit in the 
engine or boiler space. 

Applying the Lesson Taught by 
the Oil-Tanker 

The bulk oil in the tankers is carried 
in a dozen or more separate tanks or 
compartments into which the hull of 
the tanker is divided byanoiltight longi- 
tudinal centerline bulkhead and many 
transverse bulkheads. This is why one 

oil-tanker with 

A billion dollars' worth of shipbuilding 
means that the proposed ships will entail 
the production of steel enough to make two 
Woolworth Buildings, each 792 ft. high 


Popular Science Monthly 






The typical oil-tank steamship shown in section at the top and the proposed freighter beneath 
it indicate the great similarity between the two types. The oil tanks are practically made over 
into cargo holds. The small transverse section of the boiler and engine room of the upper diagram 
shows its vulnerability to torpedo attack in that portion of the ship. The lower diagram shows 
how the vitals in a similar section of the proposed ship will be protected by means of fuel-oil tanks 

In the proposed freighter, the hull will be divided into a dozen or more small compartments 
and the engines and boilers will be protected by means of fuel-oil tanks extending clear around 

Popular Science Monthly 


torpedo will not sink her. A torpedo ex- 
ploding against the hull of the ship and 
crushing one or two of these compartments 
does not sink the ship because of the re- 
latively small size of the few compartments 
punctured, compared with the remaining 
dozen or more that are left intact. 

The reason that one torpedo is not 
liable to break 
open more 
than two or 
three of these 
tanks is that 
a torpedo is 
in no sense an 

If the proposed freighter should 
be struck in a vital spot she 
would still keep afloat, the inside 
of the tank acting as a new hull 

i ng shell 
which passes 
through the 
boat from one 
side to the 
other or ex- 
plodes inside, 
everyth ing 
apart. On 
striking a vessel's side it explodes and does 
its work by the rapid expansion and con- 
cussion of the gases of its charge. 

The majority of the new boats will be 
of steel and not of wood as first planned, 


and illustrated and described in the June 
issue of the Popular Science Monthly. 
They will be of steel because there is still 
some skepticism as to the practicability of 
the 3000- or 5000-ton wood vessel, because 
such a ship has never been built before. 
Questions have arisen as to the racking 
stresses and strains which would be set up 
in a ship by 
the use of un- 
wood and as 
to our ability 
to raise a suf- 
ficient army 
of shipbuild- 
ers to carry 
on the work. 
All of these 
argu ments 
and the facts 
that wood 
ships would 
have shorter 
lives than 
steel ones and be at a disadvantage in com- 
peting with the steel ships of other nations 
after the war, seem to have killed the 
wooden fleet proposition. Besides, there 
is no longer a shortage of steel. 

The old type of oil tank sinks 
at the stern if struck in the 
engine or boiler compartments 
— its only vulnerable spots 


» sSS 






^ BsrJS? 


5> famS 

UE10IL N\\ 










the ship. In the broken-away portion of the drawing the bulkheads dividing the space into 
compartments to reduce the crushing effects of the torpedo's explosion are very clearly shown 


Popular Science Monthly 

A German Medal to Com- 
memorate the Torpedoing 
of the Lusitania 

THERE came into the 
office of Popular 
Science Monthly re- 
cently a bronze medal in 
a leather case. It was 
one of the two medals 
struck off by the German 
Government in commem- 
oration of the act that, 
more than any other, 
inflamed the American 
people against Prussian- 
ism, the torpedoing of 
the Lusitania. To 
further celebrate the 
event the school children 
of Germany were granted 
a half holiday and the 
commander of the sub- 
marine was decorated by 
the Kaiser. 

One medal (not shown 
here) depicts Neptune 
seated on a submarine 
shaking his fist at a sink- 
ing ship. On the opposite 
side is a bas-relief of 
von Tirpitz. The second 
medal, which is reproduced 
here, shows, on one side, the 
Lusitania sinking, and on the 
other the figure of Death selling 
tickets at the office of the 

The three German words above the 
sinking ship stand for "No Contraband 
On Board." Examine the illustration and 
you will see that a cannon and an airplane 
occupy the deck. Although the Lusitania 
carried rifle cartridges on her fateful trip, 
it has been indisputably proved that 
she carried no weapons of defense or 
offense. Needless to say, the 
cannon and airplane are pure 
inventions. Translated, the 
legend beneath the ship reads: 
"The steamer Lusitania sunk 
by a German submarine May 5, 
1915." Note that the date is 
given as the fifth of May in- 
stead of the seventh. Is 
the error a deliberate 

At the top of the 
lower illustration ap- 
pear the words 

Full-size illustrations of one of the 
German medals which commemo- 
rate the sinking of the Lusitania 

"Business Above Everything." 
One person is shown reading 
a newspaper, evidently the 
advertisement inserted by 
Count von Bernstorff, 
warning Americans and 
other neutrals to keep off 
vessels flying the British 
flag. Note the man in 
the rear with the menac- 
ing finger upraised; also 
the care-free attitude of 
the two men in front of 
him. Beneath the win- 
dow, in which Death is 
selling tickets, appear the 
words, "Ticket Office." 
In all, 1,198 passengers 
and crew lost their lives 
on the Lusitania. In this 
number are included 124 
Americans and 94 

An Automatic Tea- 
Making Machine 

R-R ! ting-a- 



The tea-making machine brews the tea, 
pours it into a cup and rings an electric bell 

ling ! Wake up ! 
Your tea is ready. Br-r-r-r ! 
Time to get up!" 
This is practically what 
the automatic tea-making 
machine does every morning. 
It brews a cup of good tea, and 
then it calls its master. It was 
invented by a young Englishman, George 
Weddle, of New York, and was designed 
especially to call him and serve him with 
his morning bracer. 

The machine consists of an electric stove, 
kettle, alarm clock, electric bell, battery 
and tea cup on a tray eighteen by ten 
inches. With these it brews the cup of 
tea, pours it into the cup and rings a bell 
until the master wakes up and takes his tea. 
Should coffee be preferred, there is an 
attachment to be screwed into 
the kettle that will act as per- 
colator. There is also an attach- 
ment for boiling eggs, so 
that an automatic break- 
fast, cooked and 
served at your bed- 
side, seems quite 
possible. The ma- 
chine may be easily 
taken apart and put 
into a small hand 
bag or traveling case. 

California's Conception of a "Tank 

It was designed for aid in recruiting 

PATTERNED somewhat after 
the famous British tanks pic- 
tured and described in the 
May issue of Popular Science 
Monthly, the California-made 
tank shown herewith is like its 
famous prototype in only one par- 
ticular, that of a track-laying pro- 
pelling means. There the similarity 
ceases, for it has not the large 
upswept track-laying framework in 
front that has made possible the 
almost incredible hill-climbing feats 
of the British tank. Instead it has 
two track-laying members of the 
kind used on farm tractors and a 
small guiding wheel in front. 

Formidable as it looks in armor . A 

and with the guns sticking out of its m 

turret, a heavy rain would render it use- 
less in actual service. The small wheel 
in front would bury itself in soft ground 
on a shell crater, which its foreign rival 
could negotiate with ease. The large bear- 
ing area of the caterpillar shoes makes it 
possible for the British tank to traverse 
soft, muddy ground. The pressure is said 
to be less than three 
pounds to the square 
inch with the cater- 
pillars thirty inches 
wide and with 
about fifteen 
or twenty 


■Hfr ' 

mm IHaHl 

4 ~ rs L£}'*'- - v^y"— ^-^T*** 

company of infantry using the track-laying tank 
sham battle on the outskirts of San Francisco 

feet of length in contact with the ground 
all of the time. 

Obviously, then, the truck illustrated 

would be a failure in the land of shell 

craters between the trenches in warfare as 

carried on to-day. However, it served a 

useful end in acquainting our California 

infantry with its adaptability as a war 

instrument and in arousing the martial 

spirit. The regular army used the tank for 

recruiting purposes. It is here 

shown in a sham battle in 

rough country in the 

,~*^ vicinity of San 

EXHAUST PIP%S ^'- Francisco. 


Because of the small wheel in front, the tank could not travel in a land of shell craters and muddy 
ground. It is, therefore, not in the fighting class, however formidable* it may appear 



Popular Science Monthly 

Portion of a motion picture taken through periscopes at the 
bottom of the sea in the crystal-clear West Indian waters 

Seeing the Wonders of the Ocean 
Through an Inverted Periscope 

AS is well known, the periscope enables 
±\ the submarine, while submerged, to 
see above the surface of the water. Why 
not invert the periscope, attach it to the 
side of ocean liners, and thus enable the 
passengers to study marine growths and 
fishes ? Provided there was sufficient light 
beneath the water, the inverted periscope 
might even be used to search for sunken 
treasure ! 

This is exactly the use to which it is put 
in the latest underwater motion picture film 
of the Williamson Brothers, "The Sub- 
marine Eye." It will be recalled 
that the thrilling underwater 
scenes in "Twenty Thousand 
Leagues Under the Sea," 
were photographed by the 
Williamsons. In "The 
Submarine Eye," the new 
under-sea thriller, the invert- 
ed periscope, as shown in the 
illustration above, is used to lo 
cate a safe containing treasure. In 
the crystal-clear waters of the West Indies 
the audience is shown the marvels of 
Nature at the bottom of the sea where the 
light from above is reflected from the 
dazzlingly white sand. Finally, after a 
series of harrowing adventures many 
fathoms under water, the safe is located 
by the inverted periscope. 

Importing Japanese Mos- 
quitoes for Bird Food 

THE delicate vocal organs 
of song birds respond 
magically to special care be- 
stowed upon the diet. For 
this reason birds that are 
cultivated in captivity are fed 
specially prepared foods de- 
signed to furnish maximum 
nourishment with minimum 
labor of the digestive organs. 
A food which has been 
found especially valuable to 
bird-breeders has for its prin- 
cipal ingredients Japanese 
mosquitoes and ants' eggs. 
It is prepared by George 
Jenkins, of New York city, 
an expert on the care and 
feeding of birds. The na- 
tionality of the mosquitoes is 
not supposed to make a dif- 
ference in the taste or digest- 
ibility of the food. The reason the insects 
are imported from Japan is that the Japan- 
ese have a method of catching them in 
large quantities which as yet Americans 
have not discovered. 

In the photograph below, Mr. Jenkins 
is shown inspecting a shipment of twenty- 
eight pounds of mosquitoes. The food is 
intended for soft-billed birds that do not 
feed on seeds. Among these are the 
thrushes, mocking birds, nightingales, tan- 
agers and many others. In the oval photo- 
graph an American thrush is shown feeding 
her nestling with the prepared food. She 
takes the food on 
her bill and thrusts 
it far down the 

Twenty-eight pounds of Japanese mosquitoes 
to be used as an ingredient in the bird-food 

Popular Science Monthly 


Shall Personal Vanity Prove a 
Handicap to the Government? 

BECAUSE Dame Fashion, in one 
of her capricious moods, has de- 
creed that platinum jewelry is the 
fashionable thing to wear, that metal 
has steadily advanced until to-day it 
is worth five times as much as gold. 
As a result all chemical laboratories 
and institutions throughout the coun- 
try are greatly handicapped by its 
scarcity. For producing sulphuric 
acid, which is an absolute necessity 
in the production of high explosives, 
platinum is essential. To relieve the 
present condition the rt __,_ 
American Chemical So- 
ciety suggests that the 
loyal public refrain from 
purchasing platinum in 
the form of jewelry and 
discourage the use of the 
metal for ornamental pur- 
poses. This would be in 
line with economy, also. 

opnng wind reel 

The Many-Sided Bathing Cap. Change 
It to a Suit- Bag When You TraverHome 

THE convertible bathing-cap of a New 
York merchant has many virtues. 
Inflated, it serves as a waterwing or a 
football. Deflated, it 
becomes a wrapper 
in which to carry 
your bathing suit. 

The cap is 
made from strips 
of waterproof 
material sewed 
together to a foot- 
ball's shape. It can 
be folded in half 
lengthwise by pushing 
one end down into 
the hollow of the other 
end. When this is done it will 
conform to the shape of the 
head and it will be ready for 
use as a cap. Straps are at- 
tached to the side for securing 
the cap under the chin. 

A circular bladder can be 
placed inside this same piece of 
goods and inflated to change it 
into a ball for playing on the 
beach. With a bladder of different shape 
placed inside it, it can be used as a water- 
wing with straps to fasten it around the body. 

This cap when opened out forms a bag for the 
bathing suit. When inflated it is a rubber ball 


This safety chain can 
be used for securing a 
wallet to a man's pocket 
or to a lady's handbag 

The steel chain is 
wound up on a spring- 
revolved drum when 
the wallet is pocketed 

At Last!— The Safety Chain for 
Frustrating the Pickpocket 

FROM sad experience, many a man has 
learned that placing his wallet in even 
an inside pocket will not prevent it from 
being stolen. But if 
the wallet is attached 
to the safety chain 
invented by Law- 
rence R. Delaney, 
of Gage, Okla- 
homa, a pick- 
pocket could not 
remove it with- 
out taking the coat 
along, too! 

A fine steel chain 
connects the wallet 
with the coat pocket. 
When you pocket your wallet, 
this chain is wound up on a 
spring-revolved drum in a very 
thin casing which is sewed to 
the bottom of the pocket. The 
chain, which has its free end 
secured to your pocketbook, is 
about a foot long, so that you 
can draw it out conveniently. 
When you return the wallet to 
your pocket the chain winds up automati- 
cally. Should a pickpocket attempt to rob 
you, the tug on the chain would betray him. 

Fifty Million Shots to Win a Line of Trenches 

Nearly nine million pounds of artillery projectiles 
were hurled at the Germans in a single engagement 

French Official Photos. 

Thousands upon thousands of cases of shells are unloaded at the artillery depots of the 
various armies, after which they are transported in smaller lots to distributing stations 

IN the early days of the war, when the 
Germans were turning out 250,000 
shells a day, the British were producing 
2,500 in high explosives and 13,000 in 
shrapnel. Before the war, Germany held 
an average stock of 3,000 shells for each 
gun, while France had 700. When the war 
began, France estimated a daily expendi- 
ture of 13,500 shells, but before 
a year had elapsed, she was 
firing 100,000 a day. 

According to an official re- 
port of the French Army 
Headquarters, the French 
artillery north of Arras fired 
300,000 shots within 24 hours, 
the total weight of which 
would be 8,901,000 pounds. 
During the great French of- 
fensive of September, 191 5, in 
the Champagne, the French 
fired at the rate of 900,000 
shots an hour — a total of 50,- 
000,000 shots in three days on 
a twenty-five-mile front. 

The cost of ammunition, 
considered in the light of its 
wastefulness, is appalling. A 
year ago, Canada had con- 
tributed $350,000,000 worth of 
shells. The United States had 
exported ammunition, explo- rows along 

sives and firearms worth a half-billion. It 
is needless to state that the last year has 
been the most productive of all, not only in 
the United States and Canada, but in 
European countries as well. Figures of 
shell production run into unthinkable 
billions. For this the tremendous capacity 
of the guns used is largely responsible. 

are housed in rough portable shacks arranged in 
narrow-gage tracks which lead to the fighting front 


Popular Science Monthly 


Cutting Forty Soldiers' Uniforms 
At One Time 

WITH the aid of an electric cutting 
machine one tailor can cut forty 
soldiers' uniforms at one time, and in one 
day do the work of one hundred men work- 
ing with shears. Were it not for the many 
labor-saving machines in the tailoring 
business our soldiers might 
be obliged to wait long for 
their uniforms. 

At the present time there 
are many big tailoring estab- 
lishments filling rush orders 
for suits for the 
They are working 
twenty-four hours 
a day, with two 
shifts of workmen, 
in order to turn 
out the work on 
time. The suits 
are made accord- 
ing to standard 

measurements and there is no chance to 
deviate from the regular sizes. 

A tailor operating the electric cloth cutter which cuts 
out the pattern of forty uniforms at one time 

It resembles the crude weapons used in 
the early days of gunpowder and is operated 
from the shoulder. It has a barrel in the 
form of a tube about five inches in diameter, 
at the t base of which an incandescent 
electric light is located. It is fitted with 
a stock and there is a trigger which con- 
nects with a switch that 
flashes on and off the cur- 
rent. Current is supplied to 
the signal gun by means of 
a cable that enters the 
stock. On the top of 
the barrel are sights for 
aiming the gun. 
Signals are flash- 
ed by the dot and 
dash system, 
short flashes in- 
longer ones, 

Visual signaling 
between ships at 
night is usually 
done by means of lights hung from the 
masthead, but their operation betrays the 
presence of the fleet to enemy ships that 
may be near by. The flashes from the signal 
gun are only visible to the ship at which 
the device is aimed or one that maybe in line 
with it either closer or further away from 
the ship from which the signals are sent. 
Even though no lights may be showing, 
one ship knows the approximate location 
of every other ship when they are in fleet 
formation and the signal gun may be aimed 
in the direction of any one of them. 

When the signal gun is used it is not 
necessary to "call" a vessel before 
sending a message. Knowing that 
the flashes are not visible to any 
other ship in the fleet, the men 
on watch on the bridge of the 
vessel at which the gun is 
aimed are in readiness to record 
the message as soon as they per- 
ceive the flashes. The very fact 
that they see them proves that 
the signal light is directed at 
them and that their ship is the 
one for which the message is 

The light located within the 
barrel of the gun is one of great 
power and its flashes can be 
*«StaSg" signals with the signal gun. The flashes are seen for a number of miles at sea, 
visible only to the ship at which the device is aimed even in cloudy weather. 

Flashing Signals from Electric- 
Light Guns 

A NOVEL signal gun has been devised 
by the United States Navy to trans- 
mit visual signals between ships in a fleet 
of war vessels that are running without 
lights, and yet not betray their presence 
to the enemy. Signals flashed by it are 
visible only to the ship at which it has been 
aimed or one in line with it. 

■ jw^-JH 




^S9| JQHfe jSjSjESyffiBfc 


Popular Science Monthly 

Utilizing Your Player Piano as a 
Vacuum Cleaner 

THERE is no better vacuum cleaning 
pump than 
the air pump of 
your player piano. 
So thought Max 
Rothfeld, of Phil- 
adelphia, who has 
patented the dust- 
filtering at- 
which will 
change your 
piano into a 
vacuum clean- 
er. You need 
only to discon- 
nect the air 
pipe leading 
from the piano 
bellows, from 
the air motor. 
Insert the at- 
tachment in 
this, have 

A dust-filtering chamber fits in the end of a long flexi- 
ble hose leading from the piano bellows. The suction 
created by the piano pump draws the dust into the filter 

ground-up leaves of the hay of alfalfa. By 
replacing the all-too-scarce wheat flour with 
a considerable percentage of this alfalfa, a 
bread can be made which is far more nutri- 
tious than that 
made from plain 
wheat. The high 
percentage of both 
body-building and 
bone-building ele- 
ments in the alfalfa 
makes this new 
bread a practically 
complete article of 
food. The bene- 
fits of its use will 
therefore be two- 
fold: the present 
supply of 
wheat can be 
"stretched" to 
feed a far 
greater num- 
ber of people, 
and a more 
ideal war food 
can be gained. 

work the pedals, and proceed with your 
parlor cleaning. The inventor also suggests 
that should the air-mechanism of your 
piano become clogged it can easily be 
cleaned with his device. 

The device is nothing more than a flexible 
hose having a wire filter mounted across a 
small dust chamber near its end. 

Conserving the Wheat Supply 
with Alfalfa 

A SHORT time ago alfalfa, the 
clover-like plant which 
grows so abundantly in the West, 
was considered fit only for feed- 1 
ing cattle. Thanks to the re- I 
searches of the industrial chemist, 
it is now destined to become one 
of the most important articles of \ 
human food. The present prob- 
lem of the world's shortage of 
wheat — that well-balanced and 
so essential food — may even be 
solved with the aid of this form 
of "cow fodder." 

Elizabeth C. Sprague, head of 
the department of Home Econom- 
ics at the University of Kansas, 
has found out how a most whole- 
some flour can be made from the 

Making Bad Whiskey out of Good 
Jam and Potatoes 

SOME German prisoners in the Holds- 
worthy Internment Camp, in Australia, 
rigged up a still of kerosene cans, bottles, tin 
tubes and other receptacles and made whis- 
key out of jam and potatoes ! It was effi- 
cient enough to meet the demands of the 
drinkers. Perhaps it was too efficient, for 
the intoxicated Germans themselves gave 
the secret 'away. 

Transforming a Roadster into a Truck 

A device which makes it possible for a one- 
passenger automobile to haul three trailers 


The pleasure 
car can be 
changed into 
a one-ton 
truck and 
back again 
into a pas- 
senger car in 
five minutes 

U-shaped pivot 
.supports \ Elbow, 

Solid trailer axle 

Trailer wheels 

THE conver- At right: The fifth wheel 

S i O n of a device mounted on the 

roadster framework of the car 

automobile into a 

one-ton truck and back again into a pas- 
senger car in five minutes has been made 
possible by the use of a patented fifth- 
wheel device to be set on the rear deck 
of the car to support the front end of a 
wagon-like trailer. Both trailer and fifth- 
wheel are now being made as a unit by a 
New England manufacturer to enable the 
owner of any roadster to change his car 
into a work vehicle and back again as 
often as desired. 

The fifth-wheel device is mounted on the 
framework of the car with but six bolts 
after the rear deck or luggage carrier has 
been lifted off. The device consists of two 
wheels of the same size which rub together, 
one above the other, through lubricating 
grease. One wheel is mounted on a rock- 
ing shaft and frame attached to the car, 
and the other bolted to the underside of 
the front end of the trailer. 

To connect the trailer with the car, its 
front end is simply lowered down on to 
the wheel on the car. Conversely, it may 


At left: The 
various parts 
of the wagon- 
like trailer, 
showing the 
relation of 
the small 
wheel to the 
body parts 

be removed by simply 
lifting it up by hand, if 
empty, or by a jack de- 
vice if loaded. The fifth- 
wheel device, which can be lifted easily by 
one man, is then taken off and the rear deck 
replaced. The car is then ready to take the 
owner's family out for a pleasure trip. 

The trailer may be fitted with any type 
of body, according to the class of goods to 
be carried and principally differs from the 
ordinary wagon in that it has rubber-tired 
wheels mounted on roller bearings. These 
enable the car and trailer to travel at speeds 
of twenty miles per hour or more and elim- 
inate the trouble caused by the over- 
heating of the plain iron bearings such as 
are used on slow-speed horse wagons. 

The jack device for lifting the front end 
of the trailer consists of a triangular- 
shaped framework made of pipe sections. 
It is pivoted to the underside of the 
trailer and has a telescoping bar attached 
to the trailer axle to keep the framework 
upright when in use. This eliminates the 
wooden horse formerly used and permits 
the trailer to be moved from place to place 
for loading and unloading. 

Do It With Tools and Machines 

A convenient oil 
and grease cup 
in which the grease 
is retained for an 
emergency. The 
object of this cup is 
to prevent the over- 
heating of the bear- 
ing should the oil 
passages become 
clogged or the at- 
tendant fail to start 
the oil cup feed or 
neglect to fill the 
oil cup promptly 

A triangle that can 
be used alone for 
drawing any kind of 
an angle or series 
of parallel lines di- 
rectly and easily 

With this electrically driven screw-extractor a 
broken screw may be removed as quickly 
as a new one without waste of time. It is 
made similar to the portable electric drill 

m * 


A vise for use between milling 
machine centers which saves 
much of the time of the usual set-up 

A light inclosed 
electric hoist that 
may be operated 
from a distance and 
used in a manner 
similar to the hoist- 
ing unit on travel- 
ing jib or wall 
cranes. The addi- 
tion of an operator's 
cab adapts this 
hoist for high speed 





A cotter pin extractor 
that not only draws the 
pins but straightens the 
shanks so that they may 
be used again without 
any special operation to 
permit their reinsertion 
in the opening of the 
bolt or shaft from 
which they were 
taken. The clip 
for drawing the 
cotter is worked 
by a pair of 
arms between the 
closing handles 

A handle like a saw 
grip to receive the 
shank of an ordi- 
nary file of any size 

An expansion bolt shown 
in detail in Fig. 1 and fully 
expanded in hole in Fig. 2 

Do It With Tools and Machines 

A hook made of 
strong wire with a 
snap having a tem- 
pered steel tongue 
at one end is very 
handy for holding a 
paint bucket or fruit 
pail on a ladder rung 

The usual method of 
cutting the larger sizes 
of pipe on a lathe is 
improved upon by the 
use of the hand power 
threader illustrated 
above. It may be 
taken to the job 

An ordinary electric ceiling fan is kept 
running in this vestibule and when the 
outer door is opened the air is driven 
outward so swiftly that very few flies, 
if any, will be able to effect an entrance 

A portable electric- 
ally driven valve- 
grinder which gives 
the familiar oscilla- 
ting motion. The 

By changing the 
form of the interior 
bore of this anchor 
for a screw the max- 
imum expansion 
is given where the 
greatest frictional 
contact occurs, 
which increases the 
holding capacity 

A measuring gage 
using a fluid against 
a flexible diaphragm 
to obtain readings 
in ten thousandths 
of an inch or closer 
to determine the 
thickness of stock 

speeds of the elec- 
tric grinder are far 
greater than those 
attained by the 
hand method 


Fighting in the Air 

The new machines that have been evolved and 
the way they fight four miles above the ground 

By Waldemar Kaempffert 

(The following article is based upon facts which have been kindly supplied by Major W. L. B. 
Rees of the British Commission. Major Rees was sent to this country as a member of the 
British Commission to give to our army officers the benefit of the British experiences on the 
battlefield with flying machines. He is an officer of the Royal Flying Corps who has seen 
active service in the air and who, single-handed, brought down ten German flyers. — Editor) 

THE General Staff of every European 
army knew five years ago that the 
airplane would prove a potent factor 
in war. Germans, English, French, Ital- 
ians, all had tried to evolve a system of air- 
scouting in their annual maneuvers. The 
Italian campaign against the Turks in 
Tripoli and the Balkan wars had proved 
clearly enough that a man in the air could 
see more than could a man on horseback. 

And yet all the European generals 
entered this war without even a dim realiza- 
tion of the terrible demands that would be 
made of aircraft; of their utter dependence 
on a handful of dauntless men ready to 
vault into the air and brave not only the 
unseen whirlpools and maelstroms of a 
turbulent atmosphere, but bursting shells 
hurled from the ground and the machine- 
gun fire of an adroit enemy air-fighter; of 
the inadequacy of the airplane as it was 
built before that fateful month of August, 
1914, when all Europe was plunged into 
carnage; and of the frightful wastage of 
machines and lives. Even the Germans 
were unprepared. 

New Types Had to Be Evolved for the 
Exigencies of Battle 

Every army had machines — the French 
and Germans hundreds of them. But no 
one knew that airplanes would have to 
be built for very special military purposes; 
that the same machine could not be effect- 
ively used for scouting and fighting; that 
the acrobatic performances of Pegoud and 
his imitators in "looping-the-loop" and 
diving tail-first would be elevated to the 
dignity of military tactics with which every 
fighting airman would have to be familiar. 
In two years the whole art of airplane con- 
struction has been almost miraculously 
improved, and the art of flying, too. Be- 
fore the war, some effort was made to 
adapt the machine to the man; now the 
man must adapt himself to the machine. 
Where are the elaborate, automatic stabiliz- 
ing devices with which all governments 

experimented before the war? Where are 
the machines advocated for their inherent 
stability? The machine of 1917 is only out- 
wardly identical with the machine of 19 13. 
About six types of machines have been 
developed as the result of war experience: 

1. There is the fighter — a 150-mile-an- 
hour, single seater, which is armed with a 
machine gun; which has limited fuel- 
carrying capacity, and which serves to find, 
fight and destroy the enemy. 

2. There is the two-seated fighter. It car- 
ries a fixed machine-gun at the front and a 
machine gun on an "all-around" mounting 
for the observer in the rear It is not so 
fast as the single-seated fighter. It also 
finds and fights the enemy; but it also 
escorts patrols into the enemy country and 
protects machines engaged in fire-control. 
It has more fuel-carrying capacity than the 
single-seat fighter, because it must stay up 

3. The reconnaissance machine is armed 
like the two-seated fighter; but it is not so 
fast and does not climb so rapidly. For 
short distances over the line it is amply able 
to protect itself. If it goes far, however, 
it must be protected by two-seated and 
even single-seated fighters. It is equipped 
with a built-in stereoscopic camera. The 
pictures taken are studied by staff officers 
to note changes in enemy positions and to 
discover concealments. 

4. The fire-control machine directs the 
batteries by means of wireless. A recon- 
naissance machine when fitted with wireless 
apparatus may be used for fire-control. 

5. The bomb-dropper resembles the two- 
seated fighter, although bombs can be 
carried by various machines. Bomb- 
carriers, being weight-carriers, are large. 

6. Night-flyers resemble either the recon- 
naissance machines or two-seated fighters. 

All Europe Was Aeronautically Unprepared 
— Even the Germans 

It was a very heterogenous collection of 
machines that took the air at the outbreak 


Carrying the War into the Air 

Georges Guy- 
nemer, pic- 
tured below, is 
probably the 
most skilful 
air-fighter on 
the French 
side. Although 
he joined the 
aviation corps 
a mere boy, he 
has been rapid- 
ly promoted. 
He has a record 
of thirty-seven 
German ma- 
chines to his 
credit. In the 
picture he is 
holding the 
twisted rem- 
nant of a ma- 
chine gun 
taken from a 
German battle 
plane that he 
brought down 


AT 20,000 FEET 


at 10,000 FEET 


Boelcke, pic- 
tured below, 
was by far the 
best air fighter 
that Germany 
produced. He 
was killed at 
the Somme in 
a collision with 
a member of 
his own air- 
Boelcke was 
such an im- 
portant per- 
sonal factor 
that, although 
he had been 
sent home to 
rest by the 
Emperor, he 
was recalled 
when the Ger- 
mans found 
that they were 
losing in the 
air alarmingly 
at the Somme 

AT 6,000 FEET 





The opposing squadrons watch and watch 
each other. Woe betide the man in a squad- 
ron who lags behind for a second, who man- 
ipulates his control a little too carelessly, 
who is not quite en rapport with his team- 
mate in the machine beside him! Two 
enemies swoop down upon him. He is cut 
off from his fellows. He must fight for his 
life. Up and down, in and out he maneuvers, 
shooting when he can. But his enemies out- 
number him. He has not a chance. There 
is a squirting of bullets. His machine drops — 
a sickening sight — three miles to earth 



Popular Science Monthly 

J Press Illus. Serv. 

Two extremes in airplane types — the big bomb-carrier and the fast single-seated fighter. See key diagram below 












of the war — monoplanes with tractor pro- 
pellers, biplanes with both tractor and 
pusher propellers, machines with and with- 
out streamline bodies, fast racers, and slow, 
cross-country flyers. One would suppose 
that the military brains of Europe would 
have foreseen that some effort would be 
made to beat off a prying airscout. That 
it was foreseen, the rather crude anti- 
aircraft artillery evolved before the war 
proves; one could foresee how 
combats at a height of ten and twenty 
thousand feet would be fought, or how a 
machine should be designed for effective 
fighting. Maneuvers in time of peace may 
teach much, but blank cartridges can never 
teach as much as cold lead. 

First of all, it was discovered that for 
bombing raids, for reconnaissance and for 
fighting, different types of machines must 
be employed. Your bomb-carrier cannot 
be much faster than ninety miles an hour 
— slow ,as speeds go nowadays. Such craft 
must be protected by fast fighting'machines 
during a long over-land flight to some 
hostile railway junction which is to be 
wiped off the map. Your scout and artil- 

lery-fire control machine must stay aloft 
for hours; it must carry much fuel; there- 
fore, while it may be faster than a bomb- 
carrier, it cannot be designed for high speed.- 
Slow machines must be protected from 
attack on overland journeys by fast fighters. 
And so the fighting machine was evolved 
— a marvelously swift machine, making as 
much as 130 miles an hour and as quick as 
a dragon-fly in darting and twisting about. 
Reconnaissance, artillery-control ma- 
chines, fighters — all are armed with ma- 
chine guns. But only the fighters, single 
and double seated, are built specifically 
for combat. The others fight only when 
they must — in some situation of dire 

How a Difficult Problem Was Solved 

There was no fighting in the air during 
the Tripolitan and Balkan campaigns; but 
in this war there was air fighting almost 
from the beginning. At first rifles and 
pistols were used. They proved worthless. 
A machine-gun alone could be used effec- 
tively, something that would squirt death 
like water from a hose. But the use of a 

Popular Science Monthly 


machine-gun implied the building of an 
airplane able to mount and fire it. Now 
it was soon found that the pusher type of 
airplane, which carries its propeller in the 
rear, is not so fast as the tractor, which 
carries its propeller in the front. It was 
also found that for fighting, at least, 
quick-maneuvering ability is highly essen- 
tial, which implies a small, high-powered 
machine carrying only one man. Here 
was a very difficult technical problem to 
be solved: The fighting machine had to 
be a tractor for speed; the propeller in 
front necessarily interfered with the proper 
manipulation of the machine-gun; the 
officer in the pilot's seat had not only to 
keep his machine on an even keel but 
also to fight his gun. Had the military 
strategists of Europe been told before the 
war that these were the conditions that 
would have to be fulfilled, they would have 
dismissed them as absurdities at once. 
But by the middle of 1916, the requisites 
were so clearly recognized that they were 
met, and that with astonishing ingenuity. 

The Fast Fighting Machine Appears 

By the end 
of I9i5ithad 
been discov- 
ered that of. 
all the flying 
m ac h i n e s 
used by the 
Allies, the. 
fast racing 
of Morane- 
Saulnier in 
France and 
the speedy 
racers made 
by the two 
firms of Sop- 
with and Bristol 
in England were 
best adapted for 
air fighting, sim- 
ply because they 
had speed and 
dragon-fly ma- 
neuvering abil- 
ity. They were 
given more 
speed by equip- 
ping them with 
engines of one 
hundred and 

Photo Service See key diagram below 

Fast fighting machines have engines of 150 horsepower and 
more, and are strengthened to withstand enormous stresses 

fifty horsepower and even more, and they 
were strengthened so that they might 
withstand the enormous stresses set up in 
flight by engines so powerful. 

Curiously enough, the problem of firing 
through the propeller had been solved 
before the war by some imaginative in- 
ventor with more vision than is given to 
academically trained generals, and curi- 
ously enough it was solved in both France 
and Germany simultaneously. The solution 
was this: The gun was rigidly mounted in 
front of the pilot, and it was mechanically 
connected with the engine. A propeller 
revolves at about 1,200 revolutions a 
minute; a machine-gun fires at the rate of 
600 shots a minute. Let the engine fire the 
gun at just that fraction of a second when 
no propeller blade intervenes — that is the 

Because the gun is rigidly mounted, the 
air fighter must turn the entire machine 
toward his German enemy to fire it. The 
enemy does the same; for the German 
Fokker, an adaptation of the French 
Morane-Saulnier, is similarly designed and 
equipped with a fixed machine-gun. 

these fighters 
first ap- 
peared on the 
side of the 
Allies they 
drove every- 
thing before 
them. It was 
for the slower 
Germans to 
cope with 
them. Then 
the Fokker 
appeared . 
The m a- 
chines of the 
Allies were 
made still faster; 
the fighters be- 
came more skil- 
ful, moredaring; 
fighting tactics 
were evolved. 
As a result, the 
Allies have not 
only caught up 
with each Ger- 
man improve- 
ment but have 
surpassed it. 



Popular Science Monthly 

It is rarely that German machines — fighters 
or scouts — appear over the French and 
British lines; but the machines of the Allies 
are always over the German lines. That 
meant much at Arras. 

When these fast fighters first made their 
appearance there were some single-handed 
combats. A German and British charioteer 
of the air would wheel about, jockeying for 
a position in which, for a few fleeting 
seconds, either might pour in a hundred 
bullets at his enemy. It was a favorite 
maneuver of the German flyer to rise very 
high, to plunge down on an adversary, and 
to fire as he came. But Boelcke and Im- 
melmann were about the only flyers on the 
German side who were either skilful or 
daring enough to engage in frequent single- 
handed combats. As a rule, the Germans 
attacked a single British or French machine 
in twos and threes. The procedure may be 
attributed in part to the different tempera- 
ments of Germans and British and in part 
to military policy. 

Like Flocks of Birds the Squadrons 

The result has been that fighting in the 
air is now undertaken, as a rule, only by 
squadrons. Six machines, sometimes more, 
constitute an aerial tactical unit. Their 
pilot-officers live together, sleep together, 
eat together. They know one another 
better than if they were brothers. Every 
mental and emotional characteristic is 
bared. So it happens that in the air, when 
the six machines are flying side by side in 
twos, the men know instinctively what they 
are to do. Have you not seen flocks of 
birds on the wing, circling about with a 
unanimity of understanding that makes it 
seem as if they were obeying a command? 
It is so with the air fighters of a squadron. 
They move as one, like a flock of birds, with 
never a word of instruction. 

An engagement between opposing squad- 
rons in the air is not like a battle at sea — 
a fight between fleets. Around and around 
each other the planes whirr, each team 
following the leaders with clock-like pre- 
cision and automaticity. 

The opposing squadrons watch and watch 
each other. Woe betide the man who lags 
behind for a second, who manipulates his 
controls a little too carelessly; who is not 
quite en rapport with the team-mate in the 
machine beside him! Two machines of the 
enemy swoop down. He is cut off from 
his fellows, like a bird from its flock. He 

must fight now for his life. Up and down, 
in and out, he maneuvers with his foes. He 
shoots when he can — when a hostile ma- 
chine is directly in front of him. But his 
enemies outnumber him. He cannot out- 
maneuver two machines. One, at least, 
must sooner or later swing around into 
a favorable position. Then there is a squirt- 
ing of bullets. The machine drops, a mass 
of flame, three miles to the earth — a sicken- 
ing sight even to those who have been 
steeled to the horrors of the most horrible 
of wars. A charred, twisted mass of metal 
and wood is picked up. Within it is a 
scorched, torn uniform containing an un- 
recognizable, mutilated mass, all that re- 
mains of a brave man who was not quite 
quick enough, or whose mechanism failed 
him for a fatal fraction of a second. 

How the Airplanes Carry War 
Into the Atmosphere 

Whenever that terrible artillery prepara- 
tion takes place of which we read in the 
newspapers (the deadly hail of tons and tons 
of metal that precedes an attack with the 
bayonet) the fighting squadrons are high in 
the air — twenty thousand feet above the 
ground. Below them, at perhaps ten thou- 
sand feet, are the two-seated fighters and 
reconnaissance machines each patrolling a 
section of the enemy's line, taking hundreds 
of photographs. And below, at six thou- 
and feet, are the machines that control 
the artillery fire — machines that watch 
each shot as it falls and that wireless 
back the signal "too short" or "too long." 
Without the reconnaissance officers the 
scouts and the fire-controllers could not 
perform their task; they would be attacked 
and annihilated by fast airplanes mounting 
machine-guns. To be sure, they are armed 
themselves so that they can keep up a 
running fight. But on the daring, fighting 
squadrons far, far above the battle line, on 
them depends the fate of an army; on them 
depends the possibility of gathering the 
facts that the heavy artillery in the rear 
must have to fire at a mark ten miles 

To the all-seeing eye in the air, nothing 
is concealed. It is that eye which has made 
it utterly impossible for either side to 
execute a flanking movement that would 
envelop a whole army and compel a sur- 
render, that eye which has made it necessary 
for armies to burrow in the ground and 
face each other in a nerve-racking, soul- 
trying struggle. 

Popular Science Monthly 


A garden in which nothing but weeds can find a place. It is the one spot in all the world, perhaps, 
where weeding means cultivation of weeds. Later on, various exterminators will be tried on them 

A Garden in Which Weeds Are Not 
Only Tolerated but Cultivated 

" |_r*OR every evil under the sun there is a 
3P remedy or there is none," says the 
jingling rhymster, and leaves it to the 
scientist to find out whether there is or not. 
To find the remedy for weeds, the bugbear 
of every farmer and lover of growing things, 
a garden was planted at the Agricultural 
Experiment Station of the University of 
Minnesota and 175 different varieties of the 
pests were given honorable lodg- 
ment in the perfectly good 
soil. They grew. 
They thrived 
They bore abun- 
dant seed. 
They were 
classi f ied 
and a collec- 
tion of weed 
seeds was 
and listed. 
Then repel- 
lents and ex- 
were tried 
out on them. 

Film comedy has its queer moments, such as traveling in 
freak equipages and make-up in search of suitable landscape 

Taking Motion Pictures on the 
Road in a Queer Vehicle 

THE motion picture director is a 
creature of weird fancies. If he were 
otherwise he would not be a motion picture 
director. He lies awake nights worrying 
about ways for. doing something different. 
If he becomes hum-drum, if his ideas 
smack of the commonplace, his directorship 
is soon ended. 

The quest for novelty partly explains the 
freakish caravan on rubber 
tires which the accom- 
panying photograph 
shows. The pur- 
pose of the queer 
equipage is 
serious. It 
is seeking 
the right 
for a back- 
ground for a 
special com- 
edy, and is 
the camera 
and troop to 
the spot. 

Chasing Submarines with Motor-Boats 

By Prescott Lecky 

Boats for the purpose are built up 
in sections produced in immense 
quantities, like the parts of the low- 
priced, easily assembled automobile 

After the boats are assembled in the sheds they 
are launched directly into the St. Lawrence River 

WHEN England found the submarine 
was a menace that threatened to 
destroy her paramount position as a 
maritime power and a maritime nation she 
cast about her for a means of combating 
the underwater terror. One of her purchas- 
ing agents visited the New York office of 
Henry R. Sutphen, an official of a boat-build- 
ing company and a submarine company. 

"Why don't you try motor-boats?" sug- 
gested Mr. Sutphen, and proceeded to out- 
line the sort of craft he had in mind. The 
conversation resulted in a provisional order 
for fifty boats, given subject to the approval 
of the British Admiralty. Not only was this 
order confirmed, but a short time afterwards 
it was increased to five hundred and fifty. 

The boat called for was to be 80 ft. long, 
123^2 ft. beam, 4^ ft. draft and of 32 tons 
displacement. Two standard motors of 
220 horsepower were to drive her at a speed 
of fourteen knots for 850 nautical miles or 
nineteen knots for a distance of 700 nautical 
miles. The fuel capacity was to be 2100 
gallons, and the gasoline was to be con- 
sumed at the rate of one pint per horse- 
power per hour. She was to carry a crew of 
ten men, including gunners to operate the 
3-inch rifle mounted forward. 

Applying Automobile Manufacturing 

Naturally it would have been impossible 
to construct so many boats of such a large 

size in so short a time by the usual methods. 
The methods of the automobile factory 
were adapted to the shipyard. First, "the 
master boat" was built and every part that 
went into its construction was carefully 
measured and recorded on templates or 
wooden patterns. The templates were 
then sent to the shops and five hundred 
duplicate pieces ordered. Every one of 
these pieces was lettered and numbered on 
its arrival at the plant. Three machine 
shops were kept busy turning out the 
motors. Most of the woodwork was done 
in Bayonne, N. J. More than eight and a 
half million feet of finished lumber, sawed 
and dressed to the required sizes, was 
turned out by this shop. 

When arrangements had been made for 
the material, new yards on the St. Lawrence 
River in Canada were about completed. 
The plant consisted merely of half a dozen 
huge assembling sheds, and it was here that 
most of the ships were made. 

As the keels arrived they were put in 
their places along the floor, and the 
delivery of the various ribs, beams and 
parts was so timed that no storage space 
was necessary. Every effort was made to 
simplify operations and to avoid handling 
and carting the material more than once. 
For instance, as soon as the engine, anchors 
and chains arrived they were distributed 
immediately, an anchor being laid in front 
of each keel. 

Popular Science Monthly 

All told about fifty separate operations 
were necessary in putting these parts 
together ; for each task there was a separate 
gang of workmen who did nothing else. It 
was not advisable to build a permanent 
plant of this size equipped with cables and 
roof pulleys. 
Hence progres- 
sive assembling 
in the automo- 
bile sense could 
not be applied. 
Au tomobile - 
practice was re- 
versed. The 
boats remained 
while the men 
moved along. 
there was no 
essential diff- 
erence. So rap- 
idly were the 
boats corn- 

Some of the chasers were launched from the shed but others 
were made inshore and had to be brought to the ways by rail 

pleted by this method that the sheds were 
soon crowded, and extra keels were laid 
outside. Some of the boats were launched 
directly from the shed while others were 
placed on railroad trucks and carried to the 
ways. Every vessel was thoroughly tested 
by British Naval inspectors before it was 
accepted. The boats were shipped to 
England on the decks of ocean steamers, 


four chasers being carried on one liner. 
Since the war began, the production has 
increased from three boats a year to three a 
day. Five hundred and fifty submarine 
chasers, eighty feet in length, were com- 
pleted in less than five hundred and fifty 
days from the time the con- 
tract was signed. Perhaps 
the most surprised wit- 
ness of this accom- 
plishment was the 
British Admiralty 
itself. And Eng- 
land, as every- 
one knows, is 
the greatest 
maritime na- 
tion of the 

An idea of 
the tremen- 
dous amount 
of detail that 
had to be 
looked after 
in this under- 
taking may be gained from the following 
brief list of figures: 550 gas stoves, 2,200 
fire extinguishers, 2,200 sailing lights, 550 
life boats, 550 searchlights, 25,000 incandes- 
cent lamps, 974,504 bolts and nuts, 3,850 oil 
lamps, 13,200 canvas covers, 22,000 storage 
batteries, 109,450 ft. of brass pipe, 611,000 
ft. of manila rope, 33,200 running yards of 
deck canvas, 16,500 port lights, 1,650 sinks 

iP ljl !il,llllll!l 

When the sheds in which the boats were assembled were filled, additional keels were set up 
outside. Here some of the boats are shown in an advanced stage, almost r^ady for launching 


Popular Science Monthly 


r ^ c 


'.-«- •_-■_■..-- - .. "-'"■' •" 

Picture continued on next 
Some of the finished boats ready for inspection. Each boat was thoroughly tested in the St. Lawrence 
River before being accepted. Arranged as in the photograph the five hundred and fifty boats 

and wash basins, 11,550 ventilator cowls, 
1,650 toilets, 325,000 ft. of wire rope of 
various kinds and 450,000 pounds of paint, 
varnish and putty. 

Will Every Coast Dweller Own a 

In the assembling operation alone more 
than 3,000 men were employed, and about 
9,000 others were scattered in the various 
workshops fabricating the material before 
it was sent to the main plant. This is the 
first time that the principles of standardiza- 
tion, division of labor, and progressive 
have ever 
been applied 
with any 
to shipbuild- 
ing. There is 
no reason, 
however, as 
this success- 
ful experi- 
ment proves, 
why motor- 
boats cannot 
be turned out 
enough to 
make them 
as available 
to the aver- 

age citizen as is the popular-priced car. 
The movement toward standardization 
began in 1905, when Mr. Sutphen's com- 
pany built 120 twenty-one-foot mine-yawls 
for the United States War Department. 
The same company two years later built 
33 thirty-foot mine layers on standard 
lines, and during the next six years turned 
out no thirty-six foot power life boats for 
the United States life-saving service. 
Probably the largest motor-boats ever 
built according to uniform design were two 
98-foot yachts, made in 1910. Others who 
have made experiments along the same line 
are a company 
that turned 
out a number 
of thirty- 
footers, and 
another that 
has been 
twenty- foot 
steel motor- 
boats in fairly 
large quanti- 
ties on stan- 
d.ard pat- 

It should 
not be imagin- 
ed that these 

About fifty operations were involved, each requiring 
a separate gang of men. Here is the "ribbing gang" 

subm a rine 
chasers built 

Popular Science Monthly 


Channel and the North Sea, and while their 
sea-keeping qualities are excellent, never- 
theless they do not carry enough food and 
fuel to last more than ten days. On the 
other hand, however, a boat of this size 
painted gray is invisible at a distance of 
more than three miles, so that it is often 
possible to catch the submersible unawares. 
The boats are intended for offensive opera- 
tions almost entirely, though of course they 
would make good convoys near the coast. 

The British have discovered that fighting 
the submarines is a question first of all of 
endurance. A larger chaser would be more 
comfortable, of course, but by no means so 
dangerous to the submarine. 

covered eight miles. End to end they would 
form a chain nearly twenty-five miles long 

for England were motor-boats in the 
ordinary sense. They were really yachts. 
The interior design from bow to stern was 
as follows: 

Chain locker, lavatory for crew 
forecastle for eight men, am- 
munition room, large fuel 
tanks, engine room, gal- 
ley, mess room, office 
state room for two 
and additional tank 
capacity in the ex- 
treme rear. On 
deck there was a 
platform forward for 
a three-inch gun. 
Behind this was the 
chart house, and 
further back still the 
bridge where the 
steering apparatus 
and engine telegraph 
were located. 

One feature of this 
boat is an arrange- 
ment by which the 
steering lines are laid 
along the side of the 
deck from the wheel, 
making them easily 
accessible for repairs. 

The chasers were 
designed for service 
in the English 

The buoyancy of 
you from sinking 

A Board Which Will Help You 
Learn to Swim 

A SWIMMING board invented by 
William H. Roberts, of Newburyport, 
Massachusetts, is a help in learning how to 

The device is nothing more than two 
warp-proof boards of pine which are 
fastened together at a very large angle. 
The swimmer straddles these at the narrow 
junction of the boards. Lying with his 
body flat upon the front board and 
resting more or less upon the 
saddle board, he is buoyed 
up in the natural position 
for swimming. He 
learns the leg strokes 
first and then the 
arm strokes, and he 
rests back upon the 
boards whenever he 
becomes tired. By 
keeping his legs 
going slightly, the 
board is kept from 

The buoyancy of 
the boards helps 
him to ride the 
waves and contrib- 
utes to his enjoy- 
ment. Since there 
is no danger to fear, 
confidence is soon 
gained and the 
swimming strokes 
are mastered in 
short order. The 
swimming board 
the boards prevents » used purely for 

below shoulder level Sport, also. 


Popular Science Monthly 

the operator then presses another 
button to return the money to the 
caller, just as in other pay- telephone 

This accessory has a credit fea- 
ture, however, which is unusual. 
In case the tenant is out of change, 
the operator releases a brass check 
of the size of a nickel from the coin 
box. The tenant uses this, and 
when the manager comes around to 
collect the coins deposited, the 
tenant redeems these from him. 

The tenant depos- 
its a coin in a slot 
just as in a public 
telephone. This is 
carried to the coin 
box when the con- 
nection is made 


Changing the Apartment Telephone 
into a Pay-When-You-Call System 

ANEW telephone device deserves a 
Carnegie medal for furthering the 
cause of universal peace between tenants 
and apartment house managers. It enables 
the manager to collect at the time of the 
calling, and protects him and the 
tenant as well from being over- 

The coin-collecting device works 
entirely independently of the regu- 
lar telephone system. Thus, 
the tenant calls the operator's 
switchboard in the apartment 
house lobby and is connected 
with central just as usual. 
But before the operator ac- 
tually connects the tenant with 
central, she connects the coin- 
collecting box in the tenant's apart- 
ment with a recording box on her 
switchboard prefacing the action 
with a request for "Five cents, 
please." The recording box signals 
her the instant the nickel is placed 
in the collecting box. If central 
obtains the person called, the opera- 
tor then connects him with the 
tenant, and by pressing a button, 
deposits the nickel in the coin box. 
If the person called cannot be found, 

Be Thou Wary of the 
Bubbling Cup 

APR9FESSOR in a western 
university has discovered that 
small organisms lodge in a great 
many kinds of bubbling-cup drink- 
ing fountains, and for a curious 
reason based on an ancient physical 

Twenty-five years ago writers of 
textbooks on physics had not the 
wealth of material to draw from 
that is now available. In carrying out one 
of their few experiments a rubber-tube-and- 
spout arrangement was prepared in such a 
way that it could be attached to an 
ordinary water faucet and a small jet of 
water was projected directly upward. In 
this jet a small ball would be placed — 
and, curiously enough, would remain in the 
air, almost stationary, held up by 
the jet. The jet seemed to clutch 
the ball and hang onto it instead of 
throwing it away. The stream 
would divide under the ball, 
come up equally on all sides 
and hold it in place. The 
sphere might oscillate up and 
dtown slightly, but otherwise 
it appeared to be settled per- 
manently in place. 
The western 
professor men- 
tioned has dis- 
covered that ba- 
cilli may oscillate 
up and down in 
some kinds of 
bubbling cups all 
day long, day after 
day — in the same 
way and for the 
same reason that 
the sphere did in 
• the old-time jet. 

The principle 

in accordance 

with which the 

ball is held up 

in the jet 

of water is the 

same as that of the germs 

held in the bubbling fountain 

Popular Science Monthly 


FREIGHT CAR 34'4'xa 1 

PORCH 34 'X 8' 



34V X 8' 


Dining room 


34 4* 


34 4 X 34 4 


50'x 6 ' 

Plan and finished appearance of the box-car hotel. There are eight guest rooms and the land- 
lord's apartment, besides hotel kitchen and storeroom. The two-story effect is only simulated 

Owens Valley, California, Has a 
Freight-Car Hotel 

OWENYO is a railroad junction point in 
Owens Valley, California, east of the 
Sierra Nevada Mountains. Mining and 
agricultural development have made it 
important. But it had no hotel. George 
Brown built one with the best material that 
he could find. He couldn't get steel for a 
frame or onyx for a foyer, but he could get 
box cars. So he built his hotel of box cars. 

Standard box cars are thirty-four feet 
four inches long, eight feet wide and 
eight high. Three of these 
unwheeled and with proper 
foundation, were placed in 
the form of a hollow 
square, inner corners 
connecting, with the 
open space facing the 
tracks. In this open- 
ing a front was built, 
with double doors 
and large windows. 
The center is a din- 
ing-room thirty-four 
feet four inches square 
well floored, and lighted 
by many windows in a 
superstructure which 
gives the appearance of a 
second story. Across 
the front is a fifty-foot 
porch eight feet wide and 
across the rear another. 
Behind that is a fourth car, constituting the 
residence of the landlord and his family. 

Each of the side cars is divided into three 
comfortable bedrooms, and at the rear, on 
either side, another guest room is built in, 

making eight guest rooms in all. The rear 
car in the building is the kitchen. 

The entire building is metal-roofed, 
plaster-board finished and paneled through- 
out the interior. Every room has a large 

of St. Paul, 

A float on the rising water lifts a lever 
which operates the alarm mechanism 

Turn on the Water in Your Bath. It 

Can't Overflow. This Alarm Will 

Warn You in Time 

M innesota, 
has devised an alarm 
which tells you when your 
bathtub has been filled to 
whatever depth you de- 
sire. Instead of having 
to watch the rising 
water, you simply ad- 
just the alarm and 
let it do the rest. 

A light hollow 
float is suspended in 
the water by a verti- 
cal iron rod. The 
rising water raises the 
float nearer and nearer to 
a horizontal lever con- 
nected with a bell. When 
the rod rises high enough 
its upper end touches the 
bell trigger. 

A spring is immediate- 
ly released by the trigger, 
a clapper is brought into action and the 
bell rings. By adjusting the height of the 
bell mechanism, the height to which the 
water must rise to sound the alarm can 

be regulated as desire^. 

A Ten-Ton Motor-Truck on Eight Wheels 

It combines the greatest possible carrying capacity 
with the high speed and easy riding of lighter trucks 

The eight-wheel truck is mounted on two sets of four wheels each, with tires of the pneumatic 
type. This arrangement provides an easy-riding vehicle of great stability and carrying capacity 

THE novel motor vehicle shown in the 
accompanying illustrations is mount- 
ed on two trucks, patterned after the 
old-fashioned four-wheeled railway coach 
truck, having eight supporting wheels in all. 
Each wheel helps to drive the vehicle, 
which is thus always able to secure traction, 
since it is extremely unlikely that all 
eight wheels would be mired at once. 

Because of the large number of support- 
ing wheels, the tires may be of the pneu- 
matic type, even for as large a vehicle as 
a ten-tonner. The use of such tires instead 
of the solid-rubber type, which must now 
be fitted on the conventional ten-ton 
vehicle, would cushion the driving mechan- 
ism to such a great extent that the vehicle 
could be run with safety at greatly in- 
creased speeds. This is in line with the 
most advanced trend in vehicular trans- 
portation, which is to carry as large unit 
loads as possible at the greatest speed 
compatible with safety. Large loads on 
one vehicle take the place of smaller loads 
on a larger number of vehicles of less 
capacity. This substitution means less 
traffic congestion, which is one of the 
greatest problems the police forces of our 

most important cities have to contend with. 

Aside from the advantages of carrying 
large loads at fast rates of speeds on 
pneumatic tires and of being able to secure 
the necessary driving traction at all times, 
even on bad roads, the eight-wheel ar- 
rangement also provides an extremely 
easy-riding vehicle of great stability and 
one of extremely short turning radius, 
since in the case of the vehicle shown, all 
the wheels are mounted so as to turn for 

In detail, the vehicle is mounted on two 
sets of four wheels, each set carried on a 
suitable cross-frame member. Each cross 
member has two arms on each end. Each 
end is made into the shape of a yoke to 
carry a wheel on a vertical spindle. This 
spindle simply serves to support the wheel 
so that it carries its share of the vehicle 
load and so that it can be turned in steering. 

The power for revolving the wheels is 
secured from a conventional gasoline motor 
placed off the center line of the vehicle 
to the right at the front. The motor shaft 
extends aft of the crankcase in the usual 
manner and transmits its power to a four- 
speed gearbox located between the front 


Popular Science Monthly 


and rear sets of wheels by means of a short 
driveshaft. The power is in turn trans- 
mitted through the gearbox by means of a 
silent chain drive to two shafts, one extend- 
ing forward from the front of the gearbox 
and the other aft from the rear side. Each 
of these shafts 




these meshing 
with large worm 
wheels and dif- 
mounted on 
axles which 
simply drive 
each pair of op- 
posite wheels, 
but do not sup- 
port any of the 
wheel load. Each 

the center. The separate lever serves to 
turn the vertical turn-bolt as the driver 
turns his hand-wheel to steer. Additional 
rods attached to one end of the two-armed 
bar lead to the front set of wheels, and 
other rods attached to the opposite end 
lead to each op- 
t " 


Diagram showing the driving and steering arrangement 
of the eight-wheel truck. All wheels turn for steering 

posite pair of 
the rear wheels. 
Thus as the 
turn-bolt is re- 
volved, causing 
the two-armed 
bar to revolve 
about its pivot, 
it makes the 
front truck 
wheels turn in 
one direction 
and the rear 
wheels, con- 
of the supplementary trolled from the opposite end, in the re- 
driving axles is divided into two parts on verse direction, thus giving a very short 

each side, these parts being joined by means turning radius. 

of universal joints so as to permit relative 

motion between any of the wheels of each 

truck, as when passing over road obstruc- 
tions, without binding any of the driving 


The motor must be placed rather 

high so as to clearthe front 

of the front truck. The top 

the motor extends up into th 

driver's cab and is covered 

by a removable metal hood 

The driver sits on one 

side of the motor and the 

helper on the other. This 

construction permits the 

driver's seat to be placed 

well forward, which in 

turn allows a longer 

body on the same 

length of chassis than 

would be the case in 

the usual construction 

with the motor under a 

hood out in front. 

All of the wheels are 

arranged to turn for steer 

ing, this being accomplished 

through one steering wheel 

and column by attaching the 

steering crank by means of a 

rod to a vertical turn-bolt 

carrying three arms. One of 

these arms is a separate lever, 

while the other two really 

comprise one bar pivoted at 

To Make Your Lawn Attractive You 
Must Edge It Evenly 

AN improvement on the ordinary 
. lawn edger has been invented 
Christian L. Schneider, of 
Davenport, la. It not only 
dges the lawn neatly but 
cuts a trough at the same 
time at a regulated depth. 
The edger consists of a 
J-shaped knife carried 
on an arm which ad- 
justs it to any height. 
One of the wheels of 
the edger runs on the 
path surrounding the 
lawn, with its outer 
flange pressed 
against the asphalt 
so as to insure a 
straight line. The 
other wheel is ar- 
ranged so that it will 
keep parallel with 
the wheel on the 
path, whatever 
irregulari ties 
may occur in the 
lawn over which 
it travels. This 
makes it easy to 
push and insures 
a straight edge. 


The outer wheel presses against the 
edge of the path to insure a straight 
line. A trough is dug at the same time 


Popular Science Monthly 

An Adjustable Rake for the 
"Land Patriots" 

Eliminating the Noise from 

ALL contributions to 
l\ the cause of agri- 
cultural preparedness 
will be gratefully re- 
ceived! Especially 
when they are as good 
as the adjustable garden 
rake that is shown in the 
accompanying illustra- 
tions. Instead of hav- 
ing to use a number of 
different sized rakes to 
fit between rows of diff- 
erent kinds of vegetables, 
you can adjust this one 
rake to suit all purposes. 
All the teeth of the rake, 
excepting the central 
one, are riveted to two 
rectangular side-frames 
pivoted to an iron socket 
on the end of the rake 
handle. When weeding, 

4 • '^^! -iff 


O 1 

When the central tooth is re- 
moved the rake will straddle the 
small shoots. Then both sides of 
the row can be worked at one time 

Above: The side teeth 
adjusted to a narrow 
row. At right : The 
rake opened out 

or when loosening the ground between rows 
of potatoes, for instance, the side bars are 
swung around until they aline. The rake, 
thus opened to its fullest width, is then 
locked in this position by the wing nuts 
shown. When cultivating onions, on the 
other hand, the angle between 
the side bars can be reduced to 
adjust the rake to the smaller 

When the sprouts are 
young, this rake can be 
used for cultivating both 
sides of the row at one 
time. The central tooth 
may be unscrewed and 
taken out making it 
possible for the rake to 
operate on both sides 
of the small shoots. 

Railroad Traveling 

NE railroad at least 
has solved the 
noise problem. Much 
to the delight of the 
passengers, the "Bur- 
lington Route" has 
rooted out the grinding 
of wheels, the creaking 
of axles, and the other 
noises usually attendant 
upon traveling. They 
have accomplished this 
by installing a sound-, 
proof flooring in their 
new steel cars. A layer 
of hair felt one inch 
thick, a layer of spec- 
ially prepared paper, 
and a half-inch air space 
separate the steel floor 
of the car from the 
steel sub-floor nearer 
the ground. The sounds 
coming from the wheels 
are practically all ab- 
sorbed by the insulating 
layers. Especially in 
traversing the loosely 
packed felt, the sound 
vibrations are readily 
lost in the loosely 
connected fibers, 
so that they will 
never reach the 
ears of the 

Combining a Strainer with the 
Bung of a Barrel 

A BARREL attachment which serves 
as a bung and a strainer in one has 
been devised by William R. Brison, of 
Tompkinsville, New 
York. Screw the at- 
j^^^^^^^^ tachment into the 

barrel and contents 
can be drawn through 
an exceptionally fine 
strainer, without re- 
tarding, the flow. 

The attachment 
consists of a hollow 
steel head that sup- 
ports the cheese-cloth 
The cheese-cloth strainer extends back covered wire frame- 

into the barrel like a long, hojlow tube work of the strainer. 

Popular Science Monthly 



Counting the Moisture 
Drops in a Fog 

have hitherto been crude. 

But an example of more re- 
fined measurements of fog has 
recently been afforded by experts 
of the United States Bureau of 
Standards. The measurements 
were made in the most notorious- 
ly foggy region of the world — the 
Grand Banks of Newfoundland. 

The tiny drops that constitute 
a fog are smaller than raindrops. 
They are formed by the conden- 
sation of the gaseous water in the 
air, known as water vapor. Each 
drop condenses about a "nucleus" 
— consisting of some substance 
other than water. The air always 
contains an immense number of 
nuclei, ready to form centers of condensa- 
tion, when the conditions of temperature 
and moisture are right for this process. 
A method of counting these invisible 
nuclei was devised by John Aitken. It 
consists in causing a drop to form around 
each nucleus in a sample of air, and then 
counting the drops through a microscope. 

Another process, devised by Carl Barus, 
makes it possible to determine the size of 
the drops. When a light is viewed 
through a cloud or fog it is seen 
to be surrounded by a colored 
ring, called a "corona 
You have seen such rings 
around the moon and 
around street lamps at 
night. The angular di- 
ameter, or aperture, of 
these rings depends up- 
on the size of the drops. 
Small drops produce big 
rings, and vice versa. 

The apparatus of Ba- 
rus was installed in the 
pilot-house of the Seneca, 
and the number of nuclei 
present in a given volume of 
air was measured three times 
a day, whether the weather 
was foggy or otherwise. A 
sample of air was drawn 
through a pipe, projecting 
from the port bow. It was 
admitted to a "fog chamber," 
saturated with water vapor, 
suddenly expanded, to con- 
dense water on the nuclei, 

Instrument for measuring the tiny drops of fog. Sixty 
billion drops equal one -seventh of a glass of water 

forming an artificial fog. The corona 
around a source of light, viewed through 
this fog, was measured, and the size of the 
drops was determined from the known 
amount of moisture in the chamber. 

Martha's combination umbrella 
and rain -cape. Even the 
dog can crawl under cover 

A Twelve-Year-Old Girl's Combina- 
tion Umbrella and Rain-Cape 

A LITTLE girl, Miss Martha Bachman, 
who lives in Chattanooga, Tenn., has 
evidently suffered the discomfort of 
wet stockings caused by the 
flapping of her just-so-long 
rain-cape against her legs 
on her way to school, as so 
many other little girls 
have done in days gone 
by. But Martha has an 
idea for eliminating 
such discomfort from 
future rainy days. 

Her idea is to attach 
a cape of oil-cloth or 
rubberized material to 
the rim of the umbrella 
with snap-fasteners, but- 
toning it down the front 
in ordinary rain-cape fash- 
ion. An isinglass window 
at about the level of the eyes 
would prevent the wearers 
of such an umbrella-cape 
from bumping into each 
other on the street, like 
pilotless ships. In this way 
books could be protected 
from the rain also and the 
hand holding the umbrella. 

Can the Railway Train Be Made Noiseless? 

"Yes," say the inventors, "by improving the wheels." 
"No," say the engineers, "unless you perfect the road-beds" 

By Marius C. Krarup 

wheel among those illustrated, it is well 
to remember that flexibility makes a 
constant demand on the power of the 
locomotive. In the Kinsman wheel 
the main object of inserting a non- 
metallic substance is to insulate the 
wheel and the car from the rail elec- 
trically, this being a requirement in 
some forms of electric railway service, 
and this represents a new angle of the 
subject having little to do with the 
other efforts. The Lindblad wheel, on 
the other hand, is a cushioned and anti- 
noise wheel with special wiring to pre- 
vent it from becoming non-conductive. 
The most radical and effi- 
cient method for securing 
comparatively noiseless op- 
eration as well as saving of 
road-bed and rolling stock, 
according to modern traffic 
engineers, comprises thor- 
ough grading, draining and 
ballasting of the road-bed, 
smooth hard rails of ample 
dimensions, manganese steel 
rails at crossings, frogs and 
improved design of 
switches, accurately con- 
insuutio* centric wheels and car 
springs with well damped 
flexible pad' and governed -rebound. 

At left above, the Lindblad wheel; These would reduce noise 
at right above, the Kinsman wheel and improve the service. 

The Maginn wheel is built up in 
sections secured together by 
bolts or rivets for flexibility 

THE idea of producing a 
noiseless rail wheel, and 
even making it distinct 
ly flexible to reduce the 
wear and tear of the roll- 
ing stock has seemed a 
good one to some in- 
ventive minds, and they have 
proceeded to patent their con- 
ceptions. These are all char- 
acterized by a noise-deadening 
and more or less elastic sub- 
stance which is inserted between 
the flanged rim and the hub 
portion of the wheel; by some 
provision to prevent the rim 
from slipping round on the inserted 
material, and by guide plates on the 
sides to hold the hub and rim in aline- 
ment. The details can be followed 
without difficulty in the accompanying 
illustrations but are subordinate in 
interest to. the question whether the 
whole plan is practicable. It is next 
to impossible to make the "built-up" 
wheel as cheap or as strong as the one- 
piece construction. It is almost hope- 
less to try to introduce a wheel which 
is after all only a little less noisy than 
those in use, unless it pays for itself 
from the start through savings in other 
directions. If the wheel is frankly 
intended to be flexible, as the Maginn 

The Madden sound-deadening wheel also has a 
flexible pad which fits like a lining around its rim 


The head and body 
of the suit are of 
cast metal riveted. 
The arms and legs, 
however, are of can- 
vas reenforced by 
coils of strong metal 
tubing. Flexibility 
is thus given them 
while their ability 
to protect the limbs 
from being crushed 
by the enormous 
pressure of the wa- 
ter is not impaired 

The heavily laden 
divers are lowered 
by single steel cables 
which enclose the 
telephone wires 
through which the 
orders are trans- 
mitted. Oxygen 
apparatus is at- 
tached to each suit. 
In this enough oxy- 
gen is stored to last 
for eight hours. The 
weight of the suit 
is an advantage 


Salvaging in Armor 

/%S a diver goes down, the water pressure in- 
J-\ creases at the enormous rate of over three 
tons a square foot for every one hundred 
feet. This water pressure is overcome by supply- 
ing the diver's lungs with air of an equal pressure. 
Evidently, the air pressure has to be increased the 
farther down the diver goes; but if at any time 
this pressure becomes either more or less than the 

water outside, the diver will be injured or even 


This danger is entirely done away with by the 
armored diving suit invented by B. F. Levitt, of 
Toledo, Ohio. His suit entirely separates and 
protects the diver from the water. Manganese 


Popular Science Monthly 


bronze, which is as strong as steel but not so 
likely to rust, has enabled the inventor to 
descend to one hundred and twenty feet 
below the depth attained in the former 
world's record of three hundred and sixty- 
one feet. The great strength of this bronze 
was found capable of withstanding a 
crushing pressure of some eleven tons per 
square foot. In marked contrast to the ex- 
perience of the three divers who made the 
former world's record — one died shortly 
after — Levitt experienced no hardships 
whatever. The air was supplied from an 
oxygen apparatus attached directly to the 
back of the diving suit. 

The body and the head-piece of Levitt's 
suit are of cast metal and are riveted 
together. The legs and arms, however, are 
of canvas so that they can be bent while the 
diver is working. These are prevented 
from collapsing under the water pressure by 
closely wound coils of strong bronze tubing. 
The water-tight joints at the shoulders, 
ankles and wrists run in ball-bearings so the 
pressure cannot cause them to jam. 
Obviously, the suit must be very heavy. 
This fact is by no means a drawback, how- 
ever, since every bit of the armor's weight 
is required to make the suit sink down 
straight. After the suit has been assembled 
on the diver, he is lowered into the water by 
a steel cable unwinding from a derrick on 
the salvaging boat. This cable also serves 

the purpose of hauling the diver up after- 
wards. Small telephone wires form the 
core of the cable and connect the telephone 
apparatus strapped to the diver's head with 
similar apparatus on the salvaging barge. 
Powerful electric lights and carriers for the 
loads are lowered with the diving corps. 
This method will be used in an attempt 
to salvage the Pewabic, which went down 
in Lake Huron nearly fifty years ago. 

Dummy Guns and Turrets Train 
England's Gunners for the Sea 

WHEN England trains her gunners for 
the sea, she sends them to Whale 
Island in Portsmouth Harbor. Here the 
entire island is given over to steel sheds 
which are built like gun turrets on a battle- 
ship. The great guns projecting from these 
sheds are dummies, though they are exact 
counterparts of those on a battleship. The 
prospective officers and men are made to go 
through the exercise of range-finding, 
loading, aiming and "firing" these guns as 
rigidly as if they were in a real battle at 
sea. The heavy steel projectiles are hauled 
from the magazine by hydraulic and 
electric cranes just as in an actual ship. A 
real breech mechanism locks the projectile 
and its powder charge in the gun while an 
intricate swivel mounting of steel swings 
the gun into the firing position. 

The great guns projecting from these sheds are dummies, though they are the exact counterparts 
of those on a battleship and can be loaded, aimed and "fired" by the recruits in training 

Popular Science Monthly 


The Straw Hat for Storms. The 


Top Turns Inside Out 

STRAW hat which can be taken out 
in the fiercest storm with impunity is 
a recent inven- 
tion of William 
Wilson, of New- 
ark, New Jersey. 
There is nothing- 
exceptional about 
the straw. The 
top of the hat, 
however, can be 
turned inside out. 
The folded water- 
proof covering 
that is thus ex- 
posed can be 
drawn over the 
entire upper sur- 
face of the hat. 
Ordinarily the 
waterproof cover is concealed beneath a 
cloth lining under the top. An elastic band 
keeps the lining drawn up tight. 

When it rains, the top of the 
hat is swung around and the 
elastic covering carried 
underneath the lid is drawn 
down over the entire hat 

Arthur Picard, a resident of New York 
city. It is in three sections — a handle, a 
sliding support for the pad, and the pad 
itself which may be of bristles or of ab- 
sorbent material. The sliding support has 
side jaws which 
clamp the pad 
securely in place 
when the ring 
shown on the 
tapered portion 
of the handle is 
pushed up as far 
as it will 
go on the 
p a d - 
To re- 
lease the 
pad, the 
ring is 
si ipped 
down on 

the handle, and the tongue in the groove of 
the pad-support is pushed up. This expels 
the pad from the groove. 

A Toothbrush for the Sick- 
Removable Pad 

It Has a 

The pad may be 
made of bristles or 
of absorbent ma- 
terial. It is ex- 
pelled from the 
groove and im- 
mediately destroyed 

The Private Hairbrush — The Bristles 
Can Be Locked Up 

APPARENTLY only one man of 


one man 
genius in all the United 
States has been able to 
remain unaffected by the 
zip-boom-bang of guns 
and war news and to ap- 
ply his talent to the cry- 
ing needs of everyday and 
home. He has invented a device for 
locking up his hairbrush to protect it 
from the other boarders in the house ! 
It is in the form of a cover tacked to the 
back of the brush and with overlapping 
sides which fasten with lock and key. 

THE toothbrush of an invalid 
should be destroyed after a 
single use. That is the practice in 
the more carefully conducted hospi- 
tals. Ordinarily this would necessi- 
tate having on hand a goodly supply 
of brushes if the patient's teeth are to 
be properly cared for. With the type 
of brush shown in the illustration, however, 
only the pad, or bristles, need be destroyed. 
The handle may be sterilized and used as 
long as it lasts. 

The brush is the invention of Alphonse 

Flexible brush covering ■ 

The cover is tacked to the back of the brush. The 
sides fold over and are fastened with lock and key 


Popular Science Monthly 



Iff fflKQll 


j i fj^^^^J 

1 1 Bill ^H 

ui :f 


The coat is fastened together in sections so 
that it pulls apart readily when caught 

A Safety Coat for Workmen. It 
Pulls Apart in Sections 

TWO million machineshop workers in 
the United States read safety bulletins 
each week and operate machinery equipped 
with every kind of safety appliance which 
money will buy. Yet not a week goes by 
but several careless workmen are in- 
jured and one or two killed outright be- 
cause of their own reck- 
lessness. One of the most 
common forms of acci- 
dents is the catching of 
loose and exposed gar- 
ments in revolving shafts, 
pulleys and other moving 

Only recently a man 
wearing a ragged sleeve 
while turning a bolt on a 
machine in an Omaha 
shop was stripped to his 
waist. By a miracle his 
life was saved. Had he 
worn the safety garment 
illustrated on this page 

he would have lost part of the coat only. 
Herbert P. Andrews, of Portland, Oregon, 
the inventor, has designed the coat in sec- 
tions in such a way that any unusual pull 
on any particular section will detach it 
bodily from the rest of the garment. 

The coat is not sewed together at the 
seams, but is fastened, one section to the 
other, by snap fasteners. Thus any section 
may be detached without tearing the rest 
of the garment or endangering the life of 
the wearer. If the workman is fortunate 
enough to see the machinery catch his coat, 
he can pull himself away instantly, losing 
only one section of the coat. The snap 
hooks and fasteners do not detract from the 
general appearance of the coat, and it 
meets all the demands for ordinary wear. 

Motor Attachment Which Prevents 
Injury to Rowboat Screw 

WITH the marketing by a Western con- 
cern of a tilting motor attachment, 
the motor-driven rowboat comes into its 
own. In the past when beaching the boats 
or when passing through shallow water, the 
propellers of rowboats using motor power 
were endangered. In a boat of such light 
draft as the rowboat, the propellers have 
to be held below the bottom of the boat to 
afford it sufficient "push." This, of course, 
is unsafe; for in beaching the boat, or in 
passing a rock or a snag in shallow water, 
the propellers are likely to be snapped off 
or bent out of alinement. 

The tilting motor attachment prevents 
such an accident. The entire propelling ap- 
paratus is mounted on 
the flexible tilting attach- 
ment, so that if anything 
strikes against the back 
of the propeller the ap- 
paratus automatically 
tilts up and the pro- 
peller clears the obstruc- 
tion without injury. 

If the low-sunken 
propellerhits a rock 
it swings up on its 
tilting attachment 
and clears the ob- 
struction in safety 

Popular Science Monthly 

It Stormed; So the Funeral 

Was Conducted by 


FROM Wisconsin comes 
the report of a funeral 
by telephone. A Methodist 
minister, of Oakfield, died 
and his bishop was to deliver 
the funeral sermon. But a 
severe storm came on and 
the bishop, who was on his 
way, saw no chance of getting 
to the village, since traffic was 
stopped on the short branch 
line leading to the place. 
Stopping at a farmhouse to 
telephone his predicament to 
the waiting family, he decided 
to conduct the service over 
the telephone, one of the 
members of the family re- 
peating his words to the 

Compressed air pumped into the cylinder rapidly vibrates 
the cutting bar as would a short-stroke reciprocating engine 

The Last Word in Fountain Pen 
Efficiency — An Eraser Attachment 

IF you should make a mistake while 
writing, the fault is yours, not your 
pen's. However, your pen may be made to 
correct the mistake very neatly. Daniel R. 
Markley, of Lancaster, Pa., has devised a 
plan for attaching an eraser composed of 
threads of spun glass to the top of the 
barrel of any ordinary fountain pen. 

The spun-glass threads are encased 
in a cup which is held in another 
cup which screws on to the bar- 
rel of the pen and is covered 
by a cap resembling the 
one which covers the pen. 
The inner walls of the 
cup holding the bristles, 
or threads, converge at 
the outer end so that 
the bristles are held in 
a compact little bunch, 
as shown in the illus- 
tration. As the bristles 
at the end are worn away 
the remaining lengths 
may be fed through auto 
matically by screwing the 
cup further up. 

The addition of the 
eraser does not alter the ap- 
pearance of the fountain pen 
in any other way than by 
slightly increasing its length. 

Bristles of spun glass are fast- 
ened in a cup threaded on the 
barrel of the pen for an eraser 

Removing Iron Rivets with a Pneu- 
matic Hammer 

THOUGH the pneumatic hammer has 
long been used in structural steel work 
to shape the heads on red-hot rivets, the 
old hammer-and-bar methods are still used 
in removing the rivets. A pneumatic 
hammer has been invented, however, which 
removes fifty times as many rivets in a 
given time. 

In the time that one hammer 
stroke can be given by a man, the 
pneumatic hammer gives several 
hundred. The long cutting 
bar is attached to a piston 
in a long cylinder. Air is 
pumped to the cylinder 
under pressure of one 
hundred pounds per 
square inch, and it im- 
• mediately vibrates the 
bar violently. When 
the crew press the 
hammer against a rivet, 
the pounding knocks 
the rivet's head off al- 
most instantly. 

This method of cutting 
is not only easier for the 
men, but it saves seventy- 
five per cent on the cost 
of the hand method. More- 
over, it can be used in ordi- 
narily inaccessible places. 

Giving Convicts a Real Chance 

How the Prison Farms of Florida have 
superseded the inhuman leasing-out system 

By Ewing Galloway 

A gang of convicts at Bradford Farms grading a lot for an electric powerhouse, ice plant and steam 
laundry. One of the two locomotives belonging to the prison is seen in the background 

A FEW years ago Florida's penal sys- 
tem was one of the crudest, the most 
brutal that ever existed in the 
United States. All able-bodied male con- 
victs were leased to private concerns to 
work in lumber and turpentine camps, and 
thousands of them were overworked, under- 
fed, and housed in cages unfit for wild 
beasts. Often those who failed in the 
slightest degree to please guards or over- 
seers were beaten unmercifully. 

Magazines and newspapers revealed the 
truth about the lumber and turpentine 
camps, and as a result of their exposures 
the State Government established a prison 
that might serve as a model for agricultural 
states or principalities throughout the 
civilized world. 
In 1913, aft- 
er thirty-three 
years of leasing 
out all convicts 
capable of 
earning money 
for private con- 
cerns, the 
State authori- 
ties bought 
17,000 acres of 
pine forest and 
swamps in 
County and 
started the de- 
velopment of 
what is now 
known as 

The wards are as light, clean 
make them. The men rise 

Bradford Farms. In November of that 
year crews of convicts began clearing and 
draining this tract of wilderness and laying 
the foundations of some of the buildings. 
To-day they have three thousand acres in a 
high state of cultivation, a prison town of 
thirty- five buildings, all- the implements, 
livestock and poultry they can use to ad- 
vantage, and a steam railroad of their own 
construction running to all important 
sections of the plantation. 

Offenders serving time at Bradford 
Farms are not made to feel that they are 
despised outcasts upon whom the State is 
wreaking vengeance. They are treated as 
misguided persons to be corrected morally 
and trained for lives of usefulness. They 
are given 
food, housed in 
clean, airy 
buildings, en- 
couraged to 
improve their 
personal hab- 
its, and em- 
ployed at 
healthful and 
instr uc ti ve 

The field la- 
borers work 
only nine hours 
a day, which 
is about two 
hours less than 
the time spent 

and airy as the State could 
at 4:30 and retire at 7:30 

Popular Science Monthly 


The stables and shops of the model prison farm. The land shown in the photograph was 
a wilderness of pine forests and disease-breeding swamps before the convicts improved it 

each day in labor by the average free farm 
hand in the South. They take three hours, 
exclusive of the time spent en route to and 
from the stockade, for rest and dinner in 
the middle of the day. 

They grow cotton, corn, sorghum cane, 
potatoes and all kinds of vegetables, and 
raise cattle, hogs and chickens. Last year 
their Irish potato patch was 550 acres, and 
an even larger area was given to sweet 

The methods of crop cultivation and 
livestock raising that have been adopted are 

This gives an idea of the work the convicts accomplished in 
converting the three thousand forest acres into tillable land 

the best known to the State Department of 
Agriculture. The Commissioner of Agri- 
culture, William A. McRae, sees to it that 
all the work is done in the best possible 
manner. The result is that practically all 
persons released • from Bradford Farms are 
highly skilled farm workers. The more 
intelligent ones are well trained in farm 
management also. 

At the present time the prison popula- 
tion at Bradford Farms is approximately 
650. About 250 are leased to counties to 
work on public roads. There are 736 
working for private corpo- 
rations. But the lease law 
of to-day is not like the old 
one. It places the working 
of leased convicts under 
rigid State inspection, and 
gives the Commissioner of 
Agriculture the right to 
cancel contracts whenever 
lessees fail to treat prisoners 
humanely. Only negroes of 
low-grade intelligence are 
leased, and the contracts 
are limited to two years. 

There is a rapidly in- 
creasing sentiment in favor 
of abolishing the lease sys- 
tem and sending all the 
State's convicts to Bradford 
Farms during imprisonment. 


Popular Science Monthly 

Why Not Dress Alike and Save 
Money During War Time? 

WHY not a civilian uniform as a 
measure of economy in clothing? 
suggests a Canton, Ohio, man. It could be 
worn by everyone, man, woman and child, 
and thus eliminate foolish dressing, the 
dude, and the spending of hundreds of 
thousands of dollars on needless finery. It 
would certainly bring home to the civilian 
population their part in the war, and the 
ladies would need to apologize no longer for 
appearing twice in the same dress. As the 
result of investigation carried on by the 
Ohio man, a standardized suit of wool of 
excellent quality could be sold for less than 
twenty dollars. 

The inflow of compressed air is controlled by a 
foot-treadle so that the hands are free to move 
the block to and fro under the pipe mouth 

With the Warm Weather Come Im- 
provements in Ice-Cream Making 

THE ice-cream manufacturer encounters 
the same difficulty in removing blocks 
or forms of cream from their molds as does 
the average cook or housewife with her 
frozen desserts. 

A recent device, patented by 
L. M. Hendler, of Baltimore 
Md., for overcoming this 
difficulty, is a contri- 
vance for forcing 
warmed air through a 
pipe to the bottom of 
the mold to dislodge 
the bricks of cream. 
This is more par- 
ticularly for the 
convenience of 
dealers who handle 
large oblong blocks 
of cream which 
must afterward be 
cut up into the 
smaller bricks. The 
valve which controls 
the compressed air in- 
flow is conveniently op- 
erated by a foot-lever. 

The transmission band with cork inserts, 
encircling a diagrammatic drawing show- 
ing the band in use on the automobile 

A New Type of Transmission 
Employs Cork Inserts 

THE new type of transmission band 
shown in the accompanying illustra- 
tion is designed to overcome the objection 
to the planetary form of transmission, such 
as used on the Ford car. It has cork in- 
serts like buttons. These extend out 
beyond the band proper for a very slight 
distance and come into direct contact with 
the revolving drums as the speed is changed. 
On account of the high coefficient of 
friction of cork and steel, the braking 
effect commences at once, whereas the 
plane surface fabric band usually fitted 
slips as it becomes worn and glossy and does 
not grip except when an excessive amount 
of pressure is exerted on the transmission 
pedal. Then it grips suddenly, 
causing a jarring in the 

The cork buttons 
also act as springs; 
^ for as the pressure 
increases they are 
compressed, thus 
allowing the band 
itself to come into 
contact with the 
'drum. This 
makes an easily 
operated trans- 
mission which acts 
positively without 
slipping, even after long 
service, and one in 
which the bands have a 
longer life due to this 
practical elimination of 
rhe slipping. 

Popular Science Monthly 


This Actually Happens Oftener 
Than You Would Think 

IT may be a mere 
matter of supersti- 
tion which causes so 
many hundreds of sol- 
diers to wear small 
Bibles and Testaments 
over their hearts. But 
the Pocket Testament 
League of England re- 
ports that it is very 
generally done, and oc- 
casionally we hear of 
incidents which confirm 
the report of the League. 
Superstition says that 
the heart so protected 
will never be pierced by 
a bullet. Certainly the 
soldier who wore the 
little volume shown in 
the accompanying pho- 
tograph must be a firm 
believer in its efficacy. 
He was struck by two 
machine bullets. One of 
them remained in the 
Testament, though prac- 
tically destroying it. The 
other passed through it 
and penetrated his ribs, 
but without causing seri- 
ous injury. 

Superstition also says 
that if the Testament be 
the gift of a mother or 
sweetheart it is doubly 
valuable as a talisman. 

The Siberian native enters 
his home by a ladder leading 
from a door in the roof 

The Door to This Siberian Home Is 
Located on the Roof 

MUCH of Siberia is 
a vast wilderness 
which still remains to 
be explored. In the 
winter season, when 
the streams cease to 
flow, disappearing be- 
neath the ice and snow, 
the animals hibernate 
in their dens and the 
natives repair to their 
huts to sleep away, so 
far as possible, the in- 
finite silence that broods 
over the land. 

The illustration shows 
the interior of a Siberian 
home. The odd-looking 
ladder in the foreground 
leads to the door of the 
hut, which is situated in 
the roof. The ladder is 
hewn from a big log and 
the hole rungs in it have 
all been cut by hand. It 
is necessary to enter a 
Siberian home through 
the roof during the sever- 
est winter months, be- 
cause the snow, driven 
by the gales of the 
North, forms great drifts 
which not only effectu- 
ally cover up all side 
entrances but often con- 
ceal the whereabouts of 
the hut itself. 

Notice the face on the right-hand page. 

Two bullets pierced the little pocket Testament 
without doing the wearer any serious harm 

Have You Put the Cat Out for the 
Night? Then Don't 

Says Lee S. Crandall, in Pets (Henry 
Holt & Co., New York) : "The practice 
of turning the cat out of doors at night is 
as cruel as it is unnecessary. No animal 
is fonder of warmth and comfort, and the 
pet's happiness certainly is not increased 
by a night spent outside in cold and 

"If as much energy were exhausted in keep- 
ing the cat indoors as too often is expended 
in putting her out, how great would be the 
boon to human nerves and unfortunate 
wild things! All felines are normally 
nocturnal, and it is at night, if ever, that 
a curb on their activities is needed." 

The Problem of the Automobile Top 

It may be made self-effacing and self-adjusting 




The automatic top is not only raised and lowered by the power of the 
engine but it is stored away out of sight in the extended rear end 

Cable in position when 
top is down 

hinged door 


ONE of the most conspicuous and ugly 
parts of the average automobile is the 
top. Folded, it is 
an overhanging object at 
the rear out of harmony 
with the pleasing lines of 
the body. 

To eliminate this un- 
sightliness, the engineers 
of two large companies 
have designed two types 
of disappearing tops 
which are entirely hidden 
when not in use. Both 
of these are shown here. 
One is raised by hand. 
The other differs from 
all other types of tops in 
that it is automatically 
raised and taken down 
not by hand but by 
power secured from the 
vehicle's engine, a convenience especially 
attractive to thousands of women drivers. 

When not in use the hand-raised and 
lowered disappearing top is stowed away 
out of sight in a turtle-backed compart- 
ment at the extreme rear of the car behind 
the rear seat. This turtle back serves as a 
cover but also gives the body the lines of a 
yacht. The top is inserted in the rear 
compartment through a large U-shaped 
door in the top and two smaller doors on the 
sides of the rear seat, all three doors forming U<^s fwwu;L! 
one large U-shaped opening when they are 
revolved up about their respective hinges. 
The side arms supporting the top, when up, 

Bring back \ Note position of levers 

5 P nn 9 whentopisdown 

The automatically adjusted 
top wound round the roll- 
er in the rear compartment 

are pivoted at opposite points inside the 
compartment. Suppose the top is to be 
lowered. The chauffeur 
walks to the rear of the 
car through the divided 
front seats and folds the 
top away in the con- 
ventional manner. When 
the three doors are closed 
it is entirely hidden from 
view. An eave trough is 
provided in front of the 
doors so that water can- 
not leak through the 
door joints and down 
into the compartment' 
where it might rot the 

revolving tire boi 

.6 tires! 

The hand-operated top is folded back in 
the usual way and then stowed away out 
of sight in a turtle-backed compartment 


Popular Science Monthly 


top if allowed to accumulate. The water 
drains off the eave trough through pipes to 
the ground. 

Another feature of the turtle back is a 
tire-carrier directly under the top compart- 
ment. The carrier is made of two semi- 
circular halves mounted on a 
central shaft so that one half forms 
a curved door to provide a closed 
cylindrical box when shut and pro- 
vides access to two 
horizontal shelves, 
each of which car- 
ries a tire, when 
open. This ar- 
rangement is 
especially con- 
venient because it 
eliminates lifting 
and strapping the 
tires upon a con- 
ventional carrier. 

The automatic 
top differs from 
that j ust described 
not only in that it 
is raised and low- 
ered by the power 
of the vehicle engine instead of by hand but 
that it is stowed away out of sight in the 
extended rear end of the body without any 
turtle back. When not in use. the top is 
wound around a horizontal crosswise roller 
in the rear compartment. The front end of 
the top is drawn forward to the windshield 
by means of two steel cables which extend 
down through the hollow windshield side 
posts to a small spool drum revolved 
through a friction gear from the engine fly- 
wheel. The operation of drawing the top 
forward out of its compartment and wind- 
ing the two cables around the drum is 
controlled by a small lever manipulated by 
the driver. 
The winding 
drum is re- 
v o 1 v e d 
through a set 
of gears and a 
clutch under 
the floor of 
the cab. The 
top compart- 
ment is closed 
by a door re- 
strained by 
springs and 
so arranged 
that a push 

on a small button by the driver automatically 
opens it. The manipulation of the| drum 
lever draws the top forward in ten seconds. 
It is automatically stopped when it reaches 
the windshield. 

To lower the top the operations are 
reversed, the 
cables being dis- 
connected at the 
windshield and 
the top drawn 
back by a spring- 
reel at the rear. 
The free ends of 
the cables are laid 
in small grooves in 
the body sides in 
the way of the, 
rear seat where 
they are easily 
reached by the 
driver. When up, 
the top is pre- 
vented from sag- 
ging by means of 
three thin strips 
of spring steel 
wound with it 
around the roller. The spare tires are 
carried in a horizontal position beneath the 
top roller in the rear compartment. 

A separate compartment to carry extra wheels, a 
feature which distinguishes this car from all others 

Raising the top after removing it from its hidden position in 
the turtle - backed carrier at the extreme rear of the car 

A Vast Fortune Is Chewed Up 
Every Year 

LOUD and long are the complaints of the 
/ stringency of the times and the wails 
concerning the tightness of money; but 
these laments are not coming from the 
manufacturers of chewing gum. Neither 
the war nor any other calamity has affected 
the output of this great necessity. The 
annual im- 
ports of chew- 
in g gum 
average about 
pounds, al- 
though in 
1913 the av- 
erage reached 
nearly 14,000,- 
000 pounds. 
Thus it is esti- 
mated that 
are chewed up 

Electric Newspapers in the Sky 

They flash information in flickering tidbits — 
a fresh, dazzling morsel every ten seconds 

ANY evening now 
in Chicago you 
L can look sky- 
ward and read, one 
after another, flaming 
messages to the gen- 
eral public. Up on top 
of some tall skyscraper 
is the contrivance that 
delivers these mes- 
sages. It is a form of 
electric sign, at a dis- 
tance differing but lit- 
tle from the ordinary 
kind, except that the 
messages it blazons 
forth change with far 
greater rapidity. In 
the darkness the frame- 
work of the sign is in- 
visible ; the separate 
letters seem to stand 
out like so many stars 
against the inky sky 
behind. Inside a little 
coop behind the sign 
young men are punch- 
ing small keys in an 
immense keyboard — 
setting up in electric 
type messages that 
come from various 
parts of the city ; from 
the war zones; in fact 
from all over the world. 
For this is the newest form 
of newspaper — a newspaper 
in the sky! It prints all 
that the ordinary paper 
does, excepting cartoons — 
news, advertisements, catchy 
sayings, sporting comment, 
anything that is the life of 
the ordinary penny sheet. 
And its public is even as big! 
Where old bulletin boards 
could dole out limited bits 
of information to a few 
within range of thirty or 
forty feet this new sign- 
board flashes its intelligence 
to thousands anywhere up 
and down the long ranges of 

two intersecting 

To change the word- 
ing of the sign men do 
not shift the letters 
bodily as in an ordi- 
nary theater bulletin 
board. The separate 
letters forming a given 
message simply go out, 
and others, expressing 
a new idea, light up in 
their places. This is 
possible because the 
sign is divided off into 
squares, called "letter- 
blocks," each the size 
of an ordinary letter, 
and each having fifty- 
three lamps scattered 
over its surface in such 
a way that by picking 
out the right lamps in a 
given instance any let- 
ter in the alphabet may 
be made to appear in 
that space at will. When 
the operators punch 
keys in the keyboard 

One of the newspaper 
electric signs overlook- 
ing Longacre Square, 
in New York city 


Contact ba 


Wiring diagram of 
one of the letter- 
blocks into which 
the sign is divided 


Popular Science Monthly 


previously mentioned they simply cause 
switches back of each key to pick out the 
right set of lamps to blazon forth the letter 
it is desired to show in a given letter-block. 
Since the letter-blocks are arranged in long 
lines it is possible 
to spell out words 
and phrases, simply 
by causing the indi- 
vidual letter-blocks 
to show the char- 
acter desired. The 
principle is made 
clearer in the illus- 

Changes in the 
wording of the sign 
are effected as fast 
as the operators can 
work the keyboard 
— one man devoting 
his entire attention 
to a single line on 
the sign, but to- 
gether with his fel- 
lows getting orders 
from cardboards in 
the hands of the 
chief operator. A 
given message is 
made to flash on the 
sign very much as 
type is set up on a 
linotype machine. 
In the linotype case 
the printer punches 

proper keys to spell out one line, strikes 
a lever convenient to his right hand, and 
the matrices pass on into the machine to 
mold the type while he is busying himself 
with the next line. In the same way, the 
operators of the new sign punch proper 
keys to spell out a given message, strike 
a lever, and the message flashes on the 
sign. While people are reading it, the 
men are setting keys for the next com- 
munication, which 
appears the next in- 

The sign was orig- 
inally patented by 
W. W. Arnold, of 
Hamilton, Ohio, but 
it has been worked 
out in a commer- 
cially practicable 
way by M. E. Laun- 
branch, an engineer 
of Chicago. 

A message is made to flash on a sign very 
much as type is set up on a linotype machine. 
The operators punch the keys to spell it out 

Compared with Electricity Gas Is 
Still the Cheaper Medium 

IN spite of the decreased cost of electric 
service and the increased efficiency of 
electrically operated 
devices, the fact re- 
mains that of the 
two sources of en- 
ergy generally avail- 
able for heating, 
lighting and cooking, 
namely, electricity 
and gas, gas is by far 
the cheaper medium. 
At the present time 
one thousand elec- 
tric heat units 
cost fourteen times 
as much as one 
thousand gas units. 
Furthermore, it is 
impossible to cook 
as rapidly with elec- 
tric heating devices 
as with gas cookers. 
In the lighting field 
gas is, under certain 
conditions, cheaper 
than electricity, al- 
though it has not 
the large variety of 
applications that 
electricity has. 

A Telephone Attachment Which Per- 
forms the Services of a Watch Dog 

York, has invented a meter attachment 
which is a mechanical watch-dog for your 
telephone. It consists of a 
small case containing a 
locking and registering 
mechanism, a clamp which 
fastens it to the telephone 
standard, and a rod which 
engages with the tel- 
ephone receiver. By 
removing the receiv- 
er the rod is forced 
in and out of the 
interior of the meter. 
It is impossible to 
replace the receiver 
upon the hook until 
the call has been 

The attachment which locks the telephone 
when it is not in use and registers all calls 


Popular Science Monthly 

A Silo Roof Which Opens Like 
an Umbrella 

A ROOF built like an urn 
brella is the ingenious de- 
vice of a manufacturer of ap- 
pliances for silos. It has this 
advantage: the structure 
can be filled five or six feet 
above the level of the walls; 
as the ensilage gradually 
settles, the roof will close 
down upon it automatically. 
This eliminates the need of 
a second filling of the silo 
after settling, and saves a good 
deal of labor and time. 

The silo roof is constructed of 
triangular sections of galvanized 
iron, which are joined by sections 
of tenting. When the roof is open 
it. forms a continuation of the 
cylindrical walls of the silo, and 
as it settles upon the contents the 
triangles of metal join snugly. 
By an arrangement of joints that 
overlap, a weather-proof cover is 
formed. Within this are the sec- 
tions of canvas, which are likewise 
protected from the elements. 

The supports that hold the roof 
to the upper wall of the silo are of 
wrought iron, and are so narrow 
that they offer little resistance to 
the wind. By pulling on a rope 
suspended through the center of 
the structure down to the floor, a 
single man can open the umbrella. 

The roof can be attached to silos 
of concrete, metal, wood or tile. 
It is made in diameters of eight to 
seventeen feet. 

By pulling a rope 
one man can 
easily spread the 
umbrella roof 

The United States Armies Are Pre- 
paring to Fight Vermin and Germs 

CLOTHING disinfectors of a 
portable type similar to those 
in use in Europe have been pur- 
chased by the United States Army. 
The outfit consists of a five-horse- 
power upright boiler connected by 
piping with a cylindrical chamber 
about six feet long and three feet 
in diameter. The rear end of this 
jacketed chamber is provided 
with a door that can be hermet- 
ically sealed. A rack for clothing 
slides into the chamber, while 
smaller articles are laid on a 

grating where they may be steam-soaked. 
The steam is generated in the boiler at 
about eighty pounds pressure. 
Suitable valves are provided to 
reduce this pressure to ten 
pounds when it enters the 
chamber. When the jacket 
about the chamber is thor- 
oughly heated, the articles to 
be disinfected are placed in 
the rack, which is then 
pushed into the chamber. 
The door is closed and 
made steam tight. When 
the temperature within 
the chamber has risen sufficiently, 
an exhauster is opened until the 
gage shows about fifteen inches 
of vacuum. Then a small amount 
of steam is allowed to enter the 
chamber. Following this, the ex- 
hauster again is opened until fif- 
teen inches of vacuum is indicated. 
Steam is then allowed to enter 
the chamber until the temperature 
within it rises to two hundred and 
thirty-eight degrees F. The steam 
is allowed to circulate through the 
chamber during the period of ex- 
posure. It is then cut off, and 
the exhauster draws off steam 
and vapor. After a short drying 
period the door may be opened 
and the clothing removed. 

When using formaldehyde gas 
as a disinfectant in the apparatus 
the jacket is brought to a tempera- 
ture of eighty degrees F. ; the 
clothing then is placed in the 
chamber and a vacuum of fifteen 
to twenty inches obtained. When 
a temperature of 
ninety degrees 
is reached, the 
gas is admit- 

A disinfector for our Army. It can handle fifty uniforms 
and kits in forty minutes ridding them of all germs 

Popular Science Monthly 


Flushing Streets with Water Pipes 
on Trolley Cars 

IN Worcester and Springfield, Mass., 
the day of horse-and- wagon street 
flushing is past. Trolley cars carrying 
large water- tanks and electric pumps have 
been found much more effective and con- 
siderably more rapid. The pumps force 
the water out in such powerful streams that 
the trolley-car method has proved itself 
cleaner than the horse-drawn barrel-wagon 
from which the water flowed by gravity. 

The pump supplies water to four pipes. 
Two of these lead to nozzles on the car 
itself and two lead to an arm which swings 
on the road-side of the car. This arm 
is swung back when automobiles or other 
obstructions are to be passed. 

The flushing is done early in the morning 
after the cars have first gone the rounds in 
sprinkling the streets. The cars run at 
high speed so that an entire city can be 
cleaned by a very few of them in a very 
short time. With the old horse-and-wagon 
method speed was impossible. Sometimes 
the 'sprinkling had to be started during 
the night. 

The added expense of the electric pump 
is balanced by the saving in the number of 
units and of men, so that the running ex- 
pense of the new method is not increased. 
On the other hand, only eighty-five per 
cent of the water formerly used is now 
required. The side streets which are not 
tracked are now flushed by connecting long 
hose to the street hydrants. 

Electric motors pump the water in four powerful streams that 
wash away every trace of refuse while the car runs at high speed 

Dr. L. L. Funk, using his mechanical broach 
wrapper and sterilizer. At no time during the 
process is the cotton touched by the hands 

That Wad of Dental Cotton— Was 
It Sterilized? 

IN cleaning the root-canals of affected 
teeth the dentist employs a wad of 
cotton wrapped on a steel needle. This 
wad is called a "broach," and is used in 
reaching the vital point where the nerve 
of the tooth passes out into the bony 

Usually the dentist twists the cotton 
around the needle with his fingers, which 
is neither sanitary nor safe 
in most cases. Dr. L. L. 
Funk of Chicago has invented 
the machine shown in the 
illustration. It does the 
wrapping mechanically, and 
sterilizes the cotton at the 
same time. Different meth- 
ods of sterilization are pro- 
vided for. The first is by 
means of dry heat of 275 
degrees Fahrenheit, obtained 
from the electric heating 
unit; the second employs 
steam obtained by placing a 
four-candlepower electric 
lamp in a glass water-con- 
tainer and bringing the water 
to boiling point. This is used 
for moist sterilization and for 
melting inlay wax. A car- 
bolized sponge is used for 
sterilizing the needles. 

Mountains That Float 

Why? Because the underlying materials are lighter than the mountains 

IN a remarkable series of researches con- 
ducted by the U. S. Coast and Geodetic 
Survey, under the direction, first of 
Professor John F. Hayford, and later of 
Mr. William Bowie, Chief of the Division 
of Geodesy, it has been conclusively proved 
that mountains and continents, and prob- 
ably islands, float. 

The earth is solid. How, then, can we 
say that the mountains float? 

A hundred or even a thousand years are 
as a day in the geological calendar; and 
for such periods the movement of portions 
of the earth, under any forces which may 
act on them, would probably be so small 
as to go unnoticed. But when such forces 
act for a hundred thousand or a million 
years or longer, the earth's materials 
behave as if they were plastic; in other 
words, they give way to the forces affecting 
them, and assume a state of equilibrium. 
Those who work in the deep mines of the 
earth are familiar with the movement or 
creeping of the rock which will close old 
shafts or tunnels. 

But what is the evidence that mountains 
float ? The answer is in the observed tilting 
of the plumb line and in the measurements 
of the earth's pull, called gravity. 

The Proof Furnished by Gravity 

Let us confine our attention to gravity. 
If the earth's material were a perfect 
liquid, its surface would be perfectly 
smooth and the shape of this surface would 
be that of a ball. Since the earth spins very 
rapidly, centrifugal force is set up which 
causes the maximum at the equator and a 
minimum or zero at the poles. This means 
a shortening of the axis of rotation by a 
distance of about twenty-six miles. That 
is, the distance from the north pole to the 
south pole would be that much shorter 
than the distance through the earth's 
center between two points opposite each 
other on the equator. 

Exactly the same shape would result if 
the earth's material, though solid, were 
arranged in layers according to the density, 
the densest material at the earth's center 
and the lightest at the surface. The earth 
would assume that shape because of the 
yielding under the attractive force of each 
particle of the earth's material on every 

other particle, and because of the centrif- 
ugal force due to the earth's rotation 
which tends to throw its materials out into 

The resultant of these forces, or gravity, 
would on this ideal earth vary gradually 
in intensity from the equator to the poles. 

How We Get the Idea of Floating 

The earth's materials are not arranged 
in layers exactly with respect to their 
densities. As a matter of fact gravity 
determinations show that the materials 
under the vast plains along the coasts are 
arranged very nearly in the normal way, 
but that the materials under the mountains 
are found to be lighter than normal. The 
deficiency of material under a mountain 
down to a depth of about sixty miles below 
the sea level is almost exactly equal to the 
mountain material which is above sea level. 

Similarly, under plateaus like those of 
our Western States, there is a deficiency of 
materials very nearly or exactly equal to 
the mass of material between the surface 
and the imaginary sea level surface beneath. 
The normal density is that under the 
coastal plains. 

As a result of this counterbalancing of 
the material above sea level at any part 
of a continent by material lighter than nor- 
mal under it, the pressure or weight of 
material on an imaginary surface about 
sixty miles below sea level is the same at 
all points of that surface. 

This brings out the idea of floating. If 
we should see an iceberg floating in the 
ocean, we would conclude that the ice 
showing above the water is held up or 
floated as a consequence of a greater mass 
of ice under it. As all know, ice is lighter 
than water. A block of wood thrown in the 
water has some of its material held above 
the surface by the portion under the 
water. The weight of the material of the 
whole block exactly equals that of the 
water displaced by the block. Similarly the 
weight of a mountain mass and the column 
of material directly under it to a depth 
of say sixty miles, below the imaginary sea 
level surface, equals that of the weight of a 
similar column of material of equal cross 
section, under the coastal plain, which 
has little or no material above sea level. 

Land Skates with Brakes and Pneumatic Tires 

The latest "quicker than walking" form of exercise 

A BALL - BEARING, pneumatic- 
tired skate which will run 
easier on a level road or street 

The road skates are provided with 
brakes which are operated by the braces 

than an ice skate will slide on ice, 
has been invented by Charles H. 
Clark, of New York city. 

Located on opposite sides of 
each foot are two nine-inch wheels, 
the front wheel being on the inside 
of the foot and the rear wheel on 
the outside, so as not to interfere 
in any way with the movements of 
the legs. 

On the outside of the leg, as 
shown in the illustration, is a brace 
journaled to the foot rest. The 
upper end of the brace is attached 
to the ankle, thus relieving it of 
any strain. 

In addition to this purpose of 
protecting the ankle the brace 
acts as a brake arm to set the 
band brake on the 

Int. Film Serv. 

wheel. By pushing either foot 
forward, in the same manner 
that a person would do who 
wanted to stop when walking, 
the brake is operated. The 
tires are resilient enough to 
enable the operator to steer 
with ease. According to 
the inventor a person 
equipped with the 
skates can travel 
three times as far 
with the same 
amount of effort as 
in walking. 

Considering the 
skate as a foot- 
propelled vehicle it 
is certainly efficient. 
No transmission 
system with an at- 
tendant loss of power 
is necessary because 
the propelling force 
of the legs is applied 
direct. Furthermore, 
the skate need not be 
left at the curb like 
the automobile. Ar- 
rived at your destina- 
tion you can unfasten 
your skates and take 
them into the building 
with you. 

To travel, you simply 
raise one foot and then 
the other as you would 
in walking. The 
wheels are placed in 
such a way as to 
maintain an even 
balance at all times 



Popular Science Monthly 

) Brown and Dawson 

The water is shallow and always warm. The rules of the 
sport are "Hold on tight and don't mind a ducking" 

Rafting the Rapids on the Rio Grande 
in Jamaica, British West Indies 

JAMAICA, although a tropical country, 
has a form of sport equal if not superior 
to tobogganing. The national pastime is 
shooting the rapids in the Rio Grande 
River on bamboo rafts. For about four 
miles of its length the river is one succession 
of rapids. The depth of these rapids is 
never over ten or twelve inches, and many 
of the rocks protrude above the surface, so 
it is not possible to use a boat at all. 

The natives build rafts of light, tough 
bamboo, which float where there is water 
and will slide like a sled over the 
wet, smooth stones where 
there is no water. 

Each raft is about twen 
ty-five feet long 
and is composed 
of twelve to fifteen 
stalks of bamboo. 
The bamboo is 
about six inches in 
diameter at the base 
and tapers to one 
inch at the point. 
The tips of the bam- 
boo form the bow of 
the raft and the 
base the stern. Near 
the stern is a built- 
up platform on 
which two passen- 
gers may sit and 
keep their feet out 

of the water, which often 
covers the raft. The helms- 
man stands towards the 
bow. With a long pole he 
guides the raft down the 
rapids and away from the 
worst stones. 

Shooting the rapids is 
exciting. Every cataract is 
different from its prede- 
cessor. One is short, another 
long; a third straight, and 
others are full of curves. 
We slide over the small 
stones that protrude slight- 
ly above the surface, but we 
must keep away from the 
large ones, for they will 
break up our frail raft, or, 
worse yet, turn it over on 
us. In some places jungle 
trees overhang the river 
so low as sometimes to 
sweep the passengers off; in other spots the 
channel between the high ledges is so 
narrow as to require very fine steering on 
the part of the negro helmsman. But it is 
seldom that a raft goes through without its 
passengers being thrown off, swept off or 
having their craft turn over on them. 

A glass model of a housefly, magnified 
to show its interesting construction 

Facts about Your Enemy, the 
Common Housefly 

MORE than one-third of all the known 
flies belong to one family, Musca 
Domestica, or the common housefly. This 
fly is perhaps the most cosmo- 
politan in the whole order of 
insects, being found in al- 
most every part of the 
world. The eggs are 
laid in groups, and in 
a few hours the larvae 
make their appear- 

Each female lays 
about seventy eggs. 
Though the common 
housefly has been 
"swatted" all over 
the world, the fly 
family shows no 
signs of decreasing. 
The most approved 
methods for its exter- 
mination employ pre- 
vention and sanitary 

Popular Science Monthly 


A Community Garage Comprises 
Fifty Buildings on One Lot 

FIFTY garages, set as closely 
together as possible, occu- 
py a vacant lot in New York 
city. Each one is rented to a 
car owner living in the neigh- 
borhood. The fireproof struc- 
tures are uniform in design, 
being made out of gal- 
vanized iron with the 
framework formed of an- 
gle steel. 

The doors are of wood, 
sheathed with metal, and 
the windows are of wire 
glass. Each tenant is 
provided with keys and 
has access to his garage 
at any time of the day 
or night. The build- 
ings are ten feet by 
eighteen feet, with 
cement floors. They are 
large enough to accom- 
modate the car and pro- 
vide additional room for 
a workbench. Facilities 
for cleaning are provided 
in the court yard, and 
there, too, may be found a supply station 
for gas, oil, etc. 

The garages may be provided with heat- 
ing devices if desired. Care service is ren- 
dered at a moderate charge, though this is 
optional with the owner. The lot measures 
x 55 by l 75 f eet an d besides the individual 
garages, which are placed back to back in 
the center of the lot, there is ample space 
provided for driveways. 

The oil passes over the flame and every 
particle of it becomes vaporized. The burners 
concentrate the heat where it is wanted 

Making the Kitchen Range One 
Hundred Per Cent Efficient 

THE oil-burning stove of Gar- 
ritt Van Daam, a combustion 
engineer of Buffalo, New York, is 
a recently invented rival of the 
modern coal range. 
The usual kerosene heater is a 
good little stove, but it 
is known to smoke and to 
smell generally. This 
shows that some per- 
fectly good oil is being 
wasted. Van Daam's 
heater neither smokes 
nor smells, which 
means that it is 
practically one hun- 
dred per cent effi- 
cient. The coal 
stove is seldom bet- 
ter than fifty per 
cent efficient. 

The secret of this 
burner's high effi- 
ciency is in the heat- 
ing of the kerosene 
before it burns. 
From the supply 
tank near the stove, 

One city lot accommodates fifty buildings placed back to 
back, with room for driveways, as a community garage 

the kerosene feeds by gravity through a 
heating chamber placed directly over an 
ordinary gas-burner jet. Two minutes 
after the kerosene has been lit, the chamber 
will be so hot that all the kerosene that fol- 
lows will be vaporized. In this state, 
every bit of the kerosene is combustible 
and burns fiercely. In the ordinary oil 
burner this is impossible because all the 
oil does not get the chance to vaporize. 
The portion that does not is 
wasted, because it merely 
changes into soot. 

With the oil-burner made 
practical, there will be no 
more working in an overhot 
kitchen to accomplish a little 
cooking in the summer. The 
burners are placed to direct 
the heat only where it is 
wanted. For baking, the 
oven burner will concentrate 
the heat in the oven and 
neither the whole stove nor 
the room will need to be made 
hot along with it. Equally as 
comforting is the _ fact that 
the stove cools off immediate- 

ly after the oil is turned off. 

Protecting the British Fleets with Chain-Nets 

No enemy submarine can thread the English 
Channel without being caught like a fish in a seine 

DISPATCHES from Europe tell re- 
peatedly that hostile submarines 
have been caught in nets, but none 
of them have indicated how it was done. 
The English fleet is kept in the Orkney 
Islands, protected by 
great steel chains 
woven in the form 
of simple nets which 
are not stationary 
but mobile. If they 
were anchored so 
that they could not 
be moved there is 
little doubt but that 
the industrious Ger- 
man commanders 
would find some way 
of getting through 

The nets covering 
the grand fleet are 
stretched out in great 
arms from the shores of the Islands, com- 
pletely covering the fleet. Various types 
of enemy vessels have come steaming up 
to these barriers, though of course under- 
water, in the effort to catch the great fleet 
happing. Whenever a daring commander 
has attempted such a coup he has always, 
so far, found himself not only nosing against 
a network of great chains but when he 
turned to run he has found himself in a 
circular net and doomed. 

The British operations are simple. A 
sharp lookout, and probably electric look- 

There are a few loopholes in the nets, 
known to officials only, through which 
commercial vessels may pass in safety 

outs as well, keep the chain operators in- 
formed as to what is going on. When an 
enemy submarine enters the net its presence 
is soon known and the operators, taking 
the ends of the chain, draw it together to 
form a circle. The 
trap is then sprung. 
The British wait un- 
til something hap- 
pens- — until the sub- 
marine comes cau- 
tiously to the sur- 
face to look about, 
for there is nothing 
else that the com- 
mander can do. Once 
up he has the choice 
between destruction 
by shell or surrender, 
and to the credit of 
Germans it must be 
admitted that very 
often the commander 
refuses to surrender, hoping that some 
means of escape may still lie open. 

The same sort of traps exist in the 
English Channel, where great chains are 
spread from the coast of France to the 
coast of England, with but a very few loop- 
holes which are known to British officers 
only, through which commerce may be 
carried on in safety. Every time a raider 
or a submarine cargo boat slips out of 
Germany it takes the northern passage. 
The channel is impossible to negotiate for 
any uninformed ship captain and it probably 

A r 

A decoy ship leads a pursuing submarine 
into a circle of nets which immediately 
close up around it so that there is no escape 

Once enclosed by the chain of nets, the 
commander of the intruder faces destruc- 
tion from the shells or complete surrender 


Popular Science Monthly 








The traps are spread from the coast of 
France clear across the English channel 

would still be so were the grand fleet in the 
Orkneys to be destroyed. 

When United States Naval officers were 
consulted concerning the use of these nets, 
and the possibility of such a method they 
unanimously agreed that it was possible, 
although they knew nothing about it. 
They said that nets were certainly being 
used and that very probably the minor 
difficulties in their way had been solved. 

The Latest Salvaging Device for Metals 
— An Electromagnet 

A LIGHTER acci- 
dentally turned 
over at sea, spilling 
several thousand cases 
of shells. A diver was 
put on the job, but 
owing to the ice and 
extremely cold water, 
he was able to work 
only a few hours at a 
time. At the end of a 
day less than one hun- 
dred cases had been 

An electromagnet was installed and 
dropped to the river bottom. On the 
first trip it recovered four cases. This 
was repeated again and again, until 
at the end of the day over two 
hundred boxes had been 
brought to the surface. 

A large number of 
cases were broken, so 
that the shells fell out 
and sank deep in the 
mud. This magnet was 
found powerful enough 
to draw both shells and 
cases out of the mud. 

The electromagnet diver bring- 
ing to the surface cases of shells 
some of which were buried in mud 

The English fleet, anchored in the Orkney 
Islands, is completely protected by the nets 

In fact when a shell is left at a distance of 
about twelve inches from the magnet and 
the current turned on, the shell, weighing 
about 255 pounds, jumps to the magnet. 

The outfit consists of a gasoline-driven 
generator, control apparatus for the mag- 
net, and the magnet, which weighs about 
9,000 pounds, and requires from eighty to 
ninety amperes at 240 volts direct current 
to energize it. 

The magnet was attached to the cable, 
and by means of a swinging boom could 
cover a large area without having to move 
the lighter on which the apparatus was 

In operation, the magnet was 
lowered to the bottom of the river, 
a depth of between thirty and forty 
feet; then the current was turned 
on and the magnet lifted. Then the 
boom swung the magnet over to the 
deck, the current was switched off, 
and the cases of shells 
were dropped. 

This type of magnet 
(designed for handling 
scrap iron and steel) 
though never intended 
to operate under water, 
is quickly attached and 
in this particular case 
was operated with marked 
success for ten consecutive 
days with no special at- 
tention or repairs except 
perfunctory tightening of 
the bolts and filling the 
main feed cables with tar. 
The cases of shells were 
recovered with compara- 
tive ease. The method will 
probably be used for other 
salvaging purposes. 


Popular Science Monthly 


thirty feet. The Illinois 
records show that work- 
men have fallen a hundred 
feet or more into a net 
without suffering any in- 
jury whatsoever. Had the 
men fallen on plank floors 
they would have been killed. 

Seal Your Letters by 

B 1 

Safety nets of rope are now taking the place of plank floors to 
insure the safety of those who work on skyscraper scaffolding 

" Safety First" for Skyscraper Workers 
Attained with Nets of Rope 

TO protect the men who erect the steel 
frames of skyscrapers, life nets are 
now used instead of the usual flcoring. The 
building laws of practically every state 
require that the contractor install a plank 
floor for each story as the structural work 
progresses. In building auditoriums, arch 
trusses in theaters, towers, bridges and in 
special cases, it has sometimes been impossi- 
ble to comply with the law, for plank floors 
could not be erected. Hence nets of rope 
were adopted as the 
most practicable 
measure of safety. 

The nets are made 
of manila rope and 
are provided with 
loops on the borders 
so that they can be 
readily attached to 
the iron work. In 
Chicago they have 
been used for about a 
year. At least two 
lives have been saved 
with them. Califor- 
nia has only recently 
adopted them. Ordi- 
narily a net costs 
about sixty dollars, 

provided it is of the Diagram showing the construction of the elec- 
usual size — ten by trie wax-heater, and the device in operation 

ESIDES its special task 
of keeping letters and 
packages intact and safe 
from prying eyes, sealing 
wax lends itself to many 
forms of decoration, especial- 
ly on china. The chief diffi- 
culty in the way of its use 
is in heating it to the proper 
flowing state without smok- 
ing it or spoiling its color. 
A candle or small alcohol 
lamp is usually used, but the device shown 
in the accompanying illustration serves 
the purpose more satisfactorily. 

It is the invention of Fay M. Andrews, 
of Columbus, Ohio. It consists of a hollow 
tube handle through which wires lead from 
an applying disk to conductors from the 
nearest electric lamp socket. A push- 
button near the applying disk controls a 
contact plate mounted in the handle to 
cut the resistance in or out. The applying 
disk is provided with a plug, like that of 
an ordinary small lamp, so that when it is 
screwed into the shell the proper electrical 
connection is made. 
In operating it, 
the handle is 
gripped in one hand 
and the current 
turned • on. The 
wax, which is held 
in the other hand, 
is then melted by the 
heat from the disk 
and dropped into 
place. The disk is 
then moved lightly to 
and fro over the wax 
until it is smooth, 
directing the flow 
wherever it is de- 
sired. It heats almost 
instantaneously with 
the pressure on the 

Popular Science Monthly 


An Electric Eye Watches the Smoke 
Screen During a Battle 

THE manner in 
which the den- 
sity of the smoke 
screens is now reg- 
ulated during a bat- 
tle is interesting. 
By partially shut- 
ting off the draft to 
her boilers, a battle- 
ship is made to 
emit clouds of 
smoke which screen 
her from the enemy. 
But how can the 
stokers, who are far 
below deck, see the 
stacks so that they 
can regulate the 
smoke clouds to the 
proper density? 
Answer — By an 
electric "eye." The 
eye is placed near 
the top of the 
smokestack and it 
records the exact 
density on electric 
meters convenient- 
ly located in the 
boiler room. 

This remarkably 
clever eye is simply 
a wire coil of selenium which is carried in 
a housing on the inside of the smokestack 
walls. An electric light, in another housing 
directly opposite, plays its beam of light 
squarely upon the wire. Now 
selenium, as is well known 
has the peculiar property 
of changing its resistance 
to an electric current 
when the light falling 
upon it changes. The 
weaker the light, the 
greater the resistance, 
and vice versa. 

Evidently then, the 
denser the smoke 
emitted through the 
stack, the weaker the 
light that gets through 
the smoke from the 
electric lamp and falls 
upon the selenium. By 
connecting the selenium 
with an electric meter 

Lamp control 

The selenium cell is sensitive to light. 
Hence when the smoke shuts off the light 
it can " see " what happens in the stack 

and the ship's lighting mains, the electric 
current going through the meter will be 
lowered by the increased resistance. The 
meter is very sensi-' 
tive and shows the 
slightest change in 
smoke density. 
Moreover, it is cali- 
brated to indicate 
exactly what the 
actual smoke densi- 
ty is, so that the 
stokers can regulate 
the cut-off of the 
draft to a nicety. 
Glass plates are 
placed in front of 
the lamp and of the 
selenium coil to pro- 
tect them from soot. 
The plates are kept 
clean by streams of 
compressed air di- 
rected across them. 
This device was in- 
stalled on the U.S.S. 
Conyngham and 
was called to the 
attention of the So- 
ciety of N.aval Ar- 
chitects and Marine 
Engineers by Rear 
Admiral R. T. Hall, 
U. S. N. 

An Ice Helmet to Relieve the Fever 
Patient Without Disturbing Him 

THE principal defects of the ice 
caps so frequently used on the 
heads of fever patients are that 
they do not fit the head, they 
can not be refilled with 
cracked ice without re- 
moving them from the 
patient and the water 
can not be drained off. 

A New York city in- 
ventor, M. Finkelstein, 
seems to have overcome 
all these shortcomings in 
devising the ice cap illus- 
trated. A screw-top 
opening permits the 
nurse to replenish the 
cap with cracked ice 
without disturbing the 
patient, and a drain 
pipe is provided. 

The ice helmet which can be drained 
and refilled without disturbing the 
patient. It fits the head securely 

Practical Motor-Boating 

A series of three articles on the selection, 
operation, care and upkeep of a motor-boat 

I. — Selection of a Boat 
By George M. Petersen 

Photos by Edwin Levick 

No doubt the best type of motor-boat for large bodies of water is the raised deck 
cruiser, which can be navigated through almost any storm with little or no danger 

MOTOR-BOATING, as commonly 
thought of by the amateur boat- 
man, consists mainly of trying to 
drive any kind of hull through all kinds of 
water, at any speed possible, by means of a 
mass of cast iron in the shape of a propeller 
in the stern of the boat. The old sailors 
are inclined to think of the motor-boat as 
the "dude's friend," which requires no 
knowledge of seamanship. While motor- 
boating is considerably easier to master 
than is the art of sailing a craft through all 
conditions of wind and water, there is, 
nevertheless, a knack to be acquired and 
mechanical knowledge to be obtained con- 
cerning it. 

In this series of articles we will deal, first, 
with the classification of boat models for 
various waters, selection of the boat, and 
most desirable type of engine. The most 
important point is the selection of the type 
of hull best suited to the requirements of 
the waters on which it will be used. 
For instance, a glass 
cabin cruiser, while 
affording a large 
amount of head room 
and permitting an 
unobstructed view 
from within, is not to 
be considered as even 
a fair type of boat 
for large or rough 
bodies of water ; but 
it is a desirable type 
of boat for rivers 


Arrangement of crankshafts required for 
different types of engines for motor-boats 


and quiet bays or other protected waters. 
The best type of motor-boat for large 
bodies of water like the Great Lakes is 
undoubtedly the "raised deck" cruiser, 
which may be successfully navigated 
through almost any storm with little or no 
danger. This type of boat is generally 
built from twenty-six to thirty-five feet in 
length; the 27-foot model provides com- 
fortable cruising accommodations for two 
or three persons. When equipped with a 
ten- or twelve - horsepower engine it is 
capable of a cruising speed of from eight to 
ten miles an hour. 

Authorities differ greatly as to the most 
desirable type of boat for general use, but 
practically all experienced boatmen agree 
that some type of cruiser is the most 

The long and narrow speed craft which 
delights the eye as it dashes past the Club 
House on a quiet day, is of absolutely no 
value for either cruising or long day runs 
on unprotected 
waters, as the exces- 
sive speed causes 
them to be extremely 
cranky and hard to 
handle in a seaway, 
and a quick turn is 
liable to cause them 
to capsize. How- 
ever, for pleasure 
and safety the boat 
making from seven 
to twelve miles per 




Popular Science Monthly 


For short trips and pleasure rides in protected waters the day cruiser is the most desirable of 
all boats, as it can be handled readily and will travel at a fair speed under favorable conditions 

hour is the safest and most satisfactory. 

There are three ways of obtaining a 
motor-boat; the first is to have a boat 
designed to order by an experienced naval 
architect in which all of the whims and 
fancies of the owner may be incorporated. 
The second is to purchase what is termed a 
"stock model"; the third is to pick up a 
second-hand boat for a small sum and put 
it into condition. For 
the man who can afford 
the service of a naval 
architect, this article 
will be of little interest, 
but for the man who 
must select a stock 
model craft, or who is 
willing to experiment 
for two or three seasons 
with second-hand boats 
until he is sure of the 
exact kind of boat he 
desires, it will be help 

As quantity pro- 
duction greatly re- 
duces the cost of 
any class of goods, 
the cost of the stock 
model motor-boat is 
relatively low. This 
is due to the fact that 
a certain plan is used 
for a large number of 
boats which are all made 
up at the same time; so 
the cost of designing, 
patterns, labor and inci- 
dentals is not charged up 

Deck plan of the neat glass cabin 
cruiser shown in the photograph below 

against one particular boat but against a 
large number. A few years ago the num- 
ber of stock models which it was possible to 
obtain was limited, but on account of the 
great popularity of motor-boating recently 
there is now scarcely any model which can- 
not be termed "stock." 

The "second-hand boat" method is the 
one which is undoubtedly the most satis- 
factory in the end. 
Some of these boats 
only need new hulls; 
the power plant is 
usually in good con- 
dition. At the pres- 
ent time boats rang- 
ing from twenty to 
twenty-six feet are 
the most popular. 
Real bargains in boats 
of this size are compar- 
atively scarce, but 
as we go into the 
class of the thirty- 
five and forty- 
footers, the bar- 
gains are more 

The most vital 
point of a motor- 
boat is always the 
hull, below the 
water line and 
near the keel. 
The condition 
of the timber 
may. be readily 
determined by 
jabbing the 

A glass cabin cruiser affords plenty of 
head room and is adapted for rivers 


Popular Science Monthly 

A bridge deck cruiser having two compartments is not considered a fair type of boat for large or 
rough waters but is adapted for protected waters, such as a lake, river or bay and for fair weather 

planking with a sharp-pointed knife. If 
the timber is sound, it will be difficult to 
make the point enter the wood, but if it is 
inclined to "dry rot," the blade of the knife 
will sink into the plank, meeting practically 
no resistance. While this inclination to- 
wards rot does not necessarily condemn the 
boat, it does necessitate new planking or 
timber, and this expense must be figured 
when making an offer for the craft. There 
is an old idea held by many boatmen that 
the most vulnerable part of the hull is that 
which lies between "wind and water." 
This, however, is not the case. Dry rot 
is caused in most cases by steam. For 
that reason the bilge of the boat is most 
likely to be the part affected, as there 
is always more or less water lying in the 
bilge and the hot sun 
often causes it to steam. 
The ribs should also 
be carefully examined. 
If they are spliced out 
or doubled it is a pretty 
sure indication that the 
boat is either getting 
pretty old or has at 
some time run ashore 

Deck plan of the sturdy trunk 
cabin cruiser shown below 

and been wrecked. As a general rule, a 
hull that has been re-ribbed or stiffened 
should either be inspected by an experi- 
enced boat-builder or be rejected entirely, 
for fear of its opening up badly in a 
pounding sea. 

Authorities differ as to the most desirable 
power plant; but it is the model of the hull 
rather than the power used to drive it that 
develops the speed. For instance, the 
short, beamy, heavy fishing boats used on 
the Columbia River are equipped with an 
eight horsepower, single cylinder engine 
which drives them along at a speed of about 
six miles an hour. Several years ago the 
writer endeavored to speed up one of these 
boats by installing a twenty horsepower en- 
gine. This resulted in an increased speed of 
about one mile an hour, 
and the boat was prac- 
tically wrecked from 
the excessive vibration 
and her sea-worthiness 
decreased to a large ex- 
tent by the excessive 
weight. This same idea 
holds good in practically 
any class of craft. 

Separating Russian Prisoners from Vermin 

The Germans have special stations 'on the Eastern 
frontier for "de-licing " friends or foes from Russia 

GERMANY is more afraid of vermin 
than of machine guns. To the 
German military surgeon a filthy 
Russian Cossack — and there is nothing 
f il thier — is 
more to be 
dreaded than 

Germany, in 
particular, has 
to deal with the 
problem in a 
serious way. 
Thousands of 
Russian pris- 
oners of war 
have been 
brought into 
German con- 
camps literally 
swarming with 
lice. One of 
the accompanying photographs shows four 
Russian prisoners as they arrived at a 
camp. Their caps of fur, their whiskers, 
and their heavy clothes were veritable 
breeding places for vermin of all kinds. 
The men were not long in the camp, how- 
ever, before these caps were discarded, the 
whiskers and the hair removed, and new 
clothes supplied. Then they appeared as 
in the right-hand photograph below. 

One of the disinfecting stations at which the Cossacks 
are deprived of their fur caps, coats, whiskers and vermin 

Every man, nobleman or commoner, 
friend or foe, who enters Germany from 
Russia must be "de-liced." There are 
special stations along the eastern frontier 
for that pur- 
pose. Even 
royalty is not 
spared. Prince 
Adelbert, one 
of the Empe- 
ror's sons, had 
to be thorough- 
ly disinfected 
and purified, 
not because he 
needed it, but 
because it was 
the military 
law. He re- 
ceived a guard- 
edly phrased 
certificate to 
the effect that 
"His Royal 
Highness, Prince Adelbert, is, for the time 
being, free from lice." The military disin- 
fectors were not guaranteeing the future. 
Provision is made in all armies for the 
extermination of bacteria-carrying insects. 
All men occupying the same quarters at 
the same time, or for alternating short 
periods of time, are regarded as a single 
unit and are transferred to a receiving 
station equipped with cleansing apparatus. 

Photos (Q) Brown and Daw 

This is a "Before and After" photograph. At left four Russians are shown as they appeared 
when first taken prisoners. They came out of the de-licing station cleaner i| not happier men 



An Attachment Which Will Lock Your 
Camera to the Tripod in an Instant 

AN ingenious camera 
l\ attachment has been 
invented by Clarence J. 
Dawson, of Detroit, which 
will instantly lock your 
camera to its tripod, and 
will just as quickly re- 
lease it. It does away 
with the inconvenience of 
having to turn your cam- 
era a dozen times about 
the tripod stand in order 
to screw it down tight. 
With this attachment, the 
camera can be locked down 
by the mere pressing in of 
a bar, when pointing in 
any direction. 

One-half of the attach- 
ment consists of a metal 
casing which is screwed 
permanently on the tripod 
stand. A slotted locking 
bar slides back and for- 
ward just beneath the top 
of this casing. The other 
half of the attachment consists merely of a 
metal disk through which a flat-head screw 
projects to within one eighth of an inch 
from its end. This half 
is screwed into the 
threaded aperture in 
the bottom of the cam- 
era. The camera is 
immediately ready to 
be locked to the tripod. 
This is accomplished 
by setting the camera 
down so that the flat- 
headed screw passes 
through the hole in the 
top of the metal casing, 
and through the hole in 
the locking bar, also. 
The bar is pressed in- 
ward. The wedge- 
shaped slot in the bar 
grips down upon the 
head of the screw, fast- 
ening down the camera 
in the operation. 

Simple it surely is. 
and it can be made 
very cheaply. Auto- 
matic pressing machines 
could stamp the parts 
from sheet steel. 

Popular Science Monthly 

Inclined surface 

A flat-head screw is passed 
through the top of the casing 
and the hole in the slotted bar 
to the bottom of the camera 

Making the Acetylene Light as Brilliant 
as the Electric Lamp 

THE accompanying 
' diagram shows the 
detaiis of an ingenious de- 
vice which makes the 
acetylene light almost as 
brilliant as that cast by 
the electric lamp on auto- 
mobiles and motorcycles. 
The burner consists of a 
round disk, or "button," 
three-fourths of an inch in 
diameter, set in a pressed 
metal holder. It is made 
of the same white sub- 
stance of which ordinary 
gas mantles are construct- 
ed. A tiny bunsen burner 
directs the flame against 
this disk, which is thus 
caused to give out a 
bright incandescent light. 
The burner is designed to 
fit any standard headlight 
from an acetylene tank. 

Two kinds of light may 
be produced. If the white 
disk and bunsen tube are pointed toward 
the reflector, a brilliant white light is 
thrown far ahead on the pathway. If the 
burner is turned so that 
the flame comes from 
the front, a diffused 
light is cast instead of 
the powerful ray. This 
is really equivalent to a 
dimmer, since it is a 
light which does not 
dazzle. No wrench or 
other tool is required 
for turning the burner. 
It can be easily accom- 
plished with the fingers. 



Here the light is directed into the tree 
top. At right is a diagram of the burner 



Cutting Clippings from Magazines 
with a Pin 

WHEN you lose your knife or do not 
have a pair of scissors at hand for 
cutting the paper a common pin or needle 
of any kind serves the purpose admirably. 
If it is a single sheet from which the 
clipping is to be removed, lay the part on 
another paper, hold the pin slantwise so 
that the point will follow around the 
clipping, just as if tracing its outline. 
Pass back over the scratch with the point 
in the lead and you will be surprised how 
smoothly the pin cuts the paper. This 
method can be used to good advantage by 
the housekeeper for cutting paper that re- 
quires a fairly straight line. — L. Murbach. 

Solid Board Fence with Artistic 
Upper Edge 

THE owner of a small cottage wanted a 
garden in his back yard, and to pre- 
vent prowlers running over it at night it 
was necessary to have a high wall or tight 
board fence. To secure an artistic effect 
the fence was 
made as shown 
in the illustra- 
tion. The scal- 
loped edge ef- 
fect was obtain- 
ed by using 
boards 10 or 12 
in. wide of 4 ft. 
8 in. and 5 ft. 
lengths placed 
alternately. The 
difference in the 
lengths of the 
boards is such 
that the depth 
of the opening 
is less than the width, making a rectangular 
form of a cut-out or scallop. The boxes 
are also spaced evenly and fastened on the 

Ornamented square box 
on the fence corner 

ends of the longer boards. They are square, 
slightly smaller at the bottom than the top, 
with their height about equal to the depth 
of the scallop. Four sharp-pointed orna- 
mental side pieces were nailed on the boxes 
as shown, which aid in bringing out the low 

L). j. ^dtftgfl^ 

■ J ~jMt 

A part of the solid board ornamental fence 
surrounding a corner of the rear garden 

form idea. The flowers grown in these 
boxes are bright colored and decorative. 

Within the inclosure the ground was 
artistically plotted, and laid out with 
gravel paths having wood edges. All 
boards were painted with whitewash or 
exterior water paint. — L. R. Perry. 

Rustic Furniture Made of 
Poles and Logs 

THE illustrations on the next page show 
a new idea in rustic furniture. Al- 
most any kind of wood may be used; 
however, these are small tamarack poles 
and disks sawed from an oak tree. These 
disks, when made very smooth by planing 
and sandpapering, and then given a coat 
of oil and one or two coats of spar varnish, 
present a very fine appearance, showing 
the grain to the heart of the tree. The 
completed furniture is comfortable and 
handsome enough for use anywhere. Some 
of it is heavy, however, and when used 
inside, whether on a porch or in a living- 
room, should be fitted with casters. 



Popular Science Monthly 

The larger portions of each piece of furniture consist of disks of wood sawed from a large tree 
trunk, the other parts being made up of tamarack poles with their ends smoothed and oiled 

No mortising, as in ordinary furniture 
making, is needed. The lapping of one 
piece over the other, leaving the sawed 
ends exposed, is more in keeping with the 
nature of the work. These ends should be 
smoothed, oiled and varnished, the same 
as the disks. Some bolts were put in to 
fasten the arm pieces to back and seat of 
chair, and the legs to set supports. Smaller 
braces and rustic trimmings were nailed in 

In the construction of a chair or settee 
the four most important pieces should be 
selected first — the rear legs, which also 
form the back, and the front legs. If pos- 
sible these should have slight curves. Plan 
and build the back first, arriving at the 
size and putting the cross-pieces in position. 
The front section should then be made. 

Nailing the arm-rests and braces into their 
respective positions will complete a solid, 
rigid chair. 

Tables are easier to build than chairs or 
settees. Careful measurements and simple 
tools are all that are required, and a great 
variety of chairs, tables, settees, desks, 
rustic baskets, and other useful articles 
may be made. The material, in most cases, 
may be gathered during a tramp through 
the woods in vacation-time, or it may be 
purchased at little cost. 

Branches from the wood lot, limbs 
pruned from fruit orchard or shade trees, 
small tamarack or birch trees and the 
ordinary willow from some swampy spot 
may all be used to good advantage. The 
making of the furniture is more of a pleas- 
ure than a task. — J. E. Whitehouse. 

Dimensions of each piece of furniture shown in the halftone illustration above. These dimen- 
sions are not arbitrary but merely give an idea of about the right proportions for comfort 

Using a Drop of Water for a Lens 

It Is a wonderful magnifier in microscopic photography 
By Frank M. Gentry 

EVERY amateur photographer will be 
glad to learn of a method that is both 
simple and inexpensive, by which he 
may make perfectly clear photographs of 
microscopic objects. 

It has been known 
ever since the first scien- 
tific investigations of the 
refractive properties of 
different substances, 
that water, if it could in 
some practical way be 
held in shape, would form 
a lens of extraordinary 
value. Moreover, it is 
also well known that a 
drop of water held by 
capillary attraction in a 
loop of wire forms a 
wonderful magnifying 
lens. The question, 

therefore, arises, "Why 
not use this drop of 
water as a photographic 
lens?" An explanation 
of how this might be 
done follows: 

The first step is to cut 
a disk A from very 
thin copper to fit the lens cell of the camera. 
In the center of this disk, B, there should 
be bored a 1/32-in. or smaller hole. The 
smaller the hole is, the more perfect the lens 
will be and, therefore, the greater its work- 
ing capacity. The edges of the hole should 

The camera as it is mounted on a 
pedestal for microscopic photography 

as to remove all the little particles of pro- 
jecting copper. Great care should be 
taken to follow accurately these instruc- 
tions, as the result will depend on your 
faithfulness in this re- 

Next remove the lens 
from its cell ; reverse the 
threaded ring which held 
it in place; insert the 
copper disk, and screw 
in place with the ring. 
The result may be seen 
in the illustration on 
page 125, where C rep- 
resents the lens cell; D, 
the threaded ring; E, 
the copper disk, and F, 
the drop of water. The 
cell may now be screwed 
back into the camera 
until ready for use. 

In order to place a 
drop of water in the hole, 
a wire should be bent as 
shown at G. Dip the 
straight end into the 
water. When it is re- 
moved, the drop that 
adheres will be just enough to properly fill 
the opening. Patience is required to place 
the drop accurately so that it will not run 
over the edges, which would be disastrous. 
The operation may consume over an hour 
but the results well atone for the trouble. 

then be rubbed carefully on an oilstone so Glycerine or castor oil may be used in place 

At left: Crystalline formation of a bichromate of potassium solution on a gelatine slide. In 
center: Portions of the antennae of a beetle. At right: Microtomic cross-section <>f a stem of fern 



Popular Science Monthly 

of water; in fact, the former may be 
preferred to it, for, although it necessitates 
a somewhat longer exposure, it is free from 
evaporation and is not so likely to be 
jarred out of place, on account of its 
superior capillary attraction. 

At left: Microtomic cross-section of a rue 
leaf. Right: The hair on the leg of a housefly 

A standard must next be constructed, as 
shown at H, and /. No dimensions will be 
given as the construction will vary with the 
type of camera employed. Near the top of 
the standard a 34-in. stovebolt, J, should be 
inserted and screwed into the tripod 
socket, thus holding the camera in place. 

The adjustable slide-holder is next to be 
considered. Some time was spent and a 
quantity of material utilized in devising 
methods of construction for this important 
part. The one which proved to be the most 
successful is shown at K. It represents a 
piece of H-in. wood (a cigar box will do) in 
which a ij^-in. hole, L, was cut. On each 
side of this hole a 5/32-in. bolt, M, was in- 
serted and made stationary by the nuts N. 
A long battery bolt will serve the purpose 
excellently. Another piece of K-in. stock, 
0, somewhat longer than the other, with a 
i3^-in. hole as shown at T, was also made. 
To one end of this second piece there was 
nailed a 3^-in. square strip, P, which served 
to fasten the whole part to the standard. 
On either side of the ij^-in. hole of the 
second piece, there was bored a hole cor- 
responding to the bolts, M, and large 
enough to permit them to slide up and 
down easily. Springs, Q, were then 
slipped on the bolts, which were in turn 
passed through the corresponding holes in 
O. Thumb nuts, R, such as are found on 
batteries, were then screwed on the bolts. 
By tightening or loosening the thumb nuts, 
the slide-holder was adjusted to the lens. 
A strip of spring brass, S, was then fastened 
on K, to hold the slide rigid. When it was 
desirable to use a color-screen in photo- 
graphing or examining any object, the 
filler was laid over the hole, T, on J. The 

adjustable holder was then mounted by 
means of a strip, P, on the standard near 
the lens U, in the shutter, V. On account 
of the great magnification the focus is 
necessarily very short; indeed, it has been 
found that when a 6-in. bellows extension is 
used, the focus is not quite 1/16 in. 

An adjustable mirror, W, must be 
mounted on the standard base, H, by 
means of an axle working on pivots in the 
strip X. 

To operate, the object to be photo- 
graphed must be placed on a thin glass 
slide which should be fastened by means of 
the spring brass clip, S, over the hole, L, in 
strip, K. The bellows containing the 
water lens must be extended as far as 
possible. The mirror, W, should be 
adjusted until the direct sunlight is reflected 
through the slide into the camera. Focus- 
ing is then accomplished by tightening or 
loosening the thumb nuts, R, as the case 
may be. The plate is then placed in posi- 

An ordinary camera attached to support for 
making microscopic views with a water lens 

tion and the actual photographing carried 
on as usual. An old magic lantern may be 
used as the source of illumination; but 

Popular Science Monthly 


whatever the source, the light must be very 
strong. The exposure must be found by 
experiment, as it varies with the light, size 
of the lens, the subject photographed and 

The disk for holding the drop of water in 
lens barrel and the slide holder attachment 

whether or not a color screen is used. The 
accompanying photographs show the fin- 
ished instrument and several of its photo- 

Very convenient slides may be made by 
cutting old lantern plates the right size. 
Colored glass makes very good filters when 
they are needed. It is of course under- 
stood that some transparent objects, such 
as the white blood corpuscles, must be dyed 
before photographing in order to render 
them visible. 

The magnification of this instrument 
ranges from 300 to 500 diameters, depend- 
ing upon the lens and bellows extension. I 
have successfully examined and photo- 
graphed blood corpuscles, the starch cells in 
a potato and various other things by 
this method. On one occasion while using 
a magnification of 923.5 diameters the hair 
on a fly's leg appeared 2J/2 in- 
long. Another time, while ex- 
amining the wing of a recently 
killed fly I was able to see the 
watery fluid drying up in the 
capillaries. To perfect this 

method several different instru- 
ments were tried out during 
more than a year of experi- 

The same method of con- 
structing a lens may be used in 
a similar manner for an ordinary 
microscope in cases of emer- 
gency, but the drop of water 
will need to be a trifle larger 
than for the camera lens. It can be made 
in a small loop twisted on the end of a small 
wire, allowing sufficient end for a handle. 

An Effective Fireproofing for 
Children's Clothing 

IT is a common occurrence for children's 
clothing to take fire from playing with 
matches and from other causes. This 
may be prevented by a little precaution 
which may be taken every time the chil- 
dren's clothes are washed, particularly the 
dresses, suits and petticoats. 

A non-inflammable solution of I oz. of 
alum or sal ammoniac should be added to 
the rinse water or starch. This renders 
the garments practically fireproof. Should 
they take fire, they would burn very slowly 
and without flame. — Jennie E. McCoy. 

Collecting Ants in a Sponge and 
Drowning Them 

ANTS in the house or on the lawn can 
be quickly eradicated in the following 
way: Wet a large sponge and sift sugar 
all over it and place in the infested spot. 
It will be filled with ants in a very short 
time. Sink it in a pail of water and the 
ants will leave it and drown. Repeat the 
operation until they are all destroyed. 

Exterminating Moles and Gophers 
by Asphyxiation 

IN some of the Western States moles and 
gophers are a great pest and difficult 
to exterminate. One of the best methods 
of getting rid of these animals is to fill their 
holes with the burnt gases from the ex- 
haust of a gasoline engine. The illustra- 
tion shows the method used by a Western 
farmer for the purpose. He attached a 
hose to the exhaust of an automobile 


the deadly gases from the exhaust of the auto- 
engine into the burrows of moles and gophers 

engine and forced the burnt gases into the 
burrows of the animals, causing death by 

126 Popular Science Monthly 

Exhibiting Specimens of Flowers in 
Single Blossoms 

CERTAIN flowers, such as pansies, can- 
not satisfactorily be shown in bunches, 
but should be exhibited as separate speci- 
mens. To put each in a vase by itself takes 

up too much 

impair the transparency of the cloth. 
With a little care any missing lines of the 
drawing may be drawn on the plaster 
filling the gap. — Louis Fleischer. 

room and 
more glass 

than flowers. A good way to exhibit such 
blossoms is to make a table top of soft 
wood and bore holes into it for inserting 
glass tubes. The top of the table should 
then be covered with paper, through which 
the flower stems may extend down into the 
water-filled tubes. Most amateur photog- 
raphers can soon collect a number of 
developer tubes, which are just the thing 
for this purpose. If these cannot be 
obtained, little "homeopath" vials may be 
found at the druggist's. These tubes may 
be arranged in the shape of letters, or if 
desired, emblematic designs may be formed 
for table decorations. The effect of each 
flower standing seemingly by itself without 
any support is surprising as well as pleas- 
ing. — W. H. Sargent. 

A Tracing Cloth Repair That Does 
Not Affect Transparency 

THE principal objection to patching a 
tracing cloth is that the part covered 
is no longer transparent enough for making 
a perfect blue print. If the tear is not too 
large, apply liquid court plaster to the parts 
and allow it to dry. This holds the parts 
together, fills the gap or hole and does not 

Difference in Curing Time of Parts 
Makes Poor Tire Repair 

SOME repairmen attempt to use ma- 
terials from two or more concerns on 
the same job. For example, sometimes a 
fabric is bought from one firm which cures 
at 40 lb. steam pressure for 40 minutes, 
with gum from another firm, curing at 55 lb. 
for 50 minutes. This combination in- 
evitably results in improper curing of one 
or the other, or both of these materials. It 
is best to use one make of repair materials 
for satisfactory results. 

Porcupine Removes Window Pane 
to Gain Entrance 

THE wily ways of a porcupine and its 
almost human intelligence are illus- 
trated in the accompanying picture. A 
camping party having food stuffs stored in 
a cabin, left the place for a few days to go 
fishing across the lake. They left the door 
and windows securely locked, but upon 
their return they found that a porcupine 
had gained entrance and played havoc with 

After gnawing through the window-sash frame 
the porcupine knocked out the pane of glass 

their edibles. The creature evidently tried 
various ways to get in, but finally suc- 
ceeded in gnawing through the window- 
sash frame at the corner and knocking out 
the glass pane in that section. 

Popular Science Monthly 


Round Belt Guide on a Washing 
Machine Wheel 

THE circumference of the washing ma- 
chine flywheel shown in the illustration 
is divided into 

eight equal parts 
and at each di- 
vision a pair of 
3/16-in. holes 
are drilled. Pieces 
of stiff wire bent 
U-shaped and 
about4 in. long are 
slipped through 
these holes from 
the inside of the 
wheel rim and 
their ends bent 
outward as shown . 
These wires serve 
as guides to keep 
the belt on the 
center of the wheel. — Geo. C. Rousch. 

The U-shaped belt guide 
made of pieces of wire 

A Vine Covered Tepee in the Garden 
for the Little Folks 

AVERY attractive tepee can be built of 
2 by 4-in. timbers, as shown in the 
illustration. First lay out a plot of ground 
and box it in with the timbers, filling up the 
part within with dirt to the upper edges 
of the timbers. Near each corner of the 
frame stand one of the timbers, allowing 
the upper end to slope toward the center 

of the square where all four meet. Then 
tie or spike them together. 

Morning-glory vines are planted around 
three sides of the base and are trained up 

The vine-covered tepee admits the cool 
breeze and keeps out the hot sunshine 

to trail over wire mesh fastened to the 
timbers. The fourth side is left open to 
provide an entrance-way. Lawn chairs 
and a table may be placed inside. The 
breeze from any direction can enter such 
a tepee and the hot rays of the sun will be 
kept out. — Edward F. Bigelow. 

A plot is boxed in and timbers set up in 
tepee form and covered with wire mesh 

A Shaft-Polisher Made Like a 
Lemon Squeezer 

PISTON rods, mandrels and similar 
shafts of considerable length turned in 
a lathe are usually given a high finish. 
Where no grinding fixtures are available 
this finishing must be done with files and 
emery cloth. A polisher for such work that 
gives more pressure on the surface and does 
better work with less fatigue may be made 
on the principle of a wood lemon squeezer. 
Two pieces 3^ i n - wide and 1/% in. thick are 
joined at the back with a piece of old belt 
leather for a hinge. Shallow grooves are 
cut across the boards on the inside and 
pieces of emery cloth tacked in them. The 
leverage gives as much pressure as desired. 


Popular Science Monthly 

Building an Artistic Bird -House 
For the Garden 

THE design as shown by the drawing is 
an attempt to carry out a pergola 
effect. The general dimensions are II ft. 
6 in. from center to center of round columns. 
From the ground to the under side of upper 
beam is 12 ft. The diameter of columns at 
base is 1 ft. 5 in., at the top 1 ft. 3 in. 
The general di- 
mensions can 
be changed to 
suit the partic- 
ular fancy of 
the amateur 
builder, but 
for satisfaction 
and to avoid 
mistakes they 
ought to be car- 
ried out as 
shown. The 
columns are of 
wood of built- 
up construc- 
tion, and set in 
the ground not 
less than 6 ft. 
That portion in 
the ground 
and 6 in. above 
ground line is 
coated with tar, 
both inside and 
outside. The 
inside of each 
column, partic- 
ularly the lower 
portion, is re- 

It adds much 
to the stability 
if that portion 

A very neat design for several bird-houses set on the cross 
beam of a structure resembling a pergola over a walk 

of the columns below ground line is in 
concrete. At the ground line base of the 
column there is a concrete finish, octagonal 
in form and about 7 in. high, and on the 
four sides there is a square block 6 in. high. 
The edges are slightly rounded. All are 
built of cement or stone, with suitable 
foundation. The columns, beams, and other 
woodwork are of cypress. The column cap 
is square. On top of each column cap is a 
wood beam or bracket 4 ft. long, 1 ft. 3 in. 
wide and 10 in. thick. The ends are shaped 
as shown. This short beam or bracket is of 
built-up construction and is laid trans- 

versely to the long beam above. On top 
of these two wood beams, a longitudinal 
beam is securely set in place. This beam* 
is 17 ft. long, 1 ft. 3 in. wide and 1 ft. 1 in. 
thick, and is of built-up or box construction. 
The ends are shaped as shown. The top of 
this beam slopes from the center to each 
side. The slope is about Y% in. The top is 
covered with tin, painted on each side. 
There are sixteen separate compartments 
or rooms on 
each side of the 
beam, also six 
more on top of 
the beam in the 
gables. There 
is a wood parti- 
tion dividing 
the front and 
the rear, also 
cross - pieces, 
giving each 
about 6 in. by 
6 in. floor space. 
The height is 
the height of 
the inside of 
beams, or the 
gabled roofs as 
the case may 

Each com- 
partment has 
an opening 
with semi- 
circular top. 
From the floor 
to the base of 
circle it is 2^ 
i n. high; the 
width is 2 in. 
The opening is 
splayed on the 
inside, to carry 
out the drippings during rain storms. 

Outside of each opening is a latticed shelf 
or ledge 6 in. wide with a 9 in. projection. 
On top of the beam there are gables. Each 
gable has two compartments, built in detail 
the same as specified for the lower compart- 
ments. The roof of gables is covered with 
tin. On top of this tin there is wood tile. 
This tile is thoroughly painted in red and 
thoroughly sanded. 

The openings at each end of the beam 
have a small slanting roof. The cross beam 
extending from column to column is made 

Popular Science Monthly 




^ ^::?^g jy 







I 1 I [ 1 


SECTio Hat- 


Diagrammatic drawing showing dimensions and plan. The entire structure is built up of wood 
for the framework and covered with concrete, the bird-houses on top being covered with tiles 

The inside compartments, including the 
floor, are built independent of the side wall 
and top, so that they can be let down from 
below for cleaning. These are held in place 
at each end -with a metal chain which runs 
over a suitable pulley on the inside of the 
column and down to a point opposite open- 
ing 4 ft. from the ground and suitably 
secured in place. The opening for access 
to the above chain has a suitably hinged 
door. All woodwork is painted a light gray 
color and finished in sand. 

A Printing Process for Imitating 
Hard Woods 

THE art and practice of graining dates 
back about 150 years, the exact period 
not being known; hence imitating hard- 
woods is by no means a modern idea. An 
expert grainer to do his best, uses only his 
best; whereas Nature, always variable, 
gives us her best and her worst, and the 
result is seen in poor cabinet work. In 
other words, the woodworker in making 

up a piece of work will often use pieces of 
natural wood that are not beautiful and 
often not matched so that the finished job 
will not compare with that of the expert 

For some time past there has been a 
serious shortage of fine hardwoods suitable 
for cabinet work and, to help out, veneers 
have been used. For this the wood is 
sliced into extremely thin pieces or sheets 
which are glued to a baser wood; or plain 
woods are stained to make them look like 
the finer hardwoods. Various methods 
other than graining have been adopted for 
imitating hardwoods. About 25 years ago, 
a Pittsburgh painter invented a machine 
for filling a board with punctures so that 
when it was stained the surface resembled 
oak. The board could be sawed and cut 
in the ordinary manner and finished in 
perfect imitation of oak. 

The most modern method of graining 
employs a printing roller. The roller is 
made of a strong light wood, well seasoned. 
This may be in the form of a segment of 


Popular Science Monthly 

a circle, in which case it works with a 
rocking motion. The length of the segment 
should be sufficient to cover the surface to 
be grained, otherwise it will be difficult, 
but not impossible, to make the joint un- 
noticeable. A full circle roller is made as 
follows: Take a shaft and fix upon it, by 
mortise or otherwise, spokes of proper 
length, according to the size of the desired 
circumference, and around these spokes run 
or bend a strip of 3^-in. gum wood. If the 
ends of the shaft are smoothed off and 
allowed to extend about 4 in., handles will 
be provided toehold the roller in operation. 
Place around this roller the composition for 
making the print. A large roller may be 
made with a circular head of i-in. board 
having flanges from % to I x /> in. larger 
than the roller. Turn the roller over and 
stop all holes with plaster of Paris. The 
best way to do this is to run the plaster 
all around the inside of the roller. In the 
head of the roller, as it stands upright, cut 
three or four notches along the edge, about 
1 by 2 in. to make places for pouring in the 
composition and for letting out the air. 
Make a long smooth strip of zinc large 
enough to cover the roller, rub it over well 
with grease or oil, then place it around the 
roller and pour in the composition. The 
oiled or greased side must be next to the 
composition. A very large roller will need 
collar bands to hold the zinc. Draw the 
zinc around the heads of the roller and 
pour in the composition through a strainer. 
Allow it to stand for at least 12 hours 
before removing the zinc. 

Making the Roller 

To make a smaller roller form it in a 
mold made of a light wood frame of the 
required size, set on a piece of zinc or 
glass. Pour the composition into it, then 
lay a piece of canvas on top of it. When 
cool, attach to a roller or rocker with tacks. 

The composition is made as follows: 
Heat 12 oz. of raw linseed oil to the boiling 
point and add 1 oz. of chloride of sulphur. 
In another vessel dissolve 2 lb. of the best 
white glue and when melted add 8 oz. of 
commercial glycerine. Use as little water 
as possible in melting the glue. The best 
way to dissolve or melt glue is to pour 
enough cold water on the dry glue to cover 
it and let it soak over night. It will take 
all the water it can hold. Pour off the 
surplus water and add enough boiling water 
to melt it. To the glue add 8 oz. of com- 
mercial glycerine and mix well. 

Another formula is to dissolve or melt 
24 parts of the best white glue and add to it 
12 parts of commercial glycerine, which is 
cheaper than the drug-store brand. For a 
roller requiring from 10 to 15 lb. of com- 
position add Y /2 pt. each of molasses and 
raw linseed oil. To test the composition 
for consistency, cool a little of it and if it 
dries too stiff add a little glycerine; if too 
soft add more glue. This composition 
should be kept hot until used. Boiling it 
will do no harm, as this is inclined to drive 
off more of the surplus water. 

Now for the Scraper 

A scraper will be required and it is made 
as follows: Procure a piece of white pine 
board 12 in. long, 4 in. wide and Y% in. 
thick and make a groove in one edge of it 
1 in. deep in which a piece of sole leather is 
placed after giving the depression a good 
coat of glue. The piece of leather should 
be about \]/2 in. wide and as long as the 
board. The edges of the board should be 
planed down so that it will not interfere 
with the projecting 3^2 in- of leather. 

The printing color should be a little 
heavier than oil paint. It is composed of 
pigments ground in Japan. A board is the 
next requisite. It is made from the kind 
of wood to be imitated. Select as fine a 
figured specimen as possible and make it 
perfectly smooth and even of surface. This 
board must be 6 in. wider and 1 ft. longer 
than the circumference of the roller. Nail 
thin strips around the edges of the board, 
allowing them to extend 1 in. above the 
surface. Bore a y^-m. hole in one corner 
through which to pour off the liquids when 
cleaning it off. With the board ready, 
prepare a solution of I lb. of concentrated 
lye dissolved in hot water and pour it on 
the board's surface, allowing it to remain 
for 20 minutes. Then pour it off through 
the hole in the corner and rinse with clear 
water to remove the lye, after which flow 
a little vinegar water over it to neutralize 
the lye. The board is then left to dry out 
thoroughly, after which it may be lightly 
rubbed with fine sandpaper. The lye 
removes the soft fibers of the wood, leaving 
on the harder grain an effect similar to 
etching. The board is then ready for the 
printing process; but first try it by making 
a print from it on paper. If it shows an 
imperfect or faint print apply the lye 
solution again. Pour some of the printing 
color on the impression-board through a 
strainer. The printing color is made into 

Popular Science Monthly 

a paste form with turpentine, working it 
as smooth as butter. When ready to use, 
thin out with more turpentine and add a 
little boiled linseed oil, which is to keep 
the paint from 'drying on the board. Do 
not make the printing color too thin; use 
plenty of it so that the sunken parts will 
be filled level-full. Then with the scraper 
spread the paint out evenly, pushing the 
tool forward, using both hands to press it 
down hard. This will leave the sunken 
parts full and the high parts smooth. 


An Improvised Stage for an Out of 
Doors Fairy Play 

AUTOMOBILES, four on the right and 
. two on the left, furnished most of the 
light for a fairy play, "The Merman's 
Pipe," produced under the direction of 
Mrs. A. J. Commons, at Merrill Springs, 
Wisconsin, for the benefit of a rural school 
social center five miles away from any stage 
machinery or electric lights. Each car 
was so turned as to throw the rays of the 

The brilliant rays from the headlights of six automobiles and a number of lanterns furnished 
the spotlights and footlights for a fairy play given at night in a far-from-the-city locality 

With everything ready and the impres- 
sion-board filled with color, take the roller 
in both hands and select a point on the 
roller-surface at which to start. Place this 
part down on the board, and with a firm, 
even pressure roll it along over the surface 
until one complete revolution is made. 
Be careful to stop when the starting point 
of the roller is reached. This is to avoid 
making a lap. Carefully pick up the roller, 
not permitting it to slip on the board, and 
place it down on the surface to be grained. 

The first impressions from a new board 
are seldom good and for this reason it is 
better to make several on some other 
surface until the board gets into proper 
shape. When you have finished with the 
board and roller clean them off with 
benzine and a stiff brush. 

lamps on some important scene. In that 
way they provided six areas of spotlight. 

For footlights the farmers brought their 
lanterns. The producer arranged these 
along the inside of a screen made out of 
the finest poultry wire interwoven with 
leafy branches. Sheets of tin reflected the 
light upon the stage. One scene in the 
foreground demanded stronger illumina- 
tion. There a large carriage lamp was 
used instead of a lantern. 

The lake shore was the background; 
but that was not essential, for the play was 
repeated later where there was no lake. 
A green curtain hung on wires, with brush, 
leaves, and rushes fastened to it, gave a 
dense leafy drop that helped out wherever 
Nature failed to provide the proper screens 
of foliage. - 


Popular Science Monthly 

A phonograph behind some convenient 
bushes took the place of an orchestra. 
Another clump of trees served to show 
where the fisherman's hut was supposed 
to stand. Such was the stage and its 
machinery. The audience, seated ancient 
fashion upon the hillside, enjoyed what was 
probably as lifelike a presentation of fairy- 
land as could be produced by human 
beings. — Shirley L. Seifert. 

An Experiment in Optics Using 
Heated Graphite 

AN interesting experiment in optics may 
. be performed in the following manner: 
Take a bit of hard graphite, such as a lead 
pencil, and hold it in the tip of a candle 
flame until it is completely covered with 
soot. It will then appear black in the air, 
but lay it in some water, completely 
covering the lead part, and it will appear 
like silver. The explanation of this phe- 
nomenon is that the water is unable to 
touch the object, due to surface tension and 
lack of cohesion. The water then acts 
like an unsilvered sheet of darkened glass, 
reflecting the light. — Thomas W. Benson. 

Small Hand Drill Made from 
a Cheap Watch 

IN doing some very fine repair work it 
was necessary to use a smaller drill 
than could be used in a breast drill without 

Two small clock gears used in the frame of 
a cheap watch to drive a small drill point 

breaking. To accomplish the drilling of 
very small holes I made a drill driver of 
an old dollar watch and some parts taken 

from a discarded alarm clock. All the 
wheels, ring and winding stem of the 
watch were removed, keeping the frame 
intact, as shown at A. The drill chuck 
and drive shaft B were made from the 
ring bolt taken from the alarm clock. The 
nut C was cut on the dotted line and the 
knurled part used for tightening the slotted 
end of the bolt on the drill shank. Of 
course it is necessary to drill a hole and 
saw a slot across it in the threaded end of 
the bolt for the chuck jaws. 

Two suitable gears were taken from the 
clock movement and arranged as shown 
in the watch frame. The bolt is filed or 
turned down to the dotted lines D to fit 
into the hole in the watch stem. A crank 
is attached to the driving shaft as at E. 
The handle for the crank is made from 
one of the feet on the alarm clock, the 
arm being cut from a piece of sheet metal. 

A Snap-Fastener for a Small 
Cupboard Door 

AN efficient fastener for small cupboard 
l doors can be quickly and easily made 
from a brass-headed tack, a piece of soft 
rubber, a small piece of tin and a few small 
nails. Bore a hole in the edge of the door 
% in. in diameter and 
at least Y2 in. deep at 
the location for the 
fastener. Cut a piece 
of the soft rubber to a 
shape and size that will 
entirely fill the hole 
and drive the brass- 
headed tack into the 
rubber as shown in 
section drawing, taking 
care, however, that the 
tack is not long enough 
to enter the wood at 
the bottom of the hole. 

Cut a piece of tin or 
other sheet metal about 
% in. square and form a depression in its 
center that will be just the size and shape of 
the head of the brass tack. Punch a small 
hole in each corner for nails. 

In order to find the exact spot where the 
plate should be placed, open and shut the 
door a few times, causing the tack head to 
draw a mark on the door frame. At the 
extreme end of this mark make a shallow 
depression. Place the convex surface of 
the plate in this depression, tack it into 
place and it is ready for use. 

placed on a cup- 
board door 

made at 
home, an 
outfit of 
awnings will not 
be expensive. The 
material is cheap, if pur- 
chased in bulk, and the only 
[/ IT equipment required for the manu- 
facture is a sewing machine, a pair 
of shears, a small pipe-wrench, a hack-saw, 
and a ^-in.pipe die. The frame is made from 
«H$-in. galvanized pipe and fittings. Black 
pipe will rust. For example take an awning 
24 ft. long, sup- 
ported on four 
pillars, and hav- 
ing about a 4^ ft. 
reach. Assume a 
porch 9 ft. from 
floor to plate. 
The fringe or va- 
lance should not 
be nearer the 
floor than 4 ft. 
when fully low- 
ered. This will 
protect the eyes 
when sitting from 
an almost level 
sunlight. Mea- 
sure the porch, 
and chalk out on 
the floor a profile 
view as shown in 
Fig. 1. Put a 
2-in by i^-in. 
batten along the 
front of the plate 
as shown. This 
takes the screw 
eyes used to fast- 
en the awning at 

the top, and prevents marring the paint. 
It can be taken down by removing a few 
brass screws when the awning is stored for 

oAwnmgsfoT the Veranda 
and How they areZMade. 

By H&Tallman 

the winter season. Chalk the position of 
the batten on the diagram. Lay off the 
outline of the end piece, remembering to 
allow 8 in. for the balance. If the material 
shows alike on both sides, it will save 
waste in cutting the end pieces. If it has 
alternate stripes of white and a solid color, 
this is sure to be the case. Otherwise it 
must be examined carefully before cutting, 
to make sure that no difference in appear- 
ance is visible. 

For the canopy, cut the goods into 
lengths of exactly 7 ft. This allows a 2-im 
hem at the top, 6 ft. 1^ in. for the slope, 
8 in. for the valance, with an allowance of 
3^ in. for take up where it folds around the 
frame. In selvedge sewing, lay the two 
pieces with selvedges parallel, one project- 
ing about 5/16 
in. past the other. 
Turn this pro- 
jecting edge over 
the other, and 
sew as shown at 

A. Then unfold 
until flat and sew 
again as shown at 

B. Repeat this 
process with each 
selvedge joint 
until the required 
length is put to- 
gether. Be sure 
the sewing ma- 
chine takes a 
fairly fine stitch, 
properly locked, 
and does not 

When com- 
pleted, draw each 
seam over the 
edge of a table or 
the back of a 
chair to smooth 
it and equalize 
the stitching, 
should be about 



The manner of making the cloth joints and sewing 
the seams, also the details of the pipe frame 


awning it 

For a 

24 ft., 1 }/2 in. long. The selvedge seama 

have each taken up ab^ut % in. If the 



Popular Science Monthly 

goods are 36 in. wide, there are eight of 
these seams. So 6 in. have been lost. This 
requires a portion of another strip 8 in. 
plus 1 3^2 m - plus % in., equal to ioj^ in. 
wide. Along the top edge, turn back 2 in. ; 
turn under the raw edge, and sew as in- 
dicated at F. The end flap is next attached 
as shown at G, using the method shown at 
D and allowing the finished heading to 
stand outside. If the stripes are of equal 
width, get a tin-can lid, a tea-cup, or other 
circular object the same diameter as the 
width of stripe, and with chalk draw a 
line on the goods half the width of the 
stripe from the edge of the valance, which 
must be first trimmed straight and true. 
Scribe alternate semi-circles in successive 
stripes, and cut out a wavy line on this 
scribing. The raw edge so produced must 
be bound with woolen tape, which can be 
purchased where the cloth is procured. It 
will take about eighteen yards of tape to 
bind the valance for this awning. 

An alternate method would be to cut a 
slash, 4 in. long and 1 in. wide, Yi in. on 
each side of each stripe line, or each alter- 
nate stripe line, if the stripes are equal and 
regular. For an irregular stripe a spacing 
can be selected and repeated without regard 
to the stripes. This method will require 
30 to 40 yards of tape for binding. Be 
sure to use wool tape in red, blue, white 
or green, all of which are fast colors. Cotton 
tape is always bleached by the weather. 

The frame is made of ^-in. galvanized 
pipe and malleable fittings. Cast fittings 
are too bulky. For this frame two elbows, 
and six tees are required. Four of these 
tees, which form the hinges against the 
porch posts, must be cut with a hack-saw, 
as shown at J in the drawing. This will 
reduce the length of the tee arm to about 
h /% or % in. From a piece of galvanized 
sheet steel, say }/% in. or number 10 or 12 
gage, make four double brackets as shown 
at K. Drill and countersink these on 
the center line of the back for two 10 by 
iJ4-in. wood screws. Drill a hole for a 
short ^8-in. bolt through both ears. When 
they are finished this far, drop them in a 
glass jar filled with bluestone solution, 4 oz. 
bluestone or blue vitriol to a pint of water. 
Leave them for several hours. Remove 
from the jar and dry. Polish them with 
an old rag, and you will find all the spots 
left after the galvanizing was removed are 
now plated with copper and rust proof. If 
dipped in strong vinegar before placing in 
the bluestone bath they will plate more 

readily and take a heavier coat. Do the 
same with the cut tees and the hinge bolts. 
When all this is attended to, the frame is 
assembled by screwing up the threaded ends 
of the pipe into the fittings. Make up 
good and tight, everything square, and lay 
the awning down as shown in G, lay the 
frame on it in the proper position, and pro- 
ceed to put on the pocketing material. 
This is a strip of the awning material, 
3 in. wide and 7 ft. long, sewed to the line 
where the slope stops and the valance 
begins. When sewed true on one side, turn 
the strip over the frame and sew to the 
awning above the frame as shown at L. 
This must be done along the front so that 
the weight of the frame holds the awning 
taut when lowered. For the ends, it is only 
necessary to put on a strip of the material 
3 in. wide near the hinge. All raw edges of 
the valance as well as the seams for the 
ends and where the valance joins the slope, 
should be bound with the wool braid, care- 
fully run on by machine. Soft laid cotton 
cord about x /i in. in diameter, run through 
small galvanized-iron pulleys, will serve to 
raise and lower the awning. A lead of this 
should be placed in the center of each panel 
and all cords led to one end where a cleat is 
provided to fasten them. 

Fastening an Oar-Lock to Keep 
It from Falling Out 

IF an oar fits a lock snugly the lock is 
likely to be pulled out of the socket when 
the oar is re- 
moved, and it 
may be lost. I 
have found that 
fastening such a 
lock in the man- 
ner illustrated 
will prevent 
this. A stout 
cord is tied to 
one arm of the 
lock and run 
through a screw- 
eye turned into 
the block or oar- 
lock base as shown in Fig. 1. A small 
metal bar is fastened to the other end of the 
string. The bar when turned parallel to 
the string, as in Fig. 2, can be slipped 
through the eye of the screw. To keep the 
bar from slipping out of the knot a depres- 
sion should be filed out in its center, 
circling the bar. — G. P. Lekmann. 

Fastening an oar-lock 
securely with a string 

A Boomerang Flyer , » 

A LITTLE gyroscopic flyer which can 
be adjusted so it will return like a 
boomerang can be made by any 
intelligent boy. Excepting the shaft, every 
part can be made with such simple tools as 
a jack-knife, a pair of pliers and a hammer. 
The only outside work required is the boring 
of two small holes in the shaft. This a 
watchmaker or jeweler will do. 

The flyer may be made any size, but as 
the power which is available must be con- 
sidered, the following dimensions are sug- 
gested: The disk A should be 10 in. in 
diameter made of a thin tar board, for this 
material is absolutely flat and does not 
warp or twist out of shape. Aluminum is 
also serviceable. Unlike the common glid- 
ers, lightness is not the first consideration. 
On the other hand, weight is of con- 
siderable importance, as the ability of the 
device to soar depends on the momentum of 
the disk itself. In using aluminum, No. 28 
gage is the best thickness. 

Centrally in the disk is a hole to receive a 
3/16-in. steel rod B, 4 in. long. Exactly in 
the center the rod is bent at right angles so 
that each part, B and C, is 2 in. long. The 
part C is bent laterally, at a point midway, 
as shown at D, so that it will lie flat on the 
disk, and an end E is turned up so it will 
serve as a crank handle. The object of 
this arrangement is to provide a means 
whereby the disk can be rigidly fixed to the 
stem so the plane of its surface will be 
maintained perpendicular to the stem B. 

After the stem B is placed in the central 

hole of the disk, wire staples F may be 
used to fasten it firmly, as shown. Through 
the stem portion B two small holes G are 
drilled Yi in. apart, to receive a bent pin 
or wire H, which provides a means for 
attaching a rubber band. 

The body of the flyer is made of a strip of 
pine /, g}/2 in. long, 1 in. wide and % in. 
thick. The interior portion of this strip is 
cut away to form an upper and a lower bar. 
The forward end is tapered off to form an 
A-shaped edge, while the rear end has a 
blade /, made of thin aluminum 2 in. long 
by i}/2 in. wide, to serve as a rudder. The 
metal should be thick enough to remain set 
after bending in either direction. 

A hole is bored vertically through the 
upper and lower bars of the frame to 
receive the stem B. A short tube K, % in. 
long, is placed on the stem between the 
disk A and the upper edge of the strip /, 
and a thin washer L is placed between the 
pin H and the lower side of the upper bar. 
By this means the stem B is held rotatably 
fixed to the frame. 

The rubber band M which serves as the 
motive power, should be 4 in. long by J/£ in. 
wide, a size easily obtained. The rear end 
of this elastic is secured to the side of the 
strip / by means of a wire staple N. 

If the elastic band is wound up and the 
flyer thrown into space it will sail along 
with remarkable evenness of flight, due to 
the gyroscopic action of the rotating disk. 
The propelling device consists of a pair of 
triangular-shaped blades, 0, secured to the 
opposite ends of a light wire rod P. This 
rod has at each end a projecting right- 
angled bend Q, to which the blades are 

Each blade has at its rear margin a 
downwardly-projecting and rearwardly- 
extending finger R, which passes through a 
slit in the disk A. These fingers have two 
functions; first, to hold the propelling 
mechanism in place, and second, to rock 
the wire rod P back ^id forth. The 



Popular Science Monthly 

goods are 36 in. wide, there are eight of 
these seams. So 6 in. have been lost. This 
requires a portion of another strip 8 in. 
plus \]/2 in. plus z /i in., equal to \o\i in. 
wide. Along the top edge, turn back 2 in.; 
turn under the raw edge, and sew as in- 
dicated at F. The end flap is next attached 
as shown at G, using the method shown at 
D and allowing the finished heading to 
stand outside. If the stripes are of equal 
width, get a tin-can lid, a tea-cup, or other 
circular object the same diameter as the 
width of stripe, and with chalk draw a 
line on the goods half the width of the 
stripe from the edge of the valance, which 
must be first trimmed straight and true. 
Scribe alternate semi-circles in successive 
stripes, and cut out a wavy line on this 
scribing. The raw edge so produced must 
be bound with woolen tape, which can be 
purchased where the cloth is procured. It 
will take about eighteen yards of tape to 
bind the valance for this awning. 

An alternate method would be to cut a 
slash, 4 in. long and 1 in. wide, % in. on 
each side of each stripe line, or each alter- 
nate stripe line, if the stripes are equal and 
regular. For an irregular stripe a spacing 
can be selected and repeated without regard 
to the stripes. This method will require 
30 to 40 yards of tape for binding. Be 
sure to use wool tape in red, blue, white 
or green, all of which are fast colors. Cotton 
tape is always bleached by the weather. 

The frame is made of ^8-in. galvanized 
pipe and malleable fittings. Cast fittings 
are too bulky. For this frame two elbows, 
and six tees are required. Four of these 
tees, which form the hinges against the 
porch posts, must be cut with a hack-saw, 
as shown at J in the drawing. This will 
reduce the length of the tee arm to about 
% or % m - From a piece of galvanized 
sheet steel, say Y% m - or number 10 or 12 
gage, make four double brackets as shown 
at K. Drill and countersink these on 
the center line of the back for two 10 by 
\"%-\n. wood screws. Drill a hole for a 
short %-\n. bolt through both ears. When 
they are finished this far, drop them in a 
glass jar filled with bluestone solution, 4 oz. 
bluestone or blue vitriol to a pint of water. 
Leave them for several hours. Remove 
from the jar and dry. Polish them with 
an old rag, and you will find all the spots 
left after the galvanizing was removed are 
now plated with copper and rust proof. If 
dipped in strong vinegar before placing in 
the bluestone bath they will plate more 

readily and take a heavier coat. Do the 
same with the cut tees and the hinge bolts. 
When all this is attended to, the frame is 
assembled by screwing up the threaded ends 
of the pipe into the fittings. Make up 
good and tight, everything square, and lay 
the awning down as shown in G, lay the 
frame on it in the proper position, and pro- 
ceed to put on the pocketing material. 
This is a strip of the awning material, 
3 in. wide and 7 ft. long, sewed to the line 
where the slope stops and the valance 
begins. When sewed true on one side, turn 
the strip over the frame and sew to the 
awning above the frame as shown at L. 
This must be done along the front so that 
the weight of the frame holds the awning 
taut when lowered. For the ends, it is only 
necessary to put on a strip of the material 
3 in. wide near the hinge. All raw edges of 
the valance as well as the seams for the 
ends and where the valance joins the slope, 
should be bound with the wool braid, care- 
fully run on by machine. Soft laid cotton 
cord about }/i in. in diameter, run through 
small galvanized-iron pulleys, will serve to 
raise and lower the awning. A lead of this 
should be placed in the center of each panel 
and all cords led to one end where a cleat is 
provided to fasten them. 


Fastening an Oar-Lock to Keep 
It from Falling Out 

IF an oar fits a lock snugly the lock is 
likely to be pulled out of the socket when 
the oar is re- 
moved, and it 
may be lost. I 
have found that 
fastening such a 
lock in the man- 
ner illustrated 
will prevent 
this. A stout 
cord is tied to 
one arm of the 
lock and run 
through a screw- 
eye turned into 
the block or oar- 
lock base as shown in Fig. 1. A small 
metal bar is fastened to the other end of the 
string. The bar when turned parallel to 
the string, as in Fig. 2, can be slipped 
through the eye of the screw. To keep the 
bar from slipping out of the knot a depres- 
sion should be filed out in its center, 
circling the bar. — G. P. Lehmann. 

Fastening an oar-lock 
securely with a string 

A Boomerang Flyer 

4 ... ../ bvlT.S.Zerbe 

A LITTLE gyroscopic flyer which can 
be adjusted so it will return like a 
boomerang can be made by any 
intelligent boy. Excepting the shaft, every 
part can be made with such simple tools as 
a jack-knife, a pair of pliers and a hammer. 
The only outside work required is the boring 
of two small holes in the shaft. This a 
watchmaker or jeweler will do. 

The flyer may be made any size t but as 
the power which is available must be con- 
sidered, the following dimensions are sug- 
gested: The disk A should be 10 in. in 
diameter made of a thin tar board, for this 
material is absolutely flat and does not 
warp or twist out of shape. Aluminum is 
also serviceable. Unlike the common glid- 
ers, lightness is not the first consideration. 
On the other hand, weight is of con- 
siderable importance, as the ability of the 
device to soar depends on the momentum of 
the disk itself. In using aluminum, No. 28 
gage is the best thickness. 

Centrally in the disk is a hole to receive a 
3/16-in. steel rod B, 4 in. long. Exactly in 
the center the rod is bent at right angles so 
that each part, B and C, is 2 in. long. The 
part C is bent laterally, at a point midway, 
as shown at D, so that it will lie flat on the 
disk, and an end E is turned up so it will 
serve as a crank handle. The object of 
this arrangement is to provide a means 
whereby the disk can be rigidly fixed to the 
stem so the plane of its surface will be 
maintained perpendicular to the stem B. 

After the stem B is placed in the central 

hole of the disk, wire staples F may be 
used to fasten it firmly, as shown. Through 
the stem portion B two small holes G are 
drilled Y2 in. apart, to receive a bent pin 
or wire H, which provides a means for 
attaching a rubber band. 

The body of the flyer is made of a strip of 
pine /, 9J/2 m - long. I in. wide and % in. 
thick. The interior portion of this strip is 
cut away to form an upper and a lower bar. 
The forward end is tapered off to form an 
A-shaped edge, while the rear end has a 
blade /, made of thin aluminum 2 in. long 
by 1 Y2 in. wide, to serve as a rudder. The 
metal should be thick enough to remain set 
after bending in either direction. 

A hole is bored vertically through the 
upper and lower bars of the frame to 
receive the stem B. A short tube K, y% in. 
long, is placed on the stem between the 
disk A and the upper edge of the strip /, 
and a thin washer L is placed between the 
pin H and the lower side of the upper bar. 
By this means the stem B is held rotatably 
fixed to the frame. 

The rubber band M which serves as the 
motive power, should be 4 in. long by x /i in. 
wide, a size easily obtained. The rear end 
of this elastic is secured to the side of the 
strip / by means of a wire staple N. 

If the elastic band is wound up and the 
flyer thrown into space it will sail along 
with remarkable evenness of flight, due to 
the gyroscopic action of the rotating disk. 
The propelling device consists of a pair of 
triangular-shaped blades, 0, secured to the 
opposite ends of a light wire rod P. This 
rod has at each end a projecting right- 
angled bend Q, to which the blades are 

Each blade has at its rear margin a 
downwardly-projecting and rearwardly- 
extending finger R, which passes through a 
slit in the disk A . These fingers have two 
functions; first, to hold the propelling 
mechanism in place, and second, to rock 
the wire rod P back ^nd forth. The 



Popular Science Monthly 

width of the seam must be added to the 
edges of the developed pattern. This may 
be added in two different ways. Add a sin- 
gle width on the edge of one pattern and a 
double width on the edge of the other 
pattern. The other way is to divide the 
three-seam widths in half and add the same 
allowance on each pattern, which would be 
one and a half times the width-of the seam. 
Wherever there is a corner in the seam 
or wire allowance the metal must be cut 
out or "notched" as shown in the illus- 
tration. This is done so that the ends of 
the wire or seam allowance will come 
together neatly. 

A Pin Inserted in a Cork to Make 
an Oil Dropper 

IN oiling fine machinery, clocks, watches, 
etc., too much oil is often used. Light 
oil flows so freely that it 
is difficult to get just 
enough out of the spout 
of an oil-can and to put 
it in the exact spot where 
it is needed. A needle 
inserted in the cork of an 
oil-bottle will be found to 
pick up just a drop of oil. 
This drop will be carried 
on the point of the needle 
and can be deposited ex- 
actly where desired. Care 
must be taken not to dip 
the needle too deep in 
the oil or there will be 
more oil clinging to its sur- 
face than the single drop needed for a 
bearing. — W. H. Sargent. 

Picking up a drop 
of oil with a pin 

An Automatic Watering Tank for 
Poultry Yards 

MANY types of automatic tanks have 
been invented to provide fresh clean 
water for .the fowls all during the day. 
Several of these must be tipped upside 
down in the process of filling. 

The accompanying sketch presents a 
type of tank in which the water may be 
poured in through the top. The tank can 
be made of galvanized iron. A small 
faucet, A, is placed near the bottom so 
that it will open beneath the surface of the 
water in the dish, B. The cover must fit 
tightly to make an airtight joint when it 
is screwed down. To do this a broad 
shoulder is left at C so that the gasket 
rubber D will have a firm foundation. 

The following procedure is necessary in 
filling the tank: Close the faucet, A, re- 
move the screw cap, E, and pour the water 
in at the top. The lid is then replaced and 

A reservoir from which fresh water is au- 
tomatically supplied to the poultry yard pan 

the stop-cock, A, opened. The water will 
run out until the level in the dish, B, 
comes just above the opening of the faucet. 

A Trough for Thoroughly Washing 
Film Negatives 

A SPECIAL trough for washing nega- 
tives will be found a great convenience 
to the photographer who uses films. The 
trough here illustrated is nothing more than 
a long, water-tight box, made of galvanized 
sheet steel, having a drain cock fitted at the 
bottom of one end and with a small piece 
of tubing soldered at the top of the other 
end to hold a length of rubber tubing or 

~*" A galvanized iron washing tank for rapidly 
removing all traces of chemicals from films 

hose for making connection with a faucet. 
The trough is 40 in. long, 7 in. wide and 
5 in. deep. 

In use, the trough is placed in a level 

Popular Science Monthly 

position so as to drain into a sink, wash- 
basin, bath-tub, laundry-tray or barrel. 
The hose is connected with a cold water 
faucet, the trough almost filled and the 
inlet and outlet regulated to maintain a 
constant depth of water in the trough. 
The film, with a film clip attached to each 
end, is laid in the running water, emulsion 
side up, or, better still, stood on edge where 
possible. Film pack negatives may be 
pinned on a stick the exact length of the 
trough and placed in the running water. 

Safety Guard Placed on an 
Emery-Wheel Dresser 

IN the crusade for "safety first" attach- 
ments on machine tools, one that is 
likely to be overlooked is the emery-wheel 
dresser. This, however, has been taken 
care of in a very efficient manner in one 
shop as illustrated. A piece of 1/16-in. 
boiler plate about 2 in. wider than the 

fa j 

Metal guard attached to the handle to 
prevent flying particles from striking the eye 

cutting wheels of the dresser was bent 
and fastened with two 3/16-in. screws about 
% in. long on the handle of the dresser for 
a guard. — Joseph K. Long. 

A Nest- Box Trap for Catching 
the English Sparrow 

SPARROW traps may be classified, 
according to the U. S. Department of 
Agriculture, as nest-traps and bait-traps. 
Inasmuch as sparrows usually feed in 
flocks, but approach nest-boxes singly or 
in pairs, the annual catch of a bait-trap 
will exceed that of a nest-box trap many 
times; but during the breeding season the 
nest-box traps are decidedly useful. 

A nest-box trap, as the name implies, 
looks like an ordinary nest-box. The 
weight of a bird entering such a trap puts 
into operation a mechanism which catches 
the bird and sets the trap for another. 
There are a number of devices to accomplish 
this. In designing a nest-box trap one 


should bear in mind that English sparrows, 
like other birds, dislike drafty quarters, 
and that a mechanism delicate enough to 
be operated by a sparrow's weight is likely 
to get out of order unless the parts are few 

ri 1 

1 1 
i J 1 

1 "~crt 

ir^"" v 


|\ \ ' ill 



if ' 





A trap-nest for catching the English spar- 
row in a bag hung from beneath the box 

and perfectly protected from the weather. 

Probably the simplest nest-box trap yet 
designed is the one illustrated. The essen- 
tial parts of the trap are: a box, a tipping 
chamber within the box, a down-spout 
below it and a bag at the lower end of the 
down-spout. The dimensions of the several 
parts are given in the illustration. The 
tipping chamber is made of tin, the down- 
spout of wood or tin, the box of wood. 
The roof board is cleated across the ends, 
and also lengthwise between the cross 
cleats, for the attachment of the sides, as 
shown in the side elevation. 

The close weave of a 2-bushel bag makes 
it suitable for the lower end of the down- 
spout. One of coarser fabric would allow 
a draft through the spout and thus detract 
from the efficiency of the trap. In building 
this trap the front wall is the last piece to 
put in place. It is fastened there with 
screws so that the trap can be easily over- 
hauled. It is a good plan to fasten with 
shellac a few feathers or bits of hay to the 
floor of the tipping chamber near the rear 
end to excite the interest of the sparrows. 

Look Over Stored Tires Before 
Applying Them to Rims 

BEFORE using tires laid aside examine 
them carefully for cuts on the outside, 
remove tacks and small nails, reinforce any 
breaks in the fabric inside and lubricate the 
fabric and inner tube with powdered mica. 
Apply a thin solution of graphite, shellac 
and alcohol according to instructions. 


Popular Science Monthly 

A Metal Garage Made from a 
Discarded Tank 

AN opening was cut out in one end of the 
tank large enough to admit the 
automobile; then a strip was cut out on the 
side and the metal bent out to form a 

The metal of a discarded factory tank pro- 
vides an excellent housing for the automobile 

covering in the shape of an inverted U. 
A framework was made of wood and placed 
on the ground. To this the sides and ends 
of the tank were attached. The metal 
which was carefully removed from the end 
and side, was used for making the doors, 
which were hung on ordinary hinges riv- 
eted to the metal of the tank. A flashing 
was attached above the door to keep the 
rain from beating in back of the doors. A 
window could easily be placed in the oppo- 
site end to furnish additional light if de- 
sired. — Charles Claude Wagner. 

A Cheap and Effective Method 
of Bracing a Roof 

IN many instances the partitions of frame 
buildings do not allow the rafters to be 
effectively braced from them, so that 

than trussing, is cheaper, and provides a 
stronger brace. Also, it does not interfere 
with the space under the roof. 

The trussing consists of two I by 12-in. 
boards the exact length of the distance be- 
tween the front and rear plates. As many 
1 by 3-in. pieces are used as there are 
rafters. These should be the length of the 
distance between the bottom edge of the 
outside rafters and the top edge of the 
plates at a point half way down the rafter. 
Nail these on the boards as shown, after 
having laid out the location of the rafters 
on their surfaces. Be sure that the ends 
of the bracing pieces are all in line. Then 
adjust each board under its side of rafters 
in an inclined position so that the ends 
of the braces catch under each rafter, 
supporting the ends on the front and rear 
plates of the building, and elsewhere on 
any partitions there may be in the en- 
closure. The upper edges of the boards are 
further braced with 1 by 3-in. strips nailed 
to the top edges and to the side plates. 
This keeps the top edges from bulging or 
moving. It is now only necessary to sight 
each rafter, slightly moving the braces 
until the rafter is properly lined and then 
to secure it with nails. — Henry Simon. 

Bracing a roof to provide a space in the 
center not obstructed with timber supports 

trussing is resorted to. This, however, 
spoils any room directly under the roof. 
The method illustrated is more effective 

Small Closet in Door-Frame Stile 
for Milk Bottle 

THE question of where the milkman 
shall put the" milk bottles in the 
mornings in order to prevent them from 
being stolen, upset by dogs or cats, or from 
smearing the porch or steps has been 
answered in many ways; but the neatest 
and best device for the purpose which I 
have yet seen is a little closet cut out just 
above the floor in the kitchen, between the 
inner and outer wall of a cement bungalow. 
The space between the walls is a little 
wider than the diameter of the ordinary 
quart bottle of milk, and a length of the 
side wall was cut out sufficient to accommo- 
date about four bottles. An inner door is 
provided so that the bottles may be 
placed in the little closet and the door 
shut from the inside. An outer 
door is also provided so that the 
milkman may unlatch it, take 
out the empty bottles, set in the 
fresh supply and close the door 
again leaving no trace of the 
milk visible. This outer door overlaps the 
opening, somewhat, so that no draft is ad- 
mitted through cracks. — James A. Carter. 

Winning an Athlete's Laurels 

IV. — Pole vault and potato races 
By Albert B. Wegener 

A technical instructor and director of athletics of twenty-seven years' experience 

THE pole vault is the most spectacular 
and at the same time the most 
exacting of athletic events, requiring 
strength, speed, and skill. A left-footed 
jumper should grasp the pole with the 
ordinary left-hand grasp and the right hand 
reverse grasp, hands 30 in. apart. For 
the usual vaulter the right hand grasps 
the pole according to the following instruc- 
tions: When the bar is placed 9 ft. high, 
the right hand is at 9 ft. on the pole; for 
each foot that the bar is raised the right 
hand is lowered 4 in. Carry the pole 
on the right side with the point directly 
forward and raised a little. Run squarely 
to the front, avoiding a twist. 

The take-off or jumping spot should be 
directly under the right hand when the 
pole is planted ready for the spring and 
the striding marks placed accurately at 
about 40 and 80 ft. from the stands. 
These marks must be placed so as to help 
produce accurate running, as described 
in the high jump. During the run, look at 
these marks. Start to run at about 100 ft. 

Taking the Jump 

Plant the pole lightly by thrusting the 
end into the hole just before the left foot 
strikes the take-off. At the same time 
throw the arms forward up and slide the 
left hand up close to the right. The arms 
at this point should be almost straight, the 
hands above the left foot or a few inches 
in front of that spot. Any other spot for 
the take-off will strain the chest or back 
muscles, and if the arms are too straight or 
too much bent you cannot rise well. The 
left foot should be placed upon the take- 
off a couple of inches to the right of a line 
drawn directly back of the point of the 
pole. The hole for planting the point of 
the pole should be 6 in. toward the runway 
from a point just under the bar. 

In the rise, swing the body forward at 
arm's length to the right of the pole, facing 
directly forward. When half-way up to 
the bar flex the thighs and legs so that they 
are above the head and the bar. Now 

straighten out, turn to the left, pull up and 
push up strongly with the arms. This 
brings the hips above the bar and facing it 
in an arched position with thighs flexed. 
Now push over the bar and release the 
grasp, with the left hand first, allowing the 
pole to drop back. Alight facing the bar 
or with an additional turn to the left. 

Training Hints 

For several weeks before attempting to 
vault, practice the following developing 
exercises: On the horizontal bar, chin 
several times; then do the same and circle 
backward over the bar. Circle forward 
over bar. Hang and raise feet to the bar. 
Free backward circle. Pull up and shoot 
over a cross-bar placed 2 ft. in front of 
and as high as the bar. Practice walking 
on the hands. Do the hand balance 
against the wall, then bend and straighten 
the arms. Practice the rope vault. Prac- 
tice sprinting and jogging. 

When starting to use the pole do not try 
to vault over a cross-bar for a few weeks, 
or until the movement is thoroughly 
learned. Preliminary practice with the 
pole should be, planting the pole and using 
the grasp at about 8 ft. high. Plant the 
pole and swing forward. Plant, swing, and 
rise. Plant, swing, rise, and pull up, etc. 
Introduce the bar only when able to do 
about 8 ft. without it. Do not vault more 
than ten times a day. Give much attention 
to massage. If sore and stiff, rest and 

Other Styles of Vaulting 

For those who have not the time to 
devote to learning the exacting shift-hand 
style, and especially for boys, the no-shift 
style is recommended. In this the hands 
are held about 2 ft. apart and neither of 
them is moved from that position until 
after the rise, swing, pull up, and shoot over 
are made. It is impossible to go high with 
this, but it is much easier and safer than 
the other style. The Vault for Distance 
is an event seldom, if evfr, now used in 



Popular Science Monthly 

meets, but it would be more appropriate 
for boys than the vault for height. The 
action is much like the above styles except 
that there is no necessity for getting so 
much of a "lift." 

Vaulting Rules 

The height of the bar at starting and at 
each successive elevation is determined 
by the field judges. 

Each competitor is allowed three jumps 
at each height, and the competitor who 
fails at the third attempt is disqualified. 


"balks" are always counted as a trial jump. 

Any competitor is allowed to dig a hole 
not more than 1 ft. in diameter at the take- 
off, in which to plant his pole. 

A competitor must not, in the moment 
that he makes a jump, or after leaving the 
ground, place his lower 
hand above the upper one 
or move the upper hand 
higher up on the pole. 

Plant the pole lightly by thrusting the end into the hole just before the left foot strikes the take- 
off and at the same time throw the arms forward with the left close up to the right exactly as above 

A competitor may commence at any 
height above the minimum height. He 
must, however, jump at every following 
height until he has forfeited his right to 
compete further. 

The vault is made over a bar resting 
on pegs. 

As soon as a competitor has left the 
ground for the purpose of making a jump, 
the jump is counted as a trial. 

A line is drawn 15 ft. in front of the bar 
and parallel therewith, to be known as the 
balk line, and stepping over such a line, 
or such line extended, in any attempt is 
counted as a "balk." Two successive 

Poles may have a binding, but must not 
have any further support for the hands. 

If the uprights are moved at all they 
must not be changed more than 2 ft. in 
any direction, and not more than one hole 
may be made by a competitor. The take- 
off ground about the jump must be level. 

The uprights should be at least 12 ft. 

All measurements are made perpendicu- 
larly from the ground to the upper side 
of the bar where it is lowest. 

In the pole vault, if in making a trial the 
competitor's pole is broken, it is not 
counted as a trial. 

Popular Science Monthly 

The rules governing the running broad 
jump also govern the pole vault for distance, 
except that when the man leaves the ground 
in an attempt, it is counted a trial. 

If the uprights are moved, the field 
judges should make a re-measurement, 
because if there is any inequality in the 
ground at all, changing the uprights may 
make a difference varying from I in. to \i 
in., and a competitor should not be allowed 
to obtain an advantage in that way. 

Indoor Athletic Events 

Indoor athletic events are quite as 
popular as outdoor events, and have 
the advantage in large cities of being 
more easily promoted in gymnasiums, 
large halls, and armories, and of not being 
subject to the weather. With certain 
modifications most of the outdoor events 
can be conducted indoors. 

Among the most popular indoor running 
events are the sprints. These are run 
either on the main floor or on an elevated 
track. If run on the main floor the distance 
is limited by the length of the room. 
Nothing below 25 yd. is considered satis- 
factory for "straightaway" running. 

When a circular track is used any distance 
may be run; but contestants cannot, in 
most places, start side by side on the same 
mark, on account of the narrowness of the 
track. For that reason the contestants 
must run either singly or two may start 
so as to finish directly on opposite sides of 
the track, thus allowing the judges to sight 
across and determine the winner. The 
most popular arrangement is to have four 
runners start and finish from separate 
marks a quarter distance around the 
track, each runner being timed by a set of 
watches. This is as close to a real sprint 
as can be run on a narrow gymnasium 
track. None of these methods is without 
objection for narrow track sprinting, and 
for that reason are never used in important 
meets. In such meets the sprints are 
limited to the straightaway on the main 
floor and nothing less than a half mile is 
scheduled on the narrow track. But the 
other methods may be used with profit in 
closed meets and where absolute condi- 
tions are not demanded. 

For straightaway sprinting on the main 
floor there is no difference from outdoor 
sprints, but for narrow track sprinting the 
start and "taking the curve" must receive 
special notice. Toe-blocks cannot be used 
on such a track. Thus the runner is al- 


lowed to brace his rear foot against the 
foot of another person at the start. In 
running around the banked curve a sprinter 
will make the best time by running up 
high on the outer edge and inclining the 
weight well in toward the rail. 

In track events of a half mile or more the 
contestants start together at or near the 
same mark, except of course in handicap 
races. Such races on a narrow track are 
not always satisfactory because it is almost 
impossible to pass a runner in the lead 
without fouling. The only way that this 
difficulty can be lessened is to insist that 
the "runner up" must take the outside 
and the runner ahead keep the inside of 
the track on the "straightaway" part, and 
allow no passing on the curve. 

Indoor hurdling has been found to be 
very satisfactory. It should never be at- 
tempted on the narrow elevated track 
usually constructed in gymnasiums. In- 
door hurdling, whenever it is scheduled, is 
always run as a straightaway on the main 
floor like the sprints. It is seldom possible 
to have more than two hurdles at the 
regular distances. It is, of course, possible 
to place the hurdles about 6 yd. apart and 
use a single stride between hurdles, thus 
using more hurdles. 

Relay Races in the Gymnasium 

Indoor relays, like all other sprints, are 
never run side by side like outdoor relays, 
unless run in an exceptionally large room 
with at least a 220-yd. track wide enough 
for that purpose. Relay races may be 
run on the regular gymnasium track, but 
only two teams can run at a time, and 
these must start from opposite sides of 
the track. Such races are popular and 
should be scheduled in all indoor meets. 
They are usually made short — one or two 
laps for each man — because the winning 
team must run repeatedly. Uprights 
should be erected on each side of the track 
opposite the center across which the judges 
sight on the finish. All runners should 
line-up on the inside of the track so as not 
to interfere with the other team as they 

The starter should stand at the end of 
the gymnasium rather than near one of 
the teams. One judge should be stationed 
on each side of the track at the finish line. 
Rules about passing are the same as in 
other narrow track races, but because fouls 
are almost unavoidable it has been found 
better to allow no passing. Such races are 


Popular Science Monthly 

popular as a feature of regular gymnasium 
class work in which there are many on 
each team. 

Novelty relays are not used in serious 
meets but are popular as diversions at 

light objects, ovoid in shape, the greatest 
diameter not to exceed 4 in. and the 
smallest diameter not less than 2 in. The 
first of these objects shall be placed 2 yd. 
from the receptacle. 

Each competitor must pick up each of 
the objects singly and place the same in 
his own receptacle. After having picked 
up one of the objects he must deposit it in 

For the shuttle potato race a receptacle not more than two feet high or an opening not more 
than thirty-six inches in circumference is placed upon the starting line for each competitor to fill 

gymnasium class periods and on other 
occasions when a jolly contest is in order. 
Each team has a separate course, consisting 
of some piece of apparatus placed at each 
end of the gymnasium. The course of 
each team is parallel to the others and far 
enough away so as not to interfere. The 
kind of races that may be run is limited 
only by the ingenuity of the director. 

Potato races are runs in which potatoes 
or any other Hght objects are carried from 
one place to another. There are two 
kinds of these races; namely, shuttle and 

For the shuttle potato race a receptacle 
not more than 2 ft. high or an opening not 

the receptacle before picking up another. 
After all the objects are placed in the re- 
ceptacle the competitor must cross the 
finish line, which is 5 yd. behind the re- 

In handicap competitions, the marks are 
given from behind the starting line. 

In the stadium potato races two boxes 
4 in. deep, 12 in. in diameter, are set on 
stands 2 ft. high, for each contestant. The 
outer edges of these boxes are 31 ft. apart. 
The runner may start on either side of the 
box that contains the potatoes, from a line 
parallel to its outer edge, the starting 
mark, with one potato in his hand. He 
runs around both boxes, each time placing 
one potato in the other box, and finishing 
at the starting point on the other side of 




The runner starts from the starting mark on one side of the box that contains the potatoes. 
With one potato in his hand he then runs around both boxes, placing the potato in the other box 

more than 36 in. in circumference is placed 
upon the starting line for each competitor. 
Upon a straight line drawn from the re- 
ceptacle at right angles to the starting line 
shall be placed, at distances of 2 yd., eight 

his own box. Grasping either stand in any 
way, failure to run around both boxes, or a 
failure to transfer all the potatoes singly 
from one box into the other shall disquali- 
fy the runner. 

Popular Science Monthly 


In case potatoes are dropped or upset by 
the runner he must replace them without 
assistance before proceeding with the run. 
He must not interfere with another runner 
in any way. The boxes may be fixed to 
stands, having their bases approximately 
the same size as the boxes. The stands are 
not fastened to the floor. 

The various distances and number of 
potatoes are : 

60 yards potato race requires 3 potatoes 

160 " " " " 8 

220 " " " " ir " 

440 " " " " 17 

There are two styles in running the 
potato races. Some runners keep a steady 
pace and run in large circles. Others run 
in a narrow oblong that necessitates slack- 
ing the speed on the turns. The latter is 
more generally used but is thought to be 
more exhausting than the former. 

In making the turns, the runner should 
face the box and bend well over it, if the 
narrow oblong style is used. In this it is 
also well to give attention to the striding. 
If, as usual, the run is made from right to 
left, as in track running, the turn should 
be made with three steps as follows: the 
left foot should be at the side of the box, 
then the right should be placed at the end 
of the box and then the left started on the 
new stretch. 

{To be continued) 

Saving Concrete in Setting 
Posts in Holes 

Sticky Fly Paper Used to Keep 
Insects Away from Poultry 

TO keep insects away from fowl in a 
poultry house sticky fly paper may 
be used with good results. It is placed 
sticky side down on the upright parts 
holding the roosts, which rest on the paper. 
Do not allow the paper to touch the sides 
of the building in any place. It is also 
a help to keep the roosts and parts well 
greased with some thick grease well rubbed 
in to fill all the cracks. If there are any 
night prowling insects in the coop a fair 
sample of them will be found stuck to the 
paper in the morning. 

Large poultry houses should have metal 
supports for roosts, with grooves for the 
ends of the roosts to rest in without fasten- 
ing. Raise the end of such a roost and put 
a small piece of fly paper under it, sticky 
side down. Be careful that the edge of 
the paper does not stick against the 
support. — Paul Greer. 

THE ordinary method of setting a post in 
concrete is to set the post into the hole 
and fill in around with concrete. This is 
wasteful and 
does not reach 
the highest effi- 

A square hole 
should be dug 
so that the con- 
crete will have 
square corners. 
After placing 
the post in posi- 
tion the concrete 
s ho u 1 d b e 
poured in until 
the hole is about 
one-fifth filled. 
The concrete is 
marked A in 
the drawing. 
The hole is par- 
tially filled with 
wet earth, here 
marked B, leav- 

The part of the hole be- in & r ° om for 
tween blocks filled in with dirt m <>re concrete. 
The upper con- 
crete block should be about 50 percent 
larger than the lower block to offset any 
difference in the hardness of the ground. 
There is practically no strain exerted 
against the ground between the two con- 
crete blocks. — Robert W. Phelps. 

Waterproofing Blue Prints and 
Drawings for Rough Handling 

WHEN blue prints are handled to a 
great extent or when it is necessary 
to use them outdoors, as in construction 
work, they often become spotted by water 
or soiled; which makes the prints difficult 
to read. Waterproofing them protects 
them from the water, and makes it possible 
to wash them off when they become soiled. 
The waterproofing can be accomplished by 
dipping the prints in melted paraffin wax 
and hanging them by the corner to drain. 
Another method, not so clumsy, is to 
immerse heavy blotting paper in the wax 
and when cold lay the print between two 
of the sheets and pass a hot iron over them. 
These processes are applicable to all kinds 
of papers. — Thomas W. Benson. . 


Popular Science Monthly 

A Coating Which Gives the Appearance 
of Stone to Wood 

TO make imitation stone for outdoor 
furniture, sun-dials, flower pots, etc., 
the following can be used: 

10 parts lime 
12 parts rosin 
I part linseed oil 

Dissolve ingredients thoroughly and ap- 
ply the mixture while hot to the wood as a 
coating. The result will be an attrac- 
tive stone-like appearance that will last 
indefinitely. — L. E. Fetter. 

A Special Ladder for Use in 
Boiler Shops 

THE type of ladder illustrated is 
especially made for use in boiler and 
car shops where it is necessary to climb up 
to moderate heights for doing work. Being 
of the A-type it can be used like a painter's 
ladder and a plank can be put between two 
of them to form a trestle which will ac- 
commodate more than one workman. This 
method of construction makes the best pos- 
sible ladder — strong, safe and economical. 
It is built of short pieces of i3^-in. pipe, 
each about 21 ]/% in. long, which may be 
picked up about any shop where con- 
siderable pipe is used, such short pieces 
being useless for general work. 



An A-shaped ladder made of short lengths 
of gas pipe and fittings for a boiler shop 

The pipes forming the rungs are 1 in. 
in diameter. In the making of the ladders 
illustrated, sixteen 1% in. by 1 in., brass tees 
and eight %-in. bolts, one for each rung, 

were used in each ladder. The parts were 
hinged at the top and pointed irons were 
fitted in the lower ends as shown. A chain is 
used between the parts to keep them from 

While this ladder is very heavy, yet for 
the usage to which it will be subjected the 
construction is most desirable and at the 
same time inexpensive. — Joseph K. Long. 

Three Plates and Three Color Screens 
Used in New Color Photography 

IN a recent patent on color photography 
there is brought out a process whereby 
three sensitive plates are placed together 
in such a way that the color screens in 
in them produce the desired effect on the 


10 o Drain carrier class 

these results it red-sensitive coatin&| 
is necessary to 
have all plates red color-screen- 
that are used ^-se nsitive coati 
in sets, sensi- 
tized at the 

same time so yellow color-screen 
bame urae, bo blue-sensitive coating 
that they will 
age the same 
and have the 
same emulsion. 

carrier GLASS - 

Arrangement of plates in 
pack to record natural colors 

The ordinary dry plate is sensitive to the 
blue rays. In making up the sets green- 
sensitive plates must be used, which are 
sensitized with a chemical dye. A batch of 
these plates is divided into two parts, the 
first portion being coated on the back with 
opaque substance and allowed to dry, after 
which they are treated for rendering them 
red-sensitive. In the meantime, the second 
portion of the plates, which are already 
green-sensitive, are superficially coated 
with a temporary green. Then they are 
assembled to form a plate pack, and if 
desired, a blue-sensitive is combined with 
them. By securing these together they 
make a unit which may be exposed in any 
desired manner. After exposure the plates 
are separated, developed and fixed. 

The chemical dye which gives a plate 
sensitiveness for a given color may be 
termed a color-sensitized agent and the 
plate a dye-sensitized plate. The green- 
sensitizing agent is preferably included in 
the original emulsion. The illustration 
shows the sensitive plates and their arrange- 
ment in a pack to record the natural colors 
as the rays fall, upon them successively 
from the camera-lens. 

q Amateur - 

^And Wireless Operator 

Applying Insulation to Splices 
Made in Electric Wires 

TO comply with the rules of the American 
Institute of Electrical Engineers, it is 
necessary to apply a rubber coating over a 
soldered joint in a wire. One of the best 
methods of doing this is to lay on the 
rubber over the splice before it begins to 
cool from the soldering operation. The 
thickness of the coating depends on the 
amount of voltage carried in the line. 
Cover the rub.ber insulation immediately 
with friction tape, drawing it tight, while 
putting on a sufficient number of layers to 
stand the wear. 

To make a neat covering, cut the friction 
tape into narrow strips, less than */£ in. 
wide, and a smoother joint will be the 
result after the wrapping. If this is done 
neatly and drawn tight enough there will be 
a noticeable bulge in the joint. This can 
be easily wrapped with a cord — silk if the 
case calls for it — then given a coat of 
shellac. If the proper color cord or silk is 
selected a joint that cannot be easily 
detected results. 

A Simple and Easily Made Electric 
Battery Motor 

A SIMPLE and easily made motor that 
will run at high speed with two or 
three cells of dry battery, or on an alternat- 
ing current with a transformer, is shown in 
the illustration. While this motor can be 
made in any size that will appeal to the 
experimenter, only one dimensioned draw- 
ing is given. Procure two hexagon-head 
bolts, A, 2Y2 in. long and \i in. in 
diameter under the head, also some thin 
hard fiber tubing l /i in. inside diameter 
to slip over the bolts. Cut two pieces B, 
each 2 in. long, and fit on heads or washers, 
C, about J/g in. in diameter, leaving J4 in. 
of the tubing projecting at the threaded 
end. This forms the spools for the magnets. 

Wind the spools with No. 22 or No. 24 
magnet wire in the usual manner having 
the inside as well as the outside ends come 
out at the back end of the magnet. 

The soft iron standard D is about 3 in. 
high. V2 m - wide and 3^8 i n - thick and bent 
L-shaped at the lower end to form a foot by 
which it is screwed to the base. In the 
standard are drilled three holes. Two of 
these are of the same size to allow the ends 
of the bolts or magnet core to enter and 
project on the outside for the nuts, which 
hold the back ends of the coils in position. 
The third hole is located centrally between 

Universal motor that will run on a battery 
current or reduced alternating current 

the other two to accommodate the shaft. 
The same number of holes and in the same 
position must be drilled in the brass yoke 
for supporting the front ends of the 
magnets and the front bearing. This brass 
yoke may be a flat strip about ^ in. 
wide and of a length to cover the front 
ends of the coils. When the bolts are put 
through the magnets the protruding ends 
of the fiber tube will butt up against the 
back standard and all parts will be held 
securely in place. 

The armature poles F consist of soft 
iron buttons about Y* in. in diameter and }/i 
in. thick, connected by a strip of brass % 
in. wide, having a hub # in the center for 



Popular Science Monthly 

fastening it to the shaft. The balance 
wheel may be made to suit the fancy of the 

Before assembling the parts, a commuta- 
tor must be made and slipped on the shaft 
back of the standard or between the up- 
right and end support. As it is necessary 
to have a break in the current for a short 

1 v -g^E^ ^plpMiJ ^ 

TO 6INDINGJ I t 60 ™ IN 


The parts and their assembly for the 
construction of the universal motor 

period a part of the commutator must be 
insulated from the shaft. This is ac- 
complished by making a base G cut from 
a hard fiber rod which is drilled to slip in 
the shaft. A brass tube having an inside 
diameter to fit on the fiber rod is filed as 
shown at H, and when assembled it appears 
as shown in the illustration on page 147. 

The brush-holder for making contact on 
the commutator is constructed as shown 
at J. The base is made of hard rubber, or 
fiber \}/<z in. long and % in. thick. One end 
is rounded and drilled to slip over the core 
or lower bolt between the standard D and 
the magnet end C. The thin brass spring 
makes contact with the metal strips on the 
commutator as it revolves. 

Both inside and outside ends of each coil 
are brought down through the base in 
rubber tubes. The inside ends of coils are 
soldered together. One outside end is 
connected with the iron standard D, and the 
other outside end with a binding post. The 
remaining binding post is connected with 
the spring on the brush-holder. — W. E. Day. 

Rebuilding Worn-Out Dry 
Battery Cells 

THE most difficult part of rebuilding 
dry cells in quantity is the removal of 
the contents, which consists of peroxide of 
manganese and carbon powder tightly 
compressed and covered with pitch. Strike 
the pitch a sharp blow with a hammer to 
break it; then dig it out with a pointed 
tool like that of a screwdriver. Save the 
pitch and sand in separate receptacles. 

The compressed oxide and carbon are 
also difficult to remove. About the only 
quick method is to use a twist drill Y% m - 
in diameter, placed in the chuck of a lathe. 
By pressing the zinc-cylinder of the cell 
on the drill and boring several holes in the 
compressed material to within 34 m - of 
the bottom, you will break it up so that 
all of the compound can be readily removed. 
Save the borings and the crumbled mass. 
If a small portion is left at the bottom it 
may be easily removed with the aid of a 
screwdriver. The material removed is 
spread out to dry and any lumps found 
are crushed. The exposure of this material 
in a thin layer not only permits the moisture 
to evaporate, but brings about a certain 
amount of reoxidation of the spent 
manganese dioxide. As soon as the ma- 
terial has become dry it must be heated to 
a moderate temperature — about 400 deg. F. 
will answer, but not to a bright red, as 
this will drive off some of the oxygen, 
every bit of which is needed in the renewed 
cell to act as a depolarizer. During the 
heating, which may be readily done in a 
stout iron pan, it must be well stirred. This 
process will eliminate a very large part of 
the exciting salts used in the original cell. 
The heated material must then be spread 
out and exposed to the air to cool. When 
cold it is ready to be mixed with the 
exciting salts and repacked in the original 

Almost all the cylinders may be used 
again after being soaked with hot water 
for about I hour or more. The soaking 
will loosen the original paper lining and it 
can be easily removed with a pointed tool 
inserted between the cylinder and the 
lining. Finally clean out the interior with 
a stiff brush and wet sand, or with a wire 
brush. When the cylinders are aired they 
are ready for re-filling. Some of the 
cylinders will be used up and unfit for use 
again. These may be dissolved in hydro- 
chloric acid to form a strong solution of 

Popular Science Monthly 

chloride of zinc, which is required to make 
up the exciting mixture. In preparing 
chloride of zinc, the scrap-zinc should be 
placed in a large stoneware crock and 3 or 
4 lb. of commercial hydrochloric acid 
poured over it. This must be done out- 
doors, because the hydrogen gas that is 
given off is harmful to breathe, and also 
inflammable. A great heat is generated 
and the liquid may boil up and make it 
run over the top of the crock. A small 
quantity of cold water may be poured in 
to lessen the chemical action without 
detriment to the resulting product, which 
should be left until quite cold before using. 
It is very important that this solution 
should contain no free hydrochloric acid, 
because its introduction into the made-up 
cell would cause chemical action, and the 
cell would soon be destroyed. Any trace 
of free acid is readily dispersed by adding a 
small quantity of chloride of ammonium 
in powder form and stirring the liquid until 
effusing ceases. By this method a small 
quantity of chloride of ammonium may be 
introduced without harm. As soon as the 
solution of chloride of zinc is ready it may 
be strained through a piece of damp muslin 
to free it from dirt, paper chips and other 
matter, and then filtered through a tuft 
of cotton pressed in the neck of a glass 
funnel. This will free the solution of any 
fine iron-deposit or lead that may have 
been in the zinc, thus aiding the efficiency 
of the re-made cell. This solution should 
test 32 deg. Baume. Sal ammoniac, or 
chloride of ammonium in the crystal form, 
is then dissolved in the chloride of zinc. 
Filtered or distilled water is then added 
and the mixture stirred well and tested to 
register 32 deg. Baume. The solution is 
then ready for use. 

The carbon-rods and the brass binding- 
posts and screws must be cleaned and the 
zinc-cylinder lined with a double thickness 
of blotting-paper, or blotting-board, cut so 
as to leave a margin of about Yi in. at the 
top where it is turned over on the outside. 
Cut some circular pieces of cardboard, or 
heavy blotting-board, so that they will fit 
tightly into the interior of the blotting 
paper. Press three or four of these down 
into the bottom of the blotting-paper 
lining inside of the zinc-cylinder. It is then 
ready for filling. Just before putting in the 
mixture pour in some of the chloride solu- 
tion so as to wet the paper all over, drain 
it and place the zinc upside-down to drain 
off the excess liquid. This takes about 


20 minutes, for the paper must not be over 
wet. Then place upon a smooth board 
about 1 34 lb. of the carbon and manganese 
powder that has been treated. Add about 
3 oz. of the chloride of zinc and chloride of 
ammonium solution and mix well so that 
it will hold together when gripped in the 
hand. It must not be very wet or it will 
not give the proper amperage. The right 
consistency is very important. Pour some 
of the carbon mixture into the paper-lined 
zinc-cylinder and ram it down hard ; insert 
one of the carbon rods, adjust it centrally, 
then pack some of the mixture around it 
and ram it down tight with a suitable strip 
of wood, hammering it in with a wood 
mallet. The carbon rod must be tapped 
down occasionally to prevent it from lifting. 

The tighter the mixture is packed the 
greater will be the amperage when finished. 

Cut off the outside edges of the blotting 
paper and fold the top of it inwards toward 
the carbon-rod, press it down and see that 
none of the carbon mixture makes contact 
between the zinc and the carbon-rod. This 
is essential as the connection would short 
circuit the cell. Place all the binding 
screws in position, test the cell with a 
suitable battery ammeter and see that the 
screws of the carbons are tightly fitted. It 
should give a current of 15 to 22 amperes. 

Dry the sand and pack some of it over 
the top; then melt the tar and pour it on 
the sand to completely fill the cell to the 
top. These made-over cells will give an 
excellent working current for a considerable 
length of time. 

Method of Insulating Secondary * 'Pies*' 
in Transformers 

IN most text-books on the construction 
of transformers, it is customary to 
advise the insulating of the "pies" or 
sections in the secondary winding by means 
of long strips of empire cloth, wound over 
and over through the center holes of the 
sections. This requires a good deal of 
work on the part of the constructor. 

While overhauling a transformer, the 
writer tried out a somewhat novel method. 
The core was insulated in the usual manner, 
with a number of layers of empire cloth, 
but the "pies," instead of being wound with 
strips of empire cloth, simply had round 
disks of empire cloth, of double thickness, 
between each pair of sections. This gave 
fully as good insulation, and made access to 
the different sections easier. 

150 Popular Science Monthly 

Steadying the Voltage of a Dynamo 
Driven by Gasoline Engine 

THIS problem has been solved in various 
ways. We are all familiar with the 
storage-battery system, and being ac- 
quainted with this system, realize its ex- 
pense. If a gas or gasoline engine is to be 
used to drive a 

Cast iron 
"fly-wheel **v 

dynamo, some 
provision must 
be made to 
steady the speed 
of the dynamo. 

A spiral spring in flywheel 
hub on an armature shaft to 
prevent flickering of lights 

Every time the engine ex- 
plodes, there is a momentary 
increase in the speed of 
the dynamo, causing a fluctuation of 
voltage, and a flicker of the lamps. Special 
engines with extra heavy fly-wheels have 
been built for this purpose, which give 
fair results, provided that the armature 
of the dynamo has a large moment of 
inertia. If a flywheel is put on the dynamo, 
the voltage fluctuation is lessened, but this 
induces belt slipping, and hence loss of 
power. Specially built electric lighting 
engines are expensive, and for small plants 
of from one-half to two or three kilowatts 
give but little satisfaction. 

The writer has obtained satisfactory re- 
sults in a one-kilowatt plant by using the 
spring flywheel arrangement shown in the 
diagram. The belt from the engine drives 
the pulley on the flywheel which is fastened 
to the pipe. The pipe in turn twists the 
end of the helical spring. The other end 
of the spring is fastened to the flywheel. 
In this way the impulses from the engine 
are spread over a longer interval, and the 
tendency is for the dynamo to run at a 
constant speed. The whole spring is 
packed in grease, so that there is but little 
loss of power from friction. Belt slipping 
is avoided by the freedom of motion of the 
pulley and pipe. The momentum of the 
dynamo flywheel tends to keep the speed 
of the dynamo constant while the engine 

is slowing down on the compression 
stroke, and likewise while the engine is 
on the power stroke, the spring operating 
as an elastic medium between the driving 
pulley and the flywheel. 

The spring must be made of steel of 
exceptionally good quality, on account of 
the rough usage to which it will be exposed. 
I used a No. io-gage spring steel wire. 
This wire was made up into the form of 
a coil spring and then tempered. A spring 
was tried which was made of spring steel 
which had been tempered before it was 
made into the spring. This spring lasted 
but a few hours, after which time it was 
distorted beyond usefulness. 

The results with the spring were com- 
pared with those without the spring, by 
first running the machine with the pipe 
clamped fast to the flywheel spindle, and 
then running the machine with the spring 
free to operate. In the first case there was 
a variation of between three and four volts 
upon each explosion of the engine; in the 
second case this variation was reduced to 
less than one volt, the plant operating at 
HO volts. The power losses arising from 
this arrangement were negligible. 


Increasing the Voltage of a 
Dry Battery 

OFTEN a battery of dry cells will fall in 
voltage or become reduced in pressure 
because some of the cells have polarized, 
consequently the 
current is not 
sufficient to 
operate the ig- 
nition of an en- 
gine or to per- 
form its duty. 
Such an occur- 
rence is likely to 
prove very an- 
noy i ng . In 
emergency cases 
the voltage can 
be increased 
temporarily by 
taking a good 
cell from the set, 
cutting it in half and then making the 
connections as shown. Slip the container 
out of its casing to make the cut and 
connections, then put the two parts back 
so that the cell will have the same appear- 
ance as before. This reduces the ampere 
hours, but it bridges over the difficulty. 


A good cell cut in half 
to produce more voltage 

Popular Science Monthly 

Keyless Lamp Socket for Switching 
Electric Currents 

THE well known key socket for electric 
lamps requires at least thirty separate 
and distinct pieces, the assembling of which 
is an important item in estimating the cost 
of production. 

A new socket has been devised which may 
be made of less than half the usual number 
of parts. Instead of having a key the 
bulb itself serves to switch the current on 
and off. 

Pushing the bulb inward about a quarter 
of an inch causes a spring finger to snap in- 
to contact to connect one side of the circuit, 
while the central contact point of the lamp 
is caused to engage with the terminal of 
the other side of the circuit, thus turning 
on the current without a push button or 
switch lever. 

In order to cut off the light, the lamp is 
drawn back so 
as to sever the 
the act of push- 
ing in or draw- 
ingout the bulb 
being far less 
injurious to the 
threaded end 
of the socket, or 
to the fixtures, 
A part tarn of the socket than the turn- 
awitches the current on or off |ng operation 

of the key. 

The drawing shows the socket made of 
two parts, the lower end, which is threaded 
to receive the lamp, being adapted to slide 
within the upper portion that is attached to 
the fixture. An upwardly-projecting spring 
finger, the lower end of which is attached to 
the inside of the lower shell, has its V- 
shaped upper end normally resting within 
a recess formed through the insulating 
material, so that when the bulb is pushed 
upward the V-shaped end is caused to 
snap over and engage with one terminal, 
while a spring finger on the opposite side of 
the insulating block contacts with the 
central terminal of the bulb. 

It will be observed that by this arrange- 
ment both terminals are out of the circuit 
when the electricity is cut off. By loosen- 
ing the two screws which hold the shells 
together the entire working parts may be 
withdrawn, together with the insulating 
block, affording a convenient and readily 
accessible means for attaching or repairing 
the wires. — J. S. Zerbe. 


Curious Circuit for Audion On a 
Wireless Set 

IT has often been said that it is not 
possible to use an audion bulb in con- 
nection with a simple double slide tuner. 
But experiment has proved that a 
hook-up may be tuned very closely 

Diagram showing an audion bulb in con- 
nection with a simple double slide tuner 

and accurately, the strength of signals from 
all stations being much greater than when 
the same audion is used with a receiving 
transformer. On a single-wire aerial 50 ft. 
high and 150 ft. long, the time signals from 
Arlington were received over 500 miles 
under all weather conditions. As will be 
recognized by those familiar with vacuum 
bulb circuits, the arrangement shown is 
very different from the normal arrange- 
ments on the usual wireless set. 

Conversion of Kilometers to Nau- 
tical and Statute Miles 

WIRELESS telegraph transmission dis- 
tances are often stated in kilometers, 
nautical miles or statute miles. To convert 
the number of kilometers to nautical miles, 
multiply by fifty-four and point off two 
decimal places. To convert from kilometers 
to statute miles, multiply by sixty-two and 
point off two places. If the distance is 
given in statute (or land) miles and you 
want it expressed in kilometers, multiply 
the number of miles by 161 and point off 
two decimal places. 

An Experimental Wireless Aerial 
Made of Zither Strings 

WHILE experimenting with several dif- 
ferent types of novel aerials I found 
that by connecting together all the strings 
of a zither and substituting it for the aerial 
with an inductive coupler, fixed condenser, 
silicon detector and a pair of 2000-ohm 
telephones, I could hear a number of local 
stations very clearly. — Yk Drobe. 


The Effect of Electricity and Music 
on the Human Organism 

THE effect of music upon the human 
organism, whether calming, exciting 
or otherwise, can be reproduced in a re- 
markable manner by means of electric 
currents. Dr. M. Dupont is responsible 
for much of the successful research in this 
direction and has obtained results that 
are not only interesting but of probable 
educational and medicinal value. Music 
consists of sound vibrations at certain regu- 
lar intervals. For a high note the vibrations 
are very rapid, while for a low note they 
are slower. To produce musical effects by 
electricity the alternating current is em- 
ployed, made up of periods, the frequency 
of which corresponds with the number of 
vibrations of the sound; that is to say, 
with the pitch. Upon passing the alternat- 
ing current through the body in the form 
of a mild shock an effect is produced similar 
to the physical thrill of appreciation for a 
musical performance. — H. J. Gray. 

Popular Science Monthly 

To Prevent the Ears from Perspiring 
When Using Telephones 

NO doubt the wireless operator has often 
had the annoying experience of per- 
spiring ears. This inconvenience can be 
easily overcome in the following manner: 
Take a small piece of paper slightly larger 
than the receiver and place it between 
the receiver and the ear. I have found 
this to stop all perspiration without im- 
pairing the hearing.— W. T. Derr. 

A Rain Alarm Made of a Broken 
Electric Globe 

HOW often the rain pours into a window 
at night and we know nothing of it 
until we awake and find the floor and carpet 
damaged ! This can be avoided by installing 
a simple rain alarm which will ring an 

The electric lamp socket on a wood base 
and the connections with the binding posts 

electric bell. To construct such an alarm 
proceed as follows: Remove the upper 
part of a carbon filament lamp by winding 

a piece of cotton string around the lamp 
just above where the platinum wires come 
through the stem. Saturate the string 
with kerosene, applying a lighted match, 
and, while the glass is hot, dip it into water. 

Dilute H 2 S0 4 





Wiring diagram showing the alarm gage in- 
stalled in a battery circuit for ringing bell 

Screw the lamp into a porcelain receptacle 
mounted on a board. Make connections 
with a bell and two dry cells, as shown. 
Then place the lamp outside the window 
and fill almost to the platinum tips with 
dilute sulphuric acid. When a few drops 
of rain fall into the lamp, the solution, which 
is a good conductor, will cover the platinum 
tips and form a circuit, and thus ring the 
bell. The switch should be put near the 
bed where it can be turned on and off 
conveniently. — Wm. Warthen. 

Mounting Tinfoil on Glass Con- 
denser Plates 

A GOOD shellac for fastening the foil 
to the glass in transmitting condensers 
may be made by dissolving as much pow- 
dered rosin as possible in I oz. of turpentine 
and thinning the mixture by the addition of 
^2 oz. of alcohol. Only a very small 
amount of rosin will be needed. 

About three drops of shellac should be 
put in the center of the surface of the glass 
and rubbed around well. Place the foil on 
the glass and roll it fast with a photo- 
graphic print roller. The foil must be 
placed on at once as the mixture dries 
quickly. When this varnish is used the 
plates may either be stacked or made into 
an open rack condenser. If plain turpen- 
tine is used the foil will not stick so well 
and consequently the plates must always 
be stacked. — Samuel W. Huff. 

Popular Science Monthly 


How Germany's Secret Service Wireless 
Stations Are Being Weeded Out 

THAT there are secret service wireless 
stations of Germany in and about our 
large cities and important harbors, there is 
not the slightest doubt. At the time the 
merchant submarine "Bremen" was to 
arrive from Germany, it will be remem- 
bered, German agents prepared moorings 
for her at New London, Connecticut. 
Neither the Government wireless stations 
nor our commercial stations received any 
communications from this submarine. Evi- 
dently, secret stations, whose messages we 
could not hear, must have kept in touch 
with her. 

These stations, we can rest assured, have 
not dismantled, but are working now. 
They await only the opportunity to report 
the sailing of a Europe-bound ship to a sub- 
marine waiting offshore. Unquestionably, 
such a menace must be weeded out. Our 
Government has not been idle. According 
to reliable information, it has already 
located several of these stations. The 
problem is not an easy one, and is one 
entirely of wireless engineering. 

William Dubilier, one of our most 
prominent experts, believes that the Ger- 
mans manage to keep their antennas con- 
cealed by stringing them inside high non- 
metallic structures; as, for instance, a 
hollow wooden flagpole. Though but 
one wire could be strung inside a flag- 
pole, what would be lost in antenna 
efficiency could be partly compensated 
for by the increased power of the station. 
Of course, these spies would not be 
compelled to use an aerial at all. They 

could use a close circuit system having two 
grounds. But this is not likely. The 
other method is more efficient and lends 
itself to better selectivity. 

From the antenna concealed in the flag- 
pole, the spies could run the aerial lead 
directly through the roof and into the 
garret of the building, without exposing it. 
These instruments, we can take it for 
granted, are the best that German money 
can buy. The operators obtain their 
unusual selectivity probably by the use of 
a double heterodyne or ultra-ultra system. 
That is, they superimpose a number of 
oscillation circuits one upon the other 
between the exciting transformer and the 
aerial and ground connections. The various 
ways in which each of these many circuits 
can be tuned are almost unlimited. The 
waves such a system would send out could 
be efficiently received only by a receiving 
system of similarly complex configuration. 
The usual station which has not these 
superimposed circuits could not receive 
the signals distinctly. 

These facts give some idea of the task 

our wireless engineers are up against. 

First, they must obtain a circuit which will 

receive these secret signals — a most difficult 

task which would involve the finding of 

the exact number of the superimposed 

circuits and the exact configurations! 

Second, they must locate the stations with 

some sort of direction-finder using this 

type of circuit. The methods used with 

these finders would then be similar to 

that explained in a previous article on 

the direction-finder, on page 232 of the 

February 191 7 issue of the Popular 

Science Monthly. 

.. '■ ■ 





. ■ 

The Germans conceal their aerial in the hollow of the flag pole. Their complex waves 
can be received only by submarines and other stations fitted out likt themselves 


Electric Experimenting Table Made 
from an Old Commode 

/VN old commode such as is very often 
XjL discarded or sold for little or nothing 
can be very easily and cheaply transformed 
into a high class electrical experimenting 
workbench in the following manner. First 
procure a nice smooth board and nail it 
firmly to the two uprights A, which are 
found on nearly all old commodes. This 
forms the switchboard B, upon which 
all switches, rheostats, meters, etc., can be 
conveniently mounted. 

In the accompanying drawing, a very 
convenient arrangement is shown. The 
dry cells, storage battery, or transformer is 
placed in the little cupboard C, at the 
bottom of the stand, from whence the two 
wires lead to the switchboard and are there 
connected as the user may see fit. All the 
wires are run behind the two uprights A, 
so as to make all the wiring invisible, 
which adds much in neatness. 

The terminals for connecting motors and 
other experimental apparatus are placed 
upon the little back board D. Old battery 
binding posts may be used for this purpose. 

Popular Science Monthly 







A board placed on the towel hanger sup- 
ports of a commode for an instrument board 

Each terminal is operated by a switch on 
the board so that it is not necessary to 
disconnect a wire in order to shut off the 

current. It is also very convenient to have 
one of the terminals connected in series 
with a rheostat E, so that the quantity of 

All instruments and tools may be kept in 
the drawers while the top is used for a table 

current can be regulated. A ground con- 
nection F might also prove handy for 
various experiments. 

A call bell G and small electric light H 
can also be mounted on the board. For 
anyone possessing a wireless telegraph set, 
this stand is doubly convenient, as the 
aerial switch can be placed on the board 
and the instruments mounted directly on 
the top of the stand, if desired. Innumer- 
able other connections and uses will readily 
present themselves, depending on the 
apparatus possessed. 

Tools and instruments can be kept in 
the drawers / and thus be always handy 
and out of the way. A small hand vise 
can be fastened on the stand if needed. 
The principal advantage of it all is that 
everything is conveniently contained in 
one unit. — J. Edward White. 

Panels Made Out of Rubber Storage 
Cells for Radio Apparatus 

IN making panel facings for loose couplers 
or cabinet sets cut up an old hard rubber 
storage-battery case and use it for the 
switch-panel facing. When drilling be care- 
ful not to apply too much pressure. A plane 
may be used on this material if great care is 
taken ; but it is very brittle and will break 
easily. It may be polished with sandpaper. 

Popular Science Monthly 

Japan's Commercial System of 
Wireless Telephony 

ALTHOUGH it is not generally realized, 
i Japan has been one of the most 
diligent countries in making wireless tele- 
phony a commercial possibility. The "T- 
Y-K" radiophone system which the Japa- 
nese have developed is unusual in simplicity 
and compactness. It contains no very 
intricate circuits, nor does it use a delicate 
air-sealed spark-gap, as in other telephone 
systems. The few adjustments that are 
necessary can be made by almost anybody, 
and the spark-gap will work while exposed 
to the air, without deterioration. These 
facts have .made the system so practical 
that Japan has already established wireless 
communication between her important 
islands by means of it. 

The spark-gap electrodes are made of 
oxide of iron, brass, aluminum, and similar 
materials which are practically indestruc- 
tible. The electrode surfaces are small and 
are placed nearly 


talking into the microphone transmitter. 

But all this depends upon the formation 

of a first spark which will release the charge 

of the oscillating circuit. The resistance 

Ground ' 

Diagram of connections: The transmitting 
system uses an air-exposed spark gap. A 
crystal detector system is used for receiving 

touching each other, 
so that the spark- 
producing potential 
can be comparatively 
low. Thus, the volt- 
age of the exciting 
generator is slightly 
more than one hun- 
dred, though as 
much as five hun- 
dred volts have often 
been used. As soon 
as a potential is pro- 
duced across the 
gap, an oscillating 
circuit that is 
coupled to the gap 
becomes simultane- 
ously charged. Once 
a spark jumps across 
the gap, the natural 
tendency of both the 
inductance and the 
capacity of the oscil- 
lating circuit is to send a current from one 
to the other. The result is that each is 
rapidly charged and discharged, the current 
crossing the gap at a rate of about 120,000 
times a second, producing one spark with 
every surging. The surgings in the primary 
circuit are then induced in the aerial and 
microphone circuit which is coupled to it. 
The result is that the aerial radiates its 
wireless waves, which are modulated by 

between the two electrodes — caused by the 
insulating layers of air and of the oxide 
formed on the electrodes — ordinarily pre- 
vents this. So an equilibrator is used for 
temporarily raising the potential in the 
spark-gap circuit. The equilibrator con- 
sists of a strong electromagnet which, just 
as soon as a current begins to build up in it, 
attracts the armature of a circuit-breaker. 
The circuit-breaker is sharply opened, and 
the inductance discharges at high potential, 
supplying the necessary potential across the 

Since the equilibrator works auto- 
matically, only the simple adjustments of 
the oscillating circuits require attention. 
The waves the system sends out, being of 
relatively low frequency, can be received by 
the ordinary crystal detector. Using it, a 
maximum range of thirty to forty miles has 
been obtained. 

A complete Japanese 
T-Y-K installation 

A Crystal Detector Holder for 
Wireless Apparatus 

A SIMPLE clip to hold the mineral con- 
sists of a straight piece of brass sheet- 
ing with a U-shaped piece of spring brass 
soldered on at one end. Another and 
better device for holding the mineral is a 
reflector from an old tubular flashlight 
of the larger size. Clean off the enamel and 
polish up the brass. Fit a piece of wood into 
the socket and drill a hole in it for a ma- 
chine screw which passes through into the 
base of the detector. A large brass washer 
will be required under the head of the 
machine screw. Drill and tap out three 
holes through the side of the cup for the set 
screws which clamp the mineral. The cup 
will hold odd-shaped minerals of various 
sizes and can be turned around at will. 


Popular Science Monthly 

A Trussed Aerial Spreader 
for Long Wires 

ALIGHT and strong spreader is very 
desirable when the aerial reaches over 
200 ft. in length. While bamboo answers 
the purpose for spreaders shorter than 6 ft., 
it does not do for longer ones. 


A light frame trussed so that it will 
be strong enough to hold a large aerial 

A truss-built spreader fills the conditions 
admirably. Select two straight-grained 
pieces of spruce 9 ft. 3 in. long, by 1 in. 
square and two braces 6 in. long by 1 in. 
square. The pieces are assembled as 
shown in Fig. 1. The detail showing how 
the braces are fastened to the spreader- 
piece on the side where the aerial wires are 
attached is seen in Fig. 2. The other ends 
of the braces are fastened with wood 
screws. The rope-bridle is fastened 18 in. 
from each end, to equalize the strain, as 
shown in Fig. 3. The arrows denote the 
line of strain. A spreader built with these 
dimensions is sufficiently large for an aerial 
300 ft. in length.— E. R. Thomas. 

Position of Wireless Waves Passing 
Over Land 

WHEN radio waves travel along the 
surface of the sea, or of any other 
good conductor, their fronts stand up 
nearly vertically. When they pass across 
stretches of poorly-conducting earth, how- 
ever, the tops tend to gain and the whole 
wave-front tips forward in the direction of 
motion. Resulting currents in the surface 
of the earth cause resistance losses, and the 
waves rapidly become weaker. This is 
why it is more difficult to send wireless 
signals over ground than over salt water. 

Cloudy Days Best for Wireless 
Wave Signals 

MEASUREMENTS made at the Uni- 
versity of North Dakota showed 
that on the night following a cloudy day 
signals were received much more clearly 
than on nights following days of bright 
sunlight. It appeared that the cloudiness 
was most effective when it covered the 
territory lying between the sending and 
receiving stations. 

Improving the Tone of a Test Buzzer 
Used on Wireless Detector 

THE tone of a buzzer used in finding a 
sensitive spot on the crystal detector 
can be made high-pitched by inserting a 
piece of paper, folded four times, between 
the contact spring and the bar next to the 
magnet. Also insert a folded piece between 
the cone of the first coil and the bar. 

Simple Construction of a 
Rotary-Gap Disk 

IN the accompanying illustration is shown 
a new type of rotary-gap disk which will 
give unusually good results. It is very 
easy to construct. First procure a piece of 
3^-in. sheet fiber and cut out a disk 9 in. 
in diameter. With a 4-in. radius draw a 
circle on this and divide it off into 8 equal 

Holes in a fiber disk to allow the spark to 
jump between the electrodes as it turns 

parts. Drill holes on these marks slightly 
larger than the gap-electrodes and drill a 
hole in the center for the shaft. Mount the 
disk on a motor in the usual way with a set- 
screw or clamp, and mount a stationary 
gap as shown at A. Every time a hole is 
passed, the gap is permitted to spark. 
More holes can be added if desired, 
depending on the speed of the motor. 

The Construction of a Magnetic Break Key 

With it the lightest kind of a 
Morse key may be used for sending 

By T. Lambert 

THE average experimenter's "break 
key" consists of a number of springs, 
contacts, etc., which are attached to 
his regular transmitting key in a clumsy 
manner. To send clearly a code with key 
contacts 34 in- apart is next to impossible. 
With the relay-key described herein it is 
possible to use the lightest kind of a Morse 
key for sending, since 
all the clumsy con- 
tacts of the breaks 
are on the heavier 
magnetic key. Fur- 
ther, no heavy cur- 
rent is handled by the 
small key and thereby 
arcing and sticking 
are eliminated. 

A key as described 
has been in use in my 
amateur station for 
some time and has 
never given any trou- 
ble in holding the 
detector -adjustment, 
even with the most 
sensitive minerals, 
such as galena and 

The completed in- 
strument is shown in 
the illustration. Four 
spring-contacts are 
employed, besides the 
alternating current 
break. The pair at 
the right disconnect 
the detector from 
the receiver when 
depressed. One of 
the contacts at 
the left shorts the 
telephones while the 
other one grounds the 
entire receiver while 
sending. It will be 
seen from diagram B that the receiving- 
tuner's primary is placed in series in 
the ground-lead of the oscillation-trans- 

When sending, the high voltage currents 
from the transmitter pass directly across 

Four contact springs besides the A. C. break 
are employed in this magnetic break key 

to the ground through the last mentioned 
contacts on the key. Some stray current 
may find its way into the receiver but will 
not damage either telephones or detector 
because they are amply protected by the 
other contacts. There is absolutely no 
danger of shock as all receiving apparatus is 
on the grounded side of the oscillation-trans- 
former. The magnet 
cores are shown at C. 
A good grade of soft 
iron should be used, 
as it is less liable to 
hold residual magnet- 
ism. The cores are 
threaded to fit the end 
pieces snugly. The 
windings can be made 
directly on the cores 
after a layer of tape 
is placed, but it is 
preferable for ease in 
winding to turn out 
two bobbins on a 
lathe, as shown at D, 
and wind on them. 
Use number 20 D. C. 
C. wire and wind on 
eight or ten layers, 
placing a heavy sheet 
of paper between the 
layers. On the final 
layer glue a thin piece 
of ebonite to give it 
a finished appearance. 
The brass crosspiece 
which holds the screw 
for adjustment of the 
tension of the spring E 
(page 159) is shown at 
F. The piece G is of 
hard rubber and sup- 
ports the stationary 
primary contact as 
well as the yoke H for 
regulating the play of 
the key. It is attached to the top of the 
magnets with two machine-screws. The 
armature support is cut from J^-in. brass. 
The contact and crosspiece holes are best 
located after it has been set up on its 
pivot J. This is also of fcrass, cut to the 



Popular Science Monthly 

dimensions shown. The easiest way to 
construct the pivot is to place the arma- 
ture in the position it will occupy when 
completed, and then drill a 1/16-in. hole 
through both pieces and insert a piece 
of steel rod of that size. The armature 
itself is shown at K. This is of soft 

A — Detail of the break key base giving di- 
mensions for the locations of the parts 

iron and can be attached to the armature 
with one machine-screw. 

For supporting the contact-springs a 
hard rubber crosspiece, L, is employed. 
This is attached to the armature by a 
machine-screw. Holes are drilled in it to 
receive the machine-screws holding the 
phosphor-bronze springs, M, in place. A 
brass yoke is attached to the hard rubber 
crosspiece G, and holds the setscrew for 
adjusting the play of the armature. In 
the large end is drilled a hole of such size 
as to permit a 14/20 setscrew to pass with- 
out touching. Four smaller holes in the 
corners are used for attaching to the rubber 

A brass strip is bent to the shapes shown 
at N and supports the contact-screws. 
These are ordinary 8/32 brass screws. The 
loop at the upper end of these supports 
provides an automatic lock nut to prevent 
the screws from turning when once set. 

For the contact-pieces 5/16 in. brass 
rods with dimes soldered on the ends are 
used. These are shown at O. If one is 
willing to go to the expense he can have 
silver plugs made by a jeweler, but in 
actual practise it will be found that dimes, 

when filed smooth on the faces, will carry 
all the current employed in most stations. 
The shorter contact has a threaded stud 
which screws into the armature. The other 
one is made adjustable by means of a 
setscrew in the hard rubber crosspiece. A 
good way to get the dimes together in the 
same plane is to set the brass shanks in 
their proper places and clamp the two 
dimes between them and then solder. On 
separating the pieces it will be found that 
they are in perfect alinement and meet 
exactly when the key is in use. 

The various parts are assembled on a 
wooden base of the dimensions shown at A. 
Heavy binding-posts are mounted as shown 
in the drawing of the completed instrument 
and the connections from the moving 
springs brought down to them by flexible 
cord. The magnet-leads are brought to the 
posts in the rear and the main break- 
contacts to the side posts. The dotted 
lines are the locations of the magnets and 
pivot. For setscrews, fillister head brass 
machine-screws, about 8/32 size may be 

The connection with the other apparatus 
is shown in B. The detector in this illustra- 
tion is shown at D and should be placed as 
close to the key as possible, since long 
leads have induced in them currents that 
are liable to throw the crystal out of 
adjustment and make the break-in useless. 
A battery of about ten volts should be used 



J WWW L -h 




B — The receiving tuner's primary is placed 
the oscillation-transformer 

m series 

on the magnets. Less would be sufficient 
but would not give the snappy action so 
much desired. 

The contacts should be gone over 
frequently with very fine sandpaper, as a 
poor contact is liable to cut down the 
efficiency of the receiver to no small extent. 
The left contact-screws are adjusted to 
touch the springs when the key is depressed 
while the right hand pair are to make 



] c 

Popular Science Monthly 159 

Loading Coil in Series with 
the Secondary 

WHEN a low resistance detector is 
used, it is a good plan to tune the 
secondary circuit by using a comparative- 
ly small inductance coil and a large con- 





-i ■- 


() () () 











1 *-n 

m \\ — n 

— V-i/ — 






G K 

Detail of the parts that enter into the 
construction of the magnetic break key 

contact when the armature has come back, 
and to break the contact when it has been 
drawn to the magnets. 

A little experience will make it possible 
to get an adjustment where there is no 
sparking at the contacts and no noise in 
the telephones. 

I doubt if anyone, after using a key such 
as described, will ever willingly go back to 
the old clumsy aerial switch. 

H L 

denser, for then the current flow is a maxi- 
mum and the voltage is quite low. For 
high resistance detectors the reverse is 
true. Increased efficiency with such de- 
tectors as the audion can frequently be 
secured by inserting a loading coil in series 
with the secondary, and correspondingly 
reducing the capacity of the tuning con- 
denser. This applies the highest possible 
voltage to the grid. 

An Emergency Form for Winding 
Motor Fields 

RECENTLY my rotary spark-gap, no- 
. volt A. C. motor burned out one of 
its fields. As I was in a hurry to use it I 
tried a quick method of rewinding the coil 
by driving a series of nails into a wood 
face-plate on a small lathe and winding 
the wire on them. After winding the coil 
I bent the nails together so that the coil 
could be slipped off. — Edward McClure. 

Effect of the Moon and Season on 
Wireless in the Tropics 

WHILE stationed in the tropics for 
several years as a wireless operator, 
I observed that in the periods of a full 
moon, or thereabouts, the atmospheric 
interferences are slight and the ether seems 
to carry the wireless waves with less ab- 
sorption than when the moon is in its 
quarter periods, or thereabouts. With a 
full moon, and using the same receiving set, 
I could receive from stations that were 
about 200 miles farther away than those 
which could be heard when the moon was 
in its first or last quarter. Also, during the 
winter months from about the first of 
December to April, there seemed to be bet- 
ter atmospheric conditions.-#-J. M. Cohen. 


Popular Science Monthly 

Magnetic Brake for a Wireless 
Rotary Gap 

THE radio experimenter who uses a 
rotary spark gap in connection with 
his sending apparatus is usually troubled 
with interference in his receiving set caused 

r^ A wwvwwwv_^ 




Eliminating the interference of inductive 
noises from the motor of a rotary gap 

by the inductive noises from the motor of 
the rotary gap, which if well balanced takes 
some time to come to a full stop. 

In the drawing, A represents the blade 
of a single pole, double throw, switch. The 
figures B and C are the two jaws of the 
switch. The figure D represents a rheostat 
by means of which the length of time nec- 
essary for the motor to come to a full stop 
may be regulated. At E and F are the 
fields and armature of a series-wound 

The action is as follows: To start the 
motor, throw the blade A to contact C. 
When through sending, throw blade to con- 
tact B, which causes the current from the 
line to flow to one field through the rheostat 
D, and results in stopping the motor in two 
to three seconds. After the motor has 
stopped, disengage the switch blade from 
jaw B, otherwise a waste of current will 
result. — Paul J. Hoffman. 

Adjusting the Detector of a 
Receiving Set 

WHEN the crystal or other detector of 
a wireless telegraph receiver is ad- 
justed by the use of an ordinary buzzer set 
up near the instruments, it is often noted 
that the point of contact which gave loudest 
response to the buzzer is not that which is 
most sensitive for receiving signals from 
long distances. The most sensitive spots 
sometimes do not give loud sounds when 
the local buzzer is operated. 

This has been noted by many experi- 
menters who have electrolytic and crystal 
detectors in use side by side; generally the 
crystal will give the loudest signal when the 

buzzer is worked, but the electrolytic will 
prove better for receiving from stations far 
away. This is because the character of the 
test impulses produced by the ordinary 
buzzer is quite different from the radio fre- 
quency-currents set up in the receiving 
aerial by the distant station. 

In a patent (No. 1,176,925) issued during 
1916 to G. W. Pickard, there is shown a 
method of avoiding this difficulty. As in- 
dicated in the drawing here reproduced, a 
buzzer having armature A, contact B and 
magnet C is connected in series with bat- 
tery D and test key E. Across the vibrat- 
ing contact is shunted a high-frequency 
oscillating circuit comprising the condenser 
F and the inductance G. This last named 
element is coupled variably to the sec- 
ondary H of the receiving oscillation- 
transformer, which has the usual tuning 
condenser, detector, blocking condenser, 
telephones and potentiometer arranged as 
shown. The shunt oscillation circuit F, 
G, is adjusted to produce feebly damped 
groups of radio frequency-current corre- 
sponding to the wavelength most used at 
the receiver. 

When the buzzer is put into operation 
by pressing the key E, there are generated 
in the transformer secondary radio fre- 
quency-currents corresponding to those re- 
ceived in actual radio telegraphic practice. 
The groups produce tone signals, of the 
buzzer interruption-frequency, in the tele- 
phones. The loudness of these signals de- 
pends upon the coupling between the coil 

Diagram of connections for buzzer exciter 
which permits accurate setting of the crystal 

G and the secondary, and upon the true 
sensitiveness of the detector. By selecting 
the point of crystal which gives loudest 
responses to such excitation, when the buz- 
zer coupling is set to produce an intensity 
corresponding to that of the station which 
it is desired to receive, the operator may 
have entire confidence that his detector is 
properly prepared to do the best work. 

Why Edison Succeeded 

You can't get on in the world unless you read 
— read the books which will make you more 
valuable to those for whom you work. You 
don't have to go to college. Edison never went 
to college. But he has probably the finest 
library of technical books in this country. 

If you want helpful, practical books on 
electricity, mechanics, mechanical engineering, 
wireless, airplanes, sheet metal work, repairing, 
write to the Popular Science Monthly's Readers' 
Service Bureau. Tell us in what subjects you 
are interested and we will compile a list of 
books, with their prices. 

We will send more than a mere price list. 
We will select out of a hundred or more titles 
the very book which, in our opinion, meets 
your requirements. 

Whenever you are at a loss for an inexpensive, 
practical book, or for information about books, 
write to 

Popular Science Monthly's 
Readers' Service Bureau 
239 Fourth Avenue, New York 

Destroying a Submarine with a Cable-Bomb 


The air pilot lets the bomb sink until it is just below what he gages the depth of the submarine 
to be. When the airplane passes over the submarine, dragging the bomb on its wire, the air- 
man gives the bomb a sharp pull upward. It strikes the hull of the submarine and explodes 

3 S 


Popular Science Monthly 

Vol. 91 

No. 2 

239 Fourth Avenue, New York City 

August, 1917 


Drag-Bombing Submarines from Airplanes 

A new method of airplane attack 





IN the airplane the elusive submarine 
has a deadly enemy. Flying high 
above the surface of the ocean, an air- 
plane can see a submarine which has dived 
to avoid surface boats. The airplane's 
methods of attack have ' ot been so un- 
erring as the gun fire from the boats. But 
now comes Thomas E. Li ke, the son of 
the distinguished inventor of the Lake-type 
submarine, with a new method of airplane 
attack which looks as though the clearing 
of waters infested by submarines will be 
accomplished with far more ease in the 
future than it has been in the past. 

Instead of using high 
speed airplanes to drop 
time-bombs on the sub- 
marines, Lake has de- 
vised a slower speed 
airplane for dragging 
contact bombs against 
it. His airplane, which 
uses a distributed 
wind-lifting area, is 
capable of high speed 
when scouting for sub- 
marines. But when it 
sights one, this airplane 
can slow up and can 
carefully go through 
its manuevers without 
losing buoyancy. The present-day naval 
airplane cannot do that; so that this 
marks the first advantage in the Lake 
method of attack. 

The next, and even more important ad- 
vantage of the Lake attack is the manner 
of bombing. The submarine has little 
chance of escaping it. The slow-going air- 
plane nears the submarine broadside on. 
A heavy contact bomb is quickly lowered 
to the proper depth in the water by a 
spring-controlled mechanism. 

This mechanism is an entirely new device 
which received its inception with the de- 
velopment of this plan of attack. It is very 
sensitive, for at the slightest reduction in 

the tension of the spring, the bomb re- 
sponds by sinking. It will continue to 
sink until the added upward thrust on the 
cable, caused by the water's pushing 
against the slanting wire which has just 
sunk beneath the sea, makes up the tension 
which has been lost from the spring. 
Therefore it is highly important to properly 
tighten this spring. In practice, this would 
be done by means of a turnbuckle which has 
been rigorously calibrated by factory tests. 
The air pilot lets the bcmb sink until it 
is just below what he gages the subma- 
rine's depth to be. The bomb thus drags 
along while the airplane approaches its 
prey nearer and nearer. 
Soon the airplane pass- 
es over the submarine. 
The wire dragging be- 
hind hits before long 
against the submarine 
hull. The bomb con- 
tinues on and swings 
toward the hull, the 
airplane drags it the 
short distance upward, 
and the bomb strikes 
the submarine. The 
percussion explodes the 
mine, and blows up the 
submarine without its 
having the least chance to endanger the 
airplane. Even should the bomb miss the 
submarine, it could be exploded from the 
airplane. The operator simply releases 
the brake for an instant, then presses down 
hard on the brake lever. The jerk will 
fire the emergency device within the bomb, 
and if the submarine is anywhere near it, 
the resulting explosion will disable the sub- 
marine, at the least. The ordinary method 
of dropping time-fused bombs on a subma- 
rine requires nothing short of extraordi- 
nary skill in aiming and timing the bomb 
so that its explosion will be effective. That 
method cannot be one-tenth as effective as 
this drag-bombing plan. 


Details of the spring-controlled brake 
which keeps the cable taut and enables 
the bomb to sink to the proper depth 



Popular Science Monthly 

rid Dawson 

Three exposures of the Arctic sun made on the same plate. The sun is shown rising, at noon- 
day and at sunset. It travels along the very edge of the horizon, as if just peeping above it 

How the Sun Looks in the Arctic 

Circles in the Morning, at Noon 

and at Night 

NORTH of the Arctic Circle, during 
certain periods of the year, the sun 
barely peeps over the horizon. Some days 
you have to stand on your tip-toes, so to 
speak, to see it at all. At sunrise, midday, 
and sunset it appears just above the 
horizon, and re- 

"An Army Travels on Its Belly," 

Said Napoleon — Also on Its Feet, 

Say Chiropodists 

IF your feet trouble you, you are only 
about fifty per cent efficient as a 
fighting man. In the Fourteenth Regiment 
of the National Guard, in Brooklyn, N. Y., 
the men must submit themselves to a foot 
examination. The accompanying illustra- 
tion shows a 

mains in about 
the same posi- 
tion. It never 
climbs high into 
the heavens as it 
does in warm 
countries. It 
travels around 
the horizon. 

The illustra- 
tion shows three 
exposures of the 
Arctic sun made 
on the same 
plate. The pho- 
tograph was tak- 
en December i , 
1915, at 11:45 
a. M., 12 m. and 
12:15 P- M., re- 
spectively. Nine 
days after the 
photograph was taken the sun did not 
appear above the horizon at all, but re- 
mained below for five weeks, gradually 
appearing again in reverse order. 

Graduates of a school of chiropody applying themselves 
to the relief of the foot troubles of a Brooklyn regiment 

number of them 
undergoing treat- 
men t at the 
hands of the 191 7 
class of the 
School of Chirop- 
ody of New York. 
The young grad- 
uates volunteer- 
ed their services 
long before hos- 
tilities were de- 

Regular estab- 
lished undergrad- 
uate and post- 
graduate medical 
schools pay but 
little attention to 
foot conditions 
unless they re- 
quire major sur- 
gical treatment. Consequently there is a 
particular need for chiropodists at the 
present time. Numbers of them will 
doubtless be engaged for the army. 

Popular Science Monthly 
A Mechanical Hair-Parter. It Places 
Every Hair Where It Belongs 


EOK at this hair-parting apparatus. 
It accurately outlines a straight part 
on any portion of the scalp, separating 
the hair easily and quickly with 
out dependence upon a mirror. 

The device consists of two 
flat strips of celluloid or 
vulcanized rubber which 
may be bent lengthwise 
to conform with the 
shape of the head. 
These are pivoted to- 
gether, edge to edge, 
in such a way that 
either strip may be 
swung around inde- 
pendently of the 
other. The strips 
are laid with their con- 
fronting edges along the 
line where the part is to 
be made. One is held 
down to conform with 
the shape of the head 
and the other is swung 
around carrying the free 
hair with it. Thus the 
hair is parted. 

One strip holds the hair down 
on an imaginary line, while the 
other sweeps the free hair to 
one side, making a straight part 

A Combined Ice-Box, Pantry and 
Trunk for Automobiles 

A COMBINATION refrigerator, pantry 
and trunk, which can be made to fit any 
automobile, has been invented by Ralph S. 
Hopkins of Seattle. Hopkins has found this 

m W *au U U L 


The owner of this auto- 
mobile can stop at any 
suitable spot, set his table 
and partake of a comfort- 
able meal from the re- 
frigerator on the running- 
board of the automobile 

contrivance, made of iron for his five-passen- 
ger car, most valuable for automobile trips. 
The apparatus weighs sixty pounds and 
is placed on the running board. It takes 
up the entire space on one side between the 
front and rear fenders, without detracting 
noticeably from the car's appearance. It 
is fastened in place with four bolts. 
It is as high as the top of the doors 
of the motor car. The whole ap- 
paratus is made of sheet iron, 
painted to match the car, 
with the exception of 
the refrigerator, which 
is of galvanized iron 
to prevent it from 

Hopkins uses his 
refrigerator, located 
at the lower right 
corner of the picture, 
for ice and perishables. 
The refrigerator is di- 
vided into two sections, 
the upper which holds the 
ice, and the lower which 
carries milk, butter and 
the like. In the lower 
compartment on the left 
side groceries are kept, 
while in the top section, 
which extends the whole 
length of the apparatus, are stored all other 
necessary articles for long trips, such as 
clothing, fishing tackle, guns, folding chairs 
and tables. 

There Are Five Hundred Indian 
Languages in the United States 

BEFORE you write the Govern- 
ment or the Smithsonian Insti- 
tution and request it to send you 
the Indian name for this or that 
thing, bear in mind that there is 
no one American Indian language. 
On the contrary, there are no less 
than one thousand languages in the 
two Americas and practically five 
hundred distinct Indian languages 
north of Mexico. Thus, it is impos- 
sible to give the Indian word for any 
English equivalent. If you do re- 
ceive an answer to your in- 
quiry, the word given is 
probably chosen from the 
language of the tribe which 
once inhabited the particular 
part of the country from 
which the* request comes. 



Popular Science Monthly 

A small Niagara 
which has been de- 
veloped indoors as 
a part of the hy- 
draulic laboratory 

It takes a power 
plant of 500 horse- 
power (see photo- 
graph at the right) 
to make the mini- 
ature Niagara 

also commercial forms and 
sizes of turbines under large 
energies of water may be 
studied. The whole ap- 
paratus is fitted with meas- 
uring devices so that precise 
measurements may be made 
at any point. One engineer 
who inspected the outfit said, 
"This is using a river and 
measuring its effects with a 
teaspoon," so delicate are 
the tests applied. 

In the basement of the 
school there are eight hun- 
dred feet of canals supplied 
from the Charles River Basin. 
These have turns and 
narrowings and junc- 
tions, so that the flow 
may be observed under 
all possible conditions. 
The outfit includes many 
pumps and engines for the 
work, aggregating about 
500 horsepower, together 
with compression tanks 
and all the essentials for 
a mammoth indoor hy- 
draulic laboratory. 

The Largest Indoor Waterfall 
in the World 

THIS waterfall is not out of doors, nor 
is it used for the development of 
power, but it represents the flowing of one 
hundred tons of water each minute and en- 
ergy of more than three hundred horse- 
power. It is part of the laboratory equipment 
at the Massachusetts Institute of Tech- 
nology, and illustrates how this 


school teaches by means 
of commercial quantities 
under ordinary condi- 

The water here shown 
has been lifted to an 
elevated canal, which 
the students call "the 
big brook," forty feet 
above the base of the 
pump, and returns 
through a great pen- 
stock ten feet in diame- 
ter to the outflow canal. 
The conduct of water 
under such pressure and 


Instead of tying the ends of the 
cord you simply fasten them in 
the wire loops. The wire takes 
the place of the usual knot 

It Fastens Cord Tighter Than You 
Can Tie It 

PACKAGE tie designed to fasten 
cord without tying the ends, has been 
invented by Warren L. Bald, of New York 
city. The inventor claims that his tie 
will fasten a cord tighter than any knot 
ever devised and will hold the cord more 
securely than a number of knots. 

A spring wire takes the place of the 
usual knot. Only two operations are 
necessary to tie the cord. The cord is 
hooked around the wire 
loops, and, when a strain 
is put on these loops, the 
cord is pulled tighter, the 
spreading of the wire 
acting as a lever. The 
device not only saves the 
fingers of the person who 
wraps a large number of 
packages daily, but with 
the cord properly se- 
cured in the wire loops 
it is impossible for the 
packages to fall apart. 

Popular Science Monthly 


Foiling the Pickpocket and Protect- 
ing Your Watch 

AVERY simple device to prevent 
your watch from falling out of 
your pocket has been invented by 
Carl Anton Nord of New York 
City. It consists of a case 
stamped from sheet metal 
and lined with soft fabric. 
The case, which is fast 
ened securely to the 
pocket, has a notch at 
the top, which is 
rounded to admit the 
stem of the watch. 
The stem of the watch 
is pushed down inside 
of two prongs which 
project slightly above 
the case. 

These prongs require 
some effort to separate 
them, so that the watch 
can not fall out or be 
easily pulled out by a 
pickpocket, without the 
owner being immediate- 
ly aware of it. 

The watch is held 
securely in 
which is fastened 
inside the pocket 

southern California when motoring off the 
main highways in the mountains or deserts, 
as it is sometimes necessary to do 
there as well as in other sections 
of the country. 

To demonstrate the possibilities 
of an invention to be used when 
the car is mired, a Los Angeles 
automobile dealer carried out 
the test shown in the illus- 
tration below. The rear 
end of a car weighing 
2,250 pounds and equip- 
ped with a 24-horse- 
power engine was lift- 
ed high above the floor 
by means of ropes at- 
tached to the floor 
beams above and 
passed around hub 
drums fixed to the rear 
In actual practice the 
ropes will be led 
forward to heavy 
stakes or other ob- 
jects strong 
enough to resist 
the pull. 

Testing a Car's Power to Pull Itself 
Out When Stuck 

GETTING stuck in mud, soft sand or 
snow — the particular circumstances 
depending on the season of the year — is one 
of the vicissitudes to be guarded against in 

Test designed to demonstrate the power of an automobile 
to pull itself out of mud, soft sand or snow by means of 
power from its engine and ropes wound around hub drums 

Take Good Care of the Eggs This 
Year— You Will Need Them 

THE United States Department of 
Agriculture has called attention to the 
fact that carelessness in handling eggs 
causes an annual loss of over thirteen 
millions of them. The loss 
is due to small cracks in the 
shells. Once an egg Shell 
is cracked even so slightly 
that the eye cannot detect 
it, the delicate, protective, 
gelatinous coating which Na- 
ture provides as a lining for 
it becomes exposed to the 
attack of germs and mold 
forms, lessening the keeping 
quality of the egg. 

Five per cent of all cold 
storage eggs, the specialists 
find, spoil because of these 
small, scarcely perceptible 
cracks. Just a little more 
care in handling the eggs on 
the farm and in their transit 
to market and to the con- 
sumer will greatly lessen this 

important wastage. 

Handling a Submarine 

The success of an attack and the very lives of the crew 
depend almost entirely upon their ability to act as one man 


The U. S. S. 
air nas just forced 
out the water from 
her huge ballast tanks 
so that she rides 
awash on the surface 

At left: Interior of 
the "K-l." During 
an attack, the com- 
mander stands at the 
periscope and directs 
the men at the wheels 
of the controls 

Wheels tontrollinq 
diving rudders 

Battery of compressed-air buoyancy 
controls of balance tanks. 

EVERY submarine has its commander 
— generally a captain — who acts as 
the very brains of the ship. No one 
else can give orders; for so interconnected 
are all the machines, that the conflicting 
commands from more than one officer 
would almost surely result in an accident. 
Hence every one reports directly to the 
captain through the second officer in com- 
mand, who, by the way, is also responsible 
for the correct operation of everything 

from the ballast tanks to the torpedoes. 

In making the attack, the captain mans 
the periscope in the main operating room, 
just beneath the conning tower. The 
lenses and prisms in the periscope tube 
transmit the images from the sighting-piece 
above the water down to the periscope 

When the vessel dives, the decks are 
first cleared. Then the hatches are sealed 
down and the oil engines are stopped, in 

Popular Science Monthly 169 

Storage batteries are A Tell -Tale Light System— First Assist- 
ant to the Motorcycle Cop 


quick succession. 

turned on to drive the electric propelling 
motors. Electric machinery must be used 
under water because the oil engines con- 
sume precious air and exhaust poisonous 

On the next word from the captain, 
water from 
outside is al- 
lowed to fill 
the huge bal- 
last tanks in 
the central 
hull. Other 
ballast tanks 
at the ends 
of the boat 
are partially 
filled to hold 
the ship on 
an even keel. 
This trim- 
ming of the 
course, can be deli- 
cately controlled by 
the buoyancy gages 
and controls in the 
operating room. 
The weight of all 
this water causes 
the submarine to 
sink, but not com- 
pletely. The hori- 
zontal rudders at 
the stern of the ship 
are used to give the 
final touches to the 
dive. The com- 
mander directs the 
man at the wheel 
how far down he 
wishes to go. By 
watching the depth 
gages in front of 
him, the wheelman 
can so tip the diving 
rudders that the 
proper depth can 
be found immediately and held exactly. 

It takes but a minute or two to dive. 
In torpedoing a ship, the entire vessel must 
be turned to aim the torpedo tubes, which 
lie parallel with the central axis of the sub- 
marine, in the bow. The command is given 
to fire. The gunners in the forward com- 
partment receive the order through speak- 
ing tubes or telephones. The torpedo is dis- 
charged from its tube by compressed air. 

Storage battery current is suf- 
ficient to run the system and 
also to operate a tonneau ex- 
tension of the colored lights 



30 MILES- _ 


21T0Z5 MILE5 lb TO 20 MILES 15 MILES 

Details of the mechanism by which the 
passengers and traffic policemen can be 
kept informed as to the speed of the car 

IT would profit the French General Staff 
as much to have one of its members an 
agent of the German Intelligence Bureau as 
it would profit 
a motorist, 
bent on speed- 
ing, to display 
this tell-tale 
electric signal 
on the front 
of his ma- 

The device 
consists of a 
series of col- 
ored lights, 
five in num- 
ber, arranged 
ularly in a 
metal case, 
and mecha- 
nism essen- 
tially similar 
to that of a speedo- 

When the auto- 
mobile to which this 
signal is affixed 
moves at a rate of 
less than ten miles 
an hour, no light 
shows. From ten to 
fifteen miles an hour 
is indicated by an 
amber lamp. At 
fifteen the next 
higher lamp in the 
tier — a blue one — 
flashes on. At 
twenty comes a green 
light, at twenty-five 
a clear white light, 
and at thirty miles 
an hour or more a 

red signal shows. 
Never more than one lamp is lit at any 
given time, except in the case of a car which 
has exceeded thirty-five miles an hour. At 
this point the red light short-circuits, and 
stays burning even though the car slackens 
speed or stops. If a car, therefore, shows a 
red light and a green light at the same time, 
it means that the car has been going at a 
rate higher than thirty-five miles an hour, 
and is traveling at about twenty. 

Bayonet Practice for Our Recruits 

Photo Central News 

Two methods of attacking an opponent are shown at left above. The figure is of stuffed straw, 
held rigidly in position by an iron rod. At right above is a dummy likeness of von Tirpitz. It 
served as a target at Plattsburg. The British manual of bayonet tactics has been adopted 


Why the Hindenburg Line Seemed So Impregnable 

The victorious British have unearthed the se- 
cret of the strength of the Hindenburg line. It 
lay in concealed forts of solid cement hidden in 
the most ingenious ways. In the top picture 
one is seen built so as to seem part of a ruin 

One fort discovered by the British was built 
under an old barn. It was covered over with 
grass and was entered by means of the ladder 
and pulley arrangement shown above. It 
was used as a station for a machine gun 


The Michelangelos in Bakers' and Confectioners' 

During the holiday season Paris shops contain an 
elaborate assortment of beautiful figures made of 
fat and sugar. Here a workman is shown pouring 
a fat and sugar mixture into a mold. There are a 
number of skillful artists in Paris who do nothing 
else in times of peace, but make these figures 

A windmill palace made of chocolate and butter, a 
combination which is as effective for sculptural 
purposes as clay. Locomotives, steamships, air- 
planes, and about every type of building have been 
represented in chocolate and butter. They often 
contain equally edible figures of men and animals 


Shops Do Their Work in Sugar, Chocolate and Fat 

Above: An artist smoothing out 
the imperfections in a number of 
sugar statuettes that have just 
been cast. When polished and 
varnished the sugar figures can 
not be told from marble figures. 
In special designs the sugar 
must be extremely fine grained 
to permit of delicate carvings 

Fat mixed with tallow is run through a grinder to 
soften it. When in a plastic form it can be kneaded 
like dough. To prevent it from becoming rancid, 
citric acid is added to the mixture before molding 

An automobile made of 
nuts and sugar — a good 
example of the confec- 
tioner's art. At the pres- 
ent time Paris bakers and 
confectioners are making 
their choicest sweets in the 
shape of fortresses, cannons, 
and armored automobiles 


The Vanishing Chimney Sweeps of Paris 

On account of the 
modern construc- 
tion of chimneys in 
larger cities the day 
of the chimney 
sweep is about over. 
But occasionally one 
encounters him even 
in Paris. Here one 
is seen preparing to 
clean a baker's oven 

Below: The little 
chimney sweep was 
formerly a familiar 
sight, and his shrill 
call "O-o, O-o! 
Void le ratnon- 
eur!" (Here is the 
chimney sweep) was 
one of the accus- 
tomed early morn- 
ing noises of the city 

With his tight-fit- 
ting cap pulled 
down over his head 
and his soot bag 
fastened at his side 
the little gamin 
begins his work at 
about three or four 
o'clock in the morn- 
ing so that he will 
have finished and 
disappeared from 
sight by the time 
folks are astir. 

An older man, 
called the "patron," 
accompanies the 
gamin, making his 
contracts and over- 
seeing his work. 
Where the chimney 
is too small for the 
boy to enter, his 
"porcupine" brush 
is lowered into it. 
Its stiff outstanding 
bristles scrub the 
walls mechanically 

When the sweeping 
is over the soot is 
brushed into a bag 
and carted away. 
The gamin requires 
only about ten min- 
utes to clean out 
the largest and dirt- 
iest of chimneys. 
His patron receives 
the remuneration, 
which grows less 
and less with the 
progress of time 


Novel Ways of Recruiting in the East 

They sing on ship and they sing on land 
— when there's recruiting to be done — 
of good fellowship and exciting times 


One way of making a question so effective 
it can not be ignored. "I am one half. 
Will you be the other?" reads the placard 

The Sailor Is as Handy with Knife and Rope 

Working on a deck mat. These mats are at every dcor of a battleship. 
Heavy wire is used for the base. One-inch Manila rope is twisted and 
woven in and out. When finished the mat has an elaborate rope edge 

Int. Film Serv. 

Every battleship has several collision mats, 
to be used in emergencies. The mats are 
usually thirty feet by nineteen feet. They 
are made of heaviest canvas and hemp 

Starting the work on a collision mat by 
sewing the first layer of hemp on the canvas. 
When the mat is complete it is covered with 
a thick layer of hemp and no canvas is visible 


as the Seamstress with Needle and Thread 

The strings which sup- 
port a hammock are 
called clews when ar- 
ranged in the approv- 
ed fashion. The sailors 
shown above can each 
make fifty-five clews a 
day. This work requires 
little skill and 
one of the first job; 
taught to the recruits. 
The best and strongest 
of rope is essential. 
Hammocks serve 
beds aboard ship 

The man in the oval is 
putting the finishing 
touches on an extra- 
size bumper and pad- 
ding it out. All ships 
are provided with 
bumpers, which are 
hung alongside to pro- 
tect the hull against 
scratches and cuts 
and to break the force of 
the jar should the vessel 
come in contact with an- 
other vessel or with the 
sides of the pier or dock 

Old pieces of 
rope are used 
to form the in- 
side of the 
bumper, as 
shown at the 
left. One man 
can make eleven 
bumpers a day. 
At right is shown 
the completed 
bumper. This is 
the work of a 
skilled expert 


The Betsey Rosses of Today Engaged in the Huge 

In the wave of 
patriotic fervor 
which is sweeping 
over the entire 
United States, the 
daily manufacture 
of flags and patri- 
otic emblems of 
every description 
has run up into 
many millions 

In spite of the fact 
that electrical ma- 
chinery of every 
available type is 
used, the produc- 
tion scarcely keeps 
pace with the de- 
mand. At left 
is shown the form 
used in cutting out 
stars of all sizes 

Above is shown a 
motor-driven cut- 
ting machine in 
operation on ma- 
terial for the 
blue flelds of the 
flags. These blue 
fields are cut in 
bulk, many hun- 
dreds of them at a 
single cutting. It 
is difficult to esti- 
mate the number 
of yards of bunting 
that have been cut 
up into flags since 
the United States 
announced her in- 
tention of joining 
the contestants in 
the great war 

As soon as the stars 
have been cut out 
they are pinned or 
pasted on the blue 
fields and then 
passed on to the 
operators of the 
electrically driven 
sewing machines. 
These seamstresses 
turn out an in- 
credible amount of 
work in a day 

At left: The stars 
being cut in a punch 
press. At each op- 
eration the steel 
die cuts through 
forty-eight folds of 
the white bunting, 
making forty-eight 
stars — enough for 
one complete flag — 
at one time. There 
are dies of all sizes 
of stars and eagles 


Task of Meeting the Demand for "Old Glory" 

The stripes are cut 
alternately, first 
red and then white, 
at a surprising rate 
of speed. Then 
another battery of 
workers sew the 
red and white 
stripes together. 
Big flags and little 
of silk, felt 
or bunting, all are 
cut in the same way 

The sewing on the 
very fine flags 
done by hand, but 
it must be made 
especially strong, so 
that the flags will 
be able to with- 
stand the flapping 
of the wind, which is 
no respecter of fine 
materials or deli- 
cate needlework 

In center: For spe- 
cial designs, stencils 
are made by means 
of a perforating 
machine. A black 
powder is applied 
over these stencils 
to mark the design 
on the cloth. Then 
artists bring the de- 
sign into relief with 
oil paint and brush 

The machines used 
for the stitching 
are threaded with 
great spools of cot- 
ton containing 
twenty-four thou- 
sand yards each. 
This is fed in with 
lightning swiftness 
and the sewing is 
done with never a 
"drop" stitch 


Waterspout— the Sailor's Dread for Centuries 

fg\ aaa mi nn ma ssa paa nn n» ith hh ^n lt^ m-. ^ , 

Waterspouts have always been the dread of sailing-ship captains. In the Mediterranean, 
where the waterspout shown above was photographed on a January afternoon, the ocean 
is oftentimes lashed into foam by a series of the most violent spouts. As the photograph 
shows, the waterspout appears as a conical mass of cloud with concave sides rising from 
the water surface to meet an inverted cone of cloud. The phenomenon started as a whirl- 
wind over the sea during the prevalence of a humid atmosphere. The rise of heated air 
is accompanied by inrushing wind, which literally churns up the water into waves, and 
the water and foam are sucked upwards. Fish and frogs have been carried inland by 
waterspouts. From this fact the expression "Raining bullfrogs" probably originated 

""' >•«" "" mi ■■ -ww mire.-Jnm .m ..m 

a m m lt 


Making the Summer Bearable in the Zoo 

Polar bears suffer even more 
than their brown brothers from 
the summer heat. The keepers 
of the Bronx Park "Zoo," in 
New York city, spray the ani- 
mals daily. The bears will pose 
like statues on a ledge of rock 
while the hose is played on them. 
The cubs are given ice water to 
drink through nursing bottles 


Soldiers' Art Exhibit at Leblanc's Museum, Paris 

The period of convalescence of the wounded 
soldiers is enlivened by much penknife carving 
and construction of toys, which are usually 
models of devices used in the war. Here is a Ger- 
man soldier's conception of an aerial bomb thrower 

President Wilson's Message Reaches the Germans 

■ "■* • 

" '„"•'!', .* 

|H til;n: 

■nil hi 

»<iuH : ■ 


mil Kit 



lj*«fl 4 < 

l<n da 'Soil • 

ft ran r.m 

, S4K.M 

i o»« St 



Safcn . 

n »n •&««» 


hwi n»n 

(1141.1 t«8<U<« muffto 



«<« *' 



I onr rtf 

rf<a K. 


«! 'jj.a 

* *■ * * * * * + 

*> * * * •* * * 

* *****•'*■ 

* * * «T * * * * 



Wcbc be* ^rdfibrmn 

gf baton am. 2, Wpril 1917 
iin .ttoiiflrrf* {\\ Sfofhiiiqta.. 

M wft MH mtfrrt* 

'♦if: m itm Mtxn 
JAcxatr HnrnrO- 

President Wilson's message to Con- 
gress (translated into German) 
which proclaimed to the Germans 
in the trenches that the United 
States had taken up the fight in the 
name of humanity and that right 
is more to be desired than peace 

Above: Several copies of President 
Wilson's war message attached to a 
balloon. Only parts of the message 
were printed in the German papers 
— the least important parts. That 
is the chief reason for the procedure 

How the balloons carried the mes- 
sage to the German trenches. An 
American business man contributed 
a large sum to be spent in distribut- 
ing the message, which thus reached 
the German ranks uncensored 

Recreation for the Wounded and for Prisoners 

Above: A prisoner's 
trolley car, made 
out of odds and 
ends found in a 
detention camp. 
Going down hill 
the man behind 
operates the brake; 
going up hill he gets 
off and pushes. As 
a general rule pris- 
oners are kept busy 

A pop-gun sham- 
battle between two 
wounded soldiers 
enlivens a dull hour 
in a British hospital. 
The toy cannons 
operate on the same 
principle as the 
pop-gun. One of the 
soldiers has suffered 
the loss of an eye; 
the other, a leg 

Wounded British 
soldiers listening to 
a musical comedy 
through an electro- 
phone service con- 
tributed by public- 
spirited people of 
London to the hos- 
pitals of that city. 
Even the baby ele- 
phant mascot seems 
to be enjoying the 


Queer Trees and Near-Trees— All Are Useful 

Although the spongy wood of the silk-cotton tree, found 
principally in Jamaica, West Indies, is too light to 
be of commercial value, the natives make canoes out of 
it and fill pillows and cushions with its long silky threads. 
Its root - formations make the tree earthquake-proof 

Bamboo belongs to the grass family, although 
its tall stalks resemble saplings. As material 
for rafts, fishing poles and even for houses 
it has been in use since the world was young. 
Orientals consider the young shoots, which 
resemble asparagus, a nutritious food 

The banyan tree, on account of its habit of 
putting forth numberless trunks to support 
its branches, thus crowding out all other 
trees, is regarded as a robber and murderer. 
But it yields rubber equal to Para — and 
once, centuries ago, it shdtered a Buddha 


The Automobilist's Mechanical Cost Keeper 

It tells the mileage of the car, the life of each 
tire, and the gasoline and oil consumption 


THE latest device for the convenience 
of the automobile owner who desires 
to keep a complete record of his car 
operation is an instrument on which can be 
read at will the car 
speed, the trip mile- 
age, the total mile- 
age, the mileage of 
each of the four tires 
in use, the two spare 
tires usually carried, 
the gasoline and oil 
consumption and 
warnings at 500 and 
1,000 miles of run- 
ning to indicate that 
adjustments, greas- 
ings, etc., are neces- 
sary. These thirteen 
records can be read 
as desired. 

The device is no 
larger than the ordi- 
nary speedometer 
and is mounted on 
the dashboard in the 

the fuel tank or oil into the engine crank- 

As shown in the accompanying illustra- 
tions, the thirteen odometers, nested within 
a casing on the oppo- 
site ends of parallel 
shafts, are covered 
by a ring-dial, 
around the circum- 
ference of which are 
divisions for each of 
the thirteen records. 
In the dial face is a 
slot in back of which 
the various odom- 
eters are moved ac- 
cording to the record 
desired. Those 
odometers to the 
right of the nest, as 
shown, are slid over 
to the left on their 
shafts by means of 
turning screws on 
the face of the in- 
strument so that the 

The device con- 
sists of thirteen 
separate odome- 
ters, operated in 
sequence by a 
series of spring- 
pawls in a casing 
surrounded by a 
ring dial having 
thirteen parti- 
tions for records 

'Dial" : 

This OdomeTer slid to 
--.jefT To register 
"th slots in face 

KLw the mileage of tire No. 4 is 
recorded on the instrument 

conventional manner. It is driven by 
means of one flexible cable to the front 
wheel or to the engine propeller shaft, as 
desired, and consists of thirteen separate 
odometers, operated in sequence by a 
series of spring-pawls. All of the readings 
are obtained from the mechanical operation 
of the odometers and of the driving means, 
with the exception of the gasoline and oil 
records, which are manually operated and 
must be set each time gasoline is put into 

Turning screws slide the odometers 
from right to left on their shafts 

figures register properly behind the slots 
in the dial, the latter being turned in the 
same operation. 

When a new vehicle is purchased and the 
device attached, all odometers are set at 
zero. The speed in miles per hour, the 
trip and total mileage are registered in the 
usual manner ; one odometer serves to 
give the same reading on each of the four 
tires fitted. If tire No. 1 was removed at 
1,000 miles, the face of the dial would be 


Popular Science Monthly 


turned until this reading showed through 
the slots. Then by turning the knob shown 
on thecasing, this odometer would be thrown 
out of engage- 
ment and the 
odometer for the 
new tire, No. 5, 
engaged. If this 
tire ran* 1 ,000 
miles before re- 
m o v a 1 , the 
odometer for 
tires 2, 3, and 4 
would each reg- 
ister 2,000 miles 
at that time. As 
tire No. 6 was 
put on in place 
of No. 5, these 
mileages would 
be automatically 
added to until the tires were taken off, 
which time the respective odometers would 
register accurately the mileage covered. 
The miles per gallon of gasoline or miles 
per quart of lubricating oil are obtained by 
pencil and paper calculation. 

The walls of the circular garage are eight feet 
eight inches high and are reinforced with wire mesh 

A Circular Garage for the Farm, 
Built from Silo Forms 

SILO forms 
used on a Mis- 
souri farm were 
employed to 
build the novel 
circular concrete 
garage shown in 
the accompany- 
ing illustration. 
It cost about one 
hundred and fif- 
ty dollars and is 
sixteen feet in 
diameter, with 
sufficient space 
on each side of 
the car for work 

bench and vise. It is entirely of concrete 
except for the two-part wood doors and 
window sash. The walls are four inches 
thick, reinforced with wire netting. The 
floor and the roof are also of concrete, the 
latter with a three inch slope to the foot. 

Inflate Your Tires to Full Pressure, 
Even in Hottest Weather 

OOK out! Don't inflate that tire 


this," is the costliest warning ever hurled 
at motorists. Instead of saving 
tires and money it has cost 
automobile owners millions 
of dollars. True, a tire does 
expand in hot weather, but 
so slightly as to be negligi- 
ble in its effect. It never 
expands to the danger 
point. Furthermore, in- 
ternal heat does not 
result from the tem- 
perature of the outside 
air, but from the con- 
stant bending of the tire 
as it travels along. Con- 
sequently, when you run 
your tires under-inflated in 
hot weather to combat air 
expansion, you cause in- 
creased bending of your 
tires, and thus create more 
heat — which is just the 
condition to avoid. The 
thing to guard against is 

The measuring . device for de- 
termining whether a person is 
right or left handed naturally 

Use Your Natural Arm If You Would 
Be a Good Craftsman 

THE brachiometer (don't be frightened 
at the name) is an instrument which 
has been devised by Professor H. Franklin 
Jones, of the University of South 
ikota, to determine whether an 
individual is naturally right or 
left handed. Every person is 
born with a major and a 
minor arm, and Professor 
Jones, through study of 
this fact, has discovered 
things about the man 
who is jack of all trades 
and master of none. 

To determine "hand- 
edness" he measures the 
bones of the arm with 
his brachiometer. If you 
were born with a left 
major but adopted the 
right, the fact will be shown 
by measurement of the re- 
laxed forearm circumfer- 
ence, contracted forearm, 
relaxed biceps and con- 
tracted biceps. To become 
master of your trade you 
must use your major arm. 

Roadtown— The Commuters' Utopia 

Vitalizing the country with arteries 
of energy and life from the city 

By Max Fleischer 

devoted half a life-time to housing 
problems, has conceived Roadtown, 
which, if carried out, should give us all the 
advantages of the country with none of its 
disadvantages. The Roadtown plan of 
housing may be compared with the modern 
skyscraper hotel or office building. The 
vast number of tenants occupying these 
buildings, closely alined for economic dis- 
tribution of light, heat, power, vertical 
transportation, etc., by means which are 
self-contained within the structure, make 
it possible to rent an elegantly appointed 
room or modern office at a very moderate 
figure. But is it necessary to go up into 
the clouds against gravity to minimize the 
operating cost? 

To see Roadtown through the eyes of the 
inventor, imagine a hotel skyscraper miles 
in height, as many miles as you dare 
imagine. Try five hundred miles at least. 
Have it fully equipped with every conceiv- 
able modern convenience, complete in 
every detail. Now, carefully lay this build- 
ing on its side until it reaches far across the 
country. This is Roadtown — a continuous 
unbroken line of 

Food kept cold in 
this compartment 

^v Separating wall. 
Cover - ^ 

two-story rein- 
forced con- 
crete residences 
reaching hun- 
dreds of miles 
out into the 
open country. 
What were the 
elevators in the 
skyscraper are 
now the Road- 
town subways 
running in a 
trench under 
the building. 
The lighting, 
heating and dis- 
tribution prob- 
lems for these 
reoidences on the farm now solve them- 
selves for you. In such a building it seems 
possible to live in the country — with 
every city convenience. 

One may live a hundred miles from his 
office in the city and commute; for 
distance along Roadtown should be calcu- 
lated by time rather than by miles, since 
it is planned to have, in addition to local 
service, express trains traveling at terrific 
speed (over 200 miles per hour is not an 
impossibility with the Boyes Monorail), 
and as silently as the skyscraper elevator in 
its vertical plunge. Rows of screened 
windows under the porches of the houses 
will ventilate the subway. 

Referring to the illustration, it will be 
noted that each house will have two 
private front gardens, one on either side. 
There will be no rears to these houses — 
nothing erected to obstruct light and venti- 
lation. Each house will be twenty-one feet 
wide by twenty feet deep and contain seven 
good-sized rooms. The walls, floors and 
ceilings will be of cement and sound- 
proof. Stairways will give access to the 
subways and to the continuous roof, which 
will be a roadway for pedestrians, skaters 
and light, rubber-tired vehicles. It will be 
illuminated at night with electric lights. 
A covered promenade in the center of the 
roof will pro- 

Food in containers kept hot 
during transit in this 

The automatic carriers which deliver meals already pre- 
pared from the community kitchen to the consumer's home 

tect the pedes- 
trians from 
rain. In the 
winter, it will be 
enclosed with 
glass panels. 
The promenade 
will thus be con- 
verted into a 
continuous sun 
parlor. At in- 
tervals, towers 
will be erected 
which will be 
used as social 
and shopping 
centers and con- 
tain schools, 
public service stations, libraries, theaters, 
heating-plants, telephone centrals, etc. 
The distance between these towers will be 
determined principally by the operative 

Hot water 

Double wall 
hot water. 


Popular Science Monthly 


Imagine a skyscraper hotel miles in height — say five hundred miles — and fully equipped with 
every modern convenience. Now lay this skyscraper carefully on its side on the ground, so 
that its elevators will be subways running in a trench under the building which will extend, in a 
straight line or in serpentine coils, miles out into the open country. This is Roadtown 

efficiency of the public utilities contained 

Being operated on the plan of an im- 
mense hotel, individual kitchens will not 
be necessary — the Roadtown kitchen near- 
est you will take your telephone order, and 
by means of automatic carriers running on 
a horizontal track, deliver your favorite 
dish right into your dining-room. These 
carriers will be arranged to preserve the 
heat in the food during transit, one section 
of the carrier remaining chilled for cold 
dishes. The meal finished, the carriers will 
be returned to the community dish- 
washer. The carriers will run along a single 
track and will be automatically switched to 
its proper recipient by a trip-key, similar 

in action to the type-distributing feature 
of the Linotype machine. 

Evidently, to make doubly certain that 
our new "city farmer" will have every 
advantage of civilization, the inventor of 
Roadtown proposes to instal a number of 
utilities some of which are at present avail- 
able only to the rich. For a better idea of 
this intention, it may be well to describe 
briefly those at present under consideration. 

The temperature of each room will be 
automatically regulated to suit its particu- 
lar occupant, by the use of the thermostat 
attached to the steam radiators. In very 
hot weather the refrigerating plants will 
pump cooled water through the radiators. 
Running distilled water, cooled to a health- 


Popular Science Monthly 


ful temperature, will be used for drinking. 
Heavy doors and windows will be moved 
automatically by compressed air. Gas dis- 
infecting pipes will lead to each residence. 

Vacuum cleaners will be installed. Bell 
announcers will signal a few moments in 
advance the arrival of a train 
to the nearest station, allowing 
sufficient time for the resident 
to be on the platform. This 
signal device can be made 
inoperative at will. The 
dictograph will en- 
tertain, lecture, sing 
or play for you when 
you do not care to 
go out. By simply 
phoning central the name 
of your favorite selection, 
the entertainment will be 
wired to your room or to 
the room of a convalescent 

To the practical-minded 
man the Roadtown propo- 
sition may now begin to 
assume the thinness of a 
fantastic dream, too good 
to be true. But, is it? 
The society recently or- 
ganized to further the in- 
terest in Roadtown is re- 
ceiving the cooperation of 
architects, engineers, 
builders and scientists. 
Among them are level-headed thinkers who 
are not readily bowled over by a fas- 
cinating but impractical venture, such 
men, for instance, as Mr. Boyes, inventor 
of the monorail, M. K. Turner, inventor of 
the dictograph, and Thomas A. Edison, 
electrical wizard, who has donated his 
cement-pouring patents to the Roadtown 

Estimates, costs and statistics are being 
rapidly compiled, and in view of the ex- 
treme economy of build- 
ing in a continuous line, slots 
utilizing one mold for hun- 
dreds of buildings, of pur- 
chasing building material 
in wholesale quantities, 
and the economy of close 
alinement, it has been es- 
timated that one of these 
seven - rooms and bath 
Roadtown residences 
could be rented for twenty- 
one dollars per month. 

assume that 

A New Spur Is Carried on the Reins— 
Not on the Heel 

IF you dig a horse in the ribs with nicely 
sharpened spurs, he runs. You naturally 
if you dig him in the back 
in like manner, the result 
will be the same. Herein 
lies the reason for the 
rein spurs invented by 
B. E. Jordan, of Hugo, 

The spur consists 
of a circular piece of 
steel which is at- 
tached to metal 
plates that hold it in 
position on the rein. 
The sharp points on 
the edge of the disk 
complete the spur. If 
it is sufficiently sharp 
the driver need only drop 
it gently on the horse's 
neck and, as the inventor 
says, "he will be goaded 
into activity." The prin- 
cipal advantage which the 
rein-spur has over the heel- 
spur is recognized when 
the rider has occasion to 
dismount and walk awhile. 

The spur strikes the horse's 
neck. It is attached to the 
rein within easy reach 

A Bottle Opener Which Will Not 
Break the Cork 


The self-opening device is glued 
to the neck of the bottle. It 
rolls over to form * thumb-loop 

opening a bottle with the ordinary 
corkscrew, it often happens that the cork 
is broken and difficulty is found in removing 
it without dropping crumbs of cork into the 
contents of the bottle, or of pushing the 
broken cork itself down into the bottle. 
In the illustration below a device is 
shown which eliminates all the bother con- 
nected with the 
opening of the 
bottle. It is in 
the form of a 
) loop glued to 
the top and 
around the 
sides of the 
neck of the bot- 
tle, by means 
of which 
seals and 
labels may 
be removed. 

Advertising surface 
of flap 

flexible strip 

sealing flap 

Flap sealed 

Popular Science Monthly 


apparatus^ ^T 



Electric battery* 
one eel I connects I 
with flash light ' 
both cells with coil S 

High voltage 
shocking coil 

Details of the 
cane with its 
shocking coil 

Protect Yourself Against Highwaymen 
with an Electrified Cane 

prowler, springing at 
you in the dark, how would 
you defend yourself? One 
young American believes he 
has solved the problem by 
an electric cane which would 
paralyze the muscles of the 
assailant in a twinkling. 
The cane is loaded with a 
high tension shocking coil 
and electric batteries. These 
add weight to the cane so 
that you can wield it with 
effect, and — what is still 
more important — prevent 
your assailant from pinning 
the cane down so you can- 
not use it. Press a button — 
and you electrify the cane 
and give him a shock which 
causes him to drop the cane 

The electric coil is merely 
an unusually powerful medical coil of an 
elongated type. It fits into the hollow 
of the lower end of the cane with 
the two dry cells that are con 
nected with it. The "busi- 
ness" end of the shocking 
coil is led to the metal 
plating which covers the 
entire lower half of the 
cane. While the shock 
from the cane will never 
kill a man, it will sur- 
prise him enough to 
throw him off his guard 
and upset his plans. 
The cane is further 
equipped with a flash- 
light set in its knob. One 
cell is used to operate it. 
The upper end of the cane 
carrying the electric bulb 
and this cell, can be de- 
tached and used as an 
ordinary portable flashlight. 
Such efficiency in a cane 
makes it a good companion 
on a trip through the woods 
or in the summer camp. 
Although it was originally 
protection against human 
is equally successful against four-footed 
ones, even the largest of them. 

W H /' 

The lower end of the cane is 
metal-plated so as to be electri- 
fied by the high tension coil inside 

intended for 
prowlers it 

The folding crib in use in the automobile. When 
no longer needed it folds up into compact form 

A Folding Crib in the Automobile and 
Summer Camp 

shall be 
done with the 
baby when the family 
decides to go automobil- 
ing? The question is 
answered by a new crib 
which can be carried in 
the car and which can 
fold into a very small 
space and in such a 
shape that it can be 
disposed of readily 
when not needed. 
The crib is very com- 
pact. It can be carried 
edgewise on the back of 
the rear seat against the 
back wall of the automo- 
bile top, and it does not 
protrude or interfere in any 
way with the occupants of 
the tonneau. Or it can 
stand on end by the robe 
rail without inconvenience. 
In use the crib occupies 
the space between seats, and 
gives the baby considerably more free- 
dom of action and comfort than if he were 
held continually on the lap of an adult. 
In camp, the crib is set up as at home. 

The Time Fuse and How It Works 

The number of feet, yards or miles which 
the projectile is to travel can be accurately- 
gaged by simply turning the time ring 

By Reginald Trautschold, M.E. 

The time fuse forms 
the tip of the nose 
of the projectile. 
It is in five parts: 
the body proper, 
its cap, and the 
top, bottom and 
time rings. Fitted 
between the cap 
and the body is a 
time pellet held in 
place by a stiff 
stirrup with bent- 
over ears and con- 
taining a detonator 
of highly explosive 
material. Under 
the time pellet is 
the fuse needle 










powder channel 
powder train 

Bottom ring 
detonator spring 
fowder channel 
time ring 



YOU have read in the war dispatches 
that the "troops advanced under a 
curtain of fire." What does that 
mean? Simply that a barrage of bursting 
shells, hurled over the advancing men into 
the enemy's lines, forms a protective screen. 
In order that this curtain of fire may 
be a real protection, however, and not 
a terrible menace, it is absolutely essential 
that the men who fire the guns should have 
precise control of the point at which the 
shrapnel or high-explosive shells are to 
break. It is easy enough to imagine the 
demoralization within the advancing lines 
if the men had to fear bombardment from 
the rear as well as the enemy's fire. 

That danger has been practically elimi- 
nated by the perfection of the time fuse. 
By simply adjusting the time ring of the 
fuse the gunner can predetermine the exact 
point — be it feet or miles from the muzzle 
of the gun — at which the projectile is to 
do its deadly work. Shrapnel, and the 
even uglier high-explosive shells, may be 
exploded if desired within a hundred yards 
from the muzzle of the gun, notwithstand- 
ing the fact that the projectiles start on 
their mission of destruction at the rate of 

about 1,350 miles per hour. On the other 
hand, they may be sent whirling through 
space for miles. It all depends upon the 
adjustment of the simple little time ring 
of the fuse. 

The time fuse is an ingenious little 
mechanism which forms the tip of the nose 
of the projectile. It contains a time pellet 
and a detonator of highly explosive ma- 

On leaving the muzzle of the gun, the 
projectile, traveling at a speed of close to 
2,000 feet per second, is literally shot away 
from the time pellet, the bent-over ears of 
the stirrup which held it in place are 
straightened out and the fuse needle is 
driven forcibly into the detonator. The 
resulting flash passes through the flash 
hole in the body and ignites the mealed 
powder in the powder shaft of the top ring. 
This ignites the train of powder contained 
in the circumscribing powder train. From 
the powder channel in the top ring a similar 
powder train in the lower ring is ignited 
through a connecting hollow black powder 
stick. From the second powder channel, 
the flash is transmitted to the powder 
magazine in the base of the time fuse, 


Popular Science Monthly 

through connecting sticks of black powder 
in the fuse body. The magazine connects 
with the powder pocket at the center of 
the base, from which the flash is trans- 
mitted to the powder tube in a shrapnel 
or to the corresponding "gaine" in 
the high-explosive shell, which, 
in turn, delivers to the main 
explosive charge of the 

The passage of 
the initial 

from the detonator to the powder pocket 
in the base of the time fuse is varied in 
length by adjustment of the time ring, 
and the length of the powder train which 
has to be consumed before reaching 
the top of the powder tube or "gaine" 
controls the instant at which a shrap- 
nel will "break" or a high-explosive 
shell will be shattered. The adjustment of 
the time ring simply shortens the passage 
by establishing short cuts between the 
powder channels or increasing the distance 
between points of communication. 

Should, by any mischance, the time fuse 
element fail to work, the projectile will then 
break on coming in contact with a rigid 
object, through the action of the auxiliary 
detonating element of the device. 

In the base of the mechanism is a second 
detonator which is held in place both by a 
stirrup similar to the one which holds the 
time pellet behind the cap and the body of 
the fuse and also by a coiled spring between 
the holder of the detonator fuse needle 
and the percussion pellet. On the projec- 
tile striking a firm 
object, the percus- 
sion pellet with its 
detonator is thrown 
violently forward 
against the de- 
tonator fuse needle 
and the resulting 
flash is transmitted 
immediately to the 
powder tube or to 
the "gaine," as the 
case may be, — thus 
avoiding the circum- 
scribing powder 
trains through which 


Shrapnel with its rain of 
balls, and high-explosive 
shells with their burst 
of jagged shell fragments 

the flash produced from the contact 
of the time detonator and the fuse 
needle must pass. 

Destructive as is the time fuse when 
fitted to a projectile which leaves a gun, it 
is comparatively harmless under ordinary 
conditions, on account of the rigidity of the 
stirrup holding the time pellet and of the 
springs holding the percussion pellet. 

EVERY autoist will appreciate 
funnel, invented by Walter W. 

Filling Up Your Automobile Tank 
Without Spilling the Gasoline 

rington of Texas. It is an ordinary funnel 
soldered to a plug which fits snugly in the 
tank opening. The air valve, through 
which the air in the tank escapes when the 
gasoline is poured in is attached to this 
plug, the valve stem and spring serving as 
the funnel handle. When the gasoline 
reaches the mouth of the spout, you simply 
release your pressure on the spring to let 
it close the valve. Immediately the flow 
of "gas" into the tank is stopped because 
of the air pressure. So you fill up the 
funnel and then reopen the air valve. 
All this can . be done 
in about twenty 

With this funnel 
the autoist can 
fill the tank of 
his automobile 
with gasoline 
in less than 
half a minute 

And Still the Inventors Continue to Provide Us 

This ideal sight-seeing automobile is surrounded by glass, even at the top. 
City skyscrapers and country mountains can be seen with ease by every passenger 


Two detachable 
strap-carriers which 
hold the luggage on 
the automobile 
running board 

Dirt and grease splashed 
under your mud-guard 
can be very easily re- 
moved by detaching this 
lining and washing it 

Gripping- and compres- 
sing-tongs for making bat- 
tery-plate handling easy 


A dividend-paying ad- 
vertising attachment. It 
also prevents dust and 
mud from splashing into 
the faces of passers-by 

with Automobile Improvements and Accessories 

The hot water from the 
engine can be very effect- 
ively cooled by this radi- 
ator made of water-coils 

Above: The steering 
wheel is pivoted at the 
upper section. You can 
swing it down and enter 

A fully equipped tool cab- 
inet built in the door near 
the driver's seat is always 
ready for an emergency 

This overgrown automobile on car wheels is the salvation of short-line rail- 
roads. Gasoline will here do the work of steam at a fraction of the expense 


The Misunderstood Shark 

Under- sea photography is adding to our 
scant knowledge of these wolves of the deep 

WILL a shark attack a man? "Yes," 
say the landlubbers, some of whom 
saw sharks deliberately attack and 
kill bathers along the New Jersey coast 
last year. "No," indignantly retort the 
sea captains, fishermen and shark-wise 

The truth is that only a few facts about 
sharks are well established, apart from 
the question of whether they do or do not 
kill human beings. For instance, there 
are so many different kinds of sharks that 
it would take this page, set in fine type, 
to list them. When it reaches a length 
of three feet the dog fish becomes a shark 
to most people. Yet the white or man- 
eating shark attains a length of forty 
feet. There are sand sharks, nurse sharks, 
blue sharks and others too numerous to 
mention. But the fact that the white 
shark has the designation "man-eating 
shark" is evidence enough that he is an 
eater of human flesh. His triangular teeth, 
his armor-like skin and his lightning speed 
under water make him a wolf of the deep. 
His home is in tropical waters, but he is 
an occasional visitor to the waters of 
Long Island — and without any invitation, 
too. The white shark has been blamed 

for the attacks off New Jersey. 
Sailors will tell you that 
sharks will eat anything; 
that they are shy and cow- 
ardly; that they are inactive 
in the daytime and feed 
mostly at night; that the hungrier they 
are the more ferocious they become, attack- 
ing and killing other sharks, and that they 
are the swiftest swimmers of the deep. 
There seems to be some misunderstand- 
ing concerning the way in which sharks 
attack their victims. Some claim that 
they turn over as they attack, so as to 
bite more readily with their receding under- 
jaw. Others claim that they attack head- 
on, swimming to their victim in a straight 
line. According to J. E. Williamson, whose 
work in photographing the shark under 
water for the motion-picture plays "Twenty 
Thousand Leagues under the Sea" and 
"The Submarine Eye" has been notably 
successful, the "head-on" description of 
attack is the correct one. 

"I can prove by my pictures that a 
shark does not turn over to bite," states 
Mr. Williamson. "If a shark wants to 
pick up anything from the bottom of the 
sea he goes right down to it as a cat 
pounces on a bone and picks it up. A 
shark does not turn over to bite any more 
than any other fish does." 

In photographing sharks with his sub- 
marine camera, Mr. Williamson used a 
steer as bait. The carcass floated on the 
surface of the water some ten feet from 
the camera. It did not take long for the 


Popular Science Monthly 


sharks to locate it. They approached 
cautiously at first and then attacked it, 
striking it with the force of a ram and 
tearing off huge pieces of flesh. Attached 
to the body of each shark, as the pictures 
show, were the usual pilot fish, clinging 
with the aid of sucker fins. As soon as a 
shark is dead the pilot fish attack it, 
eating their way through the dead body. 
One shark, Mr. Williamson observed, struck 
a projecting beam and was dazed mo- 
mentarily. The instant the other sharks 
saw this they fell upon the unfortunate 
one and literally tore it to shreds. 

Ordinarily, sharks are easily caught with 
bait and hook, and frequently they become 
enmeshed in fishing nets. But no one 
has ever devised a scheme whereby they 

can be caught and killed in large numbers. 
One ingenious method is here illustrated. 
On each side of a small patroling vessel 
are mounted a number of rotary reels 
each of which carries an insulated electric 
cable. To the free end of each cable is 
secured a large fish hook carrying the bait 
in the form of a fish or piece of meat 
which is let down over the side of the 
ship almost to the water's level. 

The reel drum has on one of its heads 
a number of contact pins which are con- 
nected with the insulated cable. As soon 
as the reel is turned slightly, one of these 
pins comes in contact with a stationary 
bracket connected with one pole of a 
dynamo supplying a current of 220 volts 
and five amperes, the other pole being con- 

One of the scenes 
photographed un- 
der-sea by the Wil- 
liamson Brothers 
for their thrilling 
film production, 
"The Submarine 
Eye." In this pic- 
ture Mr. William- 
son proves that a 
shark does not turn 
on its back to at- 
tack an enemy as is 
commonly supposed 

Sharks are easily caught with 
bait and hook. Here is shown 
the type of giant hooks used 

Notice the small pilot fish underneath the shark at 
the bottom of the picture. It clings to the shark 
by sucker fins and feeds on the body eventually 


Popular Science Monthly 

A vessel carrying a new device for killing sharks by electricity. The detail of the device by 
means of which the bait is charged is shown in the lower right-hand corner of the picture 

nected with the metallic hull of the vessel 
and the water. 

When a shark seizes the bait, he pulls 
on the cable, and the reel is rotated. 
The electric current then shoots from the 
dynamo through the cable, the hook, the 
shark's body, the water, and the ship's 
hull back to the dynamo. The electric 
shock contracts the shark's jaws around 
the hook like the jaws of a vise, so that 
escape is impossible. He is electrocuted 
almost instantly. 

Co-operative Kitchens to Solve the 
"High Cost" Problems 

THAT the cost of the primary necessities 
of life has increased to a point that 
causes hardship, privation and under- 
nutrition among the unemployed or in large 
families striving to exist on a small income, 
is no doubt pitifully true. In the majority 
of cases, however, it is expensive tastes 
and pampered appetites which suffer most. 

Ignorance of how to spend money in order 
to get fullest food value and of how to pre- 
pare the food to the best advantage is 
also a contributory cause of hardship. 

The food actually required for the body's 
needs costs very little. Enough pork and 
beans, bread and butter, milk and coffee, 
with the fuel to cook it, to amply nourish 
an adult for an entire day would cost 
only about twelve cents, according to 
expert dietitians. Numerous other in- 
expensive and healthful foods there are 
to add variety; but the problem is to 
govern the quantity and kinds of food 
by the needs of the individuals to be 
served and to prepare it appetizingly. 

The solution seems to lie in the co- 
operative kitchen, in which Science writes 
the menus, consulting not the personal 
appetites of the patrons but their specific 
needs. The highest cost of meals for an 
entire day in such a kitchen should be 
not more than thirty cents for each in- 
dividual, including the diagnosis. 

Popular Science Monthly 


Teaching the Proper Care of Forests 
by Object Lesson Models 

THE right and the wrong way to cut 
timber is shown by realistic models 
which the Forest Service has had prepared 
for exhibition purposes throughout the 
country. Three models are included in the 
series. The first shows a stand of one acre 
of virgin timber, an actual scene in one of 
the national forests that has been repro- 
duced on a small scale with great accuracy 
both as to proportion and coloring. 

The second of the series shows the same 
stand after a timber sale conducted in 
accordance with the regulations, of the 
Forest Service. The matured trees have 
been felled and cut into lengths which have 
been arranged in systematic piles to facili- 
tate their removal from the forest. All of 
the brush and small limbs, which, if left on 
the ground would constitute a fire hazard, 
have been arranged in compact piles in 
readiness to be burned under the watchful 
eyes of foresters. 

The third of the series shows an example 
of the wrong way to cut timber. Logs of 
various lengths are seen scattered about, 
no attempt having been made to arrange 
them in piles. Some of the trees felled 
have not been cut into lengths; many 
have been cut down without regard to 
size or maturity. All of the cut timber 
and the trunks of the standing trees are 
charted and the condition of the ground 
indicates that the forest has been burnt 
over, the inference being that careless 
methods on the part of those engaged 
in cutting out the timber have resulted 
in the spreading of a forest fire which 
might otherwise have been checked. 

The Forest Service has two 
sets of these models. One 
which shows a stand 
of Western yellow 
pine, is utilized for 
the western section 
of the country; the 
other, depicting a 
typical forest 
scene in the 
southern Appa- 
lachian region, 
for the eastern 

The three mod- 
els are exhibited 
in connection with 
lectures on forest 

One of a series of models used by the United States 
Forest Service to show how timber should be cut 

The helmet keeps the wearer alive by draw- 
ing its supply of fresh air from next to the floor 

A New Helmet for Use in Smoke 
or Gas-Filled Chambers 

THIS is not a gas mask such as is used 
in European trenches. It is a new 
helmet which the British Government has 
installed on five hundred battleships to be 
used below the decks when entering gas 
or smoke-filled compartments. It is also 
being introduced in America, in city fire 

When used in smoke or gas-filled rooms 
this new helmet draws its supply 
of fresh air from next to the floor, 
taking advantage of the well known 
natural law that heat, 
smoke, fumes, etc., 
rise, leaving a cer- 
tain amount of ox- 
ygen close to the 
floor. The trailing 
hose of the new 
helmet seeks that 
cushion of fresh air 
next to the floor. 
The helmet 
weighs only four 
pounds. One 
size is adjustable 
to fit a man, 
woman or child. 

America's Biggest Flying Machine 

Glenn Curtiss builds a giant airplane for the Navy 
By Carl Dientsbach 

IN no craft are the drawbacks of small 
size so manifest as in aircraft. Flying 
in a disturbed atmosphere is never less 
severe than navigating an angry ocean. 

into a true "whaleback" to become at least 
really seaworthy. In its new extreme size 
and shape it promises to supersede that 
homely compromise, the "seaplane," a 
moderately enlarged airplane mounted on 
high stilts on a catamaran "surf boat." 
Not infrequently, these stilted floats were 
broken off by the waves through 
which they cut better than small 
flying boats. The smooth, 
shapely hull of the new 
flying yacht which Glenn 
Curtiss has built for 
our Navy, is one piece 
with the extremely 
strongly built 
planes like 
the auxil- 

intricate observations; shells must 
be dodged, exact aim with bombs 
and machine guns taken, and rapid 
maneuvers carried out in aerial 

Increase the size of the airplane 
and at one stroke seemingly insur- 
mountable difficulties are overcome. 
Exacting duties may be divided 
among a more numerous crew. 
Strong celluloid windows protect the 
men from storm and cold ; no ham- 
pering clothing or goggles are re- 
quired ; there is space to move 
about; numerous instruments and 
conveniences can be provided and 
handled at ease. Airmen have to 
thank the ocean for all these bless- 
ings. No mere cockle shell of an 
airplane can ride the waves as a 
naval airplane must. The old 
"flying boat" had eventually not 
only to be vastly enlarged, but also 
completely decked over and turned 

The smooth, shapely hull of the new Curtis flying 
yacht is in one piece with extremely strong planes 


Popular Science Monthly 


iary floats on the wing tips, and promises 
to defy the ocean successfully. 

The difficulty of making any large air- 
plane relatively strong enough, although 
partly overcome because the unobstructed 
sea is an ideal starting and landing sur- 
face, still lingers in a certain relative de- 
ficiency in carrying capacity. On the 
other hand, there is a most welcome im- 
provement in equipment and comfort 
which permits, among other things, a 
liberal utilization of electric lights. 

Heavy loads, however, cannot be carried 
without materially cutting down the radius 
of action — loads such as heavy guns and 
ammunition. With motors of 400 aggre- 
gate horsepower, a span of 92 feet 
and a total weight of 7,000- 
8,000 pounds, this machine 
is expected to make from 
55 to 85 miles an hour. 
So low a minimum speed 
is not objectionable on 
water. With only two 
men aboard, fuel for five 
hours might be carried. 

All rudders and con- 
trols are worked by elcc 
tricity, and controlled most 
of the time, gyroscopically. 

Teaching Children Natural History 
with Animal Pictures Made of Sand 

THE approved method of teaching 
very young children is to disguise the 
instruction under the cloak of amusement. 
An interesting development in the carrying 
out of this idea is found in the sand pic- 
tures of Walter A. Ward, of New York city. 
Cardboards covered with colored pictures 
of animals are given to the children to- 
gether with bottles containing the vari- 
ously colored sand. The children paint 
the body of the animals with glue, and 
then carefully cover the colored portions 
of the animal bodies with the appropriate 
colors of sand. 

In this interesting way, while the chil- 
dren seem to be merely amusing themselves 
they are gaining very definite instruction 
as to the names, coloring and physical 
characteristics of the different animals. 
Stories in connection with their habits and 
the countries where they may be found 
naturally accompany the pictures and en- 
large the scope of the work. The rudi- 
ments of drawing and painting, as well as 
of Natural History, are indirectly taught 
in this way. 

Above: The larvae 
of the Automeris 
Io, the moth shown 
at the left. Its 
brilliant stripes and 
branching spines 
are its protection 

Sometimes an Object Is Beautiful 
Because It Is So Ugly 

EVERYBODY is familiar with the ex- 
treme ugliness of the bulldog's face 
that makes the animal positively attractive ; 
and everyone who has studied the moths 
is familiar with the marvelous hideousness 
— or beauty — of the larva of the Automeris 
io. The Io is found from Canada to Florida 
and westward and southward to Texas 
and Mexico. In the larval stage it feeds 
on the leaves of almost any tree or shrub. 
For ages the enthusiastic lepidopterist 
has regarded it as a beautiful creature. 
The dainty green body with lateral stripes 
of pink and creamy white covered with 
clusters of branching spines forms an object 
to be admired — and respected too. It 
should be handled with care or painful 
consequences may result. Yet it is a 
curious fact that in spite of all the pains 
that Nature has taken to protect this 
beautiful creature from birds and other 
large enemies, she has left it open to at- 
tack from the tiny ichneumon wasp which 
drives its sting between the spines and 
there places a parasital egg. In this way 
multitudes of the larvaf are destroyed. 

20£ Popular Science Monthly 

How Would You Like to Hold a Chinese A Wire Hood for Protection Against 
Printer's Job? Bees or Mosquitoes 

/^HINESE characters do not express ALL too often, the best fishing and out- 

V_x sounds although the pitch of the voice 

is significant. Their letters are ideo 

graphs, or writings of ideas or 

things. Hence the Chinese 

have no alphabet, strictly 


For this reason the 
Chinese must employ an 
astounding number of 
characters. It takes 
about ten thousand 
characters to print a 
book in the Chinese 
language; yet some- 
times an entire thought 
or a whole sentence is 
represented by one char- 
acter ! The word 
"black" is one character, 
and so is "mother," "dead," 
"yes," "yellow," and a 
great many other words. 
With such a conglomera- 
tion, is it any wonder that 
the American printer won- 
ders how it is possible to 
print anything in Chinese? 

The illustration shows a 
frame containing one complete font (a font 
is an assortment of type of one size and 
style) of seven thousand Chinese characters. 
It required a month's time to arrange the 
type in place. The frame is sixteen feet 
long and five feet high. 

This hood can safely be used 
through the thickest woods since 
neither the strong wire netting 
nor the heavy cloth beneath 
it can be torn by the bushes 

ing grounds are to be found where the 
mosquitoes and the wood pests are 
thickest. F. L. Rhodes, a 
fisherman of Michigan, at 
least found this the rule in 
his State. Notwithstand- 
ing the regular hoods of 
cloth mosquito -netting 
which he would use, 
the insects would final- 
ly get at him; the 
netting would catch 
in the bushes. He 
decided to devise a 
mosquito-proof hood 
which would overcome 
the difficulty. 
Unlike cloth-net 
hoods, Rhodes' protector 
is made of fine brass wire 
which will not tear. A 
piece of non-breakable 
transparent mica enables 
the wearer to see, while 
a slide-covered mouth open- 
ing is provided to accommo- 
date a pipe. To the ends 
of the wire netting two 
pieces of durable cloth are attached, the 
top cloth being used to secure the netting 
to the hat by means of a string. The 
bottom cloth of this hood is meant to be 
tucked under the coat. Such a hood is 
also useful when robbing bee-hives. 

A frame of Chinese type containing one complete font of approximately seven thousand characters. 
The frame is sixteen feet long and five feet high. It took a month to distribute the type 

A Street Cleaner Built Like a Carpet Sweeper 

Cleaning two hundred thousand square 
yards of pavement in eight hours 


THE motor-driven vacuum street clean- 
er shown in the accompanying illus- 
tration is built on exactly the same 
principle as that of the ordinary household 
carpet sweeper. It 
differs from others 
of a similar type 
in that every par- 
ticle of the dust 
and dirt picked up 
is retained in the 
vehicle storage 
bin. This is ac- 
complished by 
passing the air 
sucked up with 
the dust 
through a 
water seal. 
The passage 
of the dust- 
1 ad en air 
through the 
seal filters it 
so that when 
expelled from 
the apparatus 
it is clean and 
pure just like 
the outer air 
after a rain 

The vehicle is entirely self-contained. It 
sweeps the street, picks up the dust and 
dirt, deposits it automatically in its storage 
bin and can finally run to the point of dis- 
posal or have its load of sweepings trans- 
ferred to other vehicles to conserve its own 
time for the cleaning operation. 

While the sweeping and picking up oh he 
load is entirely automatic, the method em- 
ployed is very simple. The apparatus con- 
sists of a conventional motor truck chassis 
on which are mounted a two-part storage 
bin, a blower driven by a separate gasoline 
engine and a header or funnel-shaped pas- 
sageway by means of which the dirt is 
sucked up off the ground and transferred 
to the blower from whence it is forced in 
the two-part bin. 

The blower and its direct-connected gas 
engine are mounted transversely of. the 
frame directly behind the driver's seat un- 

der a light metal cover. At the bottom 
the funnel-shaped header spreads out into 
a long suction box in close contact with the 
ground and supported on chains for raising 
or lowering as required. Air and dirt on 
the street are sucked through this header 

Cleaned-outairtc Almost clean* into the Center of the 

atmosphere outoftopbm blower as the latter IS 

Rear door for revolved. It 

is thrown out 
at the peri- 
phery of the 
blower into a 
pipe leadingto 
the top of the 
storage bin. 
The latter is 
divided into 
two parts by 
a horizontal 

As the air 
enters the top 
portion it 
swirls around 
and deposits 
the greater 
portion of the 
dirt on the 
bottom of the 
upper com- 
partment. The air is then drawn out and 
carried down into a small bottomless pan 
with its lower edges below the surface of 
several inches of water in the lower compart- 
ment. The partly-cleaned air has to pass 
down through the water and up on the out- 
side of the pan before it is led to a pipe open 
to the atmosphere directly aft of the driver's 
seat on the side opposite the blower. The 
air is thus washed and freed of its dust 
before it is allowed to escape. The dirt 
collected is taken out through doors in 
each compartment at the rear. 

This type of cleaner prevents the scat- 
tering of dust through the air and is 
cheaper and quicker than the old hand 
method or the broom and flushing method. 
It will clean two hundred thousand square 
yards of pavement in eight hours. Another 
advantage is that it does not make the 
streets slippery as does the water flushing. 

The street-cleaner motor truck 
consists of a two-part bin, a 
blower, and a funnel shaped 
passageway through which dirt 
is sucked in. At left is shown a 
section of the brush and its nozzle 



Popular Science Monthly 


seeds over it. In the steam-heated rooms 
his crops grew in double quick time. But 
the janitor stopped him. 

"In England one big firm has manu- 
factured umbrellas of a soft, absorbent ma- 
terial, so that seeds may be planted on 
them. Thus people walking along in the 
rain with their umbrellas covered with 
short, edible grass, present a refreshing 
appearance as of moving fields of living 
green, or floating emerald isles." The 
professor says this — not the editor of 
Popular Science Monthly. Is he jesting 
or is he merely practical? 

Professor Jeggles is on his way to 

the Fiji Islands to study the 

flora and fauna there. He 

did not leave his address. 

Above : Grass growing 
on the wall paper of a 
New York city apart- 
ment. At right: How 
the salad is grown on 
a rug on the housetop 

Growing Mustard and Water 
Cress on Blankets 

English botanist, advocates some quick 
methods of salad raising. "Mustard and 
cress," he says, "can be grown anywhere. 
All that is required is an old blanket hung 
over a line and well soaked with water. 
Sprinkle the mustard 
seed on one half of 
the blanket and the 
cress on the other and 
in two weeks time you 
will have a crop ready 
for the table." 

In addition to grow- 
ing salads on his blan- 
kets and flannels, Pro- 
fessor Jeggles is report- 
ed to have engaged in 
near-mortal combat 
with the janitor of the 
apartment house in 
which he lived. The 
professor was given to 
planting seeds on his 
wallpaper. He damp- 
ened the walls until 
the paper was pulpy 
and then sprinkled the 

With a finish that makes them wash- 
able, the walls of the nursery may 
be used like ordinary blackboards 

Children May Write 
On These Walls With- 
out Fear of Punish- 

WHY would children 
rather write on im- 
maculate walls than on writ- 
ing paper? Because, first, their 
mothers caution them not to do it, and, 
second, because the walls are whiter and 
the writing looks better on them than it 
does on paper. But the time has come 
when the mother need fear for the white 
nursery walls no longer. They can, in- 
deed, be changed from a source of irrita- 
tion to educational purposes by means of 
a finish which makes them washable. In 
other words, all pencil, 
crayon and pen marks 
may be washed away. 
Consequently, the 
wall surface is as good 
a place for drawing 
pictures or working 
examples as the ordi- 
dinary blackboard. 

Although the finish 
is intended primarily 
for the walls of the 
nursery, it may be used 
in the kitchen, living 
room, or other part of 
the house where chil- 
dren are wont to try 
out their artistic ability 
on the walls. The fin- 
ish may be in any one 
of a number of differ- 
ent shades. 

Popular Science Monthly 


Plowing and Pulverizing the 
Soil in One Operation 

A ROTARY tiller which prepares 
a seed bed without the usual 
harrowing, disking and rolling opera- 
tions has been invented by Guy E. 
Lincoln, a graduate of the Minne- 
sota Agricultural College. It is 
somewhat similar to milling ma- 
chines used in Europe, but it differs 
from them in that it does its work 
on a furrow turned with an ordinary 
sulky plow, while most of 
the foreign machines work 
on the soil just as it lies 
in the field. 

The tiller attachment con- 
sists of a steel rotor tooth 
set to the right of the share 
and mold-board. The rotor 
is geared at the top to the 
shaft of a small gasoline 
motor which whirls it at the 
rate of five hundred revolu- 
tions a minute. Thus the 
teeth of the rotor shred and 
tear the weeds, grass, roots, 
fertilizer and soil into a 
finely pulverized mass, mak- 
ing a mellow seed bed for the sowing of 
any crop. For use with the tractor the tiller 
attachment can be run by the tractor power. 

The modern farmer has come to realize 
that the fertility of the soil depends upon 
the distribution of a goodly amount of 
humus (rotted vegetable matter) through- 
out the entire seed bed. Formerly this 
humus, as surface litter, was raked up and 
burned. Today it is returned to the soil 
to help feed the coming crop. When it is 
cut up, pulverized and distributed by a 
milling machine it produces a scientifically 
perfect seed bed. 

There is undoubtedly 
a large place for the 
rotary tiller in the agri- 
cultural industry if it 
will do work equivalent 
to that of harrows and 
disks at a cost not much 
in excess of that in- 
curred by horse-drawn 
implements. The prin- 
cipal drawback to till- 
ing and milling ma- 
chines has been the 
expense involved in their operation and 
breakages when encountering stones and 
other obstructions. The tiller described 

The rotary tiller plows 
and pulverizes the soil, 
weeds and roots in one 
operation, eliminating har- 
rowing, disking and rolling 

The steel rotor tooth 
which is set to the right 
of the share and mold- 
board. It is geared to the 
shaft of a gasoline motor 

will only have to deal with stones which 
pass over the mold-board — an important 
fact in its favor. On the other hand, there 
would seem to be a waste of power in raising 
the furrow of soil several inches in the air in 
order to mill it. Some tillers work on the 
soil without raising it at all. 


The handle of the brush folds 
over the bristles and keeps it 
germ-proof with disinfectant 

A Water-Tight Holder and Sterilizer 
for the Toothbrush 

THE toothbrush il- 
lustrated is made 
with a folding handle, 
somewhat like that of a 
familiar type of pocket 
comb. But the tooth- 
brush handle does more 
than fold over the bristles 
of the brush. It forms a 
receptacle for a disinfectant 
which will keep the brush 
perfectly sterilized and an- 
tiseptically clean until it is 
ready for use again. When 
the brush is clamped in its 
hollow handle it may be 
carried in the pocket, if necessary, in 
perfect safety, without danger of soiling 
or dampening the pocket. 


Popular Science Monthly 

A Two-Million-Dollar Hospital Ship 
for Our Navy 

PLANS for a hospital ship for the United 
States Navy have been completed by 
the naval constructors and officials of the 
Bureau of Medicine and Surgery, and 
work on the new ship, which will be a 
model of its kind, will soon begin at the 
Philadelphia Navy Yard. Congress has 
allowed $2,350,000 for its construction. 
Although the exact dimensions of the ship 
have not been determined, it is known that 
she is to use oil as fuel and that a special 
gyroscopic engine will be installed, to 
reduce pitch and roll to a minimum. 

The ship will be equipped with the best 
surgical instruments and paraphernalia 
known to medical science. The several 
hospital departments will consist of an 
operating room, the out-patient depart- 
ment, dental operating room and labora- 
tory, X-ray room, chemical and biological 
laboratory, several wards for the treat- 
ment of acute and venereal diseases, 
and a contagious disease compartment. 
There will be the usual wards and special 
accessory rooms for linen, wash rooms, 
pantries and kitchens. The main opera- 
ting room will be located amidships, ex- 
tending the height of two decks and pro- 
vided with every lighting facility. Special 
rooms for the examination of eye, ear, 
nose, throat and kindred ailments will 
be provided in the out-patient department, 
where patients may receive the most ex- 
pert care. 

One of the important features of the pro- 
posed ship is the contagious disease com- 
partment. This will be so designed as to be 
completely separated from the remainder 
of the ship and the latest methods of dis- 
infection will be employed. .WARRANT OFFICERS. 


Lo, the Soya Bean! A Substitute 
for Meat, Fish and Fats 

WITH all due respect to Western civil- 
ization and progress, we must never- 
theless yield the palm to China for the 
production of the soya bean, a vegetable 
so full of promising possibilities that agri- 
cultural experimental stations all over the 
United States are concentrating attention 
upon it. 

Milk from soya beans is no longer an 
experiment but has become a marketable 
commodity. It is sold in cans as a powder 
or in liquid form. As a substitute for meat 
and fish the experimenters say all that is 
required is the co-operation of good cooks 
to devise sufficient variety in preparation 
of the beans. The oil is considered of 
especial value. It may be used as a substi- 
tute for linseed oil or may be hardened into 
an edible fat suitable for cooking or even 
for table use. The pulp, or what is left 
over after the oil has been extracted, is con- 
ceded to be a valuable cattle food. 

The only difficulty encountered thus far 
in the experiments with the soya bean has 
been in finding a suitable solvent to dis- 
solve out any oil that may be left in the 
meal before the left-over portion is con- 
signed to the cattle. Naphtha has been 
found to be good, but unless care is taken 
to remove all trace of it from the meal the 
new fodder loses its value as a cattle food, 
for the cattle refuse it on account of the 
smell. Another chemical which has been 
found to answer the purpose is try-chlor- 
ethylene. It is not offensive in odor nor 
poisonous. Yet a dangerous reaction has 
at times occurred when it has been used as 
a solvent. 

How the space of the proposed two million-dollar hospital ship for the Navy will be apportioned. 
The best surgical instruments and equipment known to medical sicence, as well as the latest 

Popular Science Monthly 


The Mysterious Ice Mines of the 
United States 

THERE are several caves in the United 
States where Nature seems to have 
become confused as to the seasons. During 
the late spring and summer ice forms and 
a freezing temperature prevails, but as 
winter comes on the interior of the caves 
becomes milder, the ice gradually melts and 
a kind of subdued summer sets in under- 

One of these peculiar caves is to be found 
at Coudersport, Pa., and one at Decorah, 
Iowa. The superstitious among the resi- 
dents of those localities give the caves a 
wide berth and look with suspicion upon 
any one daring enough to attempt to in- 
vestigate them. 

Edwin S. Balch, of Philadelphia, who has 
made a study of the subterranean ice mines, 
as they are called, states that according to 
the theory evolved by investigators the 
formation of the caverns is such that the 
cold air of winter does not penetrate and 
settle in them until late in the spring at 
the time when the water from spring 
thaws is seeping through the walls and roof. 
This water meeting the cold air freezes 
and stays frozen all summer until, as the 
fall season approaches, the warm summer 
air at last finds its way into the cave and 
melts the ice. 

When the snow is flying above and ice- 
skating is the amusement of the moment 
the summer air is at work in the cave and 
still water bathing might be indulged in 
by the residents of the community if the 
environment were right and if they dared. 
By the time this summer air begins to lose 
its heat it is spring again above ground. 


Ffgfenr™ 1 " 

Poison Ivy : How to Kill It and Cure 
a Case of Inflammation 

THE cheapest and most effective method 
of eliminating poison ivy, according 
to experts of the Department of Agriculture, 
is the simple one of rooting up the plants 
and destroying them. If the poison ivy 
is in large fields it may be necessary to 
plow and cultivate the land. Ivy on large 
trees, stone walls and buildings can be 
killed by arsenate of soda, at the rate of 
two pounds to ten gallons of water. Two 
or three applications are sufficient. 

The fall of the year is the safest time to 
handle poison ivy, because at that time the 
sap and pollen are out of the plant. With 
the exercise of due care, the use of overalls 
and gauntleted gloves will enable most 
individuals to deal with the plant without 
danger. A further protection is to grease 
the hands with lard and after the plants 
have been handled to wash off the hands 
with strongly alkaline soap. 

Minute amounts of a nonvolatile oil 
in poison ivy is what makes it cause 
extensive inflammation. Alcohol or a 
solution of sugar of lead will remove this 
oil; it is insoluble in water. In cases of 
poisoning, one of the most effective methods 
is to cleanse the inflamed surface repeatedly 
with alcohol, or with a saturated solution 
of sugar of lead in alcohol, using a fresh 
bit of lint or absorbent cotton each time 
to prevent the spread of the irritant. 
Covering the inflamed parts with lint or 
absorbent cotton kept constantly moist 
with limewater or with a saturated solution 
of bicarbonate of soda will afford relief. 

It is a curious fact that many people 
are so constituted as to be able to handle 
poison ivy without being at all affected 
by it. 



methods of disinfection and communication control will be employed on board the ship. The 
main operating room will be located amidships and will extend the height of two decks 

Popular Science Monthly 

How the Government Seals Unofficial 
Wireless Stations 

l commercial sta- 
tions alike have been 
ordered closed. The 
Government cannot af- 
ford to take any 
chances of military in- 
formation leaking 
through to the enemy. 
All aerials have been 
dismantled, and the in- 
struments stored away. 
In the very powerful 
wireless stations, the 
further precaution has 
been taken of sealing 
the apparatus 

The manner of seal- 
ing such a station is 
well illustrated in the 
accompanying photo- 
graph of New York 
city's most powerful 
commercial plant. The transformer shown 
in the foreground was used to convert the 
low-potential alternating current, that is 
ordinarily used for light and power pur- 
poses, into a current of millions 
of volts in pressure, such as 
would be required for sending 
wireless signals. 

The Government's agents 
have simply wrapped a heavy 
copper wire around the trans- 
former terminals, and have se- 
cured the wire ends with sealing 
wax on which is stamped the 
great seal of the United States 
of America. It is impossible to 
remove this wire without break- 
ing the seal — and taking the 
consequences in imprisonment. 

A heavy wire short-circuits the high-po- 
tential sending transformer. If an at- 
tempt should be made to operate the 
station, the transformer would burn up 

lines are spaced by virtue of an evenly 
notched rack which allows the tablet to 
be moved away from the elbow rest by 
the distance of one 

An improvement on 
this tablet has been 
developed by Arthur E. 
Tremaine, of Boston. 
By using a straight 
edge and a brass wire 
placed three-quarters 
of an inch above it 
across the paper, the 
sightless writer is able 
to keep the size of 
his letters uniform. 
Moreover, by eliminat- 
ing the elbow-pivot 
principle, each line will 
be straight and not 
curved in the arc of a 
circle. Ink as well as 
pencil can be used since 
neither the beveled 
straight-edge nor the 
wire quite touches the 
paper surface. The straight-edge can be 
lowered line by line down the paper and 
evenly spaced by means of notches at 
the side. In this way a 
perfectly neat appearance 
is given to the written 


wt reless t ranstor me 







Teaching the Blind How to Write 
on Straight Lines 

THE December issue of the Popular 
Science Monthly contained an article 
on an instrument invented to aid the blind 
in writing. This was the writing tablet 
invented by the French scientist Dr. Emile 
Ja'-al, His tablet consists of a fixed elbow 
rest in which the writing arm swings across 
the paper. The line of writing is thus 
made comparatively straight, while the 

As the blind man writes, his letters are kept 
uniform in size by the straight-edge below 
the pencil-point and the wire above it 

A Torpedo-Proof Ship With Six Hulls 

It is to solve the food problem by 
scooping up the fish from the sea 

THE one great aim of Germany is to 
cut off America from her Allies, pre- 
venting our giving them military 
assistance and our supplying them with 
food. With his radically new inventions, 
Nels A. Ly- 
beck, of New 
York, a sea- 
man of many 
years' experi- 
ence, hopes to 
thwart Ger- 
many in both 
of these aims. 
invention of 
a multiple- 
hull ship util- 
izes a sailing 
never before 
used on any 
ship. Six 
hulls twelve 
feet wide, 
separated by 
twelve feet of 
distance, sup- 
port the rectangular decks of the ship. 
The hulls are slightly tunnel-shaped at the 
bottom, and when they speed over the sea, 
the water is packed in these tunnels, — they 
rise upward and slide through the water. 
This novel construction has still another 
virtue. The largest waves cannot roll this 
ship. The row of hulls makes the ship act 
just like a huge flat-bottom scow, longer and 
wider than the breadth of the largest wave. 
The boat virtually rides on the tops of the 
waves, rolling but slightly even in the most 
violent seas. 

But what has this to do with submarines, 
you ask? Just this: With a rectangular, 
non-rolling ship it is possible to protect 
it from submarines by means of torpedo- 
proof shields. Where V-bow boats would 
violently pitch when speeding on the high 
seas, and thereby strain their nets until 
they snapped off from their supports, this 
ship would carry a continuous, submerged 
steel wall on each side which would have 
to resist only the slight traveling strains 

The scoop on the speeding torpedo-proof ship is a hun- 
dred feet deep and one hundred and thirty feet wide 

caused by the water's friction. At bow and 
stern, she could rig herself out with strong 
steel gratings, and thus defy the biggest 
enemy torpedo afloat. 

It was not long after perfecting his sub- 
ocean freight- 
er that Ly- 
beck further 
this scheme 
into his solu- 
tion of the 
food problem. 
There are suf- 
ficient fish 
scattered in 
the ocean to 
and com- 
pletely sup- 
ply the Allies 
with food 
many times 
over. Wit- 
ness his truly 
method : 

Three searchlights are used on his mul- 
tiple-hull ship at night to send their power- 
ful rays ten miles ahead of the boat. As 
the ship draws on, the ray of light becomes 
ever narrower, so that the fish crowd 
densely together as they swim eagerly 
towards it. 

Then the huge wire scoop, a hundred 
feet deep and a hundred and thirty feet 
wide, which can be readily suspended from 
the front of the Lybeck type of boat, 
is dropped in the water. The ribs of this 
scoop are made like whalebones, so that 
water and debris can easily seep through 
and the fish can slide up, but never down 
and out of it! 

When the teeming crowd of fish reaches 
the darkened scoop, this onrushing trap 
quickly swallows it up. Once near the end 
of the scoop, an endless-belt conveyor car- 
ries the fish to the assorting deck. Here a 
hundred men distribute them into cross 
conveyors which carry each fish into its 
respective refrigerator. 


Do It With Tools and Machinery 

At right: A "gun" for 
driving nails in hard- 
to-reach places. It is 
a steel rod with a brass 
tube shank, having a 
larger tube enclosing a 
light coil-spring for a 
hand-grip. The ten- 
of the spring is 
sufficient to hold the 
nail in the chuck end 
ready to be driven 
when it is set in place 

held by threads 

Expanding sleeves 
forced into hose 

Threaded coupling 
ring binds outer ' 
casings together 


Flange forced down 
keeping watertight ,1 

A metal coupling for con- 
necting the ends of a hose 
in a perfectly steam-tight 
joint, avoiding all leaks 

A motor-operated collar ironer with 
a revolving head which irons, rolls 
and polishes collars of different 
shapes without making them rough 

A guide for use in putting 
hinges on doors and 
frames so that the holding 
pins can be inserted easily 


Do It With Tools and Machinery 

Below: A neat little attach- 
ment for the ordinary 
straight-back saw blade. It 
is used as a carpenter's 
square for laying out work 

A tool cabinet which is so compact and at the same time so com- 
modious that it will appeal to any mechanic. There are spaces 
provided for every kind of tool that ordinary shop work calls for 

A gummed paper - tape 
holder for feeding, moisten- 
ing and cutting without 
touching it with the hands 
when fastening packages 


The "Recruit"— Our Only Land Battleship 

It is New York's recruiting center for en- 
listment in America's first line of defense 

The battleship in Union 
Square, New York city, 
on Memorial Day 

Two hundred American 
Junior Naval and Marine 
Scouts on the Recruit 

WHEN Rear Admiral Bradley A. 
Fiske published his great article 
on "If Battleships Ran on Land," 
in the Popular Science Monthly for 
November, 191 5, showing, as it did, the 
tremendous energy of a battleship on land 
and the destruction it would work while 
crashing down Broadway, New York city, 
he little dreamed that a real 
battleship would be anchored 
close to the subway in Union 
Square in the year 191 7. Need- 
less to say, the land man-o'-war 
that now overlooks Broadway 
is the antithesis of the land 
monster conceived by Rear Ad- 
miral Fiske. Although it looks 
formidable enough, it is simply 
the headquarters for Naval re- 
cruiting in the New York city 
district of America's first line of 
defense. It has been aptly 
christened the U. S. S. Recruit. 
It is a fully-rigged battleship. 
On the starboard side of the 
ship flies the flag of the Navy, 

while from the port side flies the emblem ol 
the Marine Corps, the "Soldiers of the 
Sea." At the present time the ship houses 
thirty-nine bluejacket guards from the 
Newport Training Station — young fellows 
who have seen from two to six months' 
service. Their duties on board 

the Recruit I will not hinder their 

The Recruit in process of construction. It was sev- 
eral days before she resembled a superdreadnought 


Popular Science Monthly 


progress in 
will be as 

naval affairs, for the Recruit 
much of a training ship as 
it is a recruiting center. On the other 
hand, citizens may visit the ship and ac- 
quaint themselves with the makeup and 
organization of a modern sea-fighter. 

Under Acting Captain C. F. Pierce, life 
aboard the Recruit is one of ordinary naval 
routine. The land sailors arise at six o'clock, 

scrub the decks, wash their clothes, attend 
instruction classes, and then stand guard 
and answer questions for the remainder of 
the day. There is a night as well as a day- 
guard. From sundown to eleven o'clock 
all lights of the ship are turned on, including 
a series of searchlight projectors. 

Within the ship are spacious waiting 
rooms for recruits and applicants, physical 
examination rooms both fore and aft, 
doctors' quarters, officers' quarters, shower 
baths, a big air washer and ventilating de- 
vice which changes the temperature ten 
times every sixty minutes, and numerous 
other accommodations for officers and men. 
The superstructure of the vessel con- 
sists of a forward cabin, main bridge, 
flying bridge, conning tower, two masts 
fifty feet above the quarterdeck', and a 
single smokestack eighteen feet above 
the cabin top. Six 
wooden guns, repre- 
senting fourteen-inch 
naval guns, extend 
seventeen and a half 
feet beyond the turrets 
and make up the main 
battery. The second- 
ary battery consists of 
ten wooden five-inch 
guns and two models 
of one-pound breech- 
loading rifles. 

The Recruit 
measures two 
hundred feet 
from stem to 
stern, with a 
forty-foot beam 

The equipment is that of the up-to-the-minute dreadnought with accommodations on board 
for day and night life of officers and men. Searchlight projectors illuminate the ship at night 


Scraping a Bat— Why Is It Done? 
O, Just Because 

BASEBALL players are as superstitious 
as Zulus. In no way is this more 
lucidly illustrated than in the care 
which some of them lavish upon an 
ordinary baseball bat. Manu 
facturers oil and shellac their 
bats to make them sleek and 
fresh, and the superstitious 
baseball player proceeds to 
use glass, bone, sand- 
paper and what-not to 
remove thefinish. Why? 
O, "just because" — to 
give a woman's reason. 
He may have a notion 
that the bat will last 
longer without it. But 
the truth is that the 
shellac really acts as a 
preservative to the wood. 

Some baseball players 
imagine that it is impos- 
sible to make a strong hit 
with a new bat, because the 
bat is so sleek that the balls 
glance off it. Others be- 
lieve that scraping a bat 
fills up the crevices and cracks and thus 
lengthens the life of the bat. The ac- 
companying photograph shows Cueto, a 
Cuban who plays an outfield position for 
the Cincinnati Reds, combing his bat with a 
calf bone. 

A baseball player may change his bat 
occasionally for a lighter or heavier one, 
and when he does so the 
principal sporting goods 
stores in the country are at 
once apprised of the fact. 
One big store, for instance, 
has on hand the exact 
weight and style of bat 
used by every big league 
player in the United States. 
When a player breaks his 
bat all he need do is to send 
a telegram such as this: 
"Express me a bat, quick. 
Tom Jones," and he will get 
a duplicate of the bat he 
broke. Most bats are made 
of second-growth Northern 
ash, dried in the sun. This 
wood is becoming scarce. 

Popular Science Monthly 

Cueto, of the Cincinnati Reds, combs 
his bat daily with a calf bone 

An Improvised Street Railway 
Smoking Car 

INCREASED traffic and car shortage on a 
street railway property in the East 
during the past winter months made 
some of the operative heads do quick 
scheming in order to cope with the 
situation. As a result, some of 
the open summer cars were 
equipped for "shop service" 
in winter. The company 
took ordinary fourteen- 
bench open cars and 
placed electric heaters 
under the seats, except 
the two end seats and 
the two seats corre- 
sponding, just inside 
the bulkheads. The 

heaters have sheet-iron 
guards on each side 
to prevent contact 
with the passengers' 
shoes or clothing. Tests 
showed that such a 
battery of heaters pro- 
vided a comfortable tem- 

In order to retain the 
heat thus generated in the car, the sides 
were equipped with transparent, non-in- 
flammable windows. These flexible win- 
dows in the curtains provided ample light 
for reading. 

To encourage passengers to ride on the 
cars they were run on express schedules 
and termed "Express Smoking Car." 

An open summer car equipped with curtains, heaters and 
windows, for a "smoker." It ran on an express schedule 

All the specialized knowledge and information of the editorial staff of the Popular 
Science Monthly is at your disposal. Write to the editor if you think he can help you. 

He Finds a Coal Mine in His Cellar 

Coal may sell at eighteen dollars a ton but this for- 
tunate lawyer can have all he wants at thirty cents 

The vein of bituminous coal found in 
the cellar measures five feet in width 

At right above: It's only a step from 
the coal mine to the hot-water heater 

THE purchasers of property in the 
residence section of Norton, Va., 
will hereafter be inclined to ex- 
amine the cellars of their prospective 
homes very carefully in the hope of 
locating some such bonanza as did 
H. M. Bandy recently. 

Mr. Bandy was excavating in the cellar 
of his newly-purchased house in order to 
install a hot-water heating plant. Almost 
on the spot where the furnace was located, 
an old negro workman discovered the 
"bloom," which is a black carboniferous 
earth found always on the edge of a stratum 
of coal. "Boss, youse got plenty of coal 
back up in the hill," the old negro said. 
"These am the outcroppings." 

By the time the cellar had been excavated 
to the desired width, enough coal had been 
taken out to supply the family for the 
entire winter. Then Mr. Bandy started 
to drive a "heading" back up into the 
hill on which the house stands. The 
heading, which leads from the furnace out 
under the garden, is ten feet wide. Mr. 
Bandy has installed a small track of wooden 
rails on which a hand car can be pushed 
back and forth for loading and unloading. 

As the vein of coal is on a grade, even 
this work has been simplified for him; for 
when loaded, the car slides down the track 
to the dumping place almost unaided, and 

The home of Mr. Bandy, under which 
the vein of coal was discovered 

when emptied it is a child's task to push 
it back to the loading place again. This 
down-hill grade also provides natural drain- 
age for the mine, keeping it free from the 
water which seeps into it from the garden 
immediately above. 

At present the mine is yielding from ten 
to twelve tons of coal a day, with only 
one miner employed. Dynamite is used in 
minimum amounts to loosen up the strata 
and lessen the work of the miner without 
disturbing the inmates of the house or the 
rapidly developing plants in the garden. 

The town of Norton is in the center of a 
big bituminous coal region. According to 
the local recorder, "Dig a post hole and up 
comes coal. Lay a waterpipe, and some 
coal has to be removed from the right of 
way." Mr. Bandy's private coal supply 
costs him about thirty cents a ton. 



Instead of climbing the flag 
pole to repair it, one man lowers 
it to the roof where it can 
be painted with less danger 

Popular Science Monthly 

The Tender Chloroforming, Antiseptic 
Bayonet— It Wounds and Heals 

HOW can we make the soldier fight 
harder ? Can we do it by giving him 
new implements of torture, new weapons to 
increase bloodshed? "No," is the answer 
of Alexander Foster Humphrey, of Pitts- 
burgh, Pa., inventor of the gentle narcotic 
hunting bullet and the polite antiseptic, 
anaesthetic military bullet. 

"Relieve the conscience of the soldier," 
advises Mr. Humphrey, "and he will fight 
the harder. Let him know that while he 
must cause a wound, he is also giving means 
to relieve and heal that wound and he will 
fight like a tiger." 

All of which whether true or not serves as 
an introduction to Mr. Humphrey's most 
recent and most astonishing invention, the 
antiseptic, pain-deadening bayonet — a bay- 
onet that carries in its blade a capsule con- 
taining a mixture of antiseptics, anaesthetics 
and gelatin. When the bayonet is plunged 
into a soldier the heat of the body will melt 
the capsule and release its healing contents, 
the anaesthetic deadening the wounded 
man's pain, the antiseptic preventing in- 
fection, and the gelatin stopping the flow of 
blood. We wonder if a Belgian soldier would 
relish the stabbing of a German so tenderly. 

LVVire cablesto 
flower rigging 

Flag Pole Repairing 

Minus the Usual 


painters and steeple- 
jacks may soon find them- 
selves unnecessary adjuncts 
to the business world, if the ingenious flag 
raising and lowering device shown in the 
accompanying illustration becomes popular. 
It can be used on all flat roofs. Instead of 
the men climbing the pole, the pole is 
brought down to the men by means of a 
system of gears, which can be operated by 
one man. These gears are mounted on a 
short hollow post which is fastened to the 
building. They operate a drum which is 
divided into two portions. Upon these 
portions, the pole tackles wind up. 

The drum which winds up the cable 
going to the top sheaves is larger than the 
other, so that this cable will wind up faster 
and keep its tension the same as the lower 
cables, as the pole swings up on its hinging 
pin. When fully raised, two stirrups hold 
the flag pole securely against the shorter 
anchoring post. 

The bayonet which heals the wounds it 
makes. A groove in the end of the blade 
holds an antiseptic, anaesthetic capsule 

Popular Science Monthly 217 

A New French War Word Which Means A Motor-Fan That Works 

"Fooling the Enemy" Without Electricity 

SINCE the war started the Popular A LL the benefits of the electric fan mayj 
Science Monthly has published pho- 
tographs of big British and French field 
pieces covered with shrubbery, railway 
trains "painted out" 

A L 

of the landscape, 
and all kinds of de- 
vices to hide the 
guns, trains, and the 
roads from the eyes 
of enemy aircraft. 

Until recently 
there was no one 
word in any lan- 
guage to explain this 
war trick. Some- 
times a whole para- 
graph was required 
to explain this mili- 
tary practice. Here- 
after one word, a 
French word, will 
save all this needless 
writing and reading. 
Camouflage is the 
new word, and it 
means "fooling the 
enemy." Example: 
— A dead horse lay between the British and 
German lines on a bit of rising ground. 
During the night the dead horse was re- 
moved and an imitation, with a man inside, 
was substituted. The men who constructed 
and painted the fake horse practiced camou- 
flage. They are known as camoufleurs. 

now be had in places where elec- 
tricity is not available by using a fan driven 
by a motor operated by alcohol, gas, or 
kerosene. The mo- 
tor is really an 
adaptation of the 
air engine. The al- 
cohol lamp or other 
source of heat is- 
placed at one 
end of the 
This causes 
the air in 
the cylin- 
der to ex- 
Piston stem 
Inner tube 
Outer tube 

The motor of the fan is operated by 
kerosene, alcohol or gas. At right is 
shown a diagram of the equipment 

Gasoline tank 
Kerosene lamp 
Gas hose attachment 
Gas burner 


; | 



■ . 

French Official Photo 

Camoufleurs, members of an important camouflage detach- 
ment, are here shown hanging mats of leaves on a frame- 
work of tall poles, to prevent the enemy from seeing the road 

pand and to 
exert pres- 
sure on a sliding 
piston at the other 
end. This acts in such a 
manner as to push on the crankshaft. 
A second piston, called the transfer pis- 
ton, at the proper time 
forces the hot air from the 
burner end to the cool end 
of the cylinder, where it 
cools and contracts. The 
atmospheric pressure then 
pushes back the sliding 
piston, which pulls the 
crankshaft. Thus power is- 
exerted on both the upward 
and downward strokes. The 
same air is used over and 
over again, obviating the 
need for an exhaust and 
preventing odors. 

The small fuel tank, 
placed in the lower portion 
of the stand, holds enough 
fuel to last for a twenty- 
four-hour run; it drives 
the fan at 500 to 700 revo- 
lution^ per minute. 

Why They Were Rejected 

Hold that pose, Oscar, 
while we count the 
molar stalactites and 
stalagmites in your 
Mammoth Cave. By 
Jove, old top, you have 
six ivories missing. 
Sorry, but that dis- 
qualifies you. Yells 
Oscar, "Isn't it 
enough to kill the 
Germans or do I 
have to eat 'em too?" 
Bad teeth mean rheu- 
matism and poor health 

"You listen well, 
the doctor, musingly, 
"but I can tell from the 
way your internal gears 
mesh that you would 
travel in 'low' when 
leading a charge. 
Breathe naturally now, 
and I'll see whether 
your heart has a little 
movement of its own 
or not." The recruit is 
murmuring the prayer, 
"Oh death, where is 
thy sting-a-ling?" 

Photos © Press JUus. Serv, 

Stand up straight, lift 
the right leg and say 
"Uncle" three times. 
Ah! ha! he has flat 
feet, hammer and over- 
riding toes, corns, 
bunions and ingrowing 
nails. He couldn't 
march far. Otherwise 
he is admirably fitted 
for military service. 
Admire the Junoesque 
arm if you must 

The color test or does 
black belong above or 
below the Mason and 
Dixon Line? It is a 
hard test, this color 
gamble. You are 
given five minutes to 
pick black from white 
and if yOu fail the first 
time you are only given 
two other chances. A 
color-blind person 
can't shoot straight 


Why They Were Rejected 

Has he a little Prussia in his dome? Let the 
doctor decide this, and also pass upon his 
hearing. The Marine Corps demands that a 
recruit have good hearing, otherwise how 
would he know to obey an order to retreat 

At right above: Taking his measure. If the height limit 
is five feet four and the recruit but five feet three it is 
possible (so they say) to make up the extra inch between 
the waist line and shoulder. Seven-foot soldiers aren't 
nice to look at; four-footers can't march fast enough 

Underweight? Go home, fill up 
on olive oil and milk and go to 
bed. Overweight? Pick out a 
forty-storied building and walk 
to the top ten times a day. Fat 
men can't stand the pace; skinny 
ones haven't the endurance 

Close one eye and see if you can 
pick out a German at twenty 
feet. Very good. Now close 
the other and see if you can read 
those letters. Fine, you will 
make a sharpshooter after peace 
comes and firearms are taboo 

220 Popular Science Monthly 

A Dinner Served in Gondolas on a 

River of Champagne 

THE dinner being served in the accom- 
panying photograph is probably the 
wettest on 

record. It 
floated on 
(the stage 
variety). As 
one might 
suppose] the 
novelty is 
the product 
of the com- 
bined imagi- 
nations of a 
and his tech- 
nical assis- 
tant. The 
scene repre- 
sents a ban- 
quet in a 
recent Fox 

A table 
was con- 
with a canal about a foot wide running 
round it. The ends of the canal were ex- 
tended into the kitchen where a water wheel 
lifted the liquid from the lower end of the 
canal to the higher end. The gondolas 
were loaded with meats and viands at this 
end and sent on their journey. 

The gondolas loaded with dainties float from the kitchen to the 
guests and back again, on a flowing river of "stage" champagne 

Fighting German Machine-Guns with 
the French "37" 

THE great work of the French "75" in 
counterbalancing the mass of Ger- 
man artillery in the present war has 
justly made it famous. But in 
that work it has had a 
smaller ally, not so well 
known though de- 
serving of most 
mention. This r 
is the French 
"37," a small 
cannon which 
advances with 

the skirmishing first line, seeking to destroy 

the German machine-guns. 

A machine-gun destroyer it is in very 

truth. Germany relies on machine-guns 

and artillery to hold a battle line. Machine- 
guns and 
light artil- 
lery, then, 
retarded the 
advances of 
the French 
— until they 
answe red 
cannon with 
cannon in 
the famous 
"75" and 
the distin- 
g u i s h e d 


A more 
than the 
"37" for fill- 
ing the rigid 
ments of a 
cannon is 
not to be 
found any- 
where. It 
ably meets the first requisite of portability; 
the gun and mounting can be quickly 
taken apart and carried over the most shell- 
torn ground by the six or eight members of 
its crew. It is accurate — a French officer 
says there exists no other gun more ac- 
curate ! It will hit the muzzle of a machine 
gun at a distance of a mile. And its speed 
of fire is remarkable. A well trained crew, 
can fire thirty-five high-explosive shells, of 
nearly one and a half inches diameter, 
every minute, while they are crouched upon 
the ground to conceal themselves 
from the 


This French portable, quick-firing cannon advances with 
the skirmish line to destroy the enemy's machine-guns 

Military ex- 
pediency pre- 
vents the pub- 
lic from know- 
ing the details 
but when the 
story of this 
war is told, the 
"37" will not be 
found wanting. 

Popular Science Monthly 


Filling Nine Thousand Cans of 
Beans an Hour 

ARMIES may fight with bullets, but 
. they live on beans. The Civil War 
was fought on a diet of our dried army 
beans ; this war is waged with 
canned beans. 

In the photograph below 
is shown a modern bean- 
canning factory working 
at the height of produc- 
tion. To meet the ex- 
traordinary demand for 
beans, labor and time- 
saving machinery is 
used exclusively. Al- 
though located in New 
Jersey the machine il- 
lustrated fills up the cans 
with Boston baked beans 
and snaps on the covers in 
practically the same opera- 
tion. The empty cans are 
fed to the machine in an 
endless stream, the cans 
being held in place by a 
metal frame. The machine 
fills the cans at the rate of nine thousand an 
hour but it can work faster, if needed. 

The largest mouth in the world — 
a model for a dentists' exhibition 

The Largest Human Mouths in 
the, World 

DR. GREENBAUM, an enterprising 
young dentist in Cincinnati, eager to 
help Uncle Sam in demonstrating to the 
volunteer the necessity of getting 
his mouth in good shape before 
enlisting for the front, de- 
vised what are probably the 
largest scientifically-cor- 
rect models of the human 
mouth in the world. 

Each model (and 
there is an extended 
series of them) is two 
feet deep by eighteen 
inches wide and eight 
inches tall. The mod- 
els are hollow and fash- 
ioned of plaster-of- Paris, 
held together by gauze. 

Ten models of the adult 
mouth, three of the child's 
and four panels emphasiz- 
ing certain phases of disease 
of the teeth and of decay, 
comprise the set. The 
models show the pulpy substance containing 
blood vessels, nerves, as well as the harder 
root and bony portions. 

The bean-filling machine with its funnel is in the foreground. 
To the left are the solderers which seal nine thousand cans an hour 

Europe Is Starving 
for Gasoline 

FRANCE, one of our 
largest automobile and 
truck buyers, has prohibit- 
ed the importation of foreign 
motor vehicles, except for 
government account sim- 
ply because of the difficulty 
of obtaining gasoline. Gas- 
oline is now selling in 
" France at about a dollar a 
gallon. Each automobile 
owner is allotted a small 
amount per week. India 
and Holland have likewise 
prohibited the importation 
of motor vehicles for the 
same reason. Denmark's 
gasoline situation was so 
acute that it stopped the 
driving of passenger cars 
through the steets. It is 
said that taxicabs in 
Berlin have been running 
on alcohol for two years 

222 Popular Science Monthly 

A Ten-Thousand -Dollar Map of 



The map is a segment of a 90-foot globe, with heights and 
depressions clearly represented. Every battlefield is shown 

Warring Europe 

the lobby of one of Chicago's large 
office buildings is a huge relief map of the 
European countries where the war rages, 
exhibited to 
the public 
and lectured 
upon by a 
former war 
dent. The 
main map is 
io x 20 feet, 
but owing to 
its convex 
it contains an 
area of 300 
square feet. 
It is a seg- 
ment of a 90- 
foot globe. It 
was made by 
William Rob- 
ertson, with 
the assistance 
of ten men. 

It took them nine months to make it. 
Including labor and materials, the cost of 
the map is estimated to be $10,000. 

A special feature of the map is a system 
of small incandescent lamps which are 
flashed in connection with a large signboard 
made up of two hundred small transparent 
illuminated signs, each bearing the name of 
an important point on the map. When the 
lecturer mentions an important point 
in the war territory a light 
flashes at that point on the map 
and simultaneously the name 
is flashed on the large sign 
which is located at the 
left side of the map. 
This makes it possible 
for the spectator to 
follow the lecturer 
more closely and in- 

The method used in 
constructing the map 
is interesting. A work- 
ing model was first 
made. From this the 
frame was laid out, the 
map scaled and the 
countries outlined. The 
vertical parts were next 

scaled and little pegs driven down for 
measuring the mountains. A clay map 
was then made on this frame and a cast 
taken, from which the plaster of Paris 
map (the one on display) was made. The 
next task was to shave the map and gradu- 
ate it, after 
which the 
various parts 
were indi- 
cated and 
colored. At 
the same time 
the wiring 
system for 
the incandes- 
cent lights 
was installed. 
The scale of 
the map is 
one inch to 
every 7.8 
miles . It 
shows the 
cal detail of 
every battle- 

A simple bell-action attracts the arma- 
ture and re-tightens the helical driving- 
spring whenever the watch runs down 

An Electric Self- Winding Clock 
for the Automobile 

WEAK-CURRENT electricity is in- 
terestingly applied in the self-wind- 
ing mechanism of a clock which has been 
specially designed for the dashboard of the 
automobile. A simple electromagnet is 
made to drive the clock, and but three or 
four batteries are required. 

In construction, this clock dif- 
fers little from any other. 
The gears, however, are 
mounted to withstand 
the jolts of traveling. 
And instead of the or- 
dinary hair-spring a 
straight helical 
spring furnishes the 
motive power. The 
armature of the elec- 
tromagnet works 
much like that of a 
bell ; it tightens up the 
driving-spring every 
time it is attracted to 
the magnet. The spring 
loosens up while running 
the clock, the armature 
swinging slowly back. 

It Always Turns Right-Side Up 

A boat which will carry twenty-five persons and 
will not "spill" even if turned upside down 

THE chief objection to the ordinary 
type of life boat is the fact that 
almost no provision is made to 
protect the passengers from anything ex- 
cept actual drowning. Even here the pro- 
tection is not complete, for in the heavy 
storms that so often cause the mother ship 
to be wrecked the little life boat is tossed 
about unmercifully, and its occupants 
sometimes swept overboard. 

Mr. A. D. Newcomb, of Hampton, Va., 
has just perfected a life boat of entirely 
new design which is expected to meet this 
difficulty as well as several others. The 
Newcomb boat is completely closed, with 
manholes in the top by which to enter, 
and is water-tight. It might be supposed 
that it would necessarily be air-tight as 
well, thus depriving the passengers of 
oxygen, but ventilation is provided for by a 
particularly ingenious contrivance ^g 
which admits air only. This de- , 
vice is a sort of valve fitted with 
a rubber ball. The air passes 
around the ball, but water 
causes it to float and 
thereby closes the opening. 

Another ingenious fea- 
ture is a water-tight oar 
lock. Oars are not fur- 
nished with some types of 
life boats, since it is foolish 
to attempt to row to shore. 
Nevertheless they are fre- 
quently valuable in guid- 
ing the boat to persons 
in the water. This oar 
lock is made as follows: 
A canvas sleeve is fastened tight around 
the oar at the point where it fits in the 
lock. The border of this sleeve contains 
a wire, and this in turn fits into a groove 
on an oval iron collar surrounding the 
opening, or port hole, through which the 
oar protrudes. When the sleeve is adjusted 
and the wire drawn tight no water can 
enter, yet the boat can be rowed with 

Perhaps the most useful device of all, 
however, is an arrangement for freeing the 
boat from davits and cradle by levers in 
the boat itself. Often, under the present 
method, the ropes are hopelessly tangled 

In a test made by the Department of Com- 
merce the boat was rolled over. It righted 
itself without inconvenience to passengers 

in the excitement of launching. Sometimes 

they have to be cut loose. And in case 

the mother ship sinks suddenly, the 

life boats tied on deck sink 

k with her. 

In this new boat all the 
cables are attached to semi- 
circular bolts which work 
on pivots. By pulling a 
lever one end of the bolt 
is released and the 
cables drop free. 

The boat is twenty- 
six feet long, six feet 
four inches wide, and 
three feet four inches 
deep. The superstruc- 
ture or turtle back is 
one foot eleven inches 
in height above the 
hull. There is a metal bulkhead at each end, 
each bulkhead having a 16 by 16 inch open- 
ing to be closed by a metal plate on rubber 

There are seven thwarts, seventeen inches 
high from the skin, or inside bottom of the 
boat. The oar locks fit into the three port- 
holes on each side. The three hatches or 
manholes on top of the superstructure are 
twenty-four inches in diameter, and are 
provided with rubber gaskets, each fastened 
with brass turn buckles and a safety lock. 
The steamboat Inspection Service of the 
Department of Commerce, after testing the 
boat thoroughly recommended its adoptidn. 

There is an offset on deck on 
each side of the turtle back. 
The boat weighs 2600 pounds 


224 Popular Science Monthly 

The Latest Device for Easy Entrance 
to Automobile Doors 

THE last word in easy-entrance auto- 
mobile doors permits direct entrance 
to both the front and rear seats of a 
close-coupled four-passenger roadster. The 
special feature of the design 
is the fact that one-half 
of the front seat opens 
with the door. When 
closed, the division 
in the seat appears 
as a fold in the ■ 

The door may 
be opened from 
either the front or 
rear seat. It is 
provided with a 
safety lock to pre- 
vent its opening of 
its own accord 
while the car is in 
motion. It is 

hinged on two 
heavy concealed 
hinges at the front 
and runs in a track 
so that it cannot spring out of position. 

4,000 lbs, meat 
1 ,400 lbs. of sugar 
1,200 lbs. beans 
1,500 loaves of bread 
400 lbs. of coffee 

50 bags of potatoes 
100 lbs. of tea 
300 gals, of milk 
500 lbs. of butter 
600 lbs. of oatmeal 

The Largest Traveling Kitchen 
in the World 

THE ordinary dining-car, compact as a 
watch in its arrangement, can feed 
thirty persons at one sitting. The commis- 
sary car illustrated, which 
is the type used by Canada 
in transporting her troops, 
can feed 1,200 men at one 
sitting, and the food can be 
served in fifteen minutes. 

The Canadian commis- 
sary car is the largest travel- 
ing kitchen in the world. It 
is eighty feet long, has a full- 
size hotel range, steam- 
cooking apparatus, and 
sixty-foot refrigerator space 
and store room capacity for 
tons of provisions. Eight 
cooks work in it without 
interfering with each 

A battalion of 1,200 men 
en route from Camp Borden, 
Ontario, to Halifax, Nova 
Scotia, consumes: 

In the movement of a battalion, two com- 
missary cars are used, the military special 
being run in two sections. The big dining- 
car is placed in the center. of the 
train in order that it may be 
readily accessible to the waiters, 
who enter it from both front 
and rear. 

As soon as 
the first two 
W coaches have 
been supplied, 
two more squads 
of waiters arrive 
until all are served. 
Within fifteen 
minutes after the 
dinner bell has 
been sounded the 
men are all busy 
with their meal. 

Along the wide 
kitchen counter 
are spread the 
various portions of food. If it is breakfast 
time and the morning menu calls for oat- 
meal, meats, potatoes, bread and butter, 
jam and coffee, the food is served about as 
follows: — Two men take the big trays of 
meats and potatoes, another the bread, 
coffee, and so on, until all the food has been 
carried away on the trays. 

One half of the front seat opens with the 
door, making easy entrance to front and rear 

The kitchen of the Canadian commissary car. It accommodates 
eight cooks. Food for 1,200 men can be served in fifteen minutes 

Old Before She Was Launched 

There are styles in airships as well as in derby hats. The 
D. N. 1, our new navy schoolship-dirigible, is new and yet so old 

TWO years ago, the United States Navy 
contracted for a small dirigible 
to serve as a schoolship. Now that the 
craft has been finished, now that it can 
be judged in the light of the European war, 
it must be wholeheartedly 
condemned as well-nigh 

the D. N. 1 were 
not daringly original. 
They simply copied an 
Austrian airship, the 
Koerting, destroyed short- 
ly before the war in a 
collision with an airplane. 
A few fea- 
tures of some 
utterly use- 
less British 
airships (des- 
ignated by 
Greek letters 

Alpha, Beta, *ggg 

etc.) were in- 
corporated . 

In the 
Koerting, the 
car was elon- 
gated fore 
and aft to receive front and rear suspension 
ropes. Thus the strain on the tender gas 
envelope was lessened. In the D. N. 1 that 
system of suspension is copied. The 
Koerting had two motors so that it was 
safeguarded to a certain extent against 
breakdowns; but the D. N. 1 must make 
the best of a single motor. The two pro- 
pellers of the D. N. 1 are driven by bevel 
gearing, the arrangement being such that 
they can be swiveled. Hence, the craft 
can be pushed up or down by its propellers 
while it is making very little headway — a 
decided advantage in landing and starting. 
The D.N.I can be tethered by the nose of 
the gas envelope to a tall mast so as to 
ride out storms — a good idea because the 
ropes distribute the strain evenly over 
the envelope. 

The Koerting was never regarded in 
Europe as a model to be followed. The 
D. N. 1 is worse than the Koerting. Its fuel 
capacity is sufficient only for two hours 

© Int. Film Serv. 

The D.N. 1, the navy schoolship-dirigible, is 175 feet 
long. It has a 140-HP engine to drive it at a speed of 25 
miles an hour. Although new it is hopelessly antiquated 

so that it may carry an apprentice crew of 
seven. Three or four apprentices would 
have been a more reasonable number. 

The whole idea of the D. N. 1 is funda- 
mentally wrong. There may be some justi- 
fication in degrading an old diri- 
gible, which has seen active 
service, to the level of a 
schoolship, but there 
seems no excuse- for 
designing an en- 
tirely new dirigible 
which is so slow 
that the experience 
to be gained in it is 
not even remotely 
similar to that re- 
quired of the 
men in full- 
sized fast 
val airships. 
An air- 
plane has 
what is called 
dynamic lift; 
that is, it 
rises by vir- 
tue of its own 
fast motion. 
A dirigible, too, has dynamic lift when it is 
fast. A slow dirigible has little or no dyna- 
mic lift. The whole science of piloting a 
dirigible is founded on the proper utilization 
of dynamic lift — a fact which we have 
learned in this country although the ex- 
tensive German literature on the subject 
has harped on it constantly. In a dirigible 
of twenty-five miles an hour (the speed of 
the D. N. 1) little more can be learned than 
in an ordinary spherical balloon. 

The faster the dirigible, the safer will 
it prove to be for an apprentice. Its 
dynamic lift makes it easy to overcome 
mistakes in managing gas and ballast. 
Moreover, a fast dirigible is not easily 
forced to land; and an enforced landing 
is the worst danger because no dirigible 
can come down anywhere in safety like 
a spherical balloon. Even the English Alpha, 
Beta, and Gamma ships have been discarded 
in favor of the " Blimps." — small dirigibles 
whose cars are wingless airplane bodies. 


226 Popular Science Monthly 

Turn It at Any Angle. It's Always 
Ready to Shoot 

SEVERAL attempts have been made to 
mount machine guns on automobiles 
and motor boats. The principal problem to 
be confronted is that of vibration. In every 
case the inventors have devised several 
forms of 

which would 
lessen to a 
degree vio- 
lent shocks. 
Needless t o 
say, they 
have been 
hard put to 
it/to devise a 
that would 
stand up 
under the ex- 
cessive vi- 
bration of a 
travel i ng 
The ac- 
illustration shows a new mounting for a 
machine gun which enables the gun to be 
fired in any direction without changing the 
base. A ball and socket joint gives the 
greatest possible latitude of range, and the 
gun can be fired at any angle to straight 
up. The flanged base and about one foot of 
the supporting column are attached per- 
manently to the automobile floor. 
The stand can be lifted off this 
base and put on another car, or 
by driving its pointed end into 
the earth it can be used for 
land firing. 

A machine-gun mounted on a ball and socket base fastened 
permanently to the floor of an automobile. It can be fired at 
any angle to straight up without changing or altering 

vised, but it is so high that the starting 
platform has to be reached in an elevator. 
A steel car takes the place of the old 
pine board. From three to ten persons 
may be swung through space in the same 
car. The car is suspended not from a rope 
but from metal rods, preferably of steel. 
The tower which supports the swing is 

composed of 
steel pillars; 
so is the ele- 
vator build- 
ing, as well 
as the ele- 
vator itself. 
The swing 
chair or car 
is held in po- 
sition on the 
platform by 
a locking de- 
vice. When 
the car is 
ready to be 
released, a 
lever is oper- 
ated which 
lets the car 
fall. The in- 
ventor does not tell us whether or not the 
car will return to the starting platform 
every time it is released. Neither does he 
explain how the car is brought back to the 
starting platform. Perhaps he figures that 
with a minimum of resistance it will return 
to the platform and thus be caught and held 
by the lockingdevice without further trouble. 

A Giant Swing for the 
Summer Resort 

INSPIRED by the swing 'neath 
the old apple tree, Frederick 
E. Happel, of Ballston, Virginia, 
has devised a giant swing for 
parks and recreation centers to 
thrill even the person who has 
grown tired of turning figure 
eights, riding down the roller 
coaster, and chuting the chutes. 
Not only is Mr. Ballston's 
swing by far the largest ever de- 

The giant swing is an overgrown edition of 
the old apple tree swing. It is made of steel 

Two and a Half Miles a Minute 

That's the speed at which a pitched ball travels 

Providence, R. I., who is known 
all over the world as an efficiency- 
engineer and who has specialized in motion 
study, knows 
probably more 
about cham- 
pions than any 
other living 
man — cham- 
pion golf play- 
ers, champion 
fencers, cham- 
pion baseball 
players, cham- 
pion handker- 
chief folders, 
champion sur- 
geons and 
typewriters. In 
his effort to dis- 
cover the fun- 
damental laws 
of human mo- 
tion, he studies 
every sport and 
every handi- 
craft. But he 
studies with 
the camera — 
the motion-pic- 
ture camera — 
not with the eye. 

Since it is necessary to know the time 
occupied in carrying out a given motion, 
sometimes to the thousandth of a second, 
and since camera cranks are never turned 
uniformly, Mr. Gilbreth has invented a 
special clock which is photographed with 
the scene. It is a very peculiar clock; for 
it has only one hand which makes six 
revolutions every second. That clock ap- 
pears on every film and the position of its 
hand enables Mr. Gilbreth to determine the 
speed of a motion down to the one-mil- 
lionth of an hour. Behind the catcher, a 
background is hung, ruled off into one foot 
squares. Every movement of the pitcher, 
catcher, batter, ball and bat is photo- 
graphed against that background. Thus 
by referring to that background in the 
film the direction and extent of every mo- 
tion can be accurately determined. 

The clock and the background used in connection with 
motion pictures of a baseball's flight. In one of Mr. Gil- 
breth's tests, Fromme pitched a ball which, including the 
wind-up, required only .99 seconds until the batter hit it. 
The time consumed from the moment that it left the hand 
of the pitcher until it reached the bat was 0.288 seconds. 
The ball therefore traveled 210.07 feet a second, or 2 2-5 
miles a minute. Even speeds of 2.8 miles have been 
recorded. In that case the batter occupied 0.042 seconds 
swinging and striking the ball ; which means that he began 
his swing when the ball was 9.24 feet in front of him 

With White in the box, Mullaney catch- 
ing, and Snodgrass at second, it required 
4.407 seconds to pitch the ball (including 
the "wind-up") and to return it from 
the batter to 
second for a 
put-out. The 
actual time 
that elapsed 
from the mo- 
ment that the 
ball left the 
hand of the 
pitcher to the 
moment when 
it dropped into 
the glove of 
the second 
baseman was 
1.697 seconds. 
The actual 
time consumed 
from pitcher to 
catcher was 
0.351 second 
— a rate of 
more than two 
miles a minute. 
The catcher re- 
covered to 
launch the ball 
at second base 
in 0.317 sec- 
onds. It required only 0.796 seconds to 
throw the ball from catcher to second base 
■ — a distance of 129 feet. The record for 
a 100-yard dash is only 9 3-5 seconds. No 
wonder bases are difficult to steal. 

Mr. Gilbreth's films are interesting in 
showing how long it takes a player to make 
up his mind what to do next. A baseball 
player must make quick decisions. A delay 
of a tenth of a second may be fatal. 

Strange things are revealed by Mr. Gil- 
breth's camera. So swiftly does the ball 
travel that it is struck by the bat before 
the pitcher's foot has risen to its full height 
from the ground. Some pictures show the 
ball in the catcher's glove before the batter 
even began to strike. A baseball nine is a 
model of teamwork. And yet, even the 
New York baseball nine knows less about 
itself than does Mr. Gilbreth. 



Popular Science Monthly 

A gigantic pencil which when fully extended was seventy-five feet long. Eight of its "points" 
could not only write but talk. But it's a stingy pencil despite its length ; it hasn't any eraser 

Here Is a Pencil with Nine 
Good Points 

AT a masquerade ball recently given in 
jTjl Oakland, California, by the advertis- 
ing men of that city, there appeared eight 
girls standing in single file and wearing 
cone-shaped hats which resembled the 
points of pencils. They were enveloped in 
a clumsy, bag-like device which had a 
big point at the front end. 

A signal being given, these girls stepped 
forward one by one. To the amazement of 
the on-lookers, they presented a gigantic 
pencil, seventy-five feet long and thirty 
inches in diameter. For once a pencil 
became longer with use. 

on all hand derricks, the elevator platform on 
which the electric saw is mounted can be 
easily raised up to the level of any rack. 
A rod on this rack has then to be moved 
a foot or two to feed it into the saw. In a 
few minutes the biggest rod is severed by 
the' hack saw as it mechanically receives 
its rocking motion from the motor. 

In order to cut other pieces of a different 
size, the platform is merely lowered in its 
guides to the level of the racks which con- 
tain the stocks of the proper diameters. 
It would ordinarily require six men to 
carry the heavy rods across the room, 
but by this means one operator can do 
it alone and in half the time. 

The Latest Enemy of Lost 

Motion — the Portable 

Elevated Saw 

IN all manufacturing 
plants using steel 
rods, considerable 
time and labor were 
formerly required to 
carry the heavy rods 
from their racks to 
the sawing machine 
and back again when 
short pieces were to 
be cut off. But 
thanks to a new 
portable elevator de- 
signed especially for 
carrying the electric 
saw, there is practi- 
cally no loss at all. 

When it is necessary 
to cut off short pieces 
of different diameters 
and shapes from the 
stock rods, the elevator 
is simply hauled over 
to the racks. By means 
of a system of reducing 
gears such as are used 

The saw is simply raised or lowered to 
the racks containing the different sizes 
of stock. It takes the place of six men 

Deadening Noise by Past- 
ing Tar Paper on a 
Concrete Floor 

BY pasting heavy tar 
paper to the con- 
crete floor of a factory 
the thundering noise 
of passing trucks can 
be eliminated. The 
floor is first given a 
coating of gray ce- 
ment paint and, 
when that is dry, a 
second coating is 
then applied. At 
the same time one 
side of a five-ply tar 
paper is painted and 
when both paper 
and floor are wet the 
paper is laid wet side 
down on the floor and 
rolled until all air- 
pockets disappear. 
This gives a tar-paper 
flooring which acting 
as a muffler, deadens 
all noise from trucks 
or heavy vehicles. 

Putting Alcohol to Work on the Farm 

The stuff that destroys brawn and brain prom- 
ises to be the inexhaustible fuel of the future 

PROMISING to be on land what our 
great fleet of new steel ships will be to 
England on the seas, the Ford farm 
tractor shown in the accompanying illustra- 
tion has been presented to the British 

cendency of machinery over manual labor. 
Besides the light weight and cheapness of 
the Ford tractor, its main characteristic 
is its ability to burn alcohol and kerosene 
with the same ease as gasoline. The supply 


The tractor which is run by alcohol. The motor is exactly similar to that used on the Ford 
automobile, except that it is larger and heavier. Kerosene can also be used as fuel 

government for use in raising England's 
crops during the coming season, even before 
a single one has been sold in this country. 
Shortly after America's entrance into the 
war, Mr. Ford cabled the complete specifi- 
cations to the British government and 
offered to build the parts for a thousand 
such tractors in a new plant in Cork, 
Ireland. Although this raised a storm of 
protest on the part of British agricultural 
machinery makers who were afraid that 
America would obtain a firm foothold in the 
British market, the plan is proceeding 
rapidly. It is expected that the simplicity 
and cheapness of the Ford Agrimotor will 
make it possible for this year's crop in 
England to be harvested more expedi- 
tiously than ever before, because of the as- 

of alcohol is as limitless and inexhaustible 
as the air and water, while the supply of 
gasoline and kerosene is growing smaller 
and smaller every year with no natural 
process of replacement that scientists can 
discover. Thus it may be that the havoc 
which alcohol has wrought in the past may 
be offset by the good it will accomplish 
when utilized as a fuel not only for farm 
tractors but for all forms of vehicles with 
internal-combustion engines. When that 
day dawns breweries will still be making 
alcohol but not for drink, and there will be 
motor cars in numbers beyond present belief. 
The motor used on the tractor is exactly 
similar to that used on the present Ford 
passenger automobile, except that it is 
considerably larger and heavier. 


Death-Traps on German Liners 

The harrowing task of investigating an interned German liner with the 
possibility of setting off a bomb or plunging into a pitfall at every turn 

A corner flange on one of the circulat- 
ing pumps and another on a steam chest 
were broken off with a sledge hammer 

tomless chasm, and that, if you value your 
life, you must not touch a thing — wood, met- 
al, or cloth — without first investigating it. 
How would you like to explore such a 
ship with only a flashlight to guide you 
through the abysmal blackness, and with 
no means of communicating with friends on 
the top deck once you start on your 
perilous journey? This was the task 
assigned to a certain engineer in New York 
shortly after the Government seized the 
interned German ships in this country. It 
was a task fraught with the greatest danger, 
requiring an extraordinary degree of caution 
and patience, and calling for a rare display 
of courage. But so fearless was this young 
engineer and so successful 
Holes drilled ready was he in his undertaking 
to Knock out piece that thirty-six hours 

after the ship in ques- 
tion reached the Navy 
Yard, the main boilers 
were generating steam. 
Among the 
many interesting 
things revealed by 
the intrepid in- 
Cylinder walls were vestigator^ were 

ruined by drilling holes the location of 

and knocking out the missing parts of 

portion within the holes 

THINK of a great deserted 
ship, five hundred and 
forty-five feet long, seven- 
ty feet wide and over fifty feet 
deep — as black and forbidding 
as a Siberian copper mine, with 
not a ray of light from the up- 
permost deckhouse to the cav- 
erns of the lowest holds, in the 
damp and slimy bilges, or in 
the rooms filled with engines, 
pumps, dynamos, pipes and 
valves without number. 

Think of exploring it, single- 
handed, with the warning fresh 
in your ears that it is full of pit- 
falls, bombs and death-traps; 
that every door you touch will 
set off an explosive which will 
blow you into eternity; that 
every ladder you step on will 
send you sprawling down a bot- 

The steel wedge was driven 
in the cylinder head to break 
the piston and the stuffing 
box at one stroke. The 
engine was cranked over 
to cause the damage 


On one of the main en- 
gines a jackscrew was 
placed in the low pressure 
slide-valve chamber and a 
portion of the cover was 
broken out as shown above 

Popular Science Monthly 


the main engines, carefully hidden away in 
the coal bunkers ; the discovery of bolts and 
nuts which led to a minute examination of 
the cylinders and steam-chests, where it 
was disclosed that parts had been removed 
and other parts carefully substituted to 
conceal the omission; the location, in other 
places, of studs and bolts partly sawed 
through, with the saw slot filled up; the 
finding of steel 
wedges fitted 
into steam- 
ports, so 
that any 
attempt to 
turn over 
the engine 
would have 
ruined it; the 
discovery of ob- 
structions in 
pipes, smokestacks fj 

What would have 
happened had the 
damper-chain been 
pulled. Over one 
hundred pounds of 
iron and coal would 
have fallen on the 
unsuspecting person 

How the German trap on the 
Friedrich der Grosse was dis- 
covered by means of a flashlight 
and a bit of ingenuity. The light 
was lowered down the ventilator 
and its rays played on the iron 
and coal which had been placed 
on the damper to fall on the head 
of the person careless enough 
to pull the damper chain 
as shown in the picture above 

Joke No. 1. A device which was 
thought to be a death-dealing 
trap. The string enabled the 
occupant of the stateroom to 
open the ventilator without un- 
locking the door. What a relief! 

Blueprints of the important details of the 
ship were concealed. They were tacked to the 
underside of bureau drawers and boxes. In 
cleaning out the drawers they were discovered 

and ventilators — lumps of coal and bars of 
iron placed on top of the closed damper-valve 
in a ventilator, requiring only a 
pull on the damper-chain to 
precipitate the entire load down 
on the head of the person foolish 
enough to pull it, and other 
traps too numerous to mention 

Down in the engine room and 

into the boilers, went the man 

with the flashlight, crawling in 

through one small manhole and 

in and out of the slimy tubes and 

shell, where one misstep 

would have meant serious 

injury. The long disused 

Brass tube caps on 
end containing nothing 


Empty bomb 
placed in boiler 

Joke No. 2. When the rear man- 
hole plate of a boiler was re- 
moved a fake "bomb" was dis- 
covered in the position shown. 
Thereafter every boiler was mi- 
nutely searched for a real one 


Popular Science Monthly 

Holes drilled in 
cover of pump 
and filled with .. 
tar, black dirt.etc 

What was 
to happen 

Holes were drilled in the cylinder-heads of 
pumps, filled with dirt and then painted over, 
with the anticipated hope of giving someone 
an unexpected bath had the pumps been 
started before the holes were discovered 

Small bolts holding 
together the lagging 
of steam connec- 
tions were sawed 
half through and 
then replaced. Had 
the steam chests 
been under pressure 
the bolts would 
have broken and an 
explosion would 
have taken place 

way through 

fire-room came next, Throttle hand 
every nook receiving the' wheel 
closest scrutiny. Then 
came a trip through the 
furnaces, the combus- 
tion chambers beyond, 
the grimy -uptakes and 
the long and tortuous 
connections of the great 
smokestacks and up 
their sooty ladders to what 
should have been the sky, but 
what proved to be heavy wooden 
covers fastened across the stacks, all 
carefully concealed from view. 

This task done, the engine 
room was reinspected, to 
locate the pipes and valves 
Next in turn were the 
enormous bunkers, 
tanks, water-tight 
doors and bulkheads, 
reaching from one 
end of the ship to 
the other, from 
the highest deck 
down to the 
bottom - most 
chamber of the 
hold. What 
would have hap- 
pened had the 
flashlight gone 
out ? Would the 
man have fouad 
his way out 
again ? 

Valve stem 

\Main stem pipe 
from boiler 

Section of flange Other flange 

drilled around and drilled ready 

broken out with to break out 
sledge hammer. 

Broken flanges on main 
steam elbows. The sec- 
-tions were first drilled 
around and then broken 
out with sledge hammers 

At left: The main throttle 
valves had been removed 
and destroyed, leaving 
only theempty valve bodies 

Tar, Cord 

Tin can 

Coal dust Powder 

Twenty-four bombs were 
found in the coal bunkers. 
Is it any wonder the coal 
was screened four times? 
The bombs were simply 
tin-boxes wrapped with 
twine. After they were 
dipped in tar and rolled 
in coal dust they were 
placed with the coal. 
Each bomb was found to 
contain a high explosive 

Popular Science Monthly 


Getting Your Change by Machine 
From the Cashier 

IN busy stores and restaurants of the pay- 
at-the-desk variety, a new device for 
handing change back to the customers is 
proving popular. 
You simply hand in 
the check and the 
money through the 
cashier's window. 
When she has made 
the change she de- 
posits it in the open- 
ing of a cylinder, as 
shown in the illus- 
tration. By giving 
a slight upward push 
on the bottom of the 
cylinder you cause 
the two halves of the 
false bottom of the 
cylinder to open out, 
and the coin drops 
down into your 
palm. Or you can 
obtain your change 
in the usual way, 
by sliding it off the 
opening of the cylin- 
der into your hand. 
Of course the device 
will not work with 
bills or soda checks. 

Above : The coin- 
dropping device in 
operation. At right: 
The device in detail 

A Fishing Light to Lure the Fish 
to the Bait 

WE have the word of the fishermen for 
it that fish are not unlike other 
creatures of the earth in regard to curiosity. 
They are as interested in what goes on 
below sea level in their subterranean home 
as we are in what takes place above it. 

The fish 

hook with 

its bait floats 

just in front of 

the light. The depths 

are adjusted by cork floats 

William J. Ryan, of Sapulpa, Oklahoma, 
has made good use of this bit of fish 
psychology in devising his fishing ap- 
paratus. He suspends an electric light and 
a fish hook near each other under the 
water. The fish are attracted to the light 
like moths to a flame. 
Near the light they 
see the bait, investi- 
gate, and then re- 
pent when they find 
themselves on land. 
Within a wooden 
box large enough to 
hold the entire ap- 
paratus the inventor 
places two batteries. 
Wires run from these 
batteries to a lamp 
Which is suspended 
in the water. Rub- 
ber tubing around 
the wire keeps out 
the water, and so 
does a glass jar about 
the lamp. The 

depth of the light 
and the hook in 
the water is ad- 
justed by cork 
floats. Need- 
less to say, the 
brighter the 
light the more 
curious and 
careless are the 
fish, all of which 
delights the 

It Costs a Fortune to Keep French 
Army Officers in Cars 

JOY riding seems to be a regular sport of 
French army officers. According to 
charges of reckless extravagance made 
against the touring-car section of the 
French army, the officers think that the 
cars they use are their own private prop- 
erty. Indeed, competition is rampant, 
each officer wanting the best machine and 
the most expensive assortment of acces- 
sories, says the report. The cost of 
twenty-six cars for the general head- 
quarters staff cost one hundred and 
seventy thousand dollars. Three thousand 
dollars is the annual upkeep per car. The 
only remedy, as France now sees it, is to 
refuse to allow any officer, no matter what 
his rank, to have a personal car. 

Addressing Newspapers by the Thousands 

The lightning-quick method by which the news 
reaches the subscriber before it grows "stale" 

tinuously. The string of aluminum plates 
is run at rapid speed under a wheel anvil. 
A stamping plate underneath presses the 
paper mailing-strip and the inking ribbon 
against the embossed plates round the 
wheel anvil, thus printing one address as 
each plate rushes by. The result is that 
thirty thousand names can be printed on 
the paper strip in one hour. 

A motor-driven typewriter is used to 
emboss the names and addresses on the 
aluminum plates. When a key is pressed, 
two lever arms are operated instead of the 
one on an ordinary typewriter. The motor 
at the same time presses the corresponding 
letter plunger and die through the plate, 
embossing the letter upon it. After several 

A motor-driven 
typewriter em- 
bosses the subscri- 
bers' names and 
addresses on 
aluminum plates 

Reels of the alumi- 
num plates are run 
through the press, 
printing as many 
as thirty thousand 
names an hour ' 

CHEAPER and quicker than the lead- 
type methods of printing the ad- 
dresses on newspapers, is the new 
system which uses embossed aluminum 
plates. The addressing of daily news- 
papers by the former method was a tedious 
task. Now the same task can be done 
by machinery with the saving of half the 
expense and of considerably more time. 
Instead of using a printing press to 
mark each address individually, the new 
system employs a reel of embossed alumi- 
num plates which, print the addresses con- 

thousands of these plates are embossed, 
they are all built up into a huge reel by 
simply catching the hinges together on 
their ends. 

After a long mailing strip has been 
printed, the modern newspaper office runs 
it through a cutting machine. Here the 
printed names and addresses are separated 
and then pasted upon the newspapers, all 

It takes methods such as these for a 
great newspaper to reach its patrons daily 
before its news becomes "stale." 


Popular Science Monthly 235 

The Open-Air Barber Shop Where the A Wounded Man Can Dress His Own 
Prices Fit a Beggar's Pocket Wounds with This Bandage 

IN Paramaribo, capital of Dutch Guiana, r T*HE rolled bandage is in great demand. 
South America, are many East Indian A Not only in the hospitals and in the 
coolies who have been imported under a equipment of the doctors and nurses on the 
system of indenture in such numbers battlefields, but also in the comfort 

that they comprise one third of the 
entire population. 

Now, since through some 
tenet of their unfathomable 
religion, the wearing of a 
beard is not permitted ex 
cept by the very aged or 
by dignitaries, the coolie 
must needs shave con- 
tinually. Even the 
tramps and beggars must 
keep their faces clean- 
shaven and their hair 
cropped. Naturally the 
proprietors of our bar- 
ber shops do not care to 
accommodate the class of 
patron seen in the photo- 
graph below. But the 
itinerant barber has no 
such prejudice. He has 
no overhead expense to 
meet, such as would be 
entailed by a shop, so 
that his prices can suit even the beggars 

The bandage has 
an adhesive plaster 
on one end which 
sticks to the skin. 
It is then unwound 
and wrapped 

kits of the soldiers it is found — or 
should be. The one illustrated 
is an improvement on that in 
ordinary use. Its chief fea- 
ture is an outer end which is 
adhesive and which enables 
a wounded man to apply 
l the bandage himself if 

The ends of the roll 
i \ are coated with wax, 
- which keeps the ma- 
terial from unrolling, 
even if the bandage is 
dropped. This also 
prevents it from 
getting soiled 
when carried in the 
pockets. To apply 
the bandage, a 
man injured in the 
left arm, for instance, 
takes the package in 
his right hand, and the 
loop, shown in the photograph, in his teeth. 

w '**&< 

14. >» 1, 

ft* * '■' <M 


The traveling barber locates his shop wherever 
there is a group of squatting coolies to be shaved 

Olive Oil Can Be Utilized to 
Prevent Fog at Sea 

OIL, though long known to be 
effective in calming a sea, has 
only recently been proved of value 
in preventing fog. Air is prevented 
from coming in direct contact with 
water which is warmer than the air. 
Thus condensation of water vapor 
is hindered. 

It has been found that olive oil 
when spread^out over a calm sea will 
begin immediately to lift the fog. 
"Grass islands" entirely obscured by 
the fog bank at only a few yards 
have been discerned as far away as 
a mile, in line with the clearing made 
by the oil. 

Wind, of course, tends to counteract 
the effect of the oil, except in the 
direction in which it is blowing. 

Those of us interested in science, engineering, invention form a kind of guild. 
We should help one another. The editor of The POPULAR SCIENCE Monthly is 
willing to answer questions. 


Popular Science Monthly 


Inclined platforms leading to the roof of the goat-house 
were built to indulge the climbing instincts of the goats 

Wild Goats Live on the Roof of 
Their Building 

THE efforts of wild animals in captivity 
to follow their natural instincts were 
amusingly illustrated recently by the antics 
of some wild goats in a Western Zoological 

Six of the goats 
were captured and a 
loghouse, surrounded 
by a high wire fence, 
was specially con- 
structed for them in 
the" zoological park. 
For a long time, how- 
ever, they were ill at 
ease and made des- 
perate efforts to scale 
the wire fence. Find- 
ing this impossible, 
they finally attempt- 
ed to climb up the ' 
sides of their log 
house. This taught 
their keeper that they 
were not trying to es- 
cape but were merely 
following their in- 
stinct for climbing. 
So he built inclined 
platforms leading to 
the roof of the build- 
ing. As soon as these 
were finished the 
goats scampered to 

the roof, evidently This au tomobile lock, similiar to ordinary safe 

enjoying themselves. combination, is capable of 87,000 variations 

If You Use This Lock, 

Don't Forget the 


NEW lock for the 
automobile works on 
a simplified form of the 
combination principle 
commonly used in safes. 
By a combination lock the 
self-starter, battery and 
magneto circuits are con- 
nected and disconnected 
within a steel case on the 
instrument board. With 
the same operation a valve 
in the gasoline lead is 
opened and closed by 
means of a steel wire in 
metal housing extending 
from the lock on the in- 
strument board to a valve which is located 
in the gasoline lead. 

When the driver wants to lock his car 
he gives the operating handle, mounted just 
below the combination knob, a half turn to 
the off position and all ignition is instantly 
disconnected and the gasoline cut off. 
When the driver wants to unlock his car 
he simply turns the 

combination knob to 
the three-number 
combination he has 
set and all the igni- 
tion is connected and 
the gasoline valve 

The lock is capable 
of more than 87,000 
distinct changes in 
the combination, so 
that it would waste 
time for even an ex- 
pert to find the right 
one unless he knew 
it in advance. 

When a car is 
locked there is no loss 
of gasoline through 
dripping, for there is 
no pressure on the 
carbureter. The lock 
also prevents "back- 
fire" setting a car 
afire; for when "back- 
fire" occurs you 
simply turn the lock 
off and the carbure- 
ter is disconnected. 

Popular Science Monthly 


The Policeman and the 
Fainting Lady 

experienced in hand- 
ling big crowds at presidential 
inaugurations and other cele- 
brations in the national Capi- 
tal, recently set about to find 
a way to revive persons who 
have fainted on the street 
without having to call an 
ambulance and send them to 
a hospital. Now every mem- 
ber of the force when on duty 
in crowds carries in his pocket 
a pill-box full of tiny glass 
tubes of aromatic spirits of 
ammonia. The tubes are 
about an inch long and 
slightly more than an eighth 
of an inch in diameter. Each 
has a wrapping of absorbent 
cotton and over this a silk gauze covering. 
Slight pressure between the fingers is 
sufficient to break the tube. The ammonia 
is promptly absorbed by the cotton about 
it, which also serves to prevent the sharp 
particles of glass from doing any harm. 
Held beneath the nose of the person who 
has fainted, the fumes of the ammonia soon 
revive him. The tubes are stored in all the 
patrol boxes about the city and are carried 
in patrol wagons and police ambulances. 

Reviving a fainting person with aromatic 
ammonia carried in tiny tubes, as in circle 

The conveyer reaches eighteen feet into the box car and 
piles the coal in the far end of the car without breaking it 

A Conveyer Which Loads Coal in 
Box Cars Without Breakage 

IT is difficult enough to bring coal to the 
surface, but marketing it in good-sized 
lumps is a still harder problem. If the coal 
leaves the mine in large lumps and is 
delivered in small lumps, having been 
broken in freight cars on the trip, it suffers 
a depreciation in price of about thirty 
per cent. This is one of the discouraging 
factors that the shippers of -coal have 
had to contend with for years. 

Box-car loaders of various 

kinds have been used with little 

success. Mechanical shovelers 

disposed of the coal in short 

order, but they broke it badly. 

Now comes the conveyer type 

of loader, designed to load the 

coal without breakage. It does 

not throw the product it is loading 

but carries it to the end of the car, 

as shown in the illustration. It reaches 

eighteen feet into the car, fifty per cent 

further than any other make of loader. 

The conveyer is supported on two arms 
hinged from a post in such a manner as to, 
be easily moved into a box car by hand. 
The chute is on the lower side of the car and 
follows the loader in all positions. At the 
receiving end of the belt loader is a de- 
flector which turns the coal as it comes 
from the chute in the direction of the con- 
veyer, thereby reducing the breakage. The 
conveyer is tilted by turning a crank. 

Housekeeping Made Easy 

A small white enameled stand with an en- 
closed space for brushes and shoe-polish- 
ing utensils makes a handy bit of furniture 

A new way to seal cans of vege- 
tables and fruit without using 
solder. The filled can is placed 
in the "sealer" as shown above. 
A turn of the crank seals it 

A foot-rest for the bath-tub. It hooks over 
the edge of the tub like a soap holder. An 
adjustable piece in the back holds it out 

A device for removing the peel from an orange 
without soiling the hands or wasting the 
juice. It can also be used for slicing the peel 
in various patterns for decorative purposes 

A squeezer for hastening the 
process of jelly-making. The 
last vestige of fruit juice can be 
extracted in this way without 
staining the fingers or clothes 


Housekeeping Made Easy 

You do not have to turn 
this extinguisher upside 
down to use it. It has two 
gages, one to show the 
quantity of liquid and 
the other to show the 
amount of air pressure 

A vacuum washer to be attached 
to the side of the tub. The spring 
assists in lifting the cup and the 
handle controls its tub position 

A multiple tool for the 
home gardener. With 
the arrangement shown 
at right a trowel and 
rake are provided, as 
for a cultivator. Below 
is shown the method of 
turning up either tool 
out of the way of 
the one to be used 

This knife polishing machine does 
its work by means of powdered 
emery and leather disks revolved by 
the crank. It is made in two sizes 


A kerosene lamp may be 
converted into an up-to- 
date electric light by in- 
serting a bulb and con- 
necting it with the circuit 



Popular Science Monthly 

The First Life-Long Flashlight. 
A Generator Furnishes the Power 

THE first life-long flashlights are soon 
to be placed on the market by French 
manufacturers. They will be warmly 
welcomed by motorists. The usual bat- 
teries, which are frequently renewed 
if used constantly, are replaced by a 
tiny electric generator. The generator is 
driven by a clock-work mechanism which 
is simply wound up when the battery is 
to be used. Since the ordinary flashlight 
bulb requires very little power, the strong 

Sprinkler cylinder 

Regulator wheel 

Most sprinklers stay where 
they are put. This one 
hops along like a toad 
and waters new ground. 
At right is shown the 
details of the design 

A Sprinkler Which Propels Itself 
Over the Lawn 

A LAWN sprinkler which crawls or 
rather hops along the garden under 
its own power has been invented by George 
C. Bohnenkemper of Denver, Colorado. 

The apparatus is sim- Doub)eswIvel 
ply constructed, consist- 
ing mainly of a cylinder 
and piston mounted on a 
pair of wheels. A hose 
leading from the water 
supply main is attached 
to the sprinkler. When 
the water is turned on, 
the piston within the 
cylinder reciprocates. At 
each forward stroke of 
the piston a curved metal 
foot, spiked at its lower end, is 
dragged along the ground. The 
spiked foot stabs the ground on 
the backward motion of the 
piston, causing the sprinkler to 
advance the length of the piston 
stroke. The rapidity of the 
aiston movement may be regu- 
ated by means of a wheel 
ibove the cylinder controlling 
he supply of water. 

As a comparatively small 
amount of water is required to 
operate the motor, the main 
supply finds its way to the 
sprinkler-nozzle which keeps up 
a continuous spray. 

clock spring will keep 
the bulb lighted for a 
considerable time. 
There is nothing in 
the battery mechan- 
ism to deteriorate. 
With a little care, it 

_ will last for years. 

Exhaust water ' Elongated 

x lease spike . valve , 

A Spoon Hook Which Will Not Tangle 
Your Fishing Line 

FOR ten years Charles Leonard, of 
Lake Geneva, Wisconsin, got his fish- 
ing line tangled or fouled when he used a 
spoon hook and pork bait for the large 
mouthed bass that abound in 
that section of the country. 
Sometimes the hook would snarl 
his line four or five times in 
succession, taking all the pleas- 
ure out of the pastime. Making 
up his mind one day that he 
would invent a spoon hook of 
his own that would not tangle 
his line, he proceeded to the 
task, and the result is that his 
name is in the Patent Office and 
he has a spoon hook which can 
be cast all day without snarling 
the line. 

In the old type of spoon hook 
the casting weight was attached 
to the line just above the spoon. 
This was the cause of all the 
trouble. In this new hook the 
weight is attached at the top of 
the hook, above the joint. At- 
tached to the under side of the 
lead weight and leading down to 
a ring below the joint are two 
wires which prevent the spoon 
end of the hook from buckling 
or doubling back. The inventor 
says he has cast the hook for 
three hours without a tangle. 

The spoon hook 
with new position 
of lead weight, and 
two wires directly 
beneath it to pre- 
vent tangling line 

A Camera to Be Handled Like a Pistol 

It is a happy combination of a leveling and 
sighting appendage and a repeating mechanism 

The principal 
details of the 
self-leveling re- 
peating camera 



TO handle a camera as easily as a 
ranchman manipulates a six-shooter, 
and to make its aim and result 
equally effective, is the purpose of 
several ingenious inventions patented f 5IGHTS \ 
by J. N. Johnson of Albuquerque 
New Mexico. He has obviated 
the necessity of clumsily focus- 
ing the camera by means of a 
finder. In addition, he claims 
that the camera may be aimed 
and operated with one hand, 
like a revolver, and all its films 
discharged, without the loss of 
clearness and accuracy. 

The camera is the happy 
combination of two devices: a 
leveling and sighting appendage, 
and a repeating or magazine 
mechanism. These devices 
may be used separately, if de- 

The leveling and sighting ap- 
pendage is a simple contrivance 
constructed of two horizontal 
tubes connected at 
their center by a verti- 
cal tube containing 
the shutter-op- 
erating bulb. 
This bracket- 
like device may 
be placed on the 
top or the bot- 
tom of the cam- 
era, thereby en- 
abling the pho- 
tographer to 
aim in any di- 
rection he wish- 
es — horizontally, vertically, or over the 
heads of a crowd. The bracket is so piv- 
oted that the camera hangs automatically 
plumb or level, no matter how the opera- 
tor holds it. The shutter is operated in 
the familiar way by compressed air sent 
through the rubber tube by the bulb in the 
handle. The sights on the upper bar of the 
bracket take the place of the finder and 
insure the accuracy of the photographer. 

A motor-operated mechanism is the 
second important device, designed auto- 
matically to shift the film after each move- 
ment of the shutter, so that a number of 

snap shots may be taken in rapid succes- 
sion. This invention is conveniently 
adapted to the ordinary film now in use. 
Though other magazine cameras op- 
erating on this general principle are not 
unknown, the present invention is to 
improve the shifting of the film 
so that it may be turned by a 
mechanical contrivance actuated 
by air pressure. It also aims to 


"Any child can 
do it." This 
small boy, who 
never had a 
camera in his 
hand before, 
made a series of 
very fine pic- 
tures at the first 
attempt. The 
camera is bal- 
anced on a pivot 


produce a direct and running 
mechanism to prevent a double 
exposure of the film. A spring- 
like contrivance moves the film over the 
rollers, a movable pin controls the starting 
and stopping of the film at the right point; 
air pressure opens the shutter; while its 
exhaust releases this spring contrivance 
which sets the film rolling for the next 

The self-leveling repeating camera is the 
combined result of these two inventions. 
The accompanying pictures illustrate its 
makeup and its operation. They show its 
large range of possibilities as a snap shot 
camera. The camera fiend can stalk his 
prey with even lessdifficulty than in thepast. 


The Unbeaten "Constitution" 

Step on board with us and see the guns 
that won thirty-nine glorious victories 

By Thomas Stanley Curtis 

THE frigate Constitution, fighter of 
thirty-nine battles and winner of 
every one of them, to-day offers 
the student an exceptional opportunity 
to compare the naval fighting machine of 
a hundred years ago with the super- 
dreadnought of the hour. Peacefully 
floating at a wharf in the Charlestown, 
Mass., Navy Yard, "Old Ironsides" 
speaks volumes to the thoughtful visitor 
who has perhaps just a few minutes 
before stepped 
down the gangway 
of a modern ship. 

In the war of 
1812, after a long 
series of brilliant 
exploits, the Con- 
stitution, under 
command of Com- 
modore Hull, sum- 
marily defeated 
the British ship 
Guerierre in an en- 
gagement which 
lasted but a scant 
hour and a half. 

On the nineteenth day of August, the 
commander of the Constitution received 
word from the captain of an American 
brig that a British frigate had been 
sighted cruising in the vicinity. Acting 
on the information, Hull immediately 
gave chase in the direction indicated and 
at 2 o'clock p. m. the Guerierre was 
sighted. After a three-hour run, the 
Constitution came within range of the 
enemy's guns and the Guerierre let go a 
broadside, which, however, did no dam- 
age. Turning, the British ship fired her 
port broadside and scored two hits. For 
three-quarters of an hour the enemy dis- 
charged alternate broadsides with little 
effect while the American ship replied 
only with her bow guns. 

At 6:05 p. m. the Constitution had 
closed in on the Guerierre and for the 
next few minutes both ships fired one 
broadside after another at a range of 
some two hundred yards. After ten 
minutes, Hull opened at close range with 
his whole broadside and the Guerierre' s 

Constitution fighting the Guerierre. 
The most famous battle of Old Iron- 
sides. Reproduced from an old print 

mizzen mast went over on the leeward 
side. At this stage the American com- 
mander determined to cross the bow of 
the enemy and rake his deck with a 
broadside. Disabled in her rigging, how- 
ever, the ship failed to answer the helm 
quickly. After two terrific broadsides 
had swept the deck and pierced the hull 
of the British ship, practically dead- 
locked to the enemy and already weak- 
ened by the raking fire, the Guerierre 
was worked up in- 
to the wind against 
her helm by the 
fallen mizzen mast 
and thus brought 
directly under the 
guns of the Con- 
stitution. As the 
American ship 
pulled away, the 
two remaining 
masts of the 
Guerierre were shot 
away and the Brit- 
ish ship was a total 
wreck with her 
guns of the main deck under water. 
The engagement ended at 6 30 with the 
surrender of Captain Dacres of the 

From this brief account of a typical 
naval battle of the time, the reader will 
note that the conflict was little short of 
hand-to-hand; towards the close of the 
engagement the contestants were actual- 
ly locked together with the bowsprit of 
the one fouled in the rigging of the other. 
To-day the contestants scarcely see each 
other's ships. Whereas the fighters of a 
hundred years ago could actually see the 
whites of each other's eyes, now there is 
not a living thing visible on the deck of 
a ship in action. The gunners of the 
Constitution could "draw bead" on the 
hull or deck of the Guerierre, and when 
they wished to elevate a gun they 
would tilt the muzzle by withdrawing a 
wooden wedge beneath the breach. To- 
day the gunner seldom sees" his target; 
his range is given him in figures through a 
telephone and he fires at signal: the 


Battle-Scarred "Old Ironsides' 

Mf / ' 


/ mtttnl B 



<JUBvj!/fj J 

-*-- : iBhBSH» 

Peacefully floating at her 
dock the famous old frig- 
ate Constitution, once a 
dreadnought of the seas, 
presents a striking con- 
trast to the grim battle- 
ships of the present which 
rest near her. One of the 
most remarkable varia- 
tions between the new 
and the old fighting ships 
is the fact that the shell 
fired by one of our super- 
dreadnoughts weighs prac- 
tically as much as the 
biggest gun carried on 
the frigate Constitution 

The teeth of Old Ironsides which helped win thirty-nine battles. The ship has been re-rigged 
and refitted just as she was in her fiery days of a century ago. She is spending her old age 
at the Charlestown Navy Yard, in Boston. Her reputation was made in the war of 1812 



Popular Science Monthly 

muzzle of his gun is elevated, depressed or 
turned laterally by an electric motor 
through gearing. 

The spar deck of the Constitution car- 
ries twenty-two thirty-two-pound carro- 
nades, the muzzles of which project 
through square ports. The cannons are 
mounted upon massive wooden carriages 
running on chunky iron wheels. The re- 
coil carried the cannon back to a point 
determined by the length of a heavy 
hawser or rope. For reloading, the pins 
were removed from the loops in the ends 
of the rope and the gun carriage rolled back 
nearly to the center line of the deck. The 
policy of discharging alternate broadsides 
was to enable the gun crews to reload while 
the ship was turning. 

Contrasts in Actual Construction 

Aside from the vastly different methods 
of placing the guns, perhaps the most 
striking contrast between the naval archi- 
tecture of a century ago and that of to- 
day is seen in the actual structure of the 
hull and superstructures. The warship 
of today has not a piece of wood visible, 
with the possible exception of the deck, 
which is wood over a steel foundation. 
Stripped for action, the modern fighting 
craft presents a positively naked appear- 
ance with every movable object cast over- 
board or stowed away. The Constitution, 
on the other hand, presents a bewildering 
array of rigging and spars, and she is 
wholly constructed of wood. A single 
modern shell exploding under or on her 
deck would do as much damage, probably, 
as an entire broadside from a ship similar 
to the Guerierre. This vast change in the 
design is, of course, due in large measure 
to the introduction of steam as a means 
of propulsion. Following this the all- 
steel hull was introduced. 

The gun deck of the Constitution stirs 
the imagination perhaps still more than 
does the spar deck. Topped by a low 
ceiling which makes one want to stoop as 
he walks, this deck savors of a prison 
dungeon. Glancing at the row of long 
twenty-four-pounders, thirty in number, 
one can readily picture the smoke-filled 
atmosphere, the terrible din, the sweat- 
ing, half-naked figures straining to reload 
the clumsy pieces of ordnance, and ever 
and anon a shot crashing through the 
futile wooden wall sending splinters in 
all directions. Stepping from the gun 
deck and the turrets of the Rhode Island 

to this old-time chamber of horrors, the 
visitor cannot fail to wonder how in her 
famous engagement the Constitution suf- 
fered a loss of but seven killed and seven 
wounded out of a crew of four hundred 
and fifty-six officers and men. Perhaps 
the answer is found in the inaccuracy of 
the guns and poor marksmanship of the 
gunners; more likely, however, it is due 
to the fact that the explosive shell had not 
then been invented. Aside from the 
splinters, a twenty-four-pound shot through 
the hull stood little chance of doing really 
great damage unless it struck a mast, a 
gunner or the gun carriage itself. 

The guns of the Constitution's day 
had an effective range of possibly a mile, 
although history tells us that the real 
execution was done at ranges of from one 
to three hundred yards. Think of the 
engagements of the present European war, 
wherein naval duels are fought at ten miles' 
range and where the opposing ship is actu- 
ally out of sight from the gun deck and 
barely visible from the fighting tops ! 
Think of guns aimed with the aid of mathe- 
matics! What marvelous strides science 
has made in times of peace and in the short 
space of a hundred years! 

As an interesting comparison of the guns 
of to-day with those of 1812, we may call 
attention to the fact that while the total 
broadside discharge of the Constitution's 
battery would amount to six hundred and 
eighty-four pounds of metal, a single 
projectile from one of our coast defense 
mortars weighs half a ton. 

Comparison of Projectile Force 

Even more striking is the fact that 
the projectile from a modern fourteen- 
inch piece of ordnance such as that carried 
by the super-dreadnoughts, weighs prac- 
tically as much as one of the big guns of 
the Constitution; in other words, instead 
of hurling a small ball of iron at its enemy 
the modern fighter of the seas could actually 
throw one of the Constitution's cannons 
itself at the opponent were the cannon of 
suitable shape and form. And, further- 
more, the explosive charge in the projectile 
would be greater by far in power than the 
entire charge used to fire the old cannon. 
This means that the modern engine of 
destruction actually takes a mass of steel 
equal in weight to the old gun, loaded 
with high explosive, and lands this entire 
mass on the deck or inside the hull of 
the enemy's ship, where it explodes. 

Popular Science Monthly 


The Largest American 
Flag in Existence 

THE city of St. Louis, 
Missouri, possesses the 
largest American flag in ex- 
istence, as far as is known. 
It is 150 feet long and 78 feet 
wide. Each of the thirteen 
stripes is six feet wide. Imag- 
ine a plot of ground contain- 
ing 11,700 square feet — al- 
most one-quarter of an acre — 
and you will have an idea of 
the size of the flag. When used 
in parades it requires two hun- 
dred people to carry it. But on 
account of its great width it 
cannot be carried through 
many of the streets of thecity. 

The submarine hoists a sail 'and runs on the surface 
to approach within striking distance of a fast 

in order 

This Machine Is Five Times as Fast as 
an Expert Bank Teller 

AN expert bank teller can count by 
l hand from six to ten thousand coins 
per hour for one hour only. With the new 
machine illustrated one man, not an expert, 
can count fifty thousand coins per hour 

Mistakes are impossible. In the course 
of a certain, test, two thin dimes 
were glued together and mixed 
with the mass of coins. The 
machine separated the coins and 
the final registration showed the 
correct count. Mutilated 
coins or thick counterfeits 
stop the machine. 

There is a sepa- 
rate head or counter 
for each denomina- 
tion of coin, and the 
change from one size 
to another can be 
made instantly. The 
coins pass between 
two wheels, one at a 
time. The cyclome- 
ter, which is in plain 
view, shows the ex- 
act number of coins- 
which have passed 
through the machine 
at any time. The 
machine can be ad- 
justed to stop auto- 
matically. There are 
no springs in it. 

This machine automatically counts and 
wraps up coins of any denomination at fce 
rate of from 500 to 1000 coins per minute 

Submarines Disguised as Sailing 
Vessels, Creep Up to Their Prey 

TO deceive vigilant merchant ships, the 
commanders of German submarines 
disguise their vessels when they can. 
Frequently they hoist sails so that their 
craft look like peaceful sailing vessels. 

According to the captain of a swift 
British freighter, as he was standing on the 
bridge of his vessel one day he sighted a 
craft lying low in the water, far astern. 
He had looked in that direction a few 
minutes before and there was no ship in 
sight. That aroused his suspicion. 
Furthermore, the ship was moving 
along much faster 
than the wind alone 
could have taken 
her. Ordering full 
speed ahead, he kept 
his eyes on the 
strange vessel, final- 
ly becoming con- 
vinced that it was a 
German submarine 
disguised as a sailing 
vessel. There was 
not much of a breeze 
but the ship cut 
through the water at 
high speed just the 
same. After the 
mysterious craft had 
followed hia vessel 
for several hours it 
sails and all. 


Automobile Engine Cooler Operates on 
Steam Ejector Plan 

THE latest accessory to aid the water 
circulation of an auto 
mobile engine forces the 
water through the sys 
tern at a speed propor- 
tional to the engine 
heat generated. The 
device is built on the 
principle of the steam 
ejector used to draw 
water from a tank in- 
to a steam boiler. 
The harder the engine 
labors, the more water 
is circulated, so that 
the possibility of over- 
heating through an in- 
sufficient supply is 
greatly lessened. 

The device does not 
take the place of the radiator but simply 
aids it in its work. It is to be fitted on 
engines using the thermo-syphon cooling 
system in which the water automatically 
circulates because hot water rises to 
the top and colder water drops 
to the bottom. The water is 
cooled in passing through 
the radiator by the con- 
tact of the in-rushing air 
against the radiator core 
and passes from the 
bottom through the en- 
gine water jacket and 
out at the top, as shown 
in the accompanying 

The device has no mov- 
ing parts. It consists of 
two pieces, a length of pipe 
between the bottom of the 
radiator and the water jacket 
intake and a smaller pipe screwed into the 
exhaust manifold. This pipe, bent over 
the top of the engine as shown, terminates 
in a small nozzle pointed toward the en- 
gine inside of the larger pipe. Exhaust Elect 
gas through the smaller pipe escapes 
through the nozzle into the water which it 
forces forward at a speed which is directly 
proportional to the pressure of the gas. 

A ball-check valve in the small pipe 
prevents any of the water from backing I 
up into the exhaust manifold, as its 
tendency usually is when the engine is 

Popular Science Monthly 

^--i) This apparatus circulates water through 
the cooling system of an engine proportionally 
to the heat that is generated by the engine 

Cooling the Air of a Room with 
Cold Water Pipes 

THE simple but effective air cooler 
shown in the illustration below has 
in patented by Glen 
rien, of Manhattan, Kan- 
It consists of four coils 
metal pipe, fitted one 
inside the other for 
compactness. Cold 
water flows through 
the pipes while an 
electric fan blows the 
sultry air of the room 
over them. The air 
leaves the pipes cooled 
down to nearly the 
temperature of the 
water, and spreads 
out over the room. 

This apparatus is 
both economical and 

simple to operate. Few things are cheaper 
than city water. 

. Humid and damp air is also deprived 
of its disagreeableness by this apparatus. 
The mere act of lowering the air's 
temperature "squeezes" out 
most of its moisture, which 
condenses on the cold pipes. 
Any dust and germs in 
the air will be carried 
down with the water 
in the process. The 
air is thus purified. 

By merely pressing a 
push - button held in 
the hand the air of 
the room can be 
changed by the patient 


/ ^^BM-JB^^^ Dnppc 


A fan blows the air over a hundred coils 
of water pipes, cooling and purifying it 

Popular Science Monthly 

Alas! It Will Not Work— This Method 
of Foiling Bomb-Droppers 

AND now come Mary Hannah 
. Clarke, born Ashton, -v 

banker and British citizen 
but residing at Paris, France, 
engineer and Italian subject 
but residing in the same city, 
with a new invention. These 
two secured sole American 
rights to an anti- airplane 
ordnance of the most flab- 
bergasting construction. This 
ordnance is light of weight — very 
light, and might be erected on 
the roof of a house without 
interfering with insurance and 
building regulations. 

When the hostile aircraft is di- 
rectly over the house, this 
remarkable sheet-iron gun 
is fired and sends aloft gi- 
gantic whirling rings of 
combustion gases 
which twist the air- 
craft around, as a cy- 
clone the oak tree in its 
path, and forthwith 
sends it spinning in 
desperate curves pre- 
cipitately to the hard 
pavement below. 
Whereafter Maggiora 
and Mrs. Clarke go 
down the stairs and 
view the remains with lively and mutual 
satisfaction at their joint ingenuity. 

Witness the accom- 
panying drawing. The 
little thing to the right 
is the generator of the 
powerful gas. The gas 
is admitted by a valve 
to the explosion cham- 
ber below in the smoke- 
stack-gun where it is 
mixed with air. The 
choke port above this 
chamber looks scientific 
and perhaps has other 
merits. The charge is 
ignited by electric spark, 
of course. 

And now notice the 
precautions taken for 
successful operation. 
The long tube which is 
supposed to endure the 


explosion from within might collapse from 
the pressure of the atmosphere when a 
vacuum is suddenly created inside 
of it by the 
eruptive dis- 
charge of its 
Hence a series 
of large valves 
; are arranged 
' spirally. They 
open automat- 
es ically and 
admit the 
air to the 
and soft- 

u. ly * 



The tornado-spurting gun and its gas gener- 
ator in operation on a housetop. At right 
above is a diagram of the contrivance 

The ordinary policeman's 
club with a whistle in the 
handle. The whistle is 
concealed by a cap which 
flies back automatically 

The Policeman's 
"Billy" Becomes 
a Whistle 

THE inventors 
have discov- 
ered that the or- 
dinary hardwood 
club of the police- 
man is not so effi- 
cient as it looks. 

James A. Byrne, 
of West Orange, N. 
J., has been struck 
by the fact that 
when an officer clutches a prisoner with 
one hand and his club with the other, he is 
not in a position to take his whistle from 
his pocket. Mount a whistle on the end 
of his club and the problem is solved, 
whistle is inserted in the handle of 
:lub ; an opening near the top per- 
mits the escape of air 
when the whistle is blown. 
Both the neck and the 
mouthpiece of the whis- 
tle project beyond the 
handle end of the club, 
but they are concealed 
from view by a cap held 
in position by a spring 
catch. If the police- 
man wishes to blow the 
whistle in an emergen- 
cy, he presses a push 
button and the cap 
flies back, exposing the 
whistle to view. 




Applying the Idea of the Needle Bath 
in Shell-Making 

THE steel utilized in the manufacture 
of explosive shells must be carefully 
tempered. If the steel is too brittle or too 
ductile the destructiveness of the pro- 
jectile is affected. Steel of the correct 
temper, however, does 
not lend itself readily to 
heavy machine opera- 
tions. For this reason, 
steel shells, after the in- 
sides have been removed 
from the blanks and most 
of the surplus material 
cut from the outside, are 
subjected to what is 
called "heat treatment." 

The first step in heat 
treatment is to bring the 
shells to a comparatively WATE r 
high temperature. Then 
they are quenched, usu- 
ally in oil, and once more 
heated to bring the ma- 
terial to the proper 

Although projectiles of . 
all artillery ammunition 
must be heat treated, the 
cleverness of the French 
and the ingenuity of the 
Yankee has given manu- 
facturers a substitute for 
the oil bath which is an 
interesting and unusual 
adaptation of the familiar bath spray. 

The accompanying illustration could 
with very little imagination be taken as a 
model of the original needle bath. 

The shell bath is a cylindrical, double- 
walled receptacle, not unlike one ashcan 
placed within another. The space between 
the concentric walls forms a reservoir 
for a supply of water under pressure. 
The inner wall is perforated, and there 
is also a central perforated pipe passing 
through the top of the needle-bath, 
where it connects with a piece of ordinary 
rubber hose. 

The shell to be cooled is placed in the 
main chamber, the perforated pipe in- 
serted in the nose of the shell and the 
water sprayed on the inside and outside 
of the heated case. 

The shell is taken for this bath from 
a heating furnace where it has been kept 
at a temperature of 1800 degrees Fahren- 

Popular Science Monthly 


heit for some thirty minutes, and it remains 
in the bath until cooled thoroughly. 

Plunging the hot shell immediately into 
a tank of cold water after taking it from 
the furnace would be treatment too heroic 
and would without doubt do a great deal 
more harm than good ; but the gentle cool- 
ing effect of the shower bath has 
proved highly efficacious. 
rubber hose a spray of cold water 
seems to be as beneficial 
to the temper of a shell 
as it is conceded to be to 
the temper of many a 
fractious youngster. — 
Reginald Trautschold, 
M. E. 

The shell is placed in the main cham- 
ber, the perforated pipe is inserted in 
the nose of the shell and the water 
is sprayed from inside and outside 

A Fortune from Old 
Razor Blades 

is making a little 
fortune out of old safety- 
razor blades. It seems 
almost unbelievable but 
it is not more strange 
than the stories we hear 
of fortunes made by rag- 
pickers and dealers in old 
tin cans. This man pat- 
ented a suitable blade- 
holder, which he sells 
with supplies of old 
blades to tailors, mil- 
liners, show-card writers, 
and photographers. 
The holder is made from one piece of steel 
bent in half with its two sides pressing close 
together. One corner of the blade sticks 
out from the holder. It will cut one 
hundred ordinary sheets of paper or a 
dozen pieces of cloth at 
a single stroke. 

By means of a safety holder, the blades can 
be used for cutting cloth, paper or cardboard 

Popular Science Monthly 

When the Star-Spangled Banner Is 
Played Wave Your Cane Flag 

THE question of what to do with your 
cane when the orchestra strikes up 
the Star-Spangled Banner has been solved 
by Charles T. Fernandez, of Roxbury, 
Massachusetts. If 

you have one of his 
new canes you raise 
it above your head, 
turn a knob until an 
American flag con- 
cealed in theinterior 
comes out through 
the slot, and then 
wave the flag as long 
as the music lasts. 
In a word, his de- 
vice is nothing more 
than a flag wound 
round a roller inside 
the cane. The knob 
or head of the cane 
is connected with 
the roller so that the 
flag may be wound 
or unwound at will, 
appearing and disappearing through a slot. 
When the flag is inserted the flag-stick fits 
into the cane, and the flag into the slot. 

Turn the knob and the flag will come out 
through a slot from the interior of the cane 


fifteen and one-half packages. In 1916 we 
exported 718,000 pounds — say 11,129,000 
packages. We shall soon see that this is a 
mere bagatelle. The total amount of 
chicle imported, manufactured and con- 
sumed in the United States in 1916 was 
7,031,000 pounds, equivalent to 28,- 
124,000 pounds of 
chewing gum. This 
represents a per cap- 
ita consumption in 
the United States 
of about three and 
a half pounds, or 
fifty-five packages 
per annum. Every 
man and woman, 
old and young, boy 
and girl and infant 
in arms represented 
a consumption of 
fifty-five packages 
of gum last year! 
Great is the power 
of the American jaw ! 
No wonder we are 
a race of orators. — 
Ellwood Hendrick. 

Fifty-Five Packages of Chewing Gum 
for Everybody! 

AT the Kansas City meeting of the 
> American Chemical Society, Dr. Fred- 
eric Dannerth, of the Re- 
search Department 
of the Rubber Trade 
Laboratory, present- 
ed in detail the meth- 
ods for determining 
the content and val- 
ue of block chicle, of 
which chewing gum 
is made. These are 
of interest only to 
chemists, but the 
statistics that Dr. 
Dannerth gave are 
enough to drive us 
silent from sheer jaw 
weariness at the mere 
thought of them! One 
pound of chicle makes 
four pounds of chewing 
gum and one pound 
of gum produces over 

A portable nail sorter which will arrange 
nails and tacks according to their size 

A Portable Nail Distributor Saves 
the Carpenter's Hands and His Time 

A BOON to the traveling carpenter, in 
the form of a portable nail distributor 
has been invented by Robert B. Holland, of 
North Yakima, Washington. With it the 
carpenter or other workman can separate 
small nails from large ones by simply 
dropping them into a hopper. The 
various parts of the device are 
easily collapsed into a com- 
pact package of a convenient 
size for carrying. 

To distribute the 
nails according to 
their several sizes, 
the nails are first 
placed in the hop- 
per and fed down- 
ward to the chute 
by jarring the casing. The 
nails strike the partitions 
and are deflected out through 
the openings in the bottom 
into the guideways. Here 
they collect, according to 
their size, and the operator 
grasps them by the thumb 
and forefinger. 

Conquering Your Cramps Under Water 

Breaking the arm cramp by sheer strength. 
The lungs are first filled with air to prevent 
panic; then the arm is forced out straight 

THE "Old Man of the Sea," who 
figures in fiction so mysteriously 
and with such dire consequences, 
might well be named "Cramps" for 
everyday application, as far as swim- 
mers are concerned. To many swim- 
mers, otherwise absolutely fearless 
in the water, the suspicion of a cramp 
is a nerve-wrecker. But, according to 
Henry Elionsky, holder of the world's 
long distance swimming champion- 
ship, that is because they do not em- 
ploy the scientific method of breathing 
when in the water. 

The rule which Elionsky gives to 
his pupils at the Brighton Beach 
Baths near New York is: "When in 
the water breathe through the mouth 
only and gulp the air, as you would 
if you were frightened or very, much 
amazed on land." The air thus in- 
haled is driven into the lungs in about 
five times the quantity rate breathed 
through the nose. 

A cramp is merely a contraction of 
the muscles caused by the penetration 
of the cold. Obviously, it could not 
of itself cause drowning. Its worst 
effect is to cause a panic which throws 
the swimmer off his guard, causing 
him to let the air out of his lungs and 
thus allow the air passages to become 
filled with water. The safeguard 
against such a panic is absolute confi- 
dence in the floating power of the 
body and a demonstrable knowledge 
of the proper way to quickly fill 

Some valuable first-aid advice 
from the champion long 
distance swimmer of the world 

Below: Henry Elionsky swam 
from Battery Park, New York, 
to Coney Island, with hands, 
feet and legs shackled. Time 5 
hours, 20 minutes. His sister, 
with hands and legs free, ac- 
companied him. Here they are 
diving from the Battery pier 

(Pi To 

Forcing a cramped leg straight. The body will 
float as long as the lungs are kept filled with air 


Popular Science Monthly 


the lungs to utmost capacity with air. 

The moment a cramp is felt, the swim- 
mer should turn on his back and begin 
to gulp the air, making no effort to keep 
himself from 
sinking. As he 
sinks he slowly 
exhales under 
water, through 
the mouth, with 
the lips puck- 
ered as for 
whistling. If it 
is a stomach 
cramp the knees 
will be drawn 
up against the 
abdomen, but 
the swimmer 
should force 
them out, push- 
ing on them 
with both 
hands and us- 
i n g all his 

strength until they are fully extended. 
This will no doubt cause great pain for a 
few seconds, but as soon as the legs are 
straightened out the cramp will vanish, 
and the body, buoyed up by the air in the 
lungs, will shoot up to the surface. There, 
still inhaling, in great gulps and ex- 
haling through puckered lips, the 
swimmer may float until he re 
gains his strength or is picked 

In case of cramp in the leg 
or arm the same system of 
breathing is followed and 
the affected part is straight- 
ened out by sheer strength. 

When the cramp is in the stomach, turn on your back, 
gulp the air to fill the lungs and push the knees down 

pairs, the wheels of each set being coupled 
together and driven by two giant steam 
cylinders. Under full steam, the locomo- 
tive can exert an eighty-three ton pull on 
the cars behind 
it — which 
means that it 
can easily haul 
a freight train 
two miles long 
and twenty- 
three thousand 
tons in weight 
over an ordi- 
narily good 
road-bed at an 
average rate of 
about fourteen 
miles an hour 
and possibly 
more . B ad 
roads will re- 
tard it only 

The Very Biggest Loco 
motive in the World 

THE greatest steam loco- 
motive in the world has 
been put into service by the 
Baldwin Locomotive Works. It 
is so gigantic that its boiler 
had to be made flexible at three 
different joints so that the loco- 
motive could turn around a 
curve ! It is over one hundred 
feet long and weighs some four 
hundred and twenty tons. Twenty-four 
driving wheels, each standing as high as 
an average-size man, afford it traction. 
The driving wheels are distributed along 
the length of the locomotive in sets of four 

The flashlight bulb is 
clipped to the end of 
the handle of the safety- 
razor and throws the 
rays across its path 

Shave Under a Flashlight Attached 
Directly to Your Razor 

FIRST AID" in affording yourself a 
quick shave is given by a new 
razor attachment patented by Katherine 
E. Allport of Chicago. It is a com- 
bination of a flashlight and a 
razor which will illuminate a 
man's face far better than the 
regular wall light. 

A wall light which is di- 
rected upon one half of the 
face cannot intensely il- 
luminate the other. But by 
having the light attached 
directly to the razor, the 
light follows the blade and 
the strong rays are thrown 
just where they are needed. 
The chance of cutting yourself 
is thereby reduced considerably, 
and a perfectly clean shave is 

The small flashlight bulb is 
clipped with its socket on to the 
handle end of the razor. The 
conducting wires from the sock- 
et lead to small dry cells which 
occupy the bottom half of the razor box 
especially built for this attachment. From 
one to three dry cells can be employed, 
depending upon how much light you con- 
sider necessary for the operation. 


Popular Science Monthly 

thousand dollars to carry out her 
father's wishes. The model is com- 
plete in every detail, even to small 
whale boats which hang from the. 
davits. It measures fifty-nine feet 
from the figurehead to the stern, 
and it is eighty-nine feet from flying 
jibboom to spanker boom. The 
cost of the model alone was twenty- 
five thousand dollars. 

© Brown and Dawson 

A life-size model of the whaling ship, Lagoda, which 
was built in the room in which it is exhibited 

The Largest Model of a Ship Ever 
Constructed Under a Roof 

IN the days when the American merchant 
marine was the pride of the entire 
shipping world, New Bedford, Massa- 
chusetts, was the port of many a prize- 
winning cutter. It was also the 
headquarters for the whalin 
industry. One of the early 
sea captains who made a 
fortune out of whale 
oil was Jonathan 
Bourne, whose fa- 
vorite ship was the 

When Jonathan 
Bourne died he or- 
dered a model of the 
Lagoda — the largest 
model of its kind in 
the world — placed in 
a museum known as 
the Jonathan Bourne 
Whaling Museum. 
His daughter, Emily 
Howland Bourne, 
contributed fifty 

The scarab rolling a ball of manure many 
times its own size to a suitable hiding place 

The Curious Ways of Egypt's 
Holy Beetle 

THE holy beetle of the Nile is 
found carved in stone every- 
where in Egypt — a relic of a time 
when crocodiles, bugs, and beetles 
were objects of worship. As the 
scarab is a dung beetle it is naturally 
found in the vicinity of herds and 
particularly in pastures where no- 
madic herdsmen watch their flocks. 
The scarab is not satisfied with 
merely eating manure on the spot, 
as are most dung beetles. It 
fashions perfectly rounded balls out 
of manure and rolls them often con- 
siderable distances and buries them 
in the sand. 
These dung balls serve the scarab and its 
brood as food. It makes several balls for 
itself, and others similar in appearance for 
the brood. All are buried in the sand. 
When making a ball for the young the 
beetle is exceedingly careful in the selection 
of food. It rejects all un- 
digested vegetable particles. 
The ball is fashioned into 
pear-shape after having 
been placed in the ex- 
cavation made to re- 
ceive it. A single 
egg is laid in a small 
receptacle in the 
elongated part of the 
pear. The larva, slip- 
ping from the egg, 
eats out the interior 
of the greater part of 
the ball, leaving a 
hollowed-out portion 
inside of the hard 
outer crust. Within 
this shell the chrysalis 
stage is then passed. 
— Dr. E. Bade. 

Popular Science Monthly 


With an Axe and Two Springboards He 
Chops His Way Up a Giant Tree 

FROM the logging camps in the vast 
timber district of Vancouver have 
come some remarkable accounts of dar- 
ing and agility. The story that is going 
the rounds of the camps just now is the 
tree-climbing feat performed by a power- 
ful lumberman, Andrew Busby. A 
cable had to be attached to a tall 
tree at a point one hundred and 
twenty feet from the ground. 
With pole-climbing spurs and 
belt this would have been a 
simple task, but no such equip- 
ment was available. How was 
it done? 

With an axe and two spring- 
boards Busby began to climb 
the tree. Using the first 
board as a platform he 
chopped a notch five feet 
above him, slipped the 
second board into the 
notch, climbed up, and, 
pulling the first board 
after him, continued the 
operation a score of 
times. Within an hour 
he stood on the last 
springboard,, at the top 
of the tree, and affixed 
the rope, his companions 
yelling their admiration 
in the meantime. Standing more than a 
hundred feet above the ground on a little 
platform a few inches wide he was ap- 
parently as calm 
as he was when 
on the solid 

Needless to 
say, Busby is an 
expert chopper, 
skilled in the use 
of the spring- 
board and is pos- 
sessed of the fear- 
lessness natural 
to the woodsman. 
His claim to the 
title of champion 
tree-climber has 
not yet been dis- 
puted nor is it 
likely to be, ac- 
cording to his 
fellow workmen. 

With an axe and two 
springboards Busby 
climbed to the top of a 120- 
foot tree cutting grooves 
into which to insert his 
board at five-foot intervals 

The calf is photographed against a squared background 
at regular intervals to obtain records of its growth 

Studying the Effects of Calf-Foods by 
Means of Photographic Records 

IN keeping records of experiments to de- 
termine the effects of various foods and 
combinations of foods as substi- 
tutes for whole milk in the rearing 
of calves the Agricultural Ex- 
periment Station of Purdue 
University, Lafayette, 
Ind., uses photographs 
instead of tabulated 
figures to furnish an 
index in regard to the 
condition and develop- 
ment of the calves. 
The photographs are made at 
intervals of thirty days during 
the first six months. The illus- 
tration shows the equipment 
used in securing the pictures. 
The background is divided into 
six-inch squares to designate the 
height and length of the calf. 
In order to secure contrasts in 
the photographs of calves of 
different breeds, a black or a 
white background is used ac- 
cording to the color of the calf. 
The camera is placed on a 
stationary support and is situ- 
ated at a uniform height and 
distance from the background 
for each exposure. No special 
attention is given to the calf 
on the day it is to be photographed, so that 
the picture may represent its ordinary 
condition. When all preparations have 
been completed 
for the picture 
the calf is led up 
to the platform 
in front of the 
chart. When it 
reaches the cen- 
ter of the plat- 
form a helper on 
the other end 
waves a cloth or 
coat in front of it, 
just enough to 
cause the calf to 
pause and con- 
sider whether it is 
wiser to go for- 
ward or back. 
During that 
second the cam- 
era clicks. 


Popular Science Monthly 

Mr. Harold Edel, 
Managing Director 
of the Strand Thea- 
ter, New York city, 
attending to busi- 
ness in his office 
and following the 
progress of the show 
at the same time. 
At right is shown 
the details of the 
electrical devices by 
means of which the 
director can keep 
in touch with the 
stage and audience 

Directing a Motion Picture Show 
From the Manager's Office 

THE problem of keeping in touch with 
the audience and the stage while 
attending to the affairs of his own 
private office, has been solved 
in a very Twentieth Century 
way by Mr. Harold Edel, 
managing director of the 
Strand Theater, New York 
City. He sits in his office 
physically; he sits with 
the crowd electrically. 

A detectagraph leads from 
the footlights of the stage to 
a loud-speaking receiver 
mounted in a box on 
the manager's desk. 
This transmitter is like 
the concealed tele- 
phone instrument by 
means of which detec- 
tives listen to the con- 
versations of criminals. 
By the throwing of a 

switch, the director can hear the 
orchestra and the soloists as 
well as if he were one of the 

When a certain motion picture 
is scheduled on the screen, the 
director connects up the 
speedometer near him with die 
motion picture projector in the 
gallery. This meter is similar 
to those used on automobiles, 
except that it indicates feet of 
film per second instead of miles 
per hour. Hence, the director 
instantly can find out when the 
operator fails to run his picture 
at the proper speed. The opera- 
tor can then expect 
to hear from the 
d i rec tor — who 
merely speaks into 
the telephone trans- 
mitter mounted in 
the same box as the 
detectaphone re- 
ceiver. By means 
of this same trans- 
mitter the director 
can get in touch 
with any part of his 
theater when giving 
his orders to "ginger 
up" the show. 

The waterworks of the clock depend 
upon the evaporation of the water 
and the expansion of the ether vapor 

The Evaporation of Water Drives This 
Remarkable Clock 

A CLOCK designed by M. Bernardi, a 
German watchmaker, is run by ether 
and water. The driving wheel 
consists of three glass tubes 
having light glass balls fused 
to their ends. Some ether 
vapor is contained in each 
tube system. The water is 
contained in a reservoir, 
through which the balls 
pass when turning. 

An outside covering of 
cloth on the balls carries 
up a film of water when the 
balls turn out of the reser- 
voir. When water begins 
to evaporate the tempera- 
ture lowers. This lowers 
the pressure within the 
upper balls. The ether 
vapor in the lower balls 
rises upward as each cooled 
ball rises. 

Popular Science Monthly 


A Puncture-Proof, Bullet-Proof, Blow- 
out-Proof, Skid-Proof Tire 

FROM Washington there comes the 
photograph which is reproduced here- 
with, showing a Seattle citizen's ideas on 
keeping pneumatic tires out of harm's way 
and yet getting a little more service 
from them than could be obtained 
if they were locked up in a dark 
room in an atmosphere of nitro- 
gen. To accomplish his pur 
pose the inventor uses ioo to 
150 pounds (estimated) of a 
"special grade steel" for each 
tire, which might seem ex- 
cessive to the ordinary 
mind, but, having done so, 
he has the satisfaction of 
announcing that the tire by 
this heroic means is rendered 
non-skid, puncture-proof, 
bullet-proof — "of great bene- 
fit to the warring countries" — 
stone-bruise and blowout-proof 
and is endowed with four ordi- 
nary rubber-tire lifetimes. In- 
cidentally, in case that anybody 
should venture to place a wagon- 
wheel steel tire in bold competi- 
tion with his invention, he assures you that 
it will wear out three such, this referring 
perhaps mainly to a special type of his pro- 
tector which he has taken the extra trouble 
of devising for "un-inflated" rubber tires. 

Encased in this armor 
a tire should have a 
chance to die of old age 

The question arises : Given leeway to use 
100 pounds of extra material, could a tire- 
maker produce anything better than this 
protected tire? The inventor apparently 
challenges them, one and all. He bravely 
uses thirty-six steel spacers draped around 
the tire six inches apart, and on this for- 

midable base he strings about thirty 

feet of heavy coil springs and forty 
feet of lighter grade, whereas one 
lock, three clamps and twelve 
rods with threaded joints 
serve to hold the armor so 
formed tightly against the 
heaving breast of the poor 
tire, ordinarily so much 
abused. Springs are springs, 
he reasons, and keep the 
natural resilience of the 
tire unimpaired, even if 
expected to work crosswise. 
Careful inspection of his 
photograph reveals, however, 
that steel rope is used instead of 
the lighter coil spring along the 
least visible portion of the cir- 
cumference, but this is ap- 
parently an emergency arrange- 
ment for publicity purposes 

The spinal column of the whale mounted for exhibition at 
Monterey consists of forty-six sections. There are fourteen ribs 

How Monterey Turned a Whale into 
One of the City's Sights 

MONTEREY, California, 
has solved the question 
of what to do with a stray 
whale that is washed up on 
shore. After disposing of 
the flesh and oil to a refinery, 
the bones may be mounted 
on shore and kept as a 
permanent natural history 

That is what the city 
officials did with a whale 
which was washed ashore 
there. It was welcomed with 
open arms and the bones 
were saved as an educational 
feature for the benefit of the 
school children of the city 
and for interested adults. 

Since there was no build- 
ing available large enough 
to accommodate it, it was 
set up in an open lot and 
fenced in. 

What's On the Moon? 

Look through the telescope with us and see the great 
mountains, the vast dead craters and arid wastes of slag 

By Scriven Bolton, F. R. A. S. 

Illustrations specially prepared for Popular Science Monthly by the author 

SUCH is the power of our largest tele- 
scopes that a creature as large as an 
elephant might be detected on the 
moon. Hence we are more familiar with 
the lunar surface than with Central Africa. 
Since there is no appreciable air on the 
moon, our view is always clear and un- 

Why has the moon no atmosphere? 
Simply because the force of gravity is so 
small. The weight of an object on any 
planet depends upon the mass of that 
planet. On Jupiter, the largest of all 
planets, you would have difficulty in lifting 
your arm from your side. On the Sun you 
would probably need a steam crane to 
help you move about. On Mars you could 
jump over a small house. Small planets, 
including the earth, are gradually losing 
their atmosphere. The smaller they are 
the more rapid is that rate of loss. And 
since the moon is very small, it lost its 
atmosphere long ago. Thus is to be ex- 
plained the fact that the earth is still 
wrapped in air although the moon, child 
of the earth though it is, is airless. Because 
of this entire absence of air astronomers 
consider it improbable that there is any 
lunar life. Perhaps there . may be rem- 
nants of vegetation within certain low- 
lying craters and in the deepest valleys 
and chasms where a few shreds of atmos- 
phere may still pervade. But nothing of 
the kind has as yet been detected, and 
as we gaze in bewilderment into every 
crack and crevice of the surface we rightly 
conclude that the moon is a truly barren 

On Top of a Lunar Mountain 

Although we cannot fully realize existence 
on the moon, it is nevertheless the inevitable 
experience of the astronomer when tele- 
scopically raking the lunar surface with 
what might be justifiably termed an eye of 
the earth to identify himself to such an 
extent with the scrutinized scene that he 
ofttimes unconsciously thinks himself a 
lunar inhabitant. It really requires but 
little imagination to suppose oneself actually 
planted among the lunar craters and 

mountains, viewing in awe the wonderful 

Now let us endeavor to realize, by the 
help of the accompanying illustrations, that 
we have taken our stand upon one of the 
mountain peaks such as we see in these 
pictures, and by commanding an extended 
view of the surroundings we duly note the 
strange lunar conditions produced upon the 

Dawn Is as Harsh as Midday 

The lunar day is thirteen times longer 
than ours. Dawn, in an earthly sense, is 
unknown, for there is no atmosphere to 
reflect the solar beams while the sun is yet 
below the horizon. The terribly harsh 
solar beams suddenly appear on the black 
horizon, dazzlingly illuminating the moun- 
tain crests, while the valleys are still in utter 
darkness. Because there is no atmosphere, 
blending of the night into day at sunrise is 
unknown, and all the gorgeous tints which 
attend a terrestrial sunrise are on the moon 
quite absent. On earth we are accustomed 
to see the sun's light softened by an air 
screen. The fierce splendor of our luminary 
on the moon, however, is rendered more 
obvious by the blackness of the sky, owing 
to the absence of air. Even in broad sun- 
shine the sky is as dark as our darkest star- 
light nights, with the stars and planets 
shining more brightly than it is possible to 
see them here. The appendages to the 
sun, such as the Zodiacal Light, the Corona, 
and the red protuberances, appear in 
glorious perfection. 

What a magnificent object is the earth, 
thirteen times larger than the moon 
appears to us, and practically stationary in 
the heavens! It exhibits phases precisely 
as does our moon, the interval between each 
full "earth" being about twenty-nine days. 
The sublime and periodical spectacles of a 
total solar eclipse and an eclipse of the 
"earth" are attended by circumstances far 
more imposing than their earthly counter- 
parts. The spectator sees the earth-globe 
rotating on its axis, the continents, oceans, 
and polar snow caps being well displayed. 
Portions of the surface appear inter- 


How the "Full Earth" Looks from the Moon 





The long lunar night, which comprises thirteen of our nights, is substantially relieved by the 
reflected light of our globe, which at full "earth" radiates thirteen times more light than the 
moon does to us. The landscape depicted here is characteristic of many regicns on the moon, 
showing the surface strewn with volcanic craters varying in size from a few hundred feet to 
many miles in diameter, some possessing a central cone. The moon swarms with these objects 



Popular Science Monthly 

An isolated mountain at the north terminus of the Apennines. Rising 15,000 feet above the 
plain it is but one of scores of similar solitary peaks, the sublime grandeur of which cannot be 
overestimated. Even at midday the sky is darker than on our darkest starlight nights, with 
the stars and planets shining brighter than it would be possible to see them from our earth 

mittently obscured by slowly-moving white 
vapor in the terrestrial envelope, lying 
usually in long streaks roughly parallel to 
the equator. 

The Terrible Desolation of 
the Moon 

And now assuming that we have planted 
ourselves upon a more elevated portion 
of the moon, our attention, which has been 
directed to the sky, is now concentrated 
upon the surrounding landscape. We be- 
hold everywhere a scene representing the 
wildest desolation. The shadows assume 
total blackness and appear quite im- 
penetrable to one's vision ; for absence of an 
atmosphere means no diffusion of light. 
In stepping behind a bowlder or any other 
part which does not receive the direct rays 
of the sun, one becomes invisible. Volcanic 
cones, ranging in diameter from a few 
hundred feet^to many miles, literally crowd 

the surface as far as the eye can reach. At 
a distance of forty miles or so the summits 
of a gigantic mountain range are seen 
peering above the horizon, and as clearly 
defined as the adjacent neighborhood. It 
is difficult if not nearly impossible to pass 
correct judgment on the distance of the 
various features owing to the lack of aerial 
perspective. The region close by is seen to 
be composed chiefly of hills of volcanic 
debris, rocks, bottomless pits, yawning 
crevasses and piles of slag — doubtless a 
scene of inconceivable commotion in ages 
antedating mortal history, but now a world 
devoid of sound or disturbance, and minus 
evidence of organic life. Indeed we realize 
that we are in touch with a world which is 
typical of a dream of lifelessness, an 
apparition denoting not death, but a world 
upon which life has never appeared. No 
atmospheric elements have been at work to 
tarnish the pristine hues of many parts 

Popular Science Monthly 


The Valley of the Alps. This flat-bottomed valley is over 70 miles long and is about 6 miles 
wide at its broadest part. It is bordered by majestic and precipitous mountains, the peaks of 
which attain an altitude of 9,000 feet above the valley. Rugged hills in the immediate vicinity, 
as shown in the foreground, indicate piles of slag. A scene of dreary desolation, even with the 
noon sun shedding its overpowering light, although at some very remote epoch one of incon- 
ceivable commotion. The entire region appears to have passed through the fiery furnace 

which bear every evidence of having passed 
through a fiery ordeal. The entire surface 
is one of dreadful contrast; the dazzling 
brightness of the landscape compared with 
the hard black shadows; the black sky, 
even at noon, with the sun shedding a 
ghastly overpowering light; these condi- 
tions, together with no trace of life, form a 
scene of dreary desolation, but nevertheless 
one of sublime grandeur. 

The Deathly Silence of the Moon 

Although the sun pours his heat upon the 
surface throughout the long lunar day, 
which comprises over three hundred of our 
days, yet the rocks remain too cold to 
touch with safety. Everywhere there 
reigns the silence of death. Occasional 
landslides, cracking of the surface and 
shrinkage commotions, dislocation of piled 
up volcanic debris, all occur without an 
attendant sound. Because there is no air 

we cannot hear. Ten thousand volleys 
might be fired instantaneously, with a 
resultant vibration of the ground, but the 
prevailing silence would remain unbroken. 
It is indeed a world possessing conditions 
just the reverse of our own. Imagine there 
to be no water, no air, nothing to sustain 
life for a single instant! 

We see a world of mystery and destruc- 
tion, riddled as is its surface with volcanic 
formations representing primeval forces, 
but maintaining their original charac- 
teristics and freshness owing to the absence 
of disintegrating elements. Nevertheless, 
it teaches one grand lesson in that it "exalts 
our estimation of this peopled globe of 
ours," writes Carpenter, "by showing us 
that all planetary worlds have not been 
deemed worthy to become the habitation of 
intelligent beings." So we mentally "come 
back to earth," perfectly content to have 
taken only an optical flight to the moon. 


Popular Science Monthly 

Any venturesome flies seeking to enter 
when the door is opened will be blown 
away by a blast of air from the fan 

Keeping Out Flies When You 
Open the Door 

A DOOR-OPERATED fan which drives 
away venturesome flies has been 
brought out by Joel J. Hurt, of South 
Omaha, Neb. The bracket holding the fan 
is attached to the door jamb at the top of 
the door. The gear of the fan en 
gages the driving gearing 
mounted on another shaft. 
This driving-gear shaft car 
ries a small pulley on its 
lower end. A flexible 
cable wound upon this 
pulley is attached to 
the door. When the 
door is opened the 
unwinding of the ca- 
ble operates the fan. 
The gearing is made 
high so that the fan 
is whirled rapidly. 

An automatic 
clutch disconnects 
the fan from the pul- 
ley when the door 
is fully opened. Mo- 
mentum keeps the 
fan rapidly turning 
until the door is 
closed. A strong 
spring, which was 
wound up with the 
opening of the door, 
causes the door to 
close automatically. 

If Your Parrot is Thirsty, Give 
Him a Drink 

THERE is a curious superstition ex- 
istent among parrot-keepers," says 
L. S. Crandall, in Pets (Henry Holt & Co., 
New York), "to the effect that these birds 
not only require no water but are better 
off without it. The foundation for this 
absurd belief is not hard to find. When 
parrots, particularly young birds, are being 
brought from the tropics, they are custo- 
marily fed on boiled corn or bread and 
milk. What moisture they require is ob- 
tained from the food. If such birds are 
suddenly given access to unlimited water, 
the effect on the digestive organs is danger- 
ous, and may result in the death of the bird. 
On the other hand, if the parrot be given 
a drink daily, and then the water be re- 
moved for a short period, the bird will 
gradually become accustomed to it. Once 
this is accomplished, there is nothing to 
fear from clean water." 

Carrying the temple through the streets of 
India. During the month of February it 
is in great demand for wedding celebrations 

An Accommodating Church — It 
Goes Wherever It Is Wanted 

IN India and in some places of the New 
World, particularly in the British West 
Indies, many religious festivals are held 
along the roadside and in the 
open fields during the month of 
February, which is the 
month of weddings and 
special feastings. 

On such occasions the 
participants in the 
ceremonies do not go 
to church. The 
church comes to 
them. Ornate struc- 
tures of papier 
mache are used for 
the purpose, and 
these traveling 
temples are drawn 
through the streets 
and country roads 
by religious devo- 
tees, who will stop 
when called upon 
and hold a service 
or deliver prayers 
for a small sum. 

Such temples take 
a conspicuous part 
in all parades and 
religious celebra- 

Popular Science Monthly 


One Horsepower Will Run All 
the Watches in the World 

AN astute French mathematician 
l\ has found that in certain 
watches the motions exceed two 
hundred million a year in little 
equal jumps. In the same time the 
outside of the average balance 
travels seven thousand five hundred 
miles. Yet despite this astonishing 
distance traveled by the ordinary 
watch the amount of power con- 
sumed is trifling. One horsepower 
is sufficient to run two hundred and 
seventy million watches. This is 
probably all the watches that are in 
existence. But if there should be 
more there would be enough power 
left in the one horsepower to run 
an additional thousand watches 

A self-contained motor-truck equipped with standard 
electric street car trolley pole and a storage battery 

The Latest Conceit in Timepieces — A 
Buttonhole Watch 

IN spite of the fact that there is no article 
of jewelry more useful than the watch, 
it seems hard to stow it away in a suit of 
clothes. It has been tucked away in vest 
pockets and belts, attached either to an 
ornate chain or an inconspicuous ribbon, 
and has adorned the wrists of all classes. 

But the very latest and most con- 
spicuous location yet chosen for it is 
in the buttonhole of a coat lapel. 
The buttonhole watch is nec- 
essarily tiny, and fits into 
gun metal case which i 
sembles a large-sized collar 
button in shape. When 
worn merely for the con- 
venience of the owner 
the watch is usually 
turned upside down so 
that the time may be 
seen at a downward 
glance, without even 
lifting the lapel of 
the coat. 

It is said that the 
diminutive size of the 
watch does not interfere 
with the accuracy of the 
works. The principal ob- 
jection to wearing one of 
them just now is that the 
buttonhole is needed for 
flag emblems and liberty 
bond buttons. 

Making a Trolley-Car of the 

WHY can't motor-trucks and other 
commercial vehicles obtain their 
power from overhead trolley wires? So 
they can, if reports from Bradford, England, 
are true. 

In Bradford a motor-truck with a trolley 
pole attached to its cab takes power from 
overhead street car wires. The 
truck runs along on the street-car 
tracks, contact with the rails 
being made by means of a cast- 
iron block to the steering gear. 
This block also steers the 

When the truck reaches 
the end of the street-car 
tracks, the rail con- 
tactor is lifted, the 
trolley pole pulled 
down, and the stor- 
age battery is 
brought into action. 
The truck then con- 
tinues on its way as a 
self-contained vehi- 
cle. The motors are of 
twenty horsepower. 
The battery is arranged 
so that it can be charged 
with street car current 
when the truck is run- 
ning. On one charge of 
thebattery the truck can 
run for about ten miles. 

The buttonhole watch fits into a case 
resembling a large-sized collar button 

Popular Science Monthly 

Device to Remove Automobile Bodies 
Without Scratching Them 

TWO men can remove a highly-polished 
automobile body from its chassis 
without giving its surface a scratch, by 
means of the device shown in the accom- 
panying illustration. 

This new device is attached to an over- 
head trolley. It con- 
sists of two sets of ^Hum 
compass-like arms 
pivoted to the ends of 
a common cross- 
member at the top. 
The arms of each 
set may be spread 
out to reach the 
front and rear ends 
of the body in 
exactly the 
same manner 
as a compass is 
opened by 

Lifting an 
by means 

At left is 
a diagram 
of the 
5et screw 


means of a rack and quadrant device. 
Each of the arms is made with a telescop- 
ing bottom for adjustment to the various 
types of bodies. Loose collars with two 
projecting arms are slipped over the bottom 
of each arm to reach underneath the side of 
the body and support it at unpolished 
points. The looseness of the collars 
enables them to be turned in any direc- 
tion or moved up or down to obtain the 
proper point of support. 

In operation, the framework carry- 
ing the lifting device is moved along 
its trolley so that the compass arms 
are on each side of the body to be 
lifted off the chassis. The arms are 
then spread out and the lifting collars 

levers. It is then moved horizontally to 
its point of deposit. The reverse of this 
operation puts the body back on the 

Sometimes the body must be lifted clear 
off the chassis frame for a height of two or 
three inches before the projecting arms on 
the lifting collars can be placed on some 
unpolished part. This may be accom- 
plished by 
means of a two- 
part bar with 
beveled ends, 
which bar is 
held together 
at the center 
by means of a 
collar or sleeve. 
By removing 
the floor- 
boards of the 
car body, the 
beveled ends of 
the bar may 
be inserted 
between the 
bottom of the 
body sill and 
the frame. 

automobile body off its chassis 
of compass arms on a trolley 

An Automatic Revolver No Bigger 
Than Your Watch 

AUTOMATIC revolvers are made about 
l\ as big as a standard watch. 

Little as these revolvers are, they never- 
theless contain an automatic reloading 
mechanism as complete as that of any of 
their bigger brothers. They are "seven- 
shooters." Six cartridges are held in the 
magazines in the handle, and one in the 
firing chamber. The pressing of the trigger 
sends the firing-pin against a tiny percussion 
cap. The bullets are one-tenth 
jtgfg^^ inch in diameter 

and weigh 
i/i oo 

adjusted and inserted under the body; 

after which the entire device is raised 

vertically by means of a chain block, ' In a half inch of space across the breech> this revoIver 

until the body clears the projecting contains a complete automatic reloading mechanism 

Popular Science Monthly 


A Small Sand Spreader Is Useful 
All the Year Round 

THE small two-wheeled bin device 
shown below is particularly adapted 
for spreading sand over small areas such as 
icy cross walks in the winter or over oily 
streets, or for scattering fertilizer in the 
summer. The sand is spread uniformly 
with no bare spots or large piles, 
hence this is preferable to the 
hand method. The device 
also applicable to the spread- 
ing of ashes over country 

The apparatus con- 
sists of a funnel-shaped 
bin mounted on an 
axle with two wheels 
and provided with 
front and rear handles 
so that it may be pushed 
along from either end. 
A vertical rectangular open- 
ing is provided at the bot- 
tom of the bin with a slide- 
door through which the 
sand or other material to be 
spread drops upon a circu- 
lar horizontal plate held in a 
vertical shaft on a frame 
attached to the axle. The 
circular plate is directly beneath the bin 
opening and is provided with curved 
radiating fins. The plate is revolved 
at a speed varying with that at which 
the cart is pushed by means of a set 
of bevel gears and a chain driven off a 
large sprocket on one of the wheels. The 
sand dropping on the plate is thrown off by 
centrifugal force when the plate auto- 
matically revolves as the cart is 
pushed along. In this way the 
sand or fertilizer, or whatever 
may be the contents of the bin, 
is distributed evenly whether the 
cart is pushed slowly or rapidly. 

The Newest Child's "Pushmobile." 
It Is Built on a Novel Principle 

A CHILD'S hand -propelled pushmobile 
has been invented by Charles R. van 
Horn of Aberdeen, Wash. The lower end 
of the operating lever is coupled by two 
connecting rods with the gearing that 
drives the rear wheels and propels the 
vehicle. The connecting rods are 
attached to the lever at different 
points; they also engage the 
first gear wheel at different 
portions. Hence, any 
dead center is eliminated. 
Whatever its position, 
the lever will immedi- 
ately start the vehicle 
when any pres- 
sure is exerted on 

A child can drive this 
ingenious vehicle with 
one hand. The diagram 
at the right explains 
the principle involved 


Drive sprocket 

Steering wheel 

The funnel-shaped bin with its circular plate 
underneath, spreads the sand automatically 

A child can drive this machine with one 
hand. The steering is controlled by a 
rotatable handwheel mounted on the pro- 
pelling lever. Two flexible cords connect 
this steering-wheel with opposite portions 
of a cross member attached to the mounting 
of the front wheel. The propelling lever is 
not tilted from side to side like a tongue but 
always moves in a straight forward-and- 
back direction lengthwise of the platform of 
the pushmobile. In fact, this steering wheel 
is operated likethatof an automobile, so that 
the child in learning to drive the toy. push- 
mobile is really trained to govern a big car. 

For coasting, the gearing can be shifted 
out of operative connection with the 
propelling lever, the coasting device being 
regulated by the child's foot. 

As an exerciser, this form of vehicle leaves 
nothing to be desired. Practically every 
muscle of the child's body is brought into 
action — notwithstanding the fact that the 
operation is smooth and easy. Naturally, 
the faster one wishes to go the more effort 
must be expended. 


Washing the gold-containing gravel through 
a sifter which serves at other times as a hat 

Panning for Gold in Central and 
South America 

THE "battel" used by the prospector for 
gold in Central and South America 
in tropical placer mining is a better gold- 
saver than the Alaskan gold pan. Shaped 
like a platter, with a 
depressed center 
coming to a point 
in the middle, the 
gold collects in the 
point of this broad 
shallow cylinder. 
The pan is filled 
from a pool with 
quartz gravel and is 
rocked in the ortho- 
dox manner. As the 
pan rests on the bot- 
tom the contents are 
tipped and swirled 
about until the dirt 
loosens and only the 
pure gravel and hard 
substances remain. 
Of these, only that 
which is bright yel- 
low is valuable. 

When the miner 
is not sifting gold 
with it he uses his 
battel as a hat. — 
Grace S. Mathews. 

Popular Science Monthly 

Everybody Is Acquainted with 
the Squash Bug 

SOME of us know all the bad things 
about the squash bug — that it is 
proverbially ill-favored and ill-smelling 
and an enemy to the squash vines. We 
have heard the entomologist speak about 
Anasa tristis with elaborate description of 
the bug that hibernates in the adult stage, 
wakes up in the early spring and lays its 
eggs on the young leaves of the squash 
and the pumpkin. We think of it as we 
think of a pest. From the human point of 
view it is a pest, but it improves on ac- 
quaintance. It is true to its family char- 
acteristics; it is really a bug; it is a member 
of the family Heteroptera, and is somewhat 
of a beauty (we mean the "lady-bug"). 

In the accompanying photograph the 
protruding part of the sheath is the tongue 
or sucking beak. The squash bug's eyes 
are large and beautiful, and really wonder- 
ful when seen under a microscope. The 
antennae or feelers, the two branched 
prongs between the eyes and the tongue, are 
marvelous organisms of sense. It would be 
difficult to enumerate all their duties, not 
because the list is long, but because we do 
not wholly know what those duties are. 
They surely enable the bug to recognize its 

surroundings; what 

else they do is be- 
yond our under- 

But the most 
beautiful of all its 
anatomy is the curi- 
ously mottled sheath 
that covers the head 
and the thorax. 
These dots bear a 
high magnification, 
and the better one 
knows them the 
more does he admire 
them. It is indeed 
a marvelous object. 
It is astonishing that 
there should be so 
much beauty, so 
much elaborate 
structure where 
they seem misplaced 
so far as general 
human apprecia- 
tion is concerned. 
— E d w A R d F. 


Portrait of a squash lady-bug. The protuber- 
ances at the side of the body are the eyes 

Popular Science Monthly 


They look like 

Giant Mushroom Anchors for 
Holding Buoys 

MUSHROOM ' ' anchors take their nam 
from their shape, 
mushrooms upside down. 

The mushroom anchor illustrated 
was made by a prominent cast-steel 
maker of this country for use by 
the United States Department 
of Commerce in lighthouse 
service for buoys. Those 
of this type weigh 5000 
and 7000 pounds each and 
are made entirely of cast 
steel except the shackle 
pin. They are practically 
one piece. The buoys are 
attached to these. The 
anchor holds the buoy in 
the location desired. 

The test to which these 
anchors are subjected be- 
fore acceptance by the 
Government is extreme- 
ly severe. Each anchor 
is dropped on a steel 
block from a height of 
twenty-five feet. 

Should a fracture of 
any kind appear as a 
result of this test the 
anchor is rejected. 
Formerly these anchors were made of cast 
iron but the Government's requirements 
now demand steel because of t the severe 
treatment to which they are subjected in 
rough weather. 

The Rate at Which Food Prices 
Have Advanced 

HOW much has the cost of food ad- 
vanced? According to one of the 
leading statistical houses of America, cab- 
bage has gone up 850 per cent since last 
year; onions, 

1,100 per 
cent; pota- 
toes, 280 per 
cent; eggs, 77 
per cent; beef, 
20 per cent; 
pork, 70 per 
cent; butter, 
30 per cent; 
wheat and 
flour, 46 per 
cent; beans, 
90 per cent. 


•-gk -ml ^^ Air tut 

(J \J XJ •« 


The brass and wind instruments in the orchestra are played by 
compressed air instead of lung power and operated by one man 

The Compressed- Air Orchestra: 
Human Lungs Give Place to Tanks 

IF the inventors have their way, musicians 
will no longer need to blow their souls 
into their instruments. The inflated 
eye-ball, the puffed cheek, and all the 
laugh-inducing mannerisms of the 
men who play the wood and brass 
instruments will become as history. 
The flute will chirp, the saxophone 
grunt, the bass horn growl, without a 
musician's mouth at a single instru- 
ment. Human lungs will not be need- 
ed ; compressed air furnished by a mo- 
tor and a pump will take their place. 
The air, after being stored in a tank, 
as shown at the right of the illustra- 
tion below is led through a pipe to the 
music stand and thence through an air 
tube to the mouth of the instrument. 
The musician takes his accustomed 
place in front of his instrument, with 
his foot on the air- 
control pedal at the 
bottom of the 
stand. He plays 
with his hands and 
one foot. The air- 
control pedal works 
like the accelerator 
of an automobile 
engine; it enables 
the musician to accurately regulate the 
supply of air at all times. 

The inventor does not make any pro- 
vision for tone shadings. Although he can 
regulate the supply of air he can not give 
delicate gradations of expression. Conse- 
quently, music from instruments played by 
compressed air will be more or less mechan- 
ical. Moreover some brass and wood 
instruments must be played by living 
men, because the notes are formed by the 
lips. But for certain well-defined purposes 
and in places where the audiences are not 
the compress- 
ed-air orches- 
tra will prob- 
ably prove as 
popular as 
the mechanic- 
ally operated 

In this way 
one musician 
can operate 
several in- 

Mushroom anchors are used in the lighthouse 
service to hold buoys in place. They con- 
tain from 5000 to 7000 pounds of steel each 

Five Tools in One 

Here is a combined spade, knife, pick- 
axe, hammer and trench weapon 

A TOOL which permits of a wide 
variety of uses has been invented by 
Dr. F. P. Archer, of Wilkes-Barre, 
Pa., and could with advantage take its place 
beside the other necessary equipment of the 
fighting man. A modern army must not 
only be equipped, each man individually, 
with practically every necessity for fighting 
and for health and comfort that space will 
permit, but it must be equipped with tools 
to dig itself into the ground when necessary. 
The tool invented by Dr. Archer may be 
used as a spade, a knife, a pick-axe, a 
hammer and a weapon for hand-to-hand 
fighting or trench raiding. The blade of 
the spade is carried in a pocket across the 
breast, as shown. Carried in this position 
it is a shield protecting more than twenty- 
five per cent of the vital anatomy of the 
wearer while facing an enemy bayonet 
charge. On the other hand, it is made of 
chrome nickel steel 

so tempered that it ^^^^^ 

will resist a service 

Here the combination tool-weapon-shield 
is a peaceful-looking hammer-headed spade 

rifle bullet at two hundred yards and will 

be ample protection from a forty-five 

caliber revolver bullet at close range. 

The entire outfit, including the pocket, 

weighs only four and one half 

pounds. The spade shield is 

the heaviest part of 

the equipment. 

The spade blade 

can be attached to 

the handle 

of the tool 



Popular Science Monthly 


Coaxing Music from 
a Pile of Rocks 

AMR. FROST, of Mar- 
blehead, Mass., was en- 
gaged in clearing his land 
of some huge, flat rocks, 
when he accidentally struck 
one with his hammer. It 
emitted a clear musical note. 
He struck another in the 
same way. The tone given 
out was equally clear and 
sweet but different in pitch. 
Trials with other stones of 
different shapes and sizes 
convinced him that it was 
possible to arrange the stones 
so as to get the notes of the 

After various experiments 
he piled the stones as shown 
in the accompanying photo- 
graph, securing thus a primi- 
tive instrument that any cave-man might 
have envied. 

Household Bookless Bookkeeping 
on the Poker-Chip Principle 

ANEW system of bookless bookkeeping, 
designed especially for the housewife, 
happily coincides with the demand for 
careful record keeping in order to cut down 
expenditures to a wartime basis. This 
new system substitutes for old fashioned 
juggling with figures the simplicity and 
vividness of account-keeping with poker 

With the new method, books are entirely 
eliminated. The equipment con- 
sists of a box containing twenty- 
eight compartments to show ex- 
penditures for groceries, meats 
milk, butter, eggs, and 
other items of house- 
hold expense, and 
seven additional com- 
partments to hold slips 
representing various 
denominations from 
ten dollars down. 

When a purchase is 
made, slips indicating 
the amount are placed 
in the appropriate 
compartment. At the 
end of the month, the 
housewife can determine 
the amount soent for 

The "piano" made of a heap of stones (arranged so that the 
tones of the natural scale are produced by hammer-blows 

each item by counting the amounts, in the 
different compartments. 

If the article is charged, the right amount 
is placed in the proper compartment, and a 
corresponding amount in the "Charged" 
compartment. Thus there is a correct 
tab on the amount owed as well as on 
the expenditures. 

After the housewife has determined by 
a two or three months' trial about what 
her normal expenses are for the various 
items of expenditure, she may change to 
the budget system. Slips totaling the 
proper amount are placed in the various 
compartments, and, as expenditures are 
made, the amount is removed. The slips 
remaining show at all 

times the sum left in 
each "appropriation," 
so that economy or 
freedom in spending 
may be observed. If 
the slips in any com- 
partment run short, 
others may be "bor- 
rowed" from a com- 
partment with a sur- 
plus, a "due" check 
being put in to show 
the indebtedness. 
The amounts remain- 
ing at the end of the 
month indicate the sur- 

plus, and the due checks 
The bookless bookkeeping outfit for the shortages. Thus all 
housewife who dislikes keeping accounts figuring is eliminated. 


Popular Science Monthly 


Smoke inlet valve 

Device for forcing 
smoke through tube 

Rubber bulb ' x Smoke outlet 


The dummy smokes a real cigarette in a 

realistic manner. Smoke is drawn in through 

one tube and is forced out through another 

The Dumb Turk. He Smokes Cigar- 
ettes and Doesn't Know It 

A DUMMY who smokes cigarettes as 
realistically as a living human being 
is now used to advertise the fragrant aromas 
of different grades of tobacco. The idea is 
not to show the public how well a cigarette 
burns or how well the dummy smokes it, 
but to enable smokers to smell the smoke as 
it is automatically puffed out by the ap- 
paratus concealed within the dummy. 
The moment cigarette smoke is drawn into 
the mouth it loses its odor. With 
the dummy none of the frag- 
rance is lost. . 
There are two tubes within § 
the dummy. One leads to 
the cigarette in the dum- 
my's mouth and thence 
to a bulb. A second tube 
extends from the bulb to 
the mouth. The smoke is 
drawn in through the first 
tube and through a valve 
into the bulb. When the 
bulb is pressed the smoke is 
forced into the second tube 
and led to the mouth, where 
it is expelled. A small mo- 
tor operates the bulb. It 
is regulated so that the 
dummy can smoke fast or 
slow as the exhibitor desires. 

The annular rubber pad com- 
pressed between the base of 
the tire and the steel felloe 
band locks the tire in place 

An Easily Adjusted Tire. It Locks 
Itself on the Wheel 

ANEW type of tire just brought out by 
an Akron manufacturer is designed to 
eliminate the trouble experienced in mount- 
ing either a demountable or pressed-on 
solid tire on the wheel of a motor-truck. 
It employs the compression of an annular 
rubber pad between the steel base of the 
tire and the steel felloe band on the wheel 
to lock the tire on the wheel. The annular 
ring or pad of rubber is about one inch 
thick and is the same width as the tire 
proper. This rubber pad is inserted between 
the steel base of the tire and the steel felloe 
band on the wheel. The pad is retained by 
two steel rings, one on either side, bolts 
extending clear through the pad from one 
ring to the other. Twelve of these bolts are 
employed, each with a nut on the outside of 
the wheel. As these bolts are screwed down 
by means of a socket wrench, the width of 
the rubber pad is decreased while its thick- 
ness is increased. 

This swelling of the pad exerts pressure 
on both the base of the tire and on the steel 
felloe band, serving to lock them together 
and make them revolve as a unit. The tire 
is removed in a few seconds time by merely 
loosening up the twelve bolts and permit- 
ting the pad to assume its natural thick- 
ness. Then the tire is simply slid off the 

Aside from the characteristic of easy at- 
tachment and removal, the pad also serves 
as a cushion to the tire itself, tending to 
reduce the road vibration transmitted to 
the wheel, axle and driving mechanism. 
Other claimed advantages for the pad 
that it permits greater truck 
speed without harmful effect, 
greater tire mileage and abil- 
ity to wear the tires down 
nearer the base, all because 
of the greater resilience of 
the wheel as a whole due 
to the increased amount 
of rubber between the 
axle and the point' of con- 
tact with the ground. 
In application, tires of 
the next larger size or two 
inches greater in diameter 
are employed. In this way 
wheels of the same size as 
those on which the ordinary 
tires are pressed maybe used. 
The pad also prevents the sur- 
faces from rusting together. 

Closing Up a Wound Without Using 
a Surgeon's Needle 

ANEW method of drawing together 
the parts of a wound so as 
give Nature a chance to knit 
them permanently together 
again, eliminates the sur 
geon's needle, together 
with the pain of the 
sewing-up process. In 
this new method 
a lacing plaster 
is used, a strip on 
each side of the 
wound. After the 
wound has been 
cleaned and dressed, 
the plaster is ap- 
plied, one strip on 
each side of the cut, 
with the edges of the 
plaster about one- 
quarter of an inch 
from the edges of the 

Loops of thread, like a 
scalloped edging, are pro- 
vided in the plaster to 
receive the lacing, which 
is stiffened and used with- 
out a needle. The ends 
of these scallops are 
woven into the material 
so that they will not pull out. When the 
thread has been looped through opposite 
scallops in the sections of the plaster, the 
loops are drawn up, thus gently 
closing up the gap in the torn 
flesh. The wound is left 
exposed to the air through 
the threads, so that it 
may be drained and ex- 
amined occasionally with- 
out disturbing the ar- 
rangement of the plaster. 

If a dressing of gauze is 
used, it may be changed 
when desired without re- 
moving the plaster. The 
threads are clipped and 
removed, leaving the wound 
exposed for the treatment. 
Afterwards the plaster is 
laced again with fresh 
thread. One application 
of the plaster strips is 
usually sufficient for the 
entire period of healing. 

Popular Science Monthly 

Pretty Maids" of a 
Window Garden 



Lacing the plaster over a wound. The 
edges of the cut are gently drawn to- 
gether and held in place until healed 

How the "pretty maids" 
of a Chinese garden grow 
their verdant costumes 

MARY, Mary, quite contrary, 
does your garden grow?" 
"With tinkle bells and conchal shells 
and pretty maids all in a row." 
So goes the English nursery 
hyme,but it remained for the 
Chinese to make a practical 
application of the idea. 
The two photographs 
below show how the 
pretty maids are made 
to grow in the minia- 
ture flower gardens 
of China. But any 
little American girl 
may do the same 
thing with the head 
and arms of an old 
discarded doll. 
First an ordinary 
flower pot is filled 
with soil. Into the 
center of this is thrust a 
stick about ten or twelve 
inches long. To this 
other sticks are tied (ar- 
ranged as shown at left 
in the illustration) in 
order to give breadth to 
the lady's skirt when she 
is dressed in her verdant 
costume. The head of the doll should be 
fitted securely on these sticks, and the arms 
should be fastened with twine or wire. 

Plant in the soil a few seeds 
of dwarf nasturtium, morning 
glory or any small creeper 
and keep them well 
watered. As the plants 
grow up, train the shoots 
on the framework of the 
doll and pinch them off 
as soon as they reach the 
neck in order to cause a 
thicker growth at the 
sides. Soon the entire 
frame will be covered, 
and the lady will be 
gorgeously attired. But 
in order to keep her 
looking her very best 
continually, it will be 
necessary to keep the 
vines closely cropped. 
Ornamentation is pro- 
vided by the blossoms. 

Mollycoddling the Microbe 

Some of the deadliest germs are very deli- 
cate and require plenty of milk and eggs 


HINK of cultivating deadly germs, 
the typhoid bacillus, for instance 
with as much 

care and attention to 
diet and environment 
as would be given to a 
delicate orchid or even 
to a beautiful baby! 
That is what is being 
done at the American 
Museum of Natural 
History in New York 

tjp in one of the 
tower rooms there is a 
regular nursery for 
germs. They live in 
tubes, rows on rows of 
them, in neatly ar- 
ranged and classified 
wooden racks. Each 
tube contains a jelly, 
and on top of this 
jelly is a wrinkled 
mass of whitish, yel- 
lowish or brownish scum. In this scum are 
the babies — or plants, as the Museum 
bacteriologist classifies them. 

The jelly is made up of meat, peptone, 
and the extract from agar, a Japanese sea- 
weed. Some of the germs, however, are 

fastidious and require egg; others must 
have blood; still others need milk and 
special kinds of 
salts. The food 
preferences of each 
particular germ are 
as carefully studied 
and compounded as 
are the special 
dishes in the diet 
kitchen of a hospi- 

Some of the 
bacteria will live 
for weeks without 
special attention, 
while others must 
be transferred to a 
fresh tube of food 
jelly every three 
days. To transfer 
them, the bacteri- 
ologist in charge 
simply touches the 
scum in the tube 
with a platinum needle. The bacteria 
adhere to the needle but readily drop off 
into the fresh jelly. The fact that 400,000,- 
000 of the typhoid bacilli could be packed 
into a grain of granulated sugar will give 
some idea of the size of the microbes. 

Needless to say, the germ-filled tubes are han- 
dled with extreme caution by the examiners 

JI I All 

hi ail 

IS \\ JSf 

^f ^^ 



1 » 


© Phot 

In the yellowish, whitish or brownish scum which is to be found in each of the tubes there 
are millions of infinitesimal microbes feasting and flourishing on the food jelly of their choice 


Popular Science Monthly ■ 271 

Put Your Flowers Outdoors on This per cent of their passenger cars and two- 
Adjustable Window Shelf ten A th 5 Pf cent of th . eir fu r 11 equipment. 

A field army consists of three infantry 

ITH a new adjustable window-shelf divisions, one cavalry division and a 

invented by Earle H. Bartlett, of brigade technically known as a brigade 


Kansas City, Missouri, flower 
pots can be placed outside the 
windows with perfect safety, 
provided city ordinances al- 
low it. • 

The shelf permits the window 
sash to be raised or lowered. 
Besides, it can be attached to 
ledges or stools of various 
sizes, a bracket support 
compensating for different 
widths and maintaining 
the shelf in the proper 
horizontal position. The 
shelf is fastened to the 
window ledge by screws 
and a metal strip so 
that the window-sash 
can be raised without 
striking it. 
To support 
the front por- 
tion of the 
shelf there is 
a brace or 
bracket with 
a wing-bolt 


and slot connection, as the illustration 
shows. This arrangement allows the shelf 
to be adjusted up or down to fit the different 
widths of ledges, a plate on the bottom of 
the shelf being rigidly secured when the 
wing-bolt is turned. 

of field army troops 
— troops auxiliary to the 
infantry and cavalry di- 

Railroad equipment re- 
quired to move various 
organizations of the army 
at war strength is as fol- 
lows: Infantry regiment 
— 55 officers, 1,896 men, 
177 animals, 22 vehicles — 
total of 85 cars. Cavalry 
regiment — 54 officers, 
1,284 men, 1,436 animals, 
26 vehicles; 150 cars. Ar- 
tillery regiment — light — 
45 officers, 1,170 men, 
1. 1 57 animals, 32 vehicles, 
24 guns; 170 cars. Artil- 
lery regiment, horse — 45 
officers, 1,173 men, 1,571 
animals, 35 vehicles, 24 
guns; 194 cars. Artillery 
regiment, mountain — 45 
officers,- 1,150 men, 1,229 
animals, 24 guns ; 124 
cars. Engineers, pioneer 
battalion — 16 officers, 502 men, 165 ani- 
mals, 12 vehicles; 38 cars. Signal corps, 
field battalion — 9 officers, 171 men, 206 
animals, 15 vehicles; 28 cars. 

An adjustable window 
shelf which can fit any 
ledge and be kept in the 
proper horizontal position 

Figures That Give an Idea 
of the Task of Trans- 
porting Our Armies 

SOME idea of the enormity 
of the task of moving the 
great bodies of United States 
troops to be raised may be' 
gained from the following fig- 
ures: 6,229 cars are necessary 
to transport an army of 80,000 
men. These cars would be made 
up into 366 trains with as many 
locomotives. There would have 
to be 2,115 passenger coaches, 
385 baggage, 1,055 box, 1,899 
stock and 775 flat cars. 

This quantity of equipment 
represents seven - tenths per 
cent of the locomotives owned 
by American railroads, 4.2 

Can you tell at a 
glance what is wrong 
with this soldier ? 

A Sculptor's Error in a Famous 
Military Group 

WHENEVER there is a 
military parade in Wash- 
ington, D. C, and the soldiers 
or others who have had mili- 
tary experience are in the 
vicinity of the magnificent 
statue of General Sherman, 
which stands just south of the 
Treasury, there is sure to be 
comment on the blunder which 
the sculptor made in connec- 
tion with the equipment of the 
figures at the base of the statue. 
The blanket roll, which is prop- 
erly carried over the left shoul- 
der by soldiers, is here shown 
over the right shoulder, where, 
as even the small boys know 
nowadays, it would interfere 
with the gun. 

Delivering Ice Cream by Motor-Truck 

The truck is fed ice and salt in much the 
same way that a locomotive is fed coal 

ANEW type of body fitted on a 
motor- truck is designed to save 
time in the delivery of ice cream at 
retail. It has separate compartments for 
the ice cream in cans, for the mixing ice 
and for the salt. 

The compartment nearest the driver's 
seat is used to carry eighteen of the con- 
ventional ice cream cans packed in ice 
and salt in the usual manner. The ice 
compartment, of the same width and about 
the same length as that in which the cans 
are carried, is extended down at the rear 
to a point about one foot from the ground. 
It has a sloping false bottom which permits 
the ice carried therein to move to the 
bottom of the rear end by gravity while 
the truck is in motion, where an adjustable 
slide is provided to regulate the amount 
working to the rear. A hinged door is 
provided at the bottom of the rear end 
through which the ice may be taken out 
by means of a shovel. 

At the right rear side of the ice com- 
partment there is another smaller one 
extending to the top and slightly less 
than half the width. Into this the salt is 
poured through an opening in 
the top. It has a false 
bottom and a discharge 
pipe at the bottom and 

a door at the rear by which the salt can 
be taken out. 

Both the ice cream compartment and 
that for the cracked ice have folding 
covers, those on the latter being arranged 
to be swung up to a vertical position and 
used in conjunction with removable metal 
sides to form a box in which additional 
ice can be carried on hot days or long 
routes. Both compartments are cork in- 
sulated. Another small compartment at 
the rear of that for the ice is used to carry 
the pails in which the mixed ice and salt 
are carried to the cabinet or other recep- 
tacle in which the retailer keeps his ice 
cream. Running boards are provided on 
each side of the body. 

In operation, when the vehicle arrives 
at a point of delivery, the driver takes 
out the filled cans while standing on the 
running board, leaving them on the run- 
ning board for convenience. He then goes 
to the rear, takes out one of the mixing 
pails and scoops into it the desired amount 
of ice and salt while standing on the 
ground. He then carries both the filled 
cans and the mixed ice and salt into the 
store of the retailer where the cans are 
iced in the store receptacle. 

By this method considerable time 
is saved by the driver and there is 
less "cleaning up" to be done. 

The motor-truck in which the 
up-to-date wholesale dealer in 
ice cream makes his deliveries 


Popular Science Monthly 


Holding the Whetstone Where 
It Is Needed 

FOR unnumbered ages — perhaps ever 
since knives were invented — women 
and housemaids have sharpened 
those used in the kitchen on 
the edges of stone crocks or 
on the sandstone slab under 
the kitchen range, simply 
because the whetstone or 
corrugated steel for the 
purpose was not at hand 
at the moment when 
it was needed. 

Now Arthur L. 
Walker, of Hoopeston, 
111., comes forward with 
a little contrivance which 
can be fastened to the wall 
or to any upright, at a con- 
venient angle so that it wi 
always hold the whetstone 
in the correct position for 
use and in the most acces- 
sible spot. 

The devise consists merely 

The whetstone is held at a con- 
venient angle and height in a 
frame nailed to the kitchen wall 

amining physician of Harvard, found that 
596 of 746 members of the 1916 freshman 
class stood in a manner that indicated "a 
potentiality for sickness," and that 476 of 
the 596 students had feet and legs so 
imperfect that they were in- 
eligible for military duty! 
Lack of leg exercise is 
supposed to be the cause 
of this condition. Mr. 
Vaile says that the 
American • woman has 
neglected herself for so 
long that her" legs "and; 
feet are suffering mal- 
formations. There is no 
longer in her leg the 
beauty of the classic 
line. We dare not con- 
tradict Mr. Vaile on this 
phase of the subject". It 
may be that the specimens 
seen on the beaches' and 
'neath the modish skirts 
of the season are not what 
he calls representative^ 

of a piece of sheet metal so shaped that the 
whetstone fits into it securely and is held in 
place by the up-curved ends. The outer 
edges of the upper end are flattened out as 
shown in the illustration to receive screws 
which fasten it to the wall. 

A N 

What's the Matter with American 
Feet and Legs? 

AMERICA'S physical foundation — the 
l\ feet and legs of her citizens — is un- 
sound, if we are to believe P. A. Vaile, 
who has made a study of feet. If we do 
not discard the 
present mon- 
strosities in 
footgear and 
get into the 
habit of walk- 
ing, using our 
legs and feet 
instead of the 
auto mobile 
and street car, 
he says we will 
become human 
penguins. He 
call& attention 
to the fact that 
Dr. Lloyd 
Brown, the ex- 

The picker plucks the fruit and lets it drop. It hits the net 
and rolls down through a spout into a barrel or basket 

The Stationary Fruit Net— The Fruit- 
Picker's Dream Come True 

,N ingenious method of gathering fruit 
which reduces the fruit-picker's work 
to a minimum, makes use of a large net 
suspended above the ground directly under 
a tree and does away with the usual fruit- 
picking harness, buckets, pails and baskets. 
The fruit is dropped from the tree by the 
picker and it falls into the net and rolls 
down through a cone-shaped canvas spout 
into a barrel or fruit box. The net is held 
taut by a framework supported by iron 
posts driven in the ground. In addition 
to giving the 
picker the free 
use of both 
arms, the sus- 
pended net 
catches all fruit 
which may fall 
overnight or 
which may be 
shaken down 
by the wind. 
the only time, 
the picker need 
come to the 
ground is when 
the fruit box 
is full. 


Popular Science Monthly 


The "Swat the Fly" Campaign Is 
On. Here Is a New Trick 

WHILE the "swatter" has done its bit 
toward final victory over the fly, it 
has its disagreeable features. Strips of 
sticky fly-paper and similar devices are 
unsightly and disagreeable also. The 
invention of Crystal Hilgers of Chicago, 111., 
eliminates the unsight- 
ly elements of the fly- 

The invention is a 
small box-like contriv- 
ance with extending 
wings connected with 
a slowly rotating shaft 
which leads into the 
box and down into a 
channel filled with ker- 
osene. The wings are 
coated with molasses. 
The shaft rotates so 
slowly that the flies 
attracted by the mo- 
lasses are not shaken off. When they 
are inside, the kerosene fumes in the channel 
affect them, and they drop down into the 
container in the channel, which may be 
drawn out from the side and emptied oc- 

The captured flies are at no time visible 
except when the container is emptied. 




The flies are lured into the chamber by 
molasses on the slowly revolving shaft 
wings, and are dropped off into kerosene 

Going to College to Learn 
Wood Graining 

ANEW sort of school, designed solely 
to benefit the man who cannot afford 
to leave his home to acquire a broader 
knowledge of his profession, has been 
established in Iowa by the State College at 
Ames. It is a short course for the painter 
and decorator whose 
education and training 
in his profession has 
been of the "pick-up" 

Each year painters 
and decorators from 
over the state gather 
at the college to spend 
four weeks in more de- 
tailed study of the 
scientific principles of 
painting and decorat- 
ing. Two additional 
short courses are con- 
ducted under the di- 
rection of the college. These courses last 
one week, and are usually held in the differ- 
ent cities as the result of some arrangement 
with the local commercial club or some 
other public organization. In the evening 
sessions there are lectures and discussions 
of individual problems. This is believed 
to be the first school of its kind. 

Pupils of the Iowa State College Traveling School studying the best ways to grain 
wood. Every student is under the supervision of an expert instructor in the art 

Practical Motor-Boating 

II. — The proper location of the power plant and 
mechanical attachments, and their care and operation 

By George M. Petersen 

THE amateur boatman should thor- 
oughly understand the names and 
location of the various parts of his 
craft, in order to take good care of it. 
The principal ones are as follows: stem, 
keel, stern-post, dead wood, shaft-log, keel- 
son, bilge keelson, deck beams, stringers, 
knee, shear-brake, ribs, bulkheads and car- 
lines. The planking of the hull is really 
the skin or shell. It covers the ribs and 
frame of the boat and may be applied in 
several different ways. The edge nail 
construction is probably the most durable 
for a boat which is subject to severe 
pounding through seas or heavy engine 
vibration, as the planks are narrow and 
are secured through both the edge and the 

The shape of the stern of the motor- 
boat is also of vital importance, since it 
affects speed as well as seaworthiness and 
ability to run with the sea. For instance, 
the V-shaped stern shown at points A 
and B on page 277 may give the longest 
water line on a given overall length as 
well as the most protection to the rudder, 
but it is not a good design for backing or 
running with an overtaking sea. The 
"square transom" and the "rounded tran- 
som" are fairly satisfactory types, al- 
though the rounded is more expensive to 
construct. A "compromise stern," D, 
is seaworthy and dry when running before 
a storm, but it is never used on a craft 
where the maximum of accommodation is 
desired because of the large amount of 

deck-room which is sacrificed to its use. 
The old style "fan-tail" is shown at E. 
This is now almost obsolete, for the reason 
that it is almost impossible to back a 
small boat against a heavy sea because of 
the resistance offered to the hull by the 
waves. This type is inclined to be un- 
wieldly when running with a sea, as the 
waves will lift the stern. A type of stern 
which is still popular is shown in the 
illustration above. It is known as the 
"torpedo." This type is adapted to shallow 
waters where a minimum draft is desired, 
but has a tendency to squat when the boat 
is under way, thereby greatly decreasing 
her speed. It is a good "heavy weather" 
type, however. 

Strictly speaking, the power plant con- 
sists of the engine only, but it is customary 
among small motor-boat operators to in- 
clude everything that is connected with 
the actual operation of the craft. For 
instance, the engine classification includes 
the following: the crank-case, or base of 
the engine; the cylinder, including the 
water jacket, or top of the engine; the 
crank-shaft upon which is mounted the fly- 
wheel at the forward end while the shaft 
connects with the rear end ; the connecting 
rod which connects the piston with the 
crank-shaft, being attached to the form 
by means of a "wrist pin"; the carburetor, 
by means of which the proper amount of 
air is admitted with the gasoline to the 
compression chamber; the spark coil and 
battery which generate the spark which is 



Popular Science Monthly 

conveyed into the compression chamber 
through the medium of the spark plug; 
the water pump which forces the water 
through the water jacket and prevents the 
cylinder from overheating; the magneto, 
upon which the engine depends for its 
electrical energy while it is running, and 
the timer, or distributor, by means of 
which the spark occurs in the proper cylin- 
der at the proper time, advancing the spark 
and increasing the speed of the engine. 
The lubricating 
system is also of 
vital importance 
and should al- 
ways be kept 
in first class 

In connection 
with the power 
plant we may 
also mention the 
reverse gear 
which allows us 
to start the en- 
gine without 
causing the boat 
to move in 
either direction 
and which al- 
lows us to drive 

the boat ahead or astern as we desire. 
The gasoline tank is also very important 
to the successful operation of a gasoline 
engine. The tank should preferably have 
a capacity of fifteen gallons, the actual 
size depending upon the amount of room 
which may be given to it, as well as on 
the cruising radius which it is desirable to 
maintain. On small boats these tanks are 
often flat and are situated under the 
forward deck, while on the larger craft 
they are cylindrical and are situated under 
the deck or amidships on each side where 




they will be out of the way and where 
scuppers may be arranged to expel any 
leakage which may occur. Thi? will pre- 
vent the gasoline from getting into the 
bilge of the boat where the fumes may 
become ignited and cause serious damage. 
These tanks should preferably be made of 
copper and should be sweated and riveted 
together, although many of them are made 
of galvanized iron and merely soldered 
with a standing seam. The pipe from the 
tank to the car- 
buretor should 
be of lead, cop- 
per or block tin, 
and be coiled 
sufficiently to 
prevent the vi- 
bration of the 
vessel from 
breaking the 
pipe at its con- 
necting ends. It 
is also good 
practice to in- 
stall a strainer 
in the pipeline 
to prevent for- 
eign matter 
from entering 
the carburetor 
and clogging the needle valve. The proper 
location of the engine is generally decided 
by the type of boat in which it is to be 
used. For instance, in the "day cruiser" 
the engine is placed well forward so that 
the operator may sit in the bow of the 
boat and not only steer the craft, but 
handle the engine also, while in most of 
the other types of cruisers the engine is 
placed pretty nearly amidships so that the 
reverse gear lever is in the after cockpit 
where the operator usually stands when 
maneuvering the craft. One point should 
always be borne in mind, however, 
when installing the power plant, 
and that is to have the boat balance 
pretty well without a crew. To 
accomplish this result it is generally 
advisable to place the engine a little 
aft so that its weight will be an aid 
in keeping the propeller under 

The reverse gear is gener- 
ally connected up, as shown 
in the illustration of the en- 
gine installation, the halves of 
This is a fair type of stern called the rounded transom. each coupling being secured 

It is expensive to make but has a very neat appearance together by means of about 

The names and locations of the various parts of a mo- 
tor-boat should be memorized by the amateur boatman 

Popular Science Monthly 


The shape of the stern of the motor-boat is also of vital importance since it affects speed as well 
as seaworthiness and ability to run with the sea. Different shapes are adapted for different waters 

3^-in. bolts. Most of these reverse gears 
have three notches, the center one being 
neutral, so that the engine may be started 
without turning the propeller in either 
direction. The other two notches are for 
full speed ahead or astern. Although some 
of the gears are provided with two speeds 
ahead, the majority of motor-boat operators 
prefer to control the speed of the boat 
by the speed of the engine and the latter 
by means of the spark lever on the timer 
or distributor in about the same manner 
as the automobile is controlled. 

There are numerous steering devices on 
the market, but those shown at H, I 
and / are the most popular for motor-boat 
use. Sketch 
H shows the 
common type 
of steering 
wheel where 
the tiller-rope 
passes around 
the drum of 
the wheel so 
that turning 
the wheel in 
either direc- 
tion neces- 
sarily moves 
the rudder. 
In connecting up a wheel of this kind 
the turns taken around the drum must be 
uneven in number; that is, the tiller rope 
should pass around the drum three or 
five times and never two or four. Sketch / 
shows a lever arrangement which is very 
satisfactory as a side steerer, provided 
the guard is set low enough to allow of 
the lever being moved backward or forward 
far enough to turn the rudder at an angle 
of about forty-five degrees of the keel in 
either direction. This type of steerer is 
never used except on the side of the craft 
so that one man may handle the engine 
and the boat. Sketch / shows what is 
known as the auto steerer, which is a very 

The position the engine takes relative to the boat hull for 
directing the shaft downward at the stern end of the boat 

popular type for speed craft and the larger 
cruisers. In this type, the wheel is between 
the operator's knees, so that his hands 
rest on it. The shaft of this apparatus 
projects below the floor boards and has a 
sprocket wheel on the extreme end, from 
which passes the open-link chain which 
the sprocket teeth engage when the wheel 
is turned in either direction. The first- 
mentioned type often causes some annoy- 
ance through the tiller rope slipping on 
the drum; this trouble may be overcome 
by using either a small woven-wire cable 
in place of cordage or a manila line having 
a woven-wire cord. With the side steerer 
there is very little trouble except that 
caused by the 
con tinual 
shrinking and 
stretching of 
cotton or 
hemp tiller 
rope, but even 
if the line 
should get 
slack it is a 
very easy 
matter to take 
the slack out 
at the eyes at 
either side of 
the lever or with a turn-buckle. The last- 
mentioned type is preferably used in con- 
necting with a wire cable so that there is 
never any trouble through having too 
much play, or slack. 

Another piece of apparatus which is a 
desirable adjunct' to the modern motor- 
boat is the generator and magneto. These 
magnetos are known as high and low 
tension, the former being for ignition pur- 
poses only, while the latter may be used 
also for lighting purposes. In order to 
overcome the objection of the Steam Boat 
Inspection Service to this method of light- 
ing, it is advisable to have a storage 
battery connected into the lighting circuit 


Popular Science Monthly 


so that in the event of engine failure at 
night, the riding lights may be connected 
directly with the storage battery. 

There are three methods by which the 
magneto may be connected with the 
engine. They are as shown at K, L 
and M of the sketch showing the com- 
mon methods of connecting the magneto 
to the flywheel of the engine. The one 
shown at K is termed a "friction drive," 
wherein a beveled leather-faced pulley is 
held tight to the 
flywheel by 
means of a spring 
or governor. A 
belt drive is 
shown at L. The 
belt is merely 
passed around 
the magneto pul- 
ley and the fly- 
wheel. Sketch M 
shows a gear- 
driven type. 
This latter type 
is undoubtedly 
the most practi- 
cal for use in an 
open boat or 
where the bilge 

lowing instructions are closely followed. 
To start the motor, open the valves in 
the gasoline line, and the needle valve on 
the carburetor. One turn with the thumb 
nut is sufficient with most carburetors. 
Next, close all the switches and flood the 
carburetor by pressing down the priming 
cap until a few drops leak out of the bottom 
of the carburetor. Now open the throttle 
about one-half or three-quarters and set 
the timer at commutator so that the engine 
« .. , will not back-fire. 

Quad, coils 

Ground to engi 

Four-cylinder jump 
spark using 
single coils 

Ground to engine frame • 

Four-cylinder jump spark 
using quad, coil 

Four-cylinder "make and 

Three wiring diagrams for a four-cylinder marine en- 
gine, one for the jump spark, with single and quad- 
ruple coils and the make and break type connections 

About three or 
four notches from 
the end of the 
quadrant is a safe 
position. Then 
grasp the handle 
with the fingers 
and take hold in 
such a way that 
if the motor 
should back-fire 
the end will slip 
off the handle; 
but never close 
the thumb 
around the han- 
dle, as a broken 
arm or shoulder 

water may be splashed on the flywheel; 
for either type K or L will slip more or 
less if the flywheel gets wet. All of these 
magnetos are equipped with a governor 
to prevent them from being driven too 
rapidly when the flywheel is revolving at 
excessive speed. High tension magnetos 
are always geared to the engine. 

Practically all gasoline motors, especially 
marine engines, can be readily started 
whether or not the operator is familiar 
with his special type of engine, if the fol- 

may result. Rock the balance-wheel back 
and forth and give it a quick pull over 
center the way you wish the motor to go. 
The rocking operation draws the gasoline 
charge into the cylinder and if the proper 
charge is taken in, the motor will start. 
It is also good practice to prime the motor 
through the priming cock before attempting 
to start it, and a little oil mixed with the 
gasoline used for priming will be of great 

After the motor is under way, advance 





Wiring diagrams for connecting up a single cylinder as well as a double cylinder marine engine 
with ba tte ries, spark coil and timer, also magneto and timer using single and double coils 

Popular Science Monthly 


While there are 
many steering de- 
vices on the market 
these three shown are 
the most popular 

Single plank, with ordinary 
calk seam 



Single plank.with lap seam 

Single plank, ribband carvel 

I F=rT 

Single plank roughly put on 
and covered with canvas 

Plank put on 
improperly, not 
hoi lowed to fit 
•flat, on frame 

the timer until 
motor speeds up, 
and then proceed to 
adjust the needle 
valve on the carbu- 
retor until the best 
results are obtained. 
A slight movement 
of the needle valve 
will make a great 
difference in the 
mixture being fed 
into the compression 
chamber. For that 
reason it is advisable 
to go slow and try 
the different points. 
Too lean a mixture 
will cause a back fire 
while too rich a mix- 
ture will cause the 

motor to slow down. When starting the 
motor, be careful that the mixture is not 
too rich. In the case of too rich a mixture 
close the needle valve until a blue flame 
is shown through the relief cock. If the 
motor backs fire on all carburetor adjust- 
ments the gasoline pipe or needle valve is 
clogged and does not allow the proper 
flow of gasoline. 

Never use a wrench or screwdriver on 
a motor unless you know exactly why 
you are doing it. If you get a back 
kick or a sprained wrist from your 
motor, it is your own fault. Never try to 
start a motor with the spark advanced. 
The spark should be retarded before the 
engine crank is turned over. For throttling 
or slowing down, the expert uses the throt- 
tle; the amateur leaves his throttle open 
and retards the spark and thereby makes 
the motor back fire, thump and overheat. 

Oil and grease cups should be filled and 

Single plank, hoi low and 
round style of seam 

I I I I I I I I I I 

Single plank,narrow slats 
strung on a wire 


Double plank construction 

Lap strake plank 


Edge nailed construction 
J K 

l\ \ Plank properly 
V\\ hollowed and 
\\\ rounded to fit 
\V\curve of frame! 

The planking of the hull covers the ribs and frame 
of the boat and it may be applied in several ways 


The three methods 
of connecting up a 
magneto for being 
driven from the fly- 
wheel of the engine 

a small amount fed 
from each, always 
bearing in mind that 
too much lubrica- 
tion is almost as bad 
as too little, as it 
causes carbon to 
form in the cylinder. 
The fuel supply 
should now be 
turned on, both at 
the tank and at the 
carburetor. The 
needle valve on the 
carburetor should be 
opened slightly and 
the carburetor 
primed, as before 
mentioned, to make 
sure of a good sup- 
ply of fuel. As soon 
all oil cups should 

as the engine 
be opened. 

In case a four-cycle engine fails to 
start at once, turn the crank over under 
varying conditions of fuel and air sup- 
ply, after making sure that the igni- 
tion system is operating and that the 
fuel is flowing into the carburetor. 

The torpedo type of stern is a very popular 
style and is adapted for shallow waters 



Taking Snap Shot Action Pictures at 
Night with a Flashlight Pistol 

O take flashlight photographs the usual 

procedure for the 
photographer is first 
to set up his camera 
and tripod, open the 
lens with one hand, 
and then fire the 
flash powder with 
the other. Because 
of all this prepara- 
tion, it has been im- 
possible for the 
photographer to 
take instantaneous 
or snap shot photo- 
graphs by flashlight. 
Now, with the aid of 
a novel flashlight 
pistol invented by a 
California man, the 
tripod is dispensed 

The operation of 
the pistol is purely 
mechanical. The 
fact that the force of 

the powder explosion operates a lever which 
in turn manipulates the camera shutter, 
relieves the photographer of all responsi- 
bility. From the diagram it will be seen 
that the force of the explosion raises a steel 
lid which operates the control wire to the 
shutter. Hence the shutter is opened and 
closed at exactly the instant the flash is at 
its brightest. There is no possibility of an 
over or under-exposure. However the 
device permits the use of the various grada- 
tions of shutter timing. A spring-operated 
spark-wheel sets off the powder charge. 

Popular Science Monthly 

shops and offices of the railroad to facilitate 
the collection, and a baling machine has 
been installed by the company, which bales 
1,500 tons of old papers annually. This 
waste paper is sold 
for fifteen dollars per 
ton, so that about 
$22,500 is realized 
by the company in 
this way. In New 
York city, a social 
workers club is pay- 
ing one cent to the 
children of the poor, 
for every pound of 
old paper they bring 
to the club head- 

By holding the 
camera in the 
right hand and 
the flash pistol 
in the left an 
flashlight photo- 
graph is made. 


The Collection of Old Newspapers 
Has Become a Thriving 

An Elastic Cord 

for the Sash 


AN extremely 
» simple and in- 
expensive device for 
\stener holding sash cur- 
tains employs an 
elastic cord which is drawn 
through the curtain in the 
usual way, the ends being 
clamped down at the sides of 
the window as shown in the 
illustration. The elasticity of the 
cord makes it adjustable to any 
window. When it is necessary to 
remove the curtain for laundering 
or to wash the window, one end is 
undamped and the curtain is 
slipped off the cord ; then the cord 
is looped up out of the way on the other 
clamp. The cord is always taut and there 
is no possibility of sagging. 

\J p 

account of the shortage of 
paper, old newspapers and other 
waste paper have risen to an im- 
portant place in the commercial 
world. Today the man who throws 
down his paper in the cars after he 
has finished reading it is regarded as 
somewhat of a spendthrift. On the 
Pennsylvania Railroad, for instance, 
waste papers are now carefully 
collected. Ten thousand bags have 
been distributed to stations, work- 

An elastic cord holds the curtain taut 
and is adjustable to any window 


Horseshoe calks in 
rim of mower wheel 

Never- Slip Calks Used on 
Lawn-Mower Wheels 

THE wheels on a campus lawn-mower 
drawn by a horse became so smooth 
thai it was impossible to cut long grass 
with it, because the 
wheels would slide. 
The trouble was 
overcome in a satis- 
factory manner by 
using the never-slip 
calks that are ap- 
plied to horseshoes. 
Twelve of the calks 
were put in the rim 
of each wheel. The 
calks are small and 
will not tear up the 
turf, and they give 
plenty of tractive ef- 
fect for the ordinary cutter reel in long grass. 

Three Methods for Finding a 
Chosen Card 

FOR this trick the chosen card must be 
worked to the top of the pack. If it is 
there already, well and good ; but if not, it 
must be brought there by some means or 
other. This is generally an easy matter, 
even without sleight of hand, and can 
usually be effected under the pretense of 
looking through the pack. When the card 
is once at the top a false shuffle may be 
given, to throw the onlookers off the track. 
Then push the top card out sideways 
beyond the rest of the cards. Let the pack 
fall on the table. The resistance of the air 
will cause the top card to turn over and 
appear face upwards, all the other cards 
remaining face downwards. 

Another method is as follows: Get the 
chosen card to the top of the pack. Slightly 
moisten the first and second fingers of the 
right hand, and take hold of the pack with 
the fingers above, thumb below. Jerk the 
hand containing the pack smartly down- 

wards, at the same time relaxing the 
fingers, and it will be found that the entire 
pack falls to the floor, with the exception of 
the chosen card, which will stick to the 
moistened fingers. This will be the only 
card left and the card selected. 

The third method is very similar to the 
preceding. The chosen card is worked to 
the bottom of the pack. Moisten the 
fingers slightly and take hold of the pack 
with the fingers below, thumb above. 
With the disengaged hand strike the pack 
smartly and at the same moment slightly 
relax your hold on the pack. It will be 
found that the entire pack will fall to the 
floor with the exception of the bottom card 
which adheres to the fingers. 

Making a Push Cart Oil Sprinkler 
for Dusty Drives 

IN mid-summer when the suburbanite is 
confronted with dusty driveways and 
walks, he will appreciate an acquaintance 
with the home-made oil sprinkler shown in 

An oil barrel swung between a pair of 
wheels and piped to make a sprinkler device 

the illustration. It consists of a steel 
frame mounted on wheels, that carries an 
ordinary oil barrel. Inserted in the bung 
of the barrel is a short piece of pipe 



equipped with a shut-off. To this is 
attached the sprinkling pipe. This pipe 
should have perforations about 1^2 in- 
apart, of sufficient size to allow the oil to 
flow freely. The frame may be easily 
made by the average handy man, but 
where the materials are not available the 
local blacksmith will build it at a small 
cost. — J. C. Grindell. 

Popular Science Monthly 

proofing can be done by applying a facing to 
the concrete surface before it begins to 
harden. A powder can be purchased for 
this purpose which is mixed with cement in 
various proportions up to 5 lb. to a bag of 
cement. This mixture is applied to the con- 
crete surface and finished smooth with a 
plastering trowel — giving a fine, moisture 
proof wall or floor. 

Tipping Truck for a Large 
Cylindrical Oil Tank 

BECAUSE the fau- 
cet of a kerosene 
oil barrel leaked more or 
less continually, the 
owner devised the tip- 
ping truck illustrated. 
The tank was fitted with 
wheels from a discarded 
farm spring wagon. Two 
cross-pieces were run 
under the tank, the ends 
being supported on 
cleats fastened to the 
spokes on each side of 
the tank. Two planks 
were laid and cleats 
nailed to their 

The oil tank stands in an upright position 
on the wheels at the rear of the track 

upper surfaces to 
serve as a track 
for the wheels. 
Bumper pieces 
were placed at 
the right dis- 
tances on the 
ends of the tracks 
to stop the wheels 
from rolling far- 
ther than neces- 
sary to tip the 
tank horizon- 
tally. With this 
arrangement it is 
not necessary to 

have a faucet at all as a short piece of pipe 
is sufficient to guide the flowing oil into 
the retainer of a lamp or other receptacle. 

When it is required to fill a lamp or remove some of 
the oil the wheels are rolled forward tipping the tank 

Waterproofing for Concrete Walls 
and Floors 

THE general impression is that concrete 
is water and moisture proof, but such 
is not the case for if the surface were flat or 
concave it can be made to absorb almost 
any amount of water that is put upon it. 
For certain uses, it is very important to 
have a waterproof concrete and the water- 

End Mills Made of Broken and 
Worn Twisted Drills 

DRILLS which have 
been discarded be- 
cause they have become 
too short through fre- 
quent grindings or 
broken off in use, still 
have considerable value 
as end mills when placed 
in a milling machine for 
cutting keyways, etc. 
They may be held in an 
ordinary three-jawed 
chuck, or a holder may 
be made up with a taper 
shank to fit the spindle 
of the machine, and a 
number of split 
bushings pro- 
vided, one for 
each size of drill 
to be used. 

A setscrew will 
securely clamp 
and hold the drill 
in position in the 

They should 
be ground 
square, for what 
is commonly 
called bottom- 
ing, on the end 
and the clear- 
ance for steel should be about four degrees. 
On account of the shortness of a broken 
twist drill, its body will be as rigid for the 
work as the end mill, and owing to the 
construction of the shank it will stand 
considerable rough usage. If fairly deep 
cuts are to be made, each land should 
have a little additional clearance stoned 
on it right up to the edge of the flute. 
Considerable money can be saved in this 
way and the results will be almost as 
good as those obtained by the more ex- 
pensive end mills. — A. Dane. 

Popular Science Monthly 


Race meets at stated periods stimulate the manufacture of small cars in various shapes 
and forms, but generally the construction of some favorite large car is copied in miniature 

Miniature Automobiles and Their 
Race Meets 

MINIATURE but practical motor-cars 
are being built by youngsters in 
California in great numbers, and of widely 
differing designs, and the sight of them 
whizzing through the streets of Los Angeles 
is so common that they no longer attract 
special attention. The rapid development 
of junior car building in that section is 
largely due to the stimulating influence of 
frequent road races in California, planned 
especially for juniors. 

A racing association for boys has been 
formed in Los Angeles and a number of 
meets have been held, with cups and cash 
prizes awarded by motor enthusiasts. 

The little automobiles are largely home- 
made, with the exception of the engines and 
some of the more complicated parts. As a 
rule the engine from some outworn motor- 
cycle is bought for a few dollars and 
adapted for use in a diminutive car. The 
steering wheel is usually secured from an 

auto-wrecking establishment, and the 
wheels may be from bicycles, motorcycles or 
coasters ; though one or two small machines 
make use of the pneumatic-tired wheels 
designed for airplane use. 

The chassis, body, transmission, steering 
device and gas tank are as a rule of home 
manufacture. It will be seen that to build 
a neat and efficient miniature car requires 
considerable ability as a woodworker, 
machinist and tinsmith. Of course the 
manual training received in the public 
schools is very helpful in developing 
mechanical skill. The photographs show a 
number of home-made models and one 
factory-built junior car. 

Hanging Backing Cloth for 
Wall Paper 

IN hanging cheesecloth or muslin for back- 
ing on which to hang wall paper, wrinkles 
will be prevented if you first wet the cloth 
with clear water and when dry size it with 
alum water, I lb. to the pail. 

284 Popular Science Monthly 

Simple Oscillograph to Record 
Current Alternations 

ALTERNATING electric current de- 
rives its name from the fact that the 
current reverses the direction of its flow. 
It first flows in the wire in one direction and 
then dies out to zero and then flows in the 
opposite direction and dies out to zero or no 
current again. This constitutes what is 

The coil mounting and the coil, and the manner of mount 
ing a tin can on a disk phonograph to carry the filn 

known as a cycle. Alternating current of 
60 cycles means that the above operation 
occurs sixty times every second. Alternat- 
ing current is graphically represented by 
what is known as a "sine curve" as shown. 
Just why this curve represents alternating 
current may be shown by a simple experi- 
ment as follows : Take a piece of paper and 
lay it flat on the table. With a pencil in 
one hand, draw a mark by vibrating it 
rapidly across one end of the 
paper, the pencil retracing its own 
mark back and forth. At the 
same time, with the other hand 
draw the paper from beneath the 
pencil point and in a direction 
perpendicular to the line you 
have been drawing. The result 
will be as illustrated on the follow- 
ing page and represents a sine 
curve although imperfectly. Had 
you been able to vibrate the pen- 
cil regularly and draw the paper along at a 
regular rate of speed, the result would have 
been a perfect sine curve. 

The above is exactly what an oscillograph 
does, excepting that a photographic film is 
substituted for the paper and a spot of 
light for the pencil point. The spot of 

light is reflected from a mirror which is 
being vibrated by the electric current. A 
Braun Tube oscillograph operates some- 
what differently, however, no mirror being 

The illustration shows a simply made 
oscillograph, and, while imperfect in its 
action, very interesting results may be had 
with it in studying alternating current and 
its rectification. 

A rectified alternating current 
is one in which the current pulsa- 
tions have been changed (by 
electric, mechanical or chemical 
means) so that the current flow is 
in one direction only, as in the 
familiar aluminum-cell electrolytic 

The trouble in making an 
oscillograph is to get away from 
our old friend (or enemy) "in- 
ertia," which an eminent scien- 
tist once described as "the pig- 
headedness of matter." Matter 
in motion seems to want to keep 
on moving and matter at rest 
wants to stay at rest and it 
requires force to either start or 
stop it. The earth keeps on 
revolving because it is a large 
heavy mass and does not seem to meet with 
much resistance. If you have ever tried to 
push an automobile out of a garage you will 
remember that it was comparatively easy 
to keep it moving after you had once got it 

This is exactly the trouble in making the 
little mirror and moving parts of the 
oscillograph. They must be made very 
small and light to get the best results so 

The coil and magnet mounted on a base, and the delicate 
mechanism of the moving parts for casting the light ray 

that when the electric pulsation starts, the 
little mirror (influenced by it) starts, and 
when the current stops the mirror will 
stop. This is not possible to realize in 
practice but it may be approximated - 
With alternating current of 60 cycles there 
are 120 current pulsations per second and 

Popular Science Monthly 


it keeps the little mirror very busy trying to 
follow them. 

As shown, the shaft of the moving part 
consists of a small brass pin sharpened at 
both ends and with bearings made by 
small dents (not holes) in the two pieces of 
thin sheet br<*ss. A small piece of iron 
wire is fastened at right angles to the brass 

of the bearings on the shaft is made 
adjustable so that the mirror will not 
swing too far. This dampening effect is 
quite desirable in making oscillograms of 
rectified current, so that the mirror will not 
swing beyond the zero point. With no 
volt A.C. a lamp or other resistance should 
be placed in series with the coil of wire. If 


An oscillogram and a simple way of making the curve by drawing a piece of paper under a moving 
pencil to illustrate the process by which the recording oscillations are made by the machine 

pin with a drop of glue or sealing wax. A 
mirror (somewhat larger than the head of a 
pin) is glued to the center of the iron wire. 
The mirror is best made from a microscope 
cover glass. This is a small square of very 
thin glass and may be dropped into a test- 
tube of silvering solution for which there 
are various formulae. The test-tube should 
be of such size that the glass will just fit 
into it. This will support the glass upright 
in the tube so that it will be evenly silvered 
on both sides. The silver coating is after- 
wards removed from one side of the glass 
by touching it with the end of a tooth-pick 

a core is used, it should be made up of small 
iron wires. The size and amount of wire 
necessary on the spool or electromagnet is 
best found by experiment. The spool is 
fastened by rubber bands to the support, easy to substitute various spools 
containing different sizes and lengths of 
wire. Very little current is required as the 
mirror is influenced by the electromagnet 
at considerable distance from it. The- 
mirror and moving part should be mounted 
a little nearer to one pole of the permanent 
magnet than the other, so that the spot of 
light is adjustable by moving the permanent 

Oscillograms of a sixty- cycle alternating current before and after rectification, the zero line, 
indicated by a straight line in the first two, being photographed without a current in the coil 

moistened with nitric acid. After washing 
and drying, the mirror is broken into bits 
and a small piece selected as nearly round 
as possible. A piece of the silver chipped 
off the back of an old mirror might be used 
in place of a mirror. 

By means of the small screw, the tension 

magnet backwards or forwards as desired. 
As a source of light, sunlight is excellent 
for viewing the oscillograms directly. The 
sunlight is allowed to fall on the mirror and 
is then reflected on to a piece of white 
paper as a spot of light. When the mirror 
is being vibrated, the spot of reflected light 


Popular Science Monthly 

becomes a line, as in the experiment with 
the pencil and paper. By waving the 
paper screen back and forth rapidly in a 
direction perpendicular to the beam of 
light, the oscillograms may readily be seen. 
This effect is due to the persistence of 
vision. A small hand magnifying glass, 
placed between the mirror and the paper 
screen tends to sharpen and brighten the 
image of the light spot. For photograph- 
ing the oscillograms, sunlight might be 
used by reflecting it through the keyhole 
on to the mirror in a dark room. On 
account of the movement of the sun, how- 
ever, the spot of light has an annoying way 
of moving off the mirror just as all adjust- 
ments for taking the photo have been 
made; therefore a small incandescent lamp 
is more satisfactory. 

The lamp used in this case was similar to 
those used for automobile headlights and 
was a 6- volt 16-candle power lamp with a 
small concentrated tungsten filament 
known as "focusing type," it being essential 
that the light should come from as small a 
point as possible. A storage-battery was 
used, which gave a somewhat higher 
voltage than that of the lamp. This gives 
a light of greater actinic power although not 
conducive to long life of the lamp. The 
lamp was enclosed in a light-tight box 
painted black on the inside and having a 
small hole through which a beam of light 
might fall direct from the filament on to the 

A photographic plate may be drawn by 
hand rapidly across the beam of reflected 
light and the image obtained thus, although 
the results would be imperfect owing to the 
difficulty of moving the plate rapidly, 
evenly and uniformly. The uneven oscillo- 
grams shown were taken on a plate moved 
by hand. 

A disk phonograph was hit upon as being 
a device which revolves smoothly and at a 
regular speed. A hole was punched in the 
exact center of a coffee can, and fitted over 
the little knob in place of a record. The 
can was covered with black paper to 
prevent reflections. After focusing the 
spot of light on to the can, a piece of photo- 
graphic film was fastened around the can 
with rubber bands, a piece of cardboard 
between the mirror and film acting as a 
shutter. The phonograph was given a 
chance to get up speed and the shutter was 
opened and closed again when the phono- 
graph had gone around once. One revolu- 
tion is best gauged by fastening to the 

revolving table a piece of wire or cardboard 
so that it will brush past a finger held near 
it, when the piece of film has just passed the 
beam of light. When the wire touches the 
finger, it is a signal to open the shutter and 
the next touch is a signal to immediately 
close it. 

Oscillograms are shown of an alternating 
current of 60 cycles before and after 
rectification. The zero line is photo- 
graphed by allowing the phonograph and 
film to revolve once while the spot of light 
is at rest. This may be done before or 
after making the oscillogram. The oscillo- 
gram shows the rectification caused by a 
one-cell aluminum rectifier consisting of a 
lead plate and the tip end of an aluminum 
wire dipping into a solution of sodium 

A Home-Made Steam Volcano to 
Explain Volcanic Activity 

BELIEVING that steam causes the ac- 
tivity of volcanoes, a Frenchman has 
used that agent in imitating Nature in a most 
realistic way, as illustrated and described 
in La Nature. The whole experimental 
volcano is made in a shallow basin about 
2 ft. square, in which a wet mixture of 

A sectional view of miniature earth works 
showing what takes place in volcanic action 

sand and clay is placed so that the lower 
side represents the sea and the upper side 
the land. The basin is placed in an in- 
clined position, the higher part holding the 
land and the lower part the water. The 
metal basin provides a way to heat the 
bottom so that an even mean temperature 
is obtained on the surface. When the 
flame of a gas jet is applied, as shown, 

it takes only about 10 minutes for the 
volcanic phenomena to begin to appear. 

In Nature layers of hard rock or similar 
obstruction may deflect the rising fumes, 

The miniature volcano in action as it ap- 
pears from the lake end of the box 

and this may be imitated by placing a sheet 
of slate in the sand, as the dark line shows, a 
short distance from the bottom of the basin. 
With this plate in the sand several vol- 
canoes may be produced in line with its 
upper edge. By this arrangement the vol- 
canic action will appear at some distance 
from the source of heat. This illustrates 
how linear groups of volcanoes are formed 
in Nature. By varying the positions and 
the number of plates the volcanic action 
may be concentrated near the top. 

Popular Science Monthly 287 

A Double-Deck Revolving Clothes 
Hanger for a Yard 

WHERE backyard space was at a 
premium, the double-deck clothes- 
line apparatus, shown in the illustration, 
was made to serve the purpose of drying as 
satisfactorily as the ordinary line that takes 
up so much room. The double-deck ar- 
rangement is built on a center upright 
made of 25 ft. of 2-in. galvanized pipe 
purchased from a local plumber. The 
arms consist of 10 sections of i-in. pipe 
about 6 ft. long, threaded on both ends to 
fit into caps and bands that slip over the 
center pipe. The bands are movable, 
being held in place by a shoulder. Wires 
are strung around from end to end of each 
extension and each arm is supported by a 
wire. Two of these are placed on the 
center post, one for the ground level and 
the other for the second floor porch. The 
height for each hanger is adjustable. The 
lower hanger can be made just as high as it 
is desired by the person using it. The top 
circle can be arranged to reach the rear 
window or porch. The main pole is 
embedded in 3 ft. of concrete, affording a 
rigid foundation. The apparatus covers a 
circular space of the back yard about 12 ft. 

A Solution for Reclaiming Over- 
Exposed Blue Prints 

WHEN washing blue prints, if 10 drops 
of peroxide are added to each gallon 
of water a solution will be made that will 
produce even blue prints. The blue print 
is washed as usual in clear running water, 
after which it is placed in the peroxide 
solution and is finally washed m clear water 
to remove all traces of the salt. A blueprint 
of correct exposure or one under exposed 
will not be affected by it, but in over ex- 
posure the chemical will restore it to the 
true color. Where old blue prints have be- 
come faded this solution will restore them. 

Two sets of clothes hangers on a single 
pole serving a two- apartment house 

in diameter and has more than 150 ft. of 
hanging space. — Charles M. Stewart. 


To Prevent a Colt from Becoming 
Tangled in a Halter Rope 

IN the illustration a device is shown that 
will prevent a colt from becoming 
tangled in the tie-rope of the halter. The 

Popular Science Monthly 

The weight keeps the tie-rope taut all the 
time and the spring cushions the jerks 

old method of a weight is used, but a spring 
is applied to cushion the jerk a colt will 
give when first tied with a halter. The 
weight consists of a piece of hardwood 
43^ in. long and 3^ in- in diameter. A 
2-in. hole is bored in one end of the wood 
4 in. deep, and a i-in. hole bored through 
the center of the remaining 3^ in. of the 
wood. This makes a seat for the coil- 
spring A to B. The spring should be 
8 in. long, of the open variety and made of 
wire about 3/16 in. in diameter. The tie- 
rope is passed through the spring and 
secured by a knot at the bottom of the 
block as shown. The hole in the manger 
should be about i}4 m - i n diameter to 
take the tie-rope loosely. This will effec- 
tually prevent the spring from passing 
through. — J. O. McDonnell. 

Effects of Oil and Grease on 
Rubber Tires 

IT is pretty generally known that gasoline, 
grease, oil and other fatty substances are 
solvents of rubber. 

If garage floors are not kept clean and 
tires stand in a pool of oil, the treads 
soften and the traction strains in service 
stretch the rubber in a wavy outline, 
eventually causing it to separate from the 
fabric body underneath. 

Probably the most damage is experienced 
from grease, in the differential housing, 
working out into the brake drums and then 
on to the side walls of the tires. This may 
result from loose bearings, too much grease 
or from using grease not suitable for 

Grease and oil may be very easily 
removed by using a rag saturated in 
gasoline. Gasoline, although a solvent, 
evaporates quickly, and, if applied in small 
quantities, will not cause any injury when 
used as a cleaning agent. 

Ordinary injuries to the rubber cover do 
not prevent successful repairs but not often 
can work be well done when materials have 
been affected by oil or grease. Invariably 
blistering during vulcanization results. 

An Irish Thrush Rings for 
His Food 

FOR a token of remembrance of a trip 
abroad a lady promised a friend that 
she would bring back a bird of some kind. 
An Irish thrush was selected. When caged 
the bird cultivated the habit of pounding 
the metal bottom of his inclosure with a 
small gong top, taking hold of the edge 
with his bill and manipulating it just as a 

Thrush rings bells to 
attract attention when 
food cup is empty 


Calling for food by ringing a string of sleigh- 
bells which have been hung from the cage top 

workman does a pick. When his mistress 
fails to keep his food cup filled he jingles a 
string of sleigh-bells that are fastened to 
the cage top. 

Popular Science Monthly 

Iceless Refrigerator Using Evaporation sides. A little 
for Cooling 

r' is not always convenient or possible to 
have ice for refrigeration. When such 
is the case, as in a camp or isolated places, 
the evaporation method may be applied. 
Milk or butter will keep much better by 
this method than in the regular ice-box or 
refrigerator. A very satisfactory iceless 
refrigerator may be easily constructed as 
shown in the illustration. The measure- 
ments given are not arbitrary, as any size 
suitable for needs may be used, the entire 
cooling process being the result of the 
evaporation of the water as it flows down 
the burlap curtain forming the sides of the 

A suitable cabinet for ordinary purposes 
is about 1 8 in. wide, 36 in. long and 40 in. 
high. It consists of a skeleton framework 
of corner posts 2 in. square with a base and 
top band made of a board 1 in. thick and 
6 in. wide. The side to be used for the 
front is fitted with two doors built up just as 
frames and hinged to the corner posts, 
meeting at the center just like cupboard 
doors. All of these openings are filled 
with burlap set in so that the outside 
surfaces will be flush with the outside sur- 
faces of the corner posts. This may be 
done by building a light frame of quarter- 
round or light stock just to fit in the panel. 
Stretch the burlap over the panels and 
push them into the panel opening from the 
inside of the box frame. When this part is 
complete it makes a burlap inclosure 
without top or bottom. 

The bottom or support is made of a 
frame the same size as the main box with 
corner posts about 10 in. long and the band 
the same as for the top and bottom of the 
box frame. Within this box frame build an 
inverted pyramid of galvanized sheet 
metal, allowing the edge to come up and 
over the edge of the side rail on the base; 
then extend it up about ^ in. In the 
center of the pyramid solder in a metal tube 
for a drain. The upper projection of metal 
will catch any overflow of water and lead it 
to the center drain pipes. 

The top consists of a galvanized pan or 
tray the same size as the box frame and 
about 4 in. high, with a ventilator pipe 
soldered in the center. This pan is placed 
on top of the box frame. Wicks 4 in. in 
width are hung over the edge so that they 
will come in contact with the burlap sides. 
These wicks will evenly and slowly siphon 
the water placed in the tray to the burlap 

experimenting will be 
required to get the size of e the wicks right 
for the proper flow of water. These can be 
made of lamp-wick web or felt. The size 
may require altering according to the 
weather, as some days will be more humid 
than others. 

The refrigerator 
the center part 

Before placing the box frame on the base, 
small blocks of wood or the ordinary 
furniture domes should be used, under each 
corner post so that a space will be provided 
for the proper draining of the water. 
Shelves may be placed inside to rest upon 
brackets fastened to the corner posts. The 
edges of these shelves should not touch the 
burlap in any place. 

As such a refrigerator depends on the 
evaporation of water in air currents the box 
should be placed where there is a slight 
draft to produce the right circulation. The 
air passing up through the center tends to 
draw the damp air from the sides. 


Popular Science Monthly 


An Open Shelter for the Yard or 
Flat Roof of a Building 

THE flat roofs of tenement and apart- 
ment houses in large cities are often 
used as breathing places by the tenants. 
Shelters can be built 
upon them at small 
cost as protection 
from sun and rain. 
Our illustration 
shows one of these 
shacks, which is the 
result of the cam- 
paign for the preven- 
tion of tuberculosis 
by the New York 
State Department of 

In the construc- 
tion, 2 by 4-in. tim- 
bers are used for the 
frame, and sid- 
ing boards for 
the back and 
sides. The front 
of the shack 
should face 
slightly to the 
east of south 
and be left 
open, but it 
should be pro- 
vided with a 
canvas curtain, 
tacked on a 
roller so that it 
may be closed 
in stormy 
weather. The 
most economi- 
cal materials are 
rough boards 
for the frame 
and tar paper 
or something 
similar for roof- 
ing. The material list 

4 sills, 12 ft. long by 2 by 4 in. 

5 floor joists, 12 ft. long by 2 by 4 in. 
14 studs, 14 ft. long by 2 by 3 in. 

5 plates, 12 ft. long by 2 by 3 in. 
I front plate, 12 ft. by 2 by 6 in. 
1 rail for sliding sash, 12 ft. long by 2 by 8 in. 
9 rafters, 14 ft. long by 2 by 4 in. 
300 ft. of novelty siding. 
250 ft. of shiplap roof boards. 
3^ roll of roofing material. 
10 pieces of i-in. round for roofing. 
1 canvas curtain on roll. 
4 sliding sash; I casement sash and frame. 
Strips of sliding sash, hardware and paint. 

Sterilization Is the Essential Factor 
in Canning Vegetables 

THE great secret of canning or preserv- 
ing lies in complete sterilization. The 

air we breathe, the 

The flat roof space on tall buildings in all 
cities provides an excellent place for the shelter 



















Plans for the construction of an open air shelter shack 
for a yard or open air sleeping quarters on a flat roof 

as follows: 

water we drink, all 
fruits and vegetables, 
are teeming with mi- 
nute forms of life 
which we call bac- 
teria, or molds, or 
germs. These germs 
are practically the 
sole cause of decom- 
position or rotting. 
The exclusion of air 
from canned articles, 
which was formerly 
supposed to be so 
important, is unnec- 
essary provided the 
air is sterile or free 
from germs. 
The exclusion 
of air is neces- 
sary only be- 
cause in exclud- 
ing it we ex- 
clude the germ. 
In other words, 
air which has 
been sterilized 
or freed from 
germs by heat 
or mechanical 
means can be 
passed continu- 
ously over 
canned articles 
without affect- 
ing them. 

Germs which 
cause decay 
may be divided 
into three classes 
— yeasts, molds, 
and bacteria. 

Yeasts are easily killed, so they can be left 
out of consideration in canning vegetables. 
As a general rule, molds are likely to attack 
jellies and preserves. The spoiling of vege- 
tables is due primarily to bacteria. Bacteria 
are also much more resistant to heat than 
yeasts. They thrive in products like milk 
and in meats and vegetables rich in protein, 
such as peas, beans, etc. Keeping these 
products at boiling temperature for about 
1 hour, upon two or three successive days 
will kill all bacteria, even the seed forms, 
which are difficult to destroy. 

Popular Science Monthly 


A Self-Acting Fountain for the 
Home Conservatory 

THE making of any contrivance which 
when started works automatically and 
continually on its own power, is always a 
satisfaction to those mechanically inclined, 

A garden fountain worked by pressure, derived from a weighted 
piston on water in a near-by cylinder (note dotted lines) 

and I do not doubt that a fountain and fish 
pond which I made will be of interest to 
others. The basin or pond may be of any 
depth or diameter. The one shown was a 
large pan taken from the foot of a glass 
floral stand, which had a projecting neck 
in the center. This was removed to make 
room for the center pipe of the fountain. 

With the aid of my lathe I turned a piece 
of brass tube about i^ in. in diameter to 
true its end, and with this, using sand and 
water as an abrasive and keeping the lathe 
in motion while holding the pan against 
the tube with some pressure, the neck was 
easily cut off leaving a hole in the center 
the diameter of the tube. Another" hole 
was bored in the same way for the down 
pipe into the lower tank. The location of 
this hole was at one side of the center. It 
may be possible to obtain a basin where it 
can be bored ready for use. 

The stand for the fountain was built of 
two tanks made of zinc, the bottom one 
being set in a molded base. This tank is 
finished on the top with a flange all around 
and has a small faucet in the side near the 
bottom. The top tank, which is slightly 
less in depth than the lower one, is shown 
fitted to a %-in. molded board and has 
three upright pipes fitted in the positions 
shown. The left pipe passes through the 
board and the center one is fastened to 
the bottom with an inlet at each side, as 

shown by the arrows. The right pipe pas- 
ses through and down to within I in. of the 
bottom of the lower tank. All of these 
pipes are fastened to the bottom of the top 
tank before the two tanks are connected, 
after which the cover of the top tank is 
soldered at the joints. 

The center and the right 
pipe should project through 
the cover of the tank a dis- 
tance equal to the thickness 
of the basin-shell, and these 
two pipes should also be 
threaded on the inside, the 
center one to receive the 
nozzle of the basin, and the 
other the plug for starting 
the fountain. The action 
of the fountain is as follows : 
Fill the fish-basin with water, 
then screw off the upper 
part of the nozzle and allow 
the water to run into the top 
tank until it is filled to 
within Yl in. of the top. 
Replace the top part of the 
nozzle and remove the screw-plug. The 
water will rush down the pipe on the right 
side and compress the air in the lower tank, 
which forces the air up through the pipe 
into the upper tank, thus compressing and 

The weight of the piston compresses the air 
which forces the water up through the nozzle 

forcing the water up through the nozzle 
into the air. 

If the fountain is a very small one it need 
not be fitted with a screw-plug or a faucet. 


In such case it is only necessary to fill the 
lower tank through the pipe having the 
screw-plug; then by turning the fountain 
up-side-down the water will run into the 
other tank. Place the fountain in its 
proper position and half fill the basin with 
water, which will rush down the pipe and 
set the fountain into action. It is not 
advisable to keep fish in the basin. 

A simple garden fountain is shown in the 
illustration. The pressure tank of this 
fountain consists of a vertical cylinder 
about 10 in. high and 6 in. in diameter with 
a piston heavily weighted. A pipe is 
connected with a fountain basin having a 
center nozzle. To start this fountain re- 
move the piston and fill the cylinder with 
water. Replace the piston and the com- 
pressed water will force the fountain to 
act automatically. — John Y. Dunlop. 

Popular Science Monthly 

Unique Shelter of Palm Leaf Fans for 
Garden Entrance 

AN owner of a country place desiring to 
have something different from his 
neighbors made a garden entrance or shelter 
along the usual lines, but instead of cover- 


■ ■ 

Mh > m i M| ► ► X | 

«CRTIS£ M,t 

Details of the rafter framing and the man- 
ner of constructing a latticed ceiling frame 

ing it with shingles, prepared roofing or the 
like, palm leaf fans were nailed on as if 
they were shingles. These were placed 
in horizontal rows parallel with the rafters. 
To construct such a shelter the following 
materials are required : 

2 posts, 1 1 ft. long and about 6 or 8 in. in diameter. 
7 pes. of 12-ft. stock 2 by 4 in. in size. 
35 ft. of sheathing. 

A quantity of palm leaf fans. The amount neces- 
sary depends on the size of the fans. 

The two posts are set about 3 ft. in 
the ground and tamped in solidly after the 

The finished shelter 
with its artistic roof 
of palm . leaf fans 

upper ends have been cut sloping to fit the 
pitch of the roof. Two struts or joists are 
run through mortises cut in the posts 1 ft. 
3 in. from their upper ends, or about 6 ft. 
9 in. from the ground level. It is best to 
make this measure- 
ment from the upper 
ends so that the 
proper measurement 
will be secured. The 
other joists are fast- 
ened on the same 
level with pieces 
across their upper 
edges for a temporary 
support until the 
rafters are in place. 
The sheathing is firmly fastened with nails. 
The rafters are cut on what is called the 
half pitch roof, because the height at the 
center is half the distance of the width. 
At the top a ridge board is set in between 
the rafter ends. This board is fastened 
in place as the rafters are nailed. 

The amount of sheathing given in the 
list is sufficient to allow a space between 
boards. This mode of construction can be 
used where a panel is to be set in on the 
underside of the joist. In case the panel is 
not used it is best to put on the sheathing 
without spaces, and with surfaces planed 
down to produce a finished effect. In the 
latter instance it will require more boards 
or about 45 sq. ft. 

The panel shown in the illustration is 
another feature of this shelter. It is made 
of thin material such as is used in the 
ordinary market basket, and is woven to- 
gether in basket fashion or like a chair 
bottom of the old hickory kind. It is then 
cut into a rectangle as shown and fastened 
to the upper surfaces of panel boards, when 
the whole is fastened in place on the under- 
side of the joist with finishing nails. 

After applying the palm fans in the same 
manner as shingles their upper courses on 
each side of the roof are finished with pre- 
pared roofing or ridge boards at the top. 
This gives a finished effect and covers up a 
large space that cannot be filled with the 
fans. The effect of the finished shelter 
is very artistic. 

Leveling a Motion Picture 
Camera Tripod 

THE leveling of a motion picture camera 
tripod, especially if the panoramic 
head is used, is very essential. For this, 

Popular Science Monthly 


such cameras are generally equipped with 
two small spirit levels placed at right angles 
to one another. These are neither ac- 
curate nor easily read. At best the adjust- 
ment of two right angle levels on top of 
three legs is a slow process. The civil 
engineers recognize this difficulty and make 
their surveying instruments adjustable to 
the level positive by means of four screws 
instead of three. One of the camera men 
has attached to his tripod-head a very 
simple leveling device that anyone can 
adjust without loss of time. It consists of 
a brass tube rigidly attached to the under 
side of the tri- 
pod-head. The 
brass tube is 
about \ x /l in. in 
diameter and 8 
in. long and has cut in its 
lower extremity some win- 
dow-like apertures through 
which the operator can 
observe the position of the 
plumb-bob hanging from 
the center of the upper end 
of the tube. The ease and 
rapidity of adjustment of 
the camera to level position 
by observation of the plumb 
is self-evident. 

To those who care to put 
such a device on their cameras the following 
suggestions and illustration may be help- 
ful. The openings at the lower end of the 
tube should be large enough to permit the 
operator to see the plumb-bob easily and 
determine whether or not it is hanging in 
the center line or axis of the tube. The 
plumb-bob may be a straight piece of wire 
hanging freely from a ring support, which 
must be placed in the exact center of the 
upper end of the tube ; but even if a small 
plumb-bob terminal is used for the sake 
of appearance, the support should be a 
wire so that it will not be likely to foul 
as would a string or chain if the apparatus 
should be inverted. — T. B. Lambert. 

Tube enclosing 
the plumb-bob 

A Substitute for a Shoe Horn 
in an Emergency 

ONCE when I had been in swimming 
I found myself without a shoe horn, 
but a friend showed me a little trick that 
supplied my need. Simply fold your hand- 
kerchief two or three times and lay it in 
the shoe at the heel, holding one end of it. 
As you press your heel down into the shoe 

gradually draw on the end of the hand- 
kerchief, and when the heel is nearly all 
the way down draw out the improvised 
horn. The shoe will slip on the foot 
easily. — A. A. Kelly. 

Preserving Surfaces from Which 
the Paint Has Worn Off 

THERE are sometimes places on the 
exterior of a house where the paint 
gets worn off and which cannot be re- 
touched without making a "botch job" of 
it owing to the difficulty of mixing the new 
paint to match the adjoining color which 
has faded. To preserve the wood in such 
spots until the house can be repainted, 
apply two coats of linseed oil with a rag. 
This will improve the appearance also. 

Repairing a Worn Plunger in an 
Automobile Oil-Pump 

FREQUENTLY the cause of an engine 
heating up rapidly can be traced to a 
faulty oil-pump. This trouble was en- 
countered in one 
of the cars in our 
garage and upon 
examination it 
was found that 



Cap to lengthen worn 
oil-pump plunger 

*_ bronze cap the oil-pump 
Tffroi* PLJJNGER plunger was 
badly worn. 
This prevented 
it from deliver- 
ing the maximum 
amount of oil to 
the various 
bearings. The 
drawings clearly 
illustrate the 
cause of the 
trouble. The 
constant rubbing 
of the hardened cam against the some- 
what softer pump-plunger caused the 
plunger to wear rapidly. This wear de- 
creased the stroke of the plunger. 

The repair was effected by providing a 
bronze cap to the plunger ; first to bring the 
stroke of the pump back to its original 
dimensions and secondly to provide adjust- 
ment against wear. A shoulder was turned 
at the top part and a small thread cut on 
it. The cap was made from a cylindrical 
bar of bronze and was bored out and 
threaded on the inside to fit the threaded 
portion on the plunger. — Adolph Kline. 


Popular Science Monthly 

A Turned Down or Pistol Grip 
Handle for a Garden Rake 

THE straight handle on a rake makes it 
difficult to grasp when drawing it over 
the ground, especially where the heap of 
rubbish to be moved is large and long. To 
make a better hold for 
the hand I attached 
the turned down 
handle or grip 
as shown in 
the illustra- 
tion. A 
similar grip 
makes a 
handle on a garden tool as good as new. 
To apply the grip, cut a shoulder about 
3 in. from the end so that the tenon will fit 
into a hole bored in the prepared grip. 
The grip is made of a block of hard, even- 
grained wood, cut to the shape shown. A 
long wood screw passing through the grip 
and into the rake handle will make it 
rigid. — Frank L. Matter. 

A curved grip attached to 
the end of a rake handle 

A Tool for Accurately Lining 
Shop Shafting 

IN many shops where machines are belted 
from lines of shafting little attention is 
given to the alinement after the shafting 
has once been lined up unless the settling of 
the building, the weight of the pulleys and 
the tension of the belts make it so badly out 
of line that attention is called to it by the 
thumping and heating. 

Often shafting is so little out of line that 
it will show no sign of its condition although 
it will turn so hard that it will require much 
more power than it should to turn it. The 
usual test of throwing off all belts and 
trying the shaft by hand is not always 
reliable as the strain of the belts may 
change the alinement, and a section of 
shafting not perfectly straight may not 
show by that test, but may cause trouble 
when run at speed. 

The method described is a certain, 
practical and economical way of lining new 
shafting or of testing an old line of doubtful 
alinement. It can be applied in small 
spaces between belts and pulleys and will 
give dependable results of both the vertical 
and lateral alinement at one setting of the 
fingers. It is a great advantage to test a 
line of shafting while it is under the condi- 
tions of the tension imposed by its belts 
and pulleys, as a very tight belt midway 

between two hangers may spring a section 
of the shafting. This will cause trouble 
which may not be detected by any test 
made with the belt off the pulley. 

The method is based upon the fact that 
when the center lines of two cylinders form 
a perfectly straight line in their relation to 
each other, two points, one upon the surface 
of each of the cylinders, will be exactly the 
same distance apart when the cylinders are 

The fingers fastened as closely as prac- 
ticable to the ends of adjoining sections of 
shafting enlarge the diameters of the 
shafting and make possible the application 
of this principle with sufficient accuracy to 
prove whether the two sections of shaft in 
question are in perfect alinement. 

It is evident that the longer the fingers 
the greater will be the degree of accuracy 
possible to attain, though in many cases 
fingers which will permit the shaft to turn 
completely around will give sufficiently 
accurate results, as the shaft can be tested 
both above and below and on each side. 

The fingers may be made roughly, for it 
is immaterial whether they are perfectly 
square with the shaft or not, as their 
relation will be the same if each is firmly 
fastened upon the shafting. They may be 
held in place by a clamp or by a bolt as 


n h r: 

Wood arms attached to the ends of both 
shafts to determine the accuracy of the lining 

indicated by the sketch. Care is necessary 
in measuring the distance between the 
fingers in their different positions, and in 
adjusting the shafting so the distance will 
be exactly the same in whatever position 
the measurement is taken. 

In lining a new shaft by this method 
several pairs of fingers may be used at once 
to save changing, in which case the middle 
section should be correctly lined and the 
rest of the shafting lined both ways from 
it. — Charles A. King. 

Popular Science Monthly 


A Tractor Trailer Made from an 
Old Automobile 

AN old automobile having good mechan- 
ical parts, but too out of date in 
appearance to be used as a pleasure car, 
may be utilized as a truck by attaching a 
trailer. The illustrations and description 
are for changing over and attaching a 
trailer to a 35 hp. automobile having a 
4-cylinder engine with a three-speed for- 

through both for a king pin. This is 
clearly shown in the detail drawing. 

An entire rear axle for an automobile 
with springs and tires was procured. All 
brake connections were removed and the 
number of spring leaves increased. These 
were refastened to the axle in their original 
position with longer spring clips. Four 
pieces each were made of A, B and C, 
of the dimensions given, from %-in. steel. 
These pieces made the spring suspension 

5ide- sectional elevation 

%'plate riveted to . ,.,. 

chassis iz" wide 


Moo- floor pine 


Longitudinal section of frame h & 

Details of the fifth wheel to attach to the rear part of a pleasure car frame, after the body has 
been removed, to make a trailer truck. Details are also given for its frame and body construction 

ward and a reverse. The wheel base of the 
one used was about 128 in. The original 
body on the automobile was of the touring 
type. To make use of as much of the 
body as possible it was cut in two just 
back of the front seat and the rear part 
removed to make free use of the frame 
for the fifth wheel of the trailer. 

Two pieces of channel iron were then 
cut and riveted in the frame directly over 
the rear axle. These pieces support a 
plate on which the bottom part of the 
fifth wheel rests, a hole being drilled 

bracket A, the rear suspension brackets B 
and the spring shackles C. These pieces 
were cut from scrap at a structural shop 
and %-in. holes were punched for rivets 
and ^-in. holes drilled for the spring pins 
D. In fastening the pieces A and B to the 
frame it is much better to make a card- 
board or paper pattern and carefully center- 
punch and drill the holes. Securely bolt 
the pieces, using a cast iron filler as shown 
in the detail. The filler may be of any 
suitable piece of scrap iron that will fit 
into the channel. The projecting ends of 

Popular Science Monthly 


the bolt ends from the nuts was riveted 
over. Ordinary rivets can be used in place 
of the bolts, if they are put in hot. 

The trailer frame was made of 3 by 
1 13/16-in. channel iron with cross-pieces 
riveted in place, corner braces at each 
end and corner plates. The plate E is 
12 in. wide and % * n - thick, and as long as 
the trailer chassis is wide. It is securely 
riveted to the frame and cross-member F. 
The plate G is 12 in. wide, cut to shape 
from %-'m. stock. Two circular plates H, 
2% in. in diameter, were cut out and 
fastened in the center of each upper (G) 
and lower (E) plates. A 2-in. hole was 
then drilled through the center of both 
circular plates and the plates G and E 
for the king pin or bolt /, which was made 
of 1 31/32-in. stock with a i3^ by 3-in. 
head, and a steel washer 2>}A by M" m - 
under the head. This bolt is 10 in. long 
with a 4-in. length of threads. A spiral 
spring J was placed on the end of the 
bolt under the washer where it was secured 
under light tension with a nut, locknut 
and cotter. 

A groove was cut in each of the plates 
H for a grease retainer. Two holes were 
drilled in the plate G for two %-in. bolts 
to serve as bumpers for any side thrust 
that might be made. 

The floor of the trailer was placed on 
five pieces L cut from 2 by 8-in. oak. 
These were fastened with long bolts M, 
as shown. The opening left in the front 
part of the housing for the differential was 
covered with a plate bolted in place. 
The detail N is for irons to hold the stakes, 
is for the king bolt and P for the bracket 

Inflation and Weight Governs the 
Resiliency of Tires 

RESILIENCY of the tires is primarily 
u governed by the construction and 
quality, but is largely influenced by the 
inflation and weight carried. Naturally a 
4-in. tire inflated to 70 lb. air pressure 
and carrying 800 lb. weight will ride easier 
than the same size tire with the same infla- 
tion, and carrying 700 lb. weight. The 
heavier weight causes more deflection of 
the tires on the ground and increases the 
action of the side walls, thereby adding 
to the comfort of the ride. Increasing the 
deflection or flattening of tires, either by 
extra weight or reducing the air pressure, 
causes more of the vibration to be absorbed 
by the tires than by the springs of the car. 

A Cement Wash to Be Applied to a 
Damp Wall 

A GOOD cement wash for a damp wall 
may be made with 7 parts of soft, 
clear water, 1 pint of lime water and 2 oz. 
of table salt. Stir the cement enough 
to form a paint, adding any earth color 
desired, or use plain. 

A Porch Swing Made from Your 
Favorite Rocking-Chair 

A COMFORTABLE rocker can be 
converted into a swing without alter- 
ing or defacing the chair. The materials 
needed are two strips of wood about ij^ 
by 1 1 /2 in- and about 8 in. longer than the 
width of the chair seat; two sets of ham- 
mock chains; six stout screw-eyes and four 
long, slim wood screws. 

The strips are fastened with screws to 
the under part of the seat frame. The 
chains are suspended from two screw-eyes 
set in a joist in the porch ceiling and are 
hooked into screw-eyes set near the ends 
of the two cross-pieces. 

Auxiliary frame under seat of a rocking- 
chair for fastening the ends of the chains 

When the swing season is over, these 
attachments may be easily removed and 
neither the chair nor the porch will be 
any the worse for the out-of-doors usage of 
the chair.— T. H. Linthicum. 

ASH IP has recently been devised 
which carries a veritable gale pent 
up, not in an oxskin, such as Homer's 
Odysseus used to carry away the winds 
from the isle of Mo\us, but in a cylindrical 
tank. This boat was designed primarily 
as a toy, a bicycle pump being used to fill 
the tank. With one pumping, 16-in. models 
have a cruising radius of about ioo yd. 
and run from Yl to 10 minutes, depending 
upon the rate of escapement of the air. 

In the course of experiments with air 
propulsion it was found that a simple jet 
of air, allowed to escape from a boat, is 
very ineffective. Placed in a semi-circular 
tunnel the jet be- ftrrK 

comes doubly effi- 
cient. Still greater 
saving of power is 
made by leading the 
spent bubbles up in 
an incline at the 
stern to the surface, 
as shown in Fig. I. 
Thus the lifting 
power of the bubbles 
is used in propelling 
the boat, or it might 
be said that the boat is continually coasting 
down a row of bubble rollers. 

Making an Air Torpedo 

Perhaps the most simple form of an air 
boat, as a toy or for experimental work, is 
the torpedo, in which an air chamber forms 
a greater part of the boat-body. This air 
chamber, as shown in Fig. 2, is a 2-in. 
cylinder with semi-spherical ends, into one 
of which a bicycle tire air-valve is fitted. 
To this end a stern piece, containing a 

bubble-way, Fig. 3, is soldered. With the 
air-pipe and nozzle, Fig. 4, in place, and 
with the tank tested airtight, the torpedo 
is ready for use. The speed depends en- 
tirely on the size of the jet aperture. This 
can best be regulated with a pair of pliers. 
Since speed is desired, it should be adjusted 
to exhaust the air supply in 20 to 30 

How to Make a Submarine Chaser 

In the illustration, Fig. 5, there is shown 
one of the most interesting toys of 
today, the submarine chaser. It is a 
V-bottom boat, all metal, war gray, 
with an automobile-type steering 
gear that really moves the rudder. 
It is 16 in. over all, 
with a 43^-in. beam, 
and runs from 5 to 
12 minutes at a fair 
speed . Any boy who 
has a soldering set 
and tinsnips can 
build it at small 

Fig. 1. The compressed air is allowed to 
escape in a semi-circular tunnel at the stern 


The hull with the 

extension of the 
stern-plate is cut from a single piece of sheet 
tin, Fig. 6. This metal is bent on the 
lines A, B, and C to form the keel and 
sides. With three angle strips to reinforce 
it, the bow is soldered together as in Fig. 7. 
The stern-plate is next fitted on. Now it 
is ready for the tank. This is made of two 
circular cans, in the larger of which an air- 
valve is placed before the two are joined, 
to form a cylinder 8 in. long and 2^ in. in 
diameter. This is shown in Fig. 8. The 
ends of the tank are strengthened by a wire 


Speeding a Torpedo with Air from a Bicycle Pump 


Popular Science Monthly 


brace and wood wedges, Fig. 9. Through 
a hole in the keel, Fig. 5, a 3/16-in. pipe 
is led from the top of the tank to a brass 
nozzle. The bubble-way, Fig. 10, is then 
fastened in place and the strips D, Fig. 11, 
for the tank wires, are fixed to the bottom. 
At this point the tank may be wired or 
strapped in, Fig. 12, and the exhaust pipe 
soldered in the keel. If desired, a pre- 
liminary test may be made for adjusting 
the speed of the boat. 

If these trials are satisfactory, the steer- 
ing gear and rudder are put in. A hole £, 
Fig. 13, is punched through the bubble-way 

the edges of which are turned up with a 
file. The hood or turtle deck, containing a 
hatchway to make the steering accessible, 
is roughly cut out. Beginning amidships, 
the hood is bent over the tank and soldered 
along the sides, Fig. 22, the tin being 
trimmed down to fit the hull. The steering 
wheel is made from a circle or wire soldered 
to three wire spokes which in turn are 
fastened to a tin sleeve, Fig. 23. This slips 
into the steering column. 

A gun deck may be added, Fig. 24, and 
a turned wood or metal gun mounted on 
it, Fig. 25. A metal clip, Fig. 26, is soldered 



— ^1 

FI&.25 HOOD 


Patterns for making the hull of a boat that represents a submarine chaser, the parts being designed 
so that a storage tank is placed in the fore part under a turtle deck for supplying the air pressure 

and hull to take the rudder post, Fig. 14, 
made of heavy wire. This post, to prevent 
leaking, works in a tube, Fig. 15. With 
the tube soldered in, the rudder, Fig. 16, 
may be fastened to its post. The steering 
column, Fig. 17, is made and soldered to 
the side of the air cylinder and connected 
with the rudder post by a wire rod, Fig. 18. 
The boat is now ready for the super- 
structure or casing. First the face plate, 
Fig. 19, with holes for the steering column, 
air-valve, and rudder-rod, is fitted in, Fig. 
20; then the main and after decks, Fig. 21, 

to the afterdeck to take a flag. With a coat 
of enamel the chaser is complete. 

In general it is better to make cardboard 
patterns of the hull and superstructure 
parts before attempting to cut out the tin. 
It is well to see that the rod connecting 
the steering column and rudder also works 
freely before soldering it to the deck. The 
several dimensions given are merely sug- 
gestive. The casing should be fitted to the 
hull; for your tank, steering gear or some 
minor detail may differ a bit from the 
specifications given in the illustrations. 

300 Popular Science Monthly 

Making a Durable Playhouse for 
the Children 

THIS is really a young contractor's job, 
and the boy building it will have 
something to be proud of. When complete 

The setting of the door is no difficult 
task as the hinges are gained in and the 
lock attached in the usual way. The win- 
dow sash may be put in like the ordinary 
kind or swung on hinges like a casement 
window. The lattice may be arranged as 



Elevation and plan view of a children's playhouse that is so simple in design that any intelligent 
boy with a talent for carpentry can begin his contractor's career by building it for his sister 

as shown it makes an ideal playhouse for 
the children. The manner of construction 
is that employed for any house with the 
exception that it is not plastered or lined in 
any way, the studs and rafters being 
exposed. As window and outdoor frames, 
the door and window sash can be purchased, 
the actual building is not very difficult. 
The sills are built up of 2 by 6-in. material, 
as shown in the detail. The studdings are 
7 ft. 4 in. long. A plate is placed on top for 
the rafters. There will be required 12 
pairs of rafters 7^ ft. long. 

The location should be level and stone or 
brick piers should be built up a short 
distance for keeping the sills from the 
ground. The porch is a mere extension of 
the floor within. Both are built up in one 
piece. The floor plate is then run across 
33^ ft. from one end or the line of the house 
end. The roof extends over the same as 
the floor. The following is the list pf 
materials needed: 

400 ft. of 2 by 4-in. studding and rafter material. 

100 ft. of 4-in. flooring. 

605 ft. of shiplap sheathing. 
30 lineal feet of 8-in. and 
30 lineal feet of 6-in. finish lumber. 

160 lineal feet of 2 -in. strips for the lattice on porch. 

130 lineal feet of 2 by 6-in. dimension stock for 
joists and sills. 
8 bunches of shingles. 

2 double frames for side windows. 
1 single frame for the end window. 
1 door frame. 

5 window sash. 

3 door, 

shown or in any manner to suit the personal 
tastes of the builder. — W. E. Frudden. 

Mixing a Durable Water Color 
Aluminum Paint 

TO make a water color aluminum 
paint dissolve some gum shellac in 
borax water strong enough to dissolve 
the shellac, adding enough bronze powder 
to make the paint. Add a little aniline for 
color, if color is desired, or the plain 
bronze, using a very little glycerine to 
make the paint more flexible. This paint 
is bright, durable, and waterproof. 

An Old Cake Tin Makes a Good 
Watering Pan for the Poultry Yard 

A CHEAP and satisfactory watering 
pan for the poultry yard can be 
made of an ordinary funnel cake pan. 
Secure the pan to the 
ground by driving 
a stake through the 
funnel hole and into 
the earth. It is 
easily changed to 
any desirable spot, 
cannot be tipped 
over and will serve 
a dozen or more 
chicks at one time 
without danger of 
hurting them. — Jennie McCoy. 

Holding stake driven 
through hole in pan 

Sheet Metal Working Simply Explained 

III. — One-piece pattern for making 
a twenty - sided steeple ornament 

By Arthur F. Payne 

Assistant Professor Manual Arts, Bradley Polytechnical Institute 

THE problem for the development of a 
pattern for a twenty-sided finial is 
very interesting. Glancing at the 
drawing of the finial it will appear difficult 
to lay out a one-piece pattern of tin in 
such a manner that when it is bent up it 
will take the shape shown in the finished 
drawing, but if the drawing is given close 
attention and study it will be readily seen 
that all of the twenty faces are of the same 
size and shape, and that each face is an 
equilateral triangle; that is, a triangle 
having three sides the same length. 

It is necessary to get first a true pattern 
of one of these faces. The No. 4 face is 
the only one that is lying flat on the 
paper, all the others are apparently re- 

To lay out a pattern for such a finial it 
is necessary to know first how large the 
finial is to be when finished. For conven- 
ience of this problem we will consider one 
10 in. in diameter at the widest part. The 
steps taken in order are as follows: (1) 
Draw a circle 10 in. in diameter — see 
dotted circle in upper view. (2) Divide 
circle into five equal parts and connect 
these points with straight lines. (3) Pro- 
ject one of these lines down for the top 
line of the triangle 4 of the front view. 
(4) With a pair of compasses and a ruler 
draw the triangle 4 with all sides equal in 
length. This is the true pattern for one 
face. (5) Draw this pattern as No. 4 
face in the "full pattern" and then draw 

A pattern in one piece having twenty faces, each of the same size and shape, or an equilateral 
triangle, to make a twenty-sided finial to be shaped from sheet metal for a steeple ornament 

ceding from the surface of the paper. 
When a face is lying flat on the paper, as 
this one mentioned, it is called "lying 
in the plane" of the paper. All such faces 
are true patterns. 

the other faces exactly as shown in the 
full pattern. 

Cut the pattern out of tin and proceed 
to bend on the dotted lines. It will be 
necessary to bend the top and bottom row 



Popular Science Monthly 

of triangles at an angle of 120 deg. The 
center row of triangles should be bent at 
an angle of 72 deg. The bending may be 
done by means of a "brake," or over a 
"hatchet stake" with a mallet. 

The beginner, learning the trade, will 
be interested to know the scientific name 
for such a finial. In solid geometry it is 
one of a group of forms called "poly- 
hedrons," meaning many sided solids. 
The word "poly" means many. A cube is 
a polyhedron that has six equal faces and 
its special name is a "hexahedron." A 
solid with eight faces is an "octahedron." 
This finial, the pattern of which is de- 
veloped, is called an "icosahedron," because 
it has twenty faces. 

Folding Camp Fireplace Made of 
Angle Iron 

ANY one who likes to go camping will 
l be interested in these stoves. The 
only tools needed to make them are a 
hacksaw, riveting hammer and a breast 
drill with a 3/16-in. bit. The sides are 
made of two pieces of angle iron % by 
Y% in. The ones used in making the fire- 
place illustrated were taken from an old 
bedstead. The legs are % by 3/16-in. 
flat iron and the bars across the top are 
from flat galvanized steel 1 by 3/16 in. 
This is used to hold the sheets of gal- 
vanized iron together. These sheets may 
be obtained at any tinsmith's shop at a 
small price. One advantage of this style 

a. A 6 



The frame may be easily folded flat so 
that it can be put away in a narrow place 

of grid or fireplace is that it folds up com- 
pactly and is steady when set up. It also 
has the great advantage of being adjust- 

able as to width. The fireplace folds into 
a narrower but longer space than when 
open. I have found it extremely useful 
as a stand for an ordinary camp stove 
when used in a tent; for when it is opened 
to its full extent it just fits a small iron 
stove. — B. E. Dobree. 

Garden Seat with Checkerboard 
in Its Top 

GARDEN seats of the ordinary bench 
type can be made to serve a twofold 
duty by placing in the center of their upper 
surfaces a checkerboard design. In the 

The checkerboard on the garden seat 
makes checkers an inviting outdoor game 

wood top, squares may be cut out with a 
chisel or knife and alternate ones painted 
black. The checkermen can be kept in a 
small drawer placed under the seat. 

If a cement seat is made along these lines, 
black and white square tiles can be set in 
the cement to form the checkerboard 
design. In making the seat of cement, 
places must be provided for screws or ex- 
panding bolts which must be inserted on 
the underside at the center for holding the 
drawer slides. — Edward R. Smith. 

Constituency of Rubber for Side 
Walls of a Tire 

THE side walls of a tire must be flexible 
in order to properly distribute the 
strains, give resiliency, minimize heat, 
prevent sharp bending of the fabric,, break- 
ing and separation. Therefore, it is desir- 
able that the rubber on side walls of a tire 
be elastic and not too dense or firm; the 
kind of hard wear resisting rubber used on 
the tread is not suitable for covering the 
side walls. The difference in materials and 
adaptability for tires may be compared 
with automobile and machinery parts- 
some materials are required to possess great 
strength and some are selected for other 
qualities, according to their tasks. 

Popular Science Monthly 

Manufacturing Prussian Blue from 
American Products 

THE shortage of many colors and dye- 
stuffs in the United States since 
the European war has caused a thorough 
investigation into the means available 
for the direct manufacture of Prussian 
blue, which has been and still is in great 
demand for the production of printers' ink, 
dyeing, wall-paper printing, oil color and 
in compounding colors for many other uses 
where an intense blue is required. Prussian 
blue, or cyanide of iron, has hitherto been 
produced mainly from the potassium salts, 
such as the cyanide and ferro-cyanide, and 
known in trade as soluble Prussian blue 
represented by the symbols KFE2 (CN)6, 
while the insoluble blue is represented by 
FE7 (CN)i8 and FE5 (CN)i2. 

The great demand for this blue coupled 
with the increasing scarcity of it has 
caused the price to rise considerably. The 
production of this valuable color from the 
potassium salts is out of the question in the 
United States. This is because the supply 
of salts from the European market has 
ceased, and those obtainable are too costly. 
However, cyanide blue can be made at a 
very moderate cost from the following ma- 
terials to be procured in the United States: 
Sulphuric acid, 66 deg., nitric acid, 38 or 
42 deg., proto-sulphate of iron (common 
copperas) and a product known as cyanide 
mixture, which consists of a combination of 
cyanide of sodium, and chloride of sodium, 
which will yield from 39.2 to 40 per cent 
of cyanogen. The sulphuric acid and 
nitric acid are of the commercial variety, 
not necessarily chemically pure. 

A number of wine barrels will be required 
of a capacity of 50 or 60 gal. each, which 
have been dried and thoroughly coated on 
the inside with very hot, hard paraffin. 
The barrels are for use in producing and 
holding a saturated solution of proto- 
sulphate of iron called the copperas solu- 
tion, which is made by impending about 
100 lb. of the iron salt in small sacks 
attached by nailing to a simple wood frame 
made so that the ends of the frame rest 
upon the top of the barrel. The sack or 
bag when suspended should occupy about 
two-thirds the depth of the interior. By 
this means the sack hangs in the water and 
must not occupy more than three-quarters 
of the space within, because the constant 
dissolving of the iron salt will gradually 
fill the barrel. As the salt dissolves, a 


quantity of dirt will be held in the sack 
while a completely saturated solution will 
occupy the lower portion of the barrel. 
The barrel should be provided with a wood 
stop cock well soaked in hot paraffin placed 
about 6 in. from the bottom. This will 
allow for the saturated solution to be 
drawn off clear and free from dirt. The 
sacks or bags must be kept full to the brim 

Wth- Li 

! fwk 



^ ~ 



A sack or bag to hold the iron salt is 
hung from a square frame in a barrel 

with the iron salt, which is readily accom- 
plished by the use of an iron pail. The 
cyanide solution must also be prepared 
for use by employing a clean sack in a 
barrel of water the same as for the iron 
salt. In this case about 157 lb. of the 
cyanide mixture will give 50 gal. of a 
saturated solution, approximately, much 
depending on the temperature. 

The concentrated solution of cyanide 
should register on the hydrometer 100 
grains to the ounce of water. A Baume 
hydrometer will be required to test the 
iron solution, which should register 30 or 
31 when ready for use. This will be equal 
to about 100 or 110 grains of iron salt to 
each ounce of water. Several large stone- 
ware crocks will be required of a capacity 
from 30 to 50 gal. in which the saturated 
solution of iron salt is oxidized under heat 
and acid. This is carried out in the follow- 
ing manner: 

Oxidizing the Iron Solution 

Place 30 gal. of the saturated solution 

into a 50-gal. crock and pour into it 6 pints 

of sulphuric acid, 66 deg. Stir the mixture 

well and heat it with steam, using a pressure 


Popular Science Monthly 

of 60 lb. to the square inch. This is done 
by inserting a ^-in. iron pipe in the solu- 
tion, allowing the end to go within 6 in. of 
the bottom. In the course of 10 minutes 
this will bring the solution to the boiling 
point, when the steam must be turned off 
and the pipe removed. 
! The next operation is the adding of 8 or 
9 pints of nitric acid, specific gravity, 1.38 
or 142, known as 38 or 42. This must be 
added slowly to the hot mixture while a 
second person keeps it stirred with a long 

The mixture is well stirred while heat is 
applied by steam through an iron pipe 

strip of hardwood. During this operation 
dense red fumes of nitrous acid will be 
evolved and the mixture will boil vigorous- 
ly. As soon as this amount of acid has 
been added, the solution must be allowed 
time for cooling, which will require from 
14 to 16 hours, when it will be found that 
the quantity has increased from 30 to 35 
gal. This is due to the condensing steam 
and the addition of the acids. 

Preparing the Cyanide Blue 

Place 30 gal. of the cold iron mixture into 
a tub or stoneware vessel that will hold 50 
or 60 gal. and add 10 gal. of cold water. 
Draw off 8 gal. of the cyanide concentrated 
solution, add 2 gal. of water and pour it all 
into the iron solution while stirring the 
mixture vigorously. Avoid breathing the 
fumes that may be given off, because they 
consist of diluted cyanogen gas. Fill the 
vessel with cold water, cover it and allow it 
to stand for 24 hours. Upon the addition 
of the cyanide solution a dense and volu- 
minous precipitation of Prussian blue will 

take place. As soon as the blue has become 
settled at the bottom, the clear liquid must 
be drawn off with a siphon made of plain 
iron pipe, care being taken not to permit 
the blue to be drawn off. This liquid, 
which still contains a fair proportion of a 
free salt of iron, may be placed in a suitable 
vessel for further precipitation. As soon 
as the liquid has been drawn off, the tub 
must be refilled with clear cold water, 
stirred well and allowed to stand for 12 
hours, when the liquid may be drawn off 
as before and thrown away. About six 
such washings will be required to free the 
blue from the several soluble impurities. 
After drawing off the last washing water 
the precipitant is scooped up and poured 
into an unbleached muslin bag, which is 
suspended in a clean barrel in the same way 
as employed for the iron and cyanide 
solutions. The remaining blue is washed 
out of the tub or crock, placed in the 
muslin bag and allowed to drain for 24 
hours. At the end of this time the contents 
of the bag must be spread out upon muslin 
in suitable trays. These should be 3 ft. 
long, 2 ft. wide and 4 in. deep. When 
filled they are placed in a drying room like 
drawers in a file where steam may be 
applied for heating it to a high temperature. 
The room should be well ventilated so that 
a current of air coming in at the bottom 
will pass out at the top after circulating 
about the trays. This will evaporate the 
moisture left in the blue. As soon as it has 
dried thoroughly it may be ground to a 
powder in any suitable mill and it is then 
ready for the market. 

If tubs are used in the process of pre- 
cipitating the blue they should be well 
dried and the hoops tightened before they 
are used and the interior coated well with 
amyl acetate collodion by flooding and 
draining, or a solution of rubber cement 
that has been thinned with benzine or 
benzole may be used. This coating will 
preserve the interior against the action of 
the chemicals. The tubs must be well 
water-soaked previous to use until all 
leaks have ceased. The stoneware vessels 
need no preparation. 

If it is desired to manufacture this blue 
on a large scale care must be taken to get 
rid of the fumes resulting from the addition 
of nitric acid to the hot iron solution, 
because of their poisonous properties. 
Proper ventilation and respirators will 
protect the workers against any danger in 
handling the mixture. 

Popular Science Monthly 


A Plumbing System for the 
Farm Residence 

THE important points to be considered 
in the arrangement of a plumbing 
system are durability of material and 
construction, and simplicity. Avoid any 
complication of pipes, and arrange the 
water pipes so as to carry the water to the 
point of discharge in as nearly a straight 
line as possible. The use of lead pipes or 
lead lines and receptacles for drinking 
water should be avoided in small private 

The main pipe from the supply system 
should be about i34 m - an d never less than 
I in. in diameter. It leads to the kitchen 
range and then branches. One branch 
conveys water through the heater, through 
the hot water tank, and thence to the hot 
water fixtures. The hot water pipes should 
run parallel with the 
cold water pipe, but 
should not be so close to 
it that the temperature 
of either will be affected. 
The arrangement of 
water pipes, hot water 
tank, etc., is shown in 

of travel for the hot water is upward., and 
this should be aided, in arranging the hot 
water pipes, as much as possible. 

The sizes of the pipes generally used for 
supplying water to the various fixtures are 
given in the table below: 

All water pipes should have sufficient 
slant to drain them back into the tank or 
drainage system, and a drain pipe and cock 
should be provided at the low point in the 
system, so that in extremely cold weather 
the system may be drained into the sewer or 





The arrangement of water pipes and hot water tanks for a plumbing 
system in which a pressure tank is used to force water through the pipes 

the illustration. The hot water pipes are 
shown in black. All water pipes should 
be put in with red lead in the threads 
of the joints and all fittings should be 
screwed up tight. The natural direction 


To bath cocks 

To basin cocks 

To water closet flush tank . 
To water closet flush valve. 
To water closet flush pipes. 

To kitchen sinks 

To pantry sinks 

To slop sinks 










3 A- l A 



i — iji 


ih— iy 2 

H- % 




H— % 


drainage system to prevent freezing. This 
necessitates a stop-cock on the pressure- 
tank outlet to prevent draining the tank. 

Pipes should be kept from the outer walls 
to prevent freezing. Those located where 
they are in danger of freezing should be 
boxed in sawdust or some other non- 
conducting material. 

Since a plentiful supply of hot water is 
desirable and a large quantity retains 
heat for some time, it is well to provide a 
fairly large hot-water tank. However, the 
size of boiler depends on the existing condi- 
tions, such as the water supply and the size 
of the building. A safe rule istoallowa35or 
40-gal. boiler to a building having one bath- 


Popular Science Monthly 

room. Add 30 gal. additional capacity for 
extra bathroom. A water back having a 
heating surface of 100 sq. in. is sufficient for 
a 40-gal. boiler. 

Boilers should be galvanized inside and 
out, particu- 
larly inside. 
Copper boilers 
are preferable 
if properly 
coated inside 
with block tin. 
These are class- 
ed as light, 


A drainage system of a residence to carry 
away the waste from the sinks and bath 

heavy and extra heavy, the latter being 
tested to 150 lb. water pressure. Ordinary 
steel or iron boilers are tested to 150 lb. 
water pressure and extra heavy ones to 
250 lb. pressure. The latter should be used 
when the gage pressure is more than 40 lb. 
per square inch. 

Sewer Plumbing 

The sewer plumbing serves as a drain for 
the water plumbing. The drainage system 

should be so constructed as to carry away 
completely everything emptied into it, and 
it should be constantly vented, frequently 
and thoroughly flushed, and have each of 
its openings into the house securely 
guarded. All drains, soil pipes, and waste 
pipe should be water-tight and air-tight. 


Main and branch soil pipe 

Main waste pipe 

Branch waste pipes for kitchen sinks . 

Bath or sink waste pipe 

Basin waste pipe 

Pantry sink waste pipe 

Water closet trap 

Wash tubs. Traps for two tubs. . . . 
Waste pipes for three or four tubs . . . 

Main vents and long branches 

Branch vents for traps over 2 in 

Branch vents for traps less than 2 in . 





iK— 2 



iy 2 ~2 


The soil pipe, or house drainage main, 
begins at the sewer opening and passes up 
through the house as nearly vertical as 
possible and out through the roof for free 
ventilation. It should be at least 4 in. in 
diameter, of extra heavy cast iron, and all 
joints should be tightly calked with lead 
and oakum. All discharge from the wash 
basins, sinks, and toilets empties into the 
soil pipe, and connections should be tightly 
made. The sewer inside the basement wall 
should always be soil pipe; tile should 
never be used except outside of the wall. A 
soil-pipe trap should be provided at the 
house foundation as shown. Every fixture 
should have a trap to prevent foul air from 
coming back through the waste pipe. 
Vent pipes should be provided on all waste 
pipes to prevent siphonage and the con- 
sequent destroying of the traps. A good 
arrangement of sewer plumbing is shown in 
the illustration. Note the traps and vent 
pipes on each waste pipe. The smallest 
sizes of waste and vent pipes are given in 
the table above. 

All plumbing should be tested by filling 
with water or smoke to detect leaks. 

Owing to the fact that the last chapter 
on Winning an Athlete's Laurels covers all 
indoor events and does not contain any 
special features for this season of the year 
it will be concluded in a later issue, or one 
of the early winter month's, at which time 
all outdoor events will be discontinued and 
the athlete will be interested principally in 
something to occupy his leisure time indoors. 

q Amateur - 

-And Wireless Operator 

A Quick Action Electric Switch 
for Photographers' Use 

IN doing some work around my dark room 
I felt the need of an electric switch 
which would 
work more swift- 
ly and easily than 
those sold by sup- 
ply houses. The 
shows a single 
pole switch that 
met my demands 
for something 
delicate and in- 
stantaneous in 
action and it was 
constructed quickly. The base A was made 
of well shellacked wood 4 in. long 2 in. wide 
and 1 in. thick. The hinges B fasten the 
block C to the base block A. The block C 
is about 23^2 in- long an d about 1% in. 
wide. A handle D is fastened with screws 
to the piece C. The two terminals E 
consist of brass screws and washers on 
pieces of bronze or copper. Across the 
face of the block C is a strip of bronze 
tacked in place with small brads. Closing 
the block C brings the strip of bronze in 
contact with the terminals E which com- 
pletes the circuit. — Virgil R. Tharp. 

A quick acting single pole 
single throw electric switch 

Making an Electric Searchlight for 
a Motor-Boat 

A RELIABLE searchlight is a necessity 
for motor-boating at night, especially 
in crowded waters. The searchlight illus- 
trated is for use on small craft not equipped 
with a generator and is operated indepen- 
dently of the ignition batteries. 

For the light unit, purchase one of the 
hand lanterns that operate on one dry cell. 
Many types are on the market, but for this 
use it is necessary to select one with a large 
reflector. Procure a tin can into which 

the reflector of this lamp will snugly fit. 
To this can rivet a swivel arrangement, as 
shown. It is made from 3^-in. nickeled 
pipe fittings and it consists of a flange, 
tee-joint, two ells with flanges and three 
short lengths of pipe. The flange is riveted 
to the side of the can and a hole is punched 
in the can so that the wires which come 
up through the piping may pass through. 

The reflector and lamp are connected 
with the wires, a switch on the back of the 
can forms a handle to move the search- 
light, and the reflector is soldered into 
place. The flanges on the ells are screwed 
to the deck and a hole is bored under 
one to pass the wires through. The wires 
should be well taped to prevent abrasion 
and a short circuit. 

The battery for this light consists of two 
or three dry cells connected in parallel. 
The cells should be placed in a wood or 
pasteboard box, connected, then com- 
pletely covered with melted pitch or paraf- 
fin. This effectively prevents short circuits 
and prolongs the life of the cells by her- 
metically sealing them. The wiring be- 


An electric searchlight for a motor-boat 
wherein only dry cells of battery are used 

tween the batteries and light should be 
rubber-insulated . 

The light thrown is very powerful. If 
three batteries are used they will usually 
last a whole season. This is due to their 
parallel connection, which splits the load 
and lengthens the life. The light on a 
whole is neat and serviceable. A good 



Popular Science Monthly 

effect can be obtained by lacquering the 
container black and polishing the nickel 
parts. — Thomas W. Benson. 

A Simple Arc Lamp Using a 
Thermostat Control 

THE novel part of this arc lamp is the 
application of the active part of a 
thermostat for its control. A piece of 

One carbon-holder base is constructed of 
two metals to produce thermostatic action 

asbestos board 3^ in- thick makes a good 
base. To this is attached a ring-bolt for 
hanging the lamp. 

From copper tubing, y% in. outside 
diameter, cut two lengths each 2 in. long. 
A hole is drilled through the wall of each 
tube and threaded for a }/i-\n. bolt. One 
of these tubes is soldered to a strip of copper 
and clamped into position on the base by 
means of the binding post. The other tube 
is mounted on a heat-controlled strip 
formed by riveting together a piece of 
brass and a piece of sheet iron. The 
rivets should be spaced J^ in. apart. 

Around this strip wind mica and then a 
single layer of No. 18-gage German silver 
wire. One end of this wire is led to the 
strip and the other to a binding-post. The 
carbons are slipped into the tubes and held 
there by screws. The two carbons are bent 
toward each other so that they touch. 
Care should be taken in mounting the com- 
pound strip so that the brass is next the 
asbestos base. 

The operation will be clearly understood 
from the illustration. As soon as the cur- 
rent is switched into the arc it heats the 
German silver and causes the compound 
strip to bend, thus striking the arc. If the 
strip bends too far and breaks the arc add 
more wire and experiment in this manner 
until the arc burns steadily. It would be 
advisable to protect the strip from the heat 
of the arc by a shield made of asbestos 
board. — Thomas W. Benson. 

How to Make Slow Acting or 
Sluggish Relays 

PRACTICALLY all electrical circuits, 
and especially telephone and telegraph 
circuits, require relays. In telephone 
work especially, where several relays are 
used in one circuit, it is necessary that some 
of them shall be slow acting or sluggish. 
Such relays are used in circuits for a 
variety of purposes, the most important 
ones being: First, to prevent temporary 
disturbances in one part of a circuit from 
affecting some other part. Second, to 
secure a certain time interval between the 
operation of different parts of a circuit. 

A relay in itself is not generally slow 
operating or slow releasing but such 
features are determined by a combination 
of the design of the relay itself and of the 
circuit in which it is used. 

Relays may be made sluggish in a num- 
ber of ways. The first is to equip the 
relay with either a heavy copper head at 
one end of the spool or a copper tube over 
the core the full length of the winding space. 
This is equivalent to a closed circuit 
winding having a single turn of very low 
resistance around the core. Similar re- 
sults could be accomplished with a regular 
short circuited winding, although this 
would not be as effective as the copper 
head or tube. It has been found that the 
copper head is more effective with tubular 
type relays, while the tube over the core is 
more effective with the return gravity 
armature type. 

The use of either the copper head or tube 
results in any change in the field setting up 
an induced current in the short circuited 
winding in such a direction as to oppose the 
change in the field. Such an induced 
current will be of very low voltage as there 
is only one turn around the core, but of 
high amperage due to its low resistance. 
If the thickness of the copper head or 
sleeve is increased the resistance of this 
closed circuit will be correspondingly lower, 
and hence the induced current will be 
stronger for any given operating current. 

The operation of every relay depends 
upon a certain magnetizing force known as 
ampere turns and is the product of the 
number of turns in the winding and the 
current passing through it. If the winding 
and operating ampere turns are so chosen 
that the relay receives just enough current 
to operate it, the field will not become 
strong enough to move the armature until 
the effect of the short circuited winding has 

Popular Science Monthly 

been overcome and the field reaches its 
maximum strength. Such a relay will be 
slow in operating but may be~ made quick in 
releasing by choosing such a design that the 
releasing requirement will be high compared 
with the operating requirement. 

If the winding and operating require- 
ments are so chosen that the final value of 
the magnetizing force which the relay 
receives is much greater than the releasing 
requirement, then the relay will be slow 
releasing, as the magnetizing force will not 
decrease enough to allow the release of the 
armature, when the circuit is opened, until 
the effect of the short circuited winding has 
been overcome. Such a relay may be made 
quick in operating by choosing such a 
design that the releasing requirement will 
be low compared to the operating require- 

In neither of the above cases is the 
rapidity of the movement of the armature 
itself greatly lessened, the greater delay 
occurring between the time of closing or 
opening the circuit and the beginning of the 
armature movement. The above con- 
struction is sometimes used for making a 
relay that will not readily respond to 
alternating current. 

A second method is to use an external 
inductance or a non-inductive resistance 
which come under the classification of 
circuit design rather than the design of the 
relay itself, except where the non-inductive 
shunt is wound on the relay merely as a 
matter of convenience. Either of these 
means is used to cause the current through 
the winding to rise or fall more slowly than 
it would if no outside means was used to 
affect this time interval. The non-induc- 
tive shunt slows down the time of release 
but has practically no effect upon the time 
of operation, while the external inductance 
slows down the time of operation but has 
practically no effect on the time of release. 
Both effects may be accomplished by the 
use of the two in combination. As in the 
case of the first method the movement of 
the armature itself is not actually retarded. 
The action of such an arrangement is to 
increase the time between the closing and 
opening of the circuit and the beginning of 
the armature movement. 

A third method is to make the moving 
parts of the relay heavy so that it will be 
slow in responding to changes in the 
magnetizing force. If the operating cur- 
rent is just great enough to pull up the 
armature, the relay will be slow in operat- 


ing. To make such a relay slow in releas- 
ing, the restoring force, whether gravity or 
a spring, must be as small as possible and 
still cause the armature to fall back. 
Contrary to methods I and 2, with this 
construction the actual movement of the 
armature is retarded. Such relays are 
used extensively on alternating current, as 
their heavy moving parts prevent the 
opening of the relay contacts during the 
reversals of the current. 

The circuit conditions in each case 
determine which of the above methods 
should be applied, although the first and 
second methods are the ones most com- 
monly used. In some cases two of these 
methods are used on the same relay to 
meet certain peculiar circuit con- 
ditions. — F. H. Tillotson. 

Reversing Rheostat for Controlling 
a Small Motor 

IT is often desired to reverse the direction 
of rotation of direct current motors and 
at the same time adjust the speed to suit 
the new condition of operation. A service- 
able controller may be made as shown in 
the sketch. The sets of contacts A, B, and 
C, should be of brass or copper, and mount- 
ed on a slate slab 12 in. square. The re- 
sistance coils R should be fixed to the back 
of the slate board. These coils, made of 


A reversing switch in connection with a 
rheostat for controlling a small motor 

German silver, should have sufficient re- 
sistance to give the proper speed control 
without over-heating. 

Along the edge of the slate six binding 
posts are arranged and connections made, 
according to the diagram, on the reverse 
side of the panel. The switch arm D 
may be made from wood. The brass spring 
contacts E and F are connected so that 


Popular Science Monthly 

they will establish a circuit between the 
line of contacts A and B. The arm contact 
which presses on C is connected with the 
handle swivel and in turn with one of 
the binding posts. 

It can be seen that when the handle is 
in the neutral position, no connection is 
made with the motor. Moving the handle 
to the right or left causes the motor to ro- 
tate either one way or the other. This is 
accomplished through a reversal of the 
field connections. After a direction of ro- 
tation is established, the speed is varied by 
progressing the switch handle from notch 
to notch on contacts shown at A in the 
diagram. — K. M. Coggeshall. 

An Ingenious Wiring System for 
Two Inductive Transformers 

THE accompanying diagram shows a 
very good wiring system for the 
experimental set. Five different connec- 
tions are possible for the two inductive 







Transformer Fig. I 






Transformer Fig. 2 






Fessenden interfer- 
ence preventer. . 






Selective tuning. . . 






Long wavelengths 






Tabulation switch positions 
circuits shown in the diagram 

for the various 
of the wiring 

couplers by using five single-pole, double- 
throw, knife-switches. The inductive 
couplers are shown in Fig. I and 2, A, the 
Fessenden interference preventer, having 
the two primaries connected in multiple and 
the secondaries in series; B, the selective 
tuning with the secondary of the first in- 
ductive coupler connected with the primary 
of the second; and C, a long wavelength 
"hook-up" with both the primaries and the 
secondaries in series. A variable con- 
denser with short circuiting switch D may 
be placed in series with the second primary, 
and another with open circuiting switch E 
may be added to time the secondary. The 

connecting wires should be of No. 18 gage 
lamp-cord as short as possible. 

A throw of the switches will tell which of 
the two transformers is the better. It is 
a good plan to have two detectors as shown 




Very satisfactory wiring diagram of two in- 
ductive couplers for an experimental set 

connected with the switch F for the sake 
of comparing the different minerals, and 
also in case one gets "knocked out" in the 
middle of a message. — Harvey N. Bliss. 

A Variable Condenser for a 
Radio Receiving Set 

THE average amateur, in constructing 
his own wireless receiving apparatus, 
encounters his greatest difficulty in mak- 
ing a good variable condenser. A simple 
tubular condenser is shown in the illus- 
tration. It is easily constructed. The base 
is preferably of oak, 14 in. long, 3 in. 
wide and Y2 in. thick. The ends which 
hold the large cylinder are each 2^ in. 
square and Y2 in. thick. The brass pipes 
are 6 in. long and 1 Y2 m - m diameter for the 

ij BRASS PIPt 6*L0Nb 


A" tubular condenser, if properly constructed, 
will serve just as well as a plate condenser 

large one and 1 in. in diameter for the small 
one. A wire soldered to the stationary 
tube is connected with one binding post and 
a flexible cord which is soldered to the mov- 
able tube is connected with the other bind- 
ing post. — Thomas Lee Hodges. 

Popular Science Monthly 


A Drip- Pan Alarm for the 
Ice-Box Drain 

THE illustration shows a very neat and 
easily constructed drip-pan alarm 
which can be made by the home worker at 
a very slight expense. A small piece of 
glass tubing is run up through a cork 
float, on top of which is secured a light 
round copper washer. The cork with its 
guide hangs down into the pan from the 
under side of the base-piece of the re- 
frigerator as shown in the illustration. 

An Amplifying Electrostatic 
Radio Receiver 

IN THE development of radio telegraphy 
inventors have constantly striven to 
produce detectors or receivers which would 
be not only sensitive, but also rugged and 
easy to adjust and to keep in adjustment. 
Some of the instruments in common use 
meet these requirements, but in general 
the more sensitive of them are rather deli- 
cate in operation and seem likely to be 
rendered inoperative, or at least less 

The cork float details and the manner of hanging it to the underside of a refrigerator to sound 
a bell when the drip -pan is about full and there is danger of it overflowing 

It will be noticed at A that the perma- 
nent contact points or wires are so high that 
they in no way interfere with the sides of 
the pan when it is withdrawn to be emptied. 
The batteries of the door-bell circuit are 
utilized to operate the buzzer or bell of 
the pan-alarm, as at B. A simple one-point 
switch is placed in the circuit for con- 
venience if the pan cannot be emptied 
at once, the contacts being so arranged 
that the alarm will sound continuously 
after the water is within I in. of the top 
of the pan. — F. W. Bentley. 

Treating Cardboard Tubes for Tuners 
on Wireless Apparatus 

A GOOD way to make a cardboard tube 
non-shrinkable is to give it several 
coats of varnish before commencing the 
winding. — Charles Wildinger. 

sensitive, by receipt of loud signals or 
heavy strays. It has often been said that 
a wide departure from present principles 
would be necessary before an ideal receiver 
could be produced. 

A device shown in 1916, United States 
patent to R. A. Fessenden, number 
1,179,906, is interesting in this connection. 
A diagrammatic view of this instrument 
shows that the apparatus consists essen- 
tially of a combined electrostatic telephone 
and amplifying carbon microphone. The 
antenna 1 is connected through the tuned 
transformer primary 2 to earth 3, and 
coupled to the primary is the secondary 
coil 4. A secondary loading coil 5 is in 
series with this last-named inductance, and 
both are shunted by the static receiver con- 
sisting of the thin movable diaphragm or 
plate 6 placed close to, but not touching, 
the fixed plate 7. 


Popular Science Monthly 

The moving plate is pivoted on a vertical 
arm supported by two horizontal wires 
under tension, whose section is shown at 
8, 9, and which are in turn held by the 
frame io. The lower end of the vertical 

A combined electrostatic telephone and car- 
bon microphone that is sensitive and rugged 

arm carries an electrode which dips into 
the carbon granules of the differential 
microphone amplifier II. This variable- 
resistance cell has two opposing contact 
surfaces 12 and 13, and is in circuit with 
the battery 14 and the divided primary 
winding of the telephone transformer 15, 
16. The telephones 17 are connected to 
the secondary 18. 

In operation the supporting wires are 
stretched to the tightness which tunes them 
to vibrate at the group frequency of the 
desired incoming signals. Currents in- 
duced in the antenna by the arriving waves 
produce opposing charges upon the plates 
7, 6 and cause an attraction. This moves 
the lever toward the contact 12 and away 
from 13, so changing the current in both 
branches of the primary of the telephone 
transformer. By suitably winding these 
two coils the effects upon the secondary are 
made to add, and the change of current 
resulting in the circuit containing the 
telephone causes it to respond. By this 
resultant action it becomes possible to 
secure responses to comparatively weak 
signals of the desired group frequency, 
while interference of other spark frequencies 
is largely reduced. 

The same apparatus may be used on the 
heterodyne principle, by adding a local 
source of sustained waves which will inter- 
act with the incoming signals to produce 
musical-toned beats. In this case the sen- 
sitiveness of the device is still further In- 
creased. The tension of the supporting wires 
is adjusted to the pitch of the beat-note. 

Strong Wireless Signals in 
Winter Time 

A SERIES of tests lasting over two 
years were completed some time 
ago, with the object of finding out how 
much stronger radio signals between two 
selected stations would be in winter than 
in summer. The test signals were sent 
nearly every day during that time, and 
the amount of power sent and the intensity 
of signals received were carefully measured. 
It was found that the best time of year was 
from November to February, and that then 
the messages were about six times as loud 
as during the months from May to August. 

A Testing Set That Does Not 
Use a Battery 

THE testing set illustrated, which does 
not use a battery or magneto in the 
circuit, is novel and interesting. The 
current used is set up by the action of the 
saliva on the zinc and copper plates. While 
it is not recommended for constant use it 
can be worked in case of emergency. 

The mouth piece is made of wood or 
fiber cut tapering at one end. It is about 
2 in. long, Y2 i n - wide and % in. thick. A 
piece of sheet zinc is cut 2 in. long and 
34 in. wide, also a piece of sheet copper of 
the same dimensions. These metal strips 
are fastened to the edges of the insulator 
so that there is no contact between them. 
Solder a small screw-eye on the outer end 
of each piece of metal for terminals. 

The current for making the test is set up 
by the action of the saliva on the metal 

Connect a single head receiver in series 
as shown and place the block in the mouth. 
A distinct click may be heard when a clear 
circuit is made. — Albert Fertick. 

Popular Science Monthly 

How the Radio Inspectors Trapped 
a Disorderly Amateur 

IUST before Secretary of the Navy 
** Daniels issued his order for the dis- 
mantling of all unofficial wireless stations, 
the Government radio inspectors about 
New York found it necessary to track a 
disorderly amateur who continued to send 

An automobile was used to carry 
about a simple loop direction-finder 

out false "S O S" signals. Their method 
of running down this amateur is of especial 
interest now that we are at war. 

The false distress signals were sent out 
every night or so. Luckily the wavelength 
was short and ships at sea did not hear 
them. But the Herald wireless station 
and the Brooklyn Navy Yard did. Recog- 
nizing the signals to be the work of an 
amateur, they immediately reported to the 
authorities, and Louis L. Krumm, chief 
radio inspector of the Department of 
Commerce, started on his track. He first 
acted upon a hint from the Herald operator 
who explained that he could hear the sig- 
nals more loudly on his own apparatus in 
Brooklyn than on the sensitive instruments 
in the Herald station in Manhattan. 

This at once confined the search to 
Brooklyn. To locate the transgressor ex- 
actly, a small directive-loop receiving set 
was "hitched up" in an automobile which 
was run about the Brooklyn streets. The 
wire loop was about four square feet in 
area, and could be turned about to face 
in any direction. The circuit of this 
loop was closed by the ordinary condenser 
and coupler secondary of an audion receiv- 
ing outfit (see illustration at right). 

Starting from a given point in Brooklyn, 
the inspectors found that when the plane 
of the loop was turned in a certain direction 
the "S O S" signals were heard most 
plainly. This meant that the amateur's 


station lay somewhere along that direction ; 
for, as every amateur should know, when 
a wireless wave passes through a wire 
loop end-on, the electromagnetic lines of 
force will induce a certain current in one 
vertical wire of the loop, and a different 
electric current in the other vertical wire, 
the resultant current flowing around the 
loop being equal to the difference in these 
two induced currents. The reason why 
the two induced currents are different is 
shown in the diagram on the follow- 
ing page. At A the lines of force pass 
through the loop end-on, and the intensity 
of the lines of force cutting the vertical 
wire nearer the sending station S is less 
than that of the lines cutting the other 
vertical wire, causing a corresponding dif- 
ference in the two currents. Obviously, 
the resulting current flowing in the loop is 
a maximum and the signals are heard the 
loudest when the loop is pointing directly 
towards the sending station, as the loop 
at A is doing. At C, on the other hand, 
the two vertical wires are equally distant 
from the station S. The same current is 
induced in the two wires, since the same 
intensity of the lines of force are cutting 
them. The induced currents, on "bucking" 
each other, are simply neutralized and no 
resultant current will affect the audion 
detector coupled to the loop. 

Now that the radio inspectors knew 
one line of direction to the amateur's 

With the regular audion equipment, a wire 
loop was used instead of an aerial ground 

station, they immediately proceeded at 
right angles to this line of direction; as 
from A to B in diagram. At B they de- 
termined a new line of direction to the 
culprit by again turning the loop around 


Popular Science Monthly 

to the point from which the signals were 
heard most clearly. Then they knew that 
the amateur must be located at the point 
where these two lines of direction inter- 
sected ! 

After repeating their maneuvers many 

Fbsition of loudest 

Diagram illustrating the principle em- 
ployed to locate the sending station 

times, continually getting nearer and nearer 
to the unsuspecting amateur, the inspectors 
found themselves within a block of his 
station. The rest* was easy. There was 
only one antenna on that block from which 
the signals could come. The arrest of the 
youngster followed. Needless to say he 
has been taught a lesson and is not likely 
to cause any further trouble. 

How to Make a Kick- Back Preventer 
for Wireless Apparatus 

IN many instances where a wireless set is 
employed for sending purposes the fire 
underwriters require a kick-back preventer. 

The several instruments are con- 
nected as shown to make the 
kick-back preventer effective 

This piece of apparatus is, in some cases, 
expensive to purchase; but it can be 
easily made, at little expense. 

The essentials are a 16-C.P. carbon 
filament electric-light bulb, with a socket to 
fit it — a Mazda bulb will not do — two fuse- 

blocks and fuses, three binding-posts with 
holes in the center to admit pieces of copper 
wire, and a baseboard on which to fasten 
the apparatus. The binding-posts are 
used for a three-point safety-gap. The 
several instruments must be carefully con- 
nected as in the diagram, or the coil will 
not work. 

This device is intended for no volts 
with grounded power line. To find the 
grounded side of the line take a 1 10-v. bulb, 
with wires attached, and connect one wire 
with the ground and the other with one of 
the mains. The bulb lights only when it \i 
connected with the other main — not with 
the grounded side. 

In using this kick-back preventer, when 
the key is pressed the bulb will light up and 
the coil or transformer will operate. In 
case of a kick-back this device will send the 
excess current into the ground, and will 
save the coil and fuses from burning out. 

Variable Primary Coil Using a 
Switch Instead of a Slider 

IN winding tuning coils for long wave- 
lengths, if the slider runs the 
whole length of the tube it 
causes extra labor and expense. 
The following plan may be 

1 ■■ ■■ Switch points used instead of slider 

contacts on a vertical primary coil 

used to prevent it from doing so. Scrape a 
few inches of the wire and use a rod of the 
length designated. At intervals equal to 
the length of the scraped wire take off taps 
and run leads to switch-points. The 
finished coil is manipulated in the same way 
as the primary of a Navy type inductive 
coupler. — Glenn Dunfee. 

A Use for Discarded Cylindrical 
Food Boxes 

CYLINDRICAL cardboard boxes, such 
as certain food products are packed 
in, make excellent forms upon which to 
wind tuning coils. By using two, one of 
which is slightly smaller than the other, 
a very satisfactory inductive coupler may 
be made. — Edward McClure. 

Popular Science Monthly 



jj ] [Jtransf 



America's New Semi- 
Wireless System for 
Telephoning from 
Captive Balloons 

WHAT will be still another addition 
to the long list of America's contribu- 
tions to the technique of modern warfare 
is a Mtt'raZ-wireless system for communi- 
cating from balloons. The gun-fire of 
artillery is directed, as everybody knows, 
by battery commanders who ascend to 
high altitudes in anchored balloons. From 
here the commanders take their observa- 
tions and telephone their orders down to 
their batteries which may be concealed 
several miles away. To provide suitable 
telephone transmission lines, the Allies 
have been using the wire cables which 
anchor the balloons. They have built 
these cables up with an internal steel core 
which they insulate from the outer 
strands. But in providing two insulated 
conductors in this way, they were com- 
pelled to use a bulky, very expensive cable 
which was likely to be rendered, worse 
than useless if too roughly handled. For 
if once this cable should become injured 
and the two conductors become short-cir- 
cuited, the telephones could not work and 
the commander would be cut off from 
his men. 

The semi-wireless system which has 
just been brought out by William Dubi- 
lier and Robert Goll, two American 
engineers, does away with any need for 
the internal core. Their system, which is 
fully protected by patents, is expected 
to be officially adopted by our Govern- 
ment. For connecting paths between 
the balloon and the ground, the new 
system uses an ordinary solid steel cable 
as one path, and the air itself as the 


other. It therefore uses one transmission 
line, as in wire telephony, and it also uses 
the air as in wireless. 

Considering the diagram of con- 
nections it will be seen that the 
system has one secondary circuit 
consisting of the secondaries of the 
two telephone transformers, of the 
two telephone receivers and their 
shunt condensers, and of the two 
metal sheets which, with the air be- 
tween as their dielectric, form a balanc- 
ing capacity. This one secondary has 
two primaries : the telephone transmitter, 
batteries and the primary of the trans- 
former, in the basket, and the similar 
instruments down below at the gun 
battery. The three circuits are mutually 
tuned to provide a maximum of current 
in the secondary. 

When the commander talks into his 
transmitter, the corresponding primary 
current is modulated accordingly. The 
variations in the primary currents are 
induced into the secondary through the 
step-up transformer. Here the variations 
become very marked, due to the strength- 
ening effect afforded by the' inductance 
of the transformers and the capacity of 
the air-condenser, which together natur- 
ally tend to cause the secondary current 
to oscillate. These variations are changed 
into sound waves by the telephone re- 
ceivers — and the gun captain thus re- 
ceives his orders. 

A Polarity-Changer for Reversing 
Lighting Battery Current 

SOME audion detectors work better if 
the current from the lighting battery 
is reversed. To do this quickly a polarity- 
changer is very bandy. There are many 
kinds of polarity-changers, but the one 
here described is very compact and looks 
neat. To make it, mount five contact 
points on a fiber-base as shown in the 
drawing on the following page; space 
them about half their diameter apart. 
The positive side of the battery is 
connected with No. I and 5; the 
negative with No. 3, while No. 2 
an^l 4 are connected with the fila- 



merit and rheostat in the circuit. The two 
brass contact-arms on the switch-handle are 
insulated from each other and are of the 
edgewise-contact type. They should be 
made of thin spring-brass and split at the 
end as shown, so that each blade will make 
perfect contact with two points at a time. 
The switch-arms are fastened to the handle 
by laying them on the back of the insulating 

Popular Science Monthly 

To filament and rheostat 

\z ^ 

^ 5 X 





A polarity changer for reversing a cur- 
rent taken from a lighting battery circuit 

handle in their proper position, placing 
over them a fiber-washer and drawing it 
up tight against the blades by means of a 
nut screwed on to the bolt through the 
handle. Adjust the knob so the ends of 
the blades strike the contacts in the center. 
Then adjust the blades so that when one 
arm is in contact with No. 2 and 1, the 
other is in contact with No. 3 and 4; and 
when one connects No. 2 and 3 the other 
connects 4 and 5. Care should be taken 
to see that all contacts are the same height 
and all equally spaced ; for then it will be 
easy to get each arm to touch two contacts. 
A good holder for the handle is made of an 
old binding post which has a wide base. 
Force the post into a hole in the base with 
the base projecting, in order to keep it from 
going clear through. The shaft on the 
handle is then screwed into this until the 
contacts are made certain by the pressure 
of the spring. Be sure that a good contact 
is made, otherwise the instrument will be 
inefficient. — Frank Sahlman. 

A Simple and Dependable 
Multiplication Method 

AN interesting and simple method of 
multiplication is performed as follows: 
Suppose, for example, that it is desired 
to multiply 145 by 39. Write 39 in one 
column, 145 in a second. Divide 39 by 2, 

neglecting the remainder, and multiply 
145 by 2; write the first result in the first 
column, the second result in the second. 
Continue the process of dividing the num- 
ber in the first column by 2 and multiplying 
the number in the second column by 2 
(always neglecting the remainder if one 
occurs in the division) until the number in 
the first column is 1. Then strike out all 
of the numbers in the second column that 
are opposite even numbers in the first 
column and add the numbers remaining 
in the second column. The result will be 
the required product. The work for this 
problem is shown : 








2 J20- 




The method depends on the fact that 
any number may be expressed as the sum 
of powers of 2 (including 2° = 1). The 
number 39, for instance, is equal to 
2° + 2 1 + 2 2 + 2 5 , that is, 1 + 2 + 4 4- 32. 
The numbers remaining in the second 
column are 1 x 145, 2 x 145, 4 x 145, and 
32 x 145, so that their sum is equal to 
39 x 145. — Paul R. Rider, Ph.D., In- 
structor in Mathematics, Yale University. 

An Insulation for Secondary 
Terminals on Transformers 

THE insulation of secondary terminals 
on home-made transformers is often 
very poor, resulting 
in leakage and low- 
ered efficiency. The 
hard rubber shells 
from telephone re- 
ceivers can be used 
in such cases with 
excellent results. 
The shells should be 
mounted as shown 
in the illustration. 
A long brass rod 
threaded on both 
ends is run com- 
pletely through the 
device and clamps ™ cotL " 
it firmlv in oosi- Method of mounting the 
it nrmiy in posi sheUs for insulation 

tion. Connections 

are easily made with both ends of this rod. 

Wireless Work in Wartime-L 

The beginning of a series which will cover every 
present-day application of the principles of wireless 

By John L. Hogan, Jr. 

IN military and naval warfare there are 
many times when no man is of more 
importance than the radio operator. 
Upon his speed and accuracy, and on his 
knowledge of the principles of his appa- 
ratus, may depend the failure or success of 
great strategic moves. Radio amateurs 
and operators, as well as those who have 
an aptitude for this work and are now 
taking it up, are indeed fortunate in having 
the opportunity to serve the Nation so 
well in the present crisis. Radio operators 
are needed in the Sig- 
nal Corps of the Army 
and in several branches 
of the Naval service, 
including the new fleet 
of submarine chasers 
now being equipped. 
The call for men to 
take up these classes of 
military work will leave 
other positions open, 
particularly with the 
commercial radio or- 
ganizations, positions 
which probably can be 
effectively filled by 
competent women. 
There is and will con- 
tinue to be a demand for skillful wireless op- 
erators, both experienced and newly trained. 

Fundamental Knowledge 

The fundamental knowledge which all 
radio operators must possess relates to the 
use of the Continental or International 
Morse code. It is absolutely essential to 
be able to send well-formed Morse char- 
acters rapidly, and to have the ability to 
write clean "copy" when receiving signals 
from a distant station. Without this 
ability none can claim to be a radio oper- 
ator. And of only slightly less importance 
is the understanding of the basic principles 
of the apparatus used, together with the 
ability to adjust it quickly and accurately. 
This first article will take up the study of 
the code, pointing out not only the best 
and quickest way to learn it but also the 
elements which characterize good and bad 
sending. Just as many engineers fail to 


4^y W4y 


a y^y k4 

?^y t*k4M 

a §s§ 

in n [ ] 

y kssa y 

j nti n 

N 1 1 1 



\ r r T 



sssa fea fcSSsa sssss 

TT] Mm] 

sMM fe^y y =^ 


Letter chart with dots 
cross section paper to 

appreciate what is going on inside their 
instruments, so many operators fail to 
realize that there are good reasons for a 
number of rules of sending which appear 
unimportant at first glance. Either atti- 
tude leads to results which must necessarily 
be poor when compared with what is 
attainable by a little careful study. 

It has been stated as a general rule 
that men and women who have a feeling 
for musical rhythm make the best teleg- 
raphers. It seems curious that the same 
quality of beating time 
enters so strongly into 
both music and teleg- 
raphy. A keen time- 
sense, or the ability to 
note and correct small 
variations in time in- 
tervals, is of extreme 
importance to the tele- 
graph operator. This 
is because the tele- 
graph signals are sent 
by turning electric 
currents on and off 
for definite times. 
The elements of the 
Continental code 
are dots, dashes 
and spaces. Spaces of various lengths 
are merely periods of idleness, when 
no current is turned on. They occur 
between letters and between words, as well 
as in separating the dots and dashes which 
combine to form each character. The dot 
is the short active element, and is formed by 
turning the current on for a brief time; the 
dash is a longer active element, made by 
allowing the current to flow about three 
times as long as for a dot. Various combi- 
nations of dots and dashes stand for the 
various letters of the alphabet, and words in 
any language are spelled out letter by 

Learning Telegraphy 

There are three steps in learning tele- 
graphy: viz., memorizing the code, manipu- 
lating the sending key, and writing out 
incoming messages (reading by sound). 
These are independent to some degree, but 


and dashes plotted on 
show length of spaces 



the study of each promotes progress in the 
other two; consequently, all three should 

Popular Science Monthly 

mi i i i iiii i i i 

milium *] 







i nn i 



s fessy k 

wn H p 

Tn H r 

vti rrr 


FIG. 1 
Letters divided into four classes of one, 
two, three and four signals, dots and dashes 

be carried along together. The first two 
can be studied easily without assistance; 
but practice in sound reading requires 
either a companion student or a skilled 
telegrapher with whom to practice sending 
and receiving messages, or else an auto- 
matic sending machine. Probably the most 
interesting, and certainly one of the most 
effective, ways to learn the code is to 
practice it with another student of about 
equal ability. Thus there is the incentive 
of competition, and, from the very first 
work, the satisfaction of actually com- 
municating with another person through 
the vehicle of the Morse 
code. The only difficulty N A 

in pursuing this two-student ffT l H 1 1 HBB 
method lies in the danger of 
falling into improper habits 
of sending (e. g., incorrect 
spacing); but this can be 
corrected by getting the occasional criti- 
cisms of a skilled operator. 

be done. The only way to get this rapidity 
of translation from written letters to 
Morse letters is by continued practice. 

In Fig. i is reproduced the most im- 
portant part of the code, i. e., the symbols 
which represent the letters of the English 
alphabet and the period. With these 
twenty-seven characters in mind, any 
message can be transmitted. Numerals 
and punctuation marks other than the 
period may be spelled out by name, so 
that for the first work it is only necessary 
to memorize these. It will be noted that 
the letter chart of Fig. i is different from 
that usually used for showing the Morse 
code, in that the dots and dashes are plotted 
on square-section ruling. This shows at 
once the time allowance which should be 
made for each dot, space and dash, since 
each small square represents the time of a 
"dot-element." This dot-element is ab6ut 
one-twentieth of a second long in moder- 
ately fast sending, and is the length of 
time the current is turned on to form a dot. 
It is equal to the length of time the current 
is allowed to remain turned off to form a 
space between dots and dashes within 
the same letter. It is one-third of the 
time the current is turned on to form 
a* dash. 

Subdividing the Alphabet 

In memorizing the code it is best to take 
up the letters in groups. Several modes of 
division are practicable, but the best 
seems to be that illustrated in Fig. 2. 
Here the characters are divided into four 
classes, according to whether they are 
formed from one, two, three or four signals 

t l T 

H i r w m i 

Memorizing the Code 

The first thing, then, is to memorize the 
code itself. Without the ability to call to 
mind instantaneously the dot-and-dash 
symbol corresponding to each letter it is 
impossible to operate effectively. One 
must be able to recall the Morse equivalent 
of any character without any mental effort 
— the process must be automatic or sub- 
conscious before satisfactory sending can 

A time layout of normal spacings, but for the sake of clearness 
the space between words and letters should be slightly exaggerated 

(dots or dashes). The simplest characters 
are E and T, which comprise a single dot 
and single dash respectively. These are 
very easy to remember, so that one may 
proceed at on^e to the two-signal letters 
I, M, A and N. It will be noted that the 
left hand part ot the chart is devoted to 
the letters in each group which begin with 
a dot, while the right hand part shows 
those commenci.ig with a dash. Wherever 
feasible to do so, letters which are the 
reverse of each other are arranged side 
by side, — for instance, A is dot-dash, and 

Popular Science Monthly 

N, beside it, is the exact reverse, namely, 

Having the six letters of the first two 
groups fairly well in mind, practice in 
word-formation should be begun. A num- 
ber of simple words can be formed from 
these letters alone, and they should be 
practiced until there is not the slightest 
hesitation in spelling out any word using 
these characters. In learning the Morse 
symbols the signals may be called by 
name at first, but it is well to accustom 
oneself to the corresponding signal sounds 
almost from the beginning of study. That 
is, instead of continuing to call M "dash 
dash" or "two dashes" the student should 
begin very early in his work to attempt 
to reproduce the sound of the signal itself. 
This may be done by whistling or hissing 
for short or longer times, representing dots 
and dashes, and so imitating as nearly as 
may be the actual sound of the wireless or 
buzzer signals. 

Word Practice 

Practice words, using the first six letters 
learned, are as follows: 



















In spelling them in Morse, great care 
must be taken to give every dot and dash 
its full value of time, and particularly to 
space the letters properly. The space or 
idle interval between every pair of signals 
within the same letter is equal in length 
to the time of a single dot. The space 
between letters is longer, and equal to 
three dots (the time of a dash). At first 
it is a good plan to make the space between 
letters even longer, so that there can be 
no confusion. Even skilled operators oc- 
casionally run letters together to form 
"combinations" which are difficult to read 
and which often lead to errors in the trans- 
mission of messages. The space between 
words should be still greater, and equal 
to the time of at least five dots. 

The thing to bear in mind constantly 
is that the operator receiving your message 
can not transcribe it correctly unless you 
form your characters correctly, and that 
you must consequently strive to make 
perfect signals built up of perfectly formed 
dots and dashes carefully spaced. Fig. 3 


shows the time-interval layout of the words 
NAME ITEM, with normal spacing be- 
tween signals, letter and words; in practice 
the spaces between signals within a single 
letter should not be longer than the dots, 

The proper method of connecting the key, 
buzzer and battery together on a circuit 

but it is often well to exaggerate the spaces 
between letters and between words, for 
the sake of clearness. 

Using the Buzzer 

Before taking up the third and fourth 
groups of letters (Fig. 2), buzzer practice 
should be commenced. This will require a 
buzzer, a Morse key and one or two dry- 
cells. The key should be purchased rather 
than home-made, and should be of the 
regulation form with normal-sized key- 
knob, for the reason that the physical 
habits of key sending must be based on 
muscular practice. If one becomes accus- 
tomed to using an abnormally large or 
wrongly adjusted key, he will be handi- 
capped in the later use of the standard 
instrument. The key, buzzer and battery 
should be connected together, as shown in 
Fig. 4, when the buzzer, will sound con- 
tinuously so long as the key-knob is de- 
pressed and the circuit closed. The key 
should be screwed directly to the practice 
table, well toward the right and rear, so 
that the operator's elbow can rest on the 
table surface while he is sending. The 
distances must be selected so that the 
key-knob is within easy reach, and yet 
not so close that operation is cramped. 
It is important to fasten the key directly 
to the table top, without any sub-base 
which tends to lift the knob too high above 
the surface. A very good plan for the new 
student to follow is to call at some local 
telegraph office and see the actual arrange- 
ment of keys there used. The operators 
and office managers are usually glad to 
explain the key arrangements and the best 
way of holding the knob for sending, 
though one should of course not ask such 
favors during the busy hours of the day. 


Popular Science Monthly 

Holding the Morse Key 

Having mounted the key, the next thing 
to learn is how to hold it properly. There 
are variations in the "grip" from operator 
to operator, but the essentials are that the 
fingers should be arched into an approx- 
imate quarter circle and have their tips 
resting on top of the knob, the thumb 
should press gently but firmly on the side- 
rim of the knob, the wrist should be held 
up clear of the table surface and the elbow 
should rest upon it. The key should be 
pressed shut, never "tapped," and should 
open easily through the action of its own 
spring. The muscular impulse which closes 
the circuit must be gentle and firm, coming 
from the full arm. The wrist must not 
be stiff, nor yet must the lower arm muscles 
be used (through the wrist-joint) for the 
entire key manipulation. The proper dis- 
tribution of muscular effort, and the cor- 
rect use of the inertia of the fore-arm 
for rapid sending can only come from long 
practice; nevertheless, it is important to 
bear the above suggestions in mind at 
first, so as to form correct habits at the 
beginning of work. 

Practicing Dots and Dashes 

The first actual sending should consist 
of dots only. Make dots slowly, being 
careful to keep the interval between each 
pair of them exactly the same length as 
the dots themselves. As you find that you 
can make them perfectly, increase the 
number until you can send three or five 
per second without difficulty. Then take 
up dashes, slowly at first, increasing the 
speed till about one per second can be 
made perfectly. Remember that when 
sending dashes the space between each 
pair of signals must be only one third as 
long as the dash itself; this is the only 
difference between the rapid series of dashes 
and the slow series of dots. Next take up 
alternate dots and dashes, being careful 
to keep the spaces between the signals 
correct. Although speeds corresponding 
to those suggested must be attained 
through practice, never sacrifice accuracy 
for the sake of sending fast. Reliable, 
smooth and carefully-spaced transmission 
is the first requisite; speed follows as a 
matter of course. 

When the student overcomes the difficulty 
of changing from dots to dashes by prelimi- 
nary practice of the sort just described, he 
may begin sending Morse letters and words. 

The first two groups of letters (Fig. 2) 
and the practice words given here will 
afford ample work for some time. As 
soon as the first six letters are thoroughly 
learned, the third group may be used. 
New practice words and sentences may 
now be made up easily, since the fourteen 
letters using three or fewer signals permit 
spelling a large number of words. At this 
stage of practice it is advisable to commence 
reading by sound. Consequently an auto- 
matic sender or a companion student is 
needed. In the next article, circuits for a 
buzzer telegraph line, over which messages 
may be sent between two houses or rooms, 
will be described. Meanwhile learn and 
practice the code, and remember that care 
and accuracy are the two essentials for 
which to strive. 

(To be continued) 

A Fixed Adjustment Detector 
Easily Made at Home 

A SIMPLE "permanent" detector is 
constructed of materials found in al- 
most every experimenter's workshop. 

Secure a piece of mica j4 in - square. 
Next, select a piece of sensitive galena. It 
should not be larger than a B-B shot. Cut 
a hole, just the shape of the galena, only 
slightly smaller, in 
the center of the 
square of mica. 
Push the galena 
half way through 
the hole and fill up 
the cracks between 
the galena and 
mica, with glue. 
Be careful, how- 
ever, not to get any glue on either protrud- 
ing face of the crystal. 

While waiting for the glue to harden, 
remove the two thumb-nuts from the bind- 
ing posts on any ordinary dry battery. 
Glue these nuts, top outwards, to each side 
of the mica so that the galena will be 
between the burrs but touching neither of 
them. After the glue is dry the projecting 
mica may be cut away. 

Pour fine brass-filings in on either side of 
the galena and screw in on either side a 
brass bolt taken from a dry battery. 

The whole is then mounted on a suitable 
base and held in place by spring clips. 
This detector may be easily adjusted by 
simply tightening or loosening the bolts as 
desired. — Edward M. Weyer, Jr. 

Filings in nuts be- 
tween the bolt ends 

Let the Popular Science Monthly 
Send You a Check 

Do you know an interesting photograph when you see 
one ? 

Then you should be receiving checks regularly from 
Popular Science Monthly. 

Go to the nearest newspaper office and ask the editor 
for the names of inventors in your town. Find out what 
each is doing. If one has invented a device to catch chicken- 
hawks with kites, another an apparatus to kill flies by elec- 
trocuting them, and a third a treadmill for his dog, and 
so on, let us have articles, with photographs or drawings — 
quick ! 

Do you know that photographers' studios are mines for 
some authors ? Go to the nearest studio. Ask the photog- 
rapher to let you look through his plates and prints. Pick 
out the novel, the curious pictures, and mail them to us. 

Is there a big manufacturing plant in your town ? Did 
you ever go through it with your eyes open ? How do you 
know but some mechanic in that very plant has invented a 
machine which is saving his boss a thousand dollars a week ? 
Shouldn't the whole manufacturing world hear of that man ? 

How about the big engineering jobs in your neighbor- 
hood ? Do you know that contractors never dig two cellars 
alike ? Keep an eye on them. Look out for new labor and 
time-saving machines. 

Now get busy and receive some checks. 

News to you is something which is new to you. 

Is the picture of Italian soldiers with blackened faces 
on Page 382 of this issue news to you ? We put it there 
believing that it would be. 

On Page 333 is shown a roof bungalow. One of our 
readers happened to discover this unique mode of living, and 
recognizing something new, he immediately obtained photo- 
graphs, and sent them to us. They were news to us and we 
paid him" for them. 

The Land Torpedo in Action 

A small, but high-speed automobile is sent straight for the enemy. Caterpillar wheels and 
wire cutters can be provided when necessary. On reaching the trenches, the half ton of 
explosive and shrapnel is ignited electrically, blowing the barbed-wire entanglements to pieces 








Popular Science Monthly 

Vol. 91 
No. 3 

239 Fourth Avenue, New York City 

September, 1917 



Why Not the Land Torpedo? 

Mount it on an automobile; open the throttle wide; 
and let the machine rush to the enemy's trenches 

THE submarine torpedo is the most 
destructive weapon of the sea. Then 
why not a land torpedo? A cheap 
vehicle could be made to carry a high- 
explosive mine, a huge shrapnel, or a mis- 
sile which would be a combination of both. 
Where necessary, provide the vehicle with 
caterpillar wheels and with a wire-cutter, 
and dispatch it toward the enemy, over 
shell craters and through entanglements 
into the opposing trenches. There the 
charge could be exploded, and the men and 
property within blasted into oblivion. 
ii The originator of this plan is Felix 
Sabah, of Philadelphia, whose idea as he 
has conceived it is illustrated in action. 
The ground of "No-Man's Land" being 
flat, ordinary gasoline automobiles of small 
size are used. In them the charge is 
carried, consisting of about a thousand 
pounds of explosive, mounted on the 
crutch-like frames. The firing wires which 
lead back to the electric igniting coils are 
seen in our picture projecting from the 
rear. The outposts are telephoning the 
order to fire. The fatal button is pressed — 
then ghastly destruction. 

And the enemy? Has he no defense? 
No doubt he will erect concrete barriers, 
and blast huge craters. Caterpillar wheels, 
however, would be a single means of over- 
coming the craters. The use of percussion 
caps, which would ignite the torpedo charge 
on striking the walls, would be one way 
of smashing through them. 

Let us not forget that once we can get 
the torpedoes there, the rest will be easy. 
If nothing else can be used, time-fuses 
will set off the charge at the proper instant. 

The other military considerations in- 
volved in the practical application of the 
project are much more simple. There will 
be no difficulty in constructing the light 
type of automobile that would be required. 

In fact, the plan would provide the means 
of giving many an antiquated automobile 
which is about ready for the junk heap, 
its opportunity for making its last sacrifice. 

From the shipping point in Europe, the 
men of the "Land Torpedo Corps" could 
each ride an automobile directly up to the 
front, thus relieving the railroads of the 
burden. Here the torpedo charges could 
be mounted, tests could be made, and 
everything could be planned for a con- 
certed assault. 

To launch the torpedoes on this drive, 
competent officers would have to set and 
lock the steering gears. Throwing open a 
clutch from the rear of the machine, the 
automobile leaps ahead audaciously. The 
vital parts being armored, the enemy will 
be unable to damage it severely when the 
machine is seen to be rushing towards 
them at some sixty miles an hour. 

Closely resembling this land torpedo is 
the torpedo car described on page 526 
of the April issue of the Popular Science 
Monthly. It too is designed to take the 
place of artillery in preparing the way for 
infantry attack. A torpedo carrying several 
hundred pounds of high explosive is mount- 
ed on a chassis. The propelling power may 
be either gas, steam, compressed air or a 
storage battery or electric motor. Its most 
important feature concerns the method by 
which it is guided and fired. This is done 
by means of cables and wires in the hands of 
the attacking party, which is a noteworthy 
advantage over the land torpedo described 
in this article. Furthermore, the torpedo 
car, should it not reach the enemy because 
of rough ground, can be drawn back to the 
trench from which it was started by a simple 
pull on the control cable. The torpedo car 
would cost about one thousand dollars, 
whereas the modern naval torpedo costs 
seven thousand dollars. 



Popular Science Monthly 


Salvaging Motor Wrecks with a 
Special Equipment Gar 

E have long been familiar with the 

wrecking train of the railroad with 
its special crew of trained mechanics and 
its hoists and derricks for clearing away 
debris or setting cars back on the track 
again in case of wreck or collision. But 
it is only recently that the wreckers for 
the motor world have come into view. One 
of the best equipped cars of this kind is 
operated by Mr. Meehl in Port- 
chester, N. Y. 

The wrecking car with its crew 
is ready for instant service 
and answers calls within 
a radius of one hundred 
miles at any hour of the 
day or night. The car 
itself is a simple chas- 
sis. On the rear end 
is a two-ton hoist 
and all sorts of rope 
pulleys and tackle, 
besides jacks and 
tools for emergency 
repairs. A two- 
wheeled truck is part 
of the equipment and 
is used when towing 
cars whose wheels are 
out of commission. Two 
powerful acetylene 
searchlights are used 
to light up any night 
work and two heavy 
jacks are carried on the 
running board which are 
used to jack up the rear 

The wrecking car answers calls within a 
radius of one hundred miles, night or day 

wheel when there is any hoisting to do and 
take the strain off the tires. With this 
car it is possible to tow in a wrecked car, no 
matter how badly it may be broken up and 
it is possible to pull the car out of any kind 
of a hole. It has frequently had occasion 
to hoist cars out of streams or up an em- 
bankment twenty-five or thirty feet high. 

The slits in these opaque glasses 
admit only a small percentage 
of direct light rays to the eye 

How the Eskimos Taught Us to Take 
the Glare Out of Motion Pictures 

HAVING suffered from the 
flickering and glare of 
motion pictures, Dr. F. C. 
A. Richardson, of New 
York City, developed a 
pair of opaque eye- 
glasses with narrow 
slits in them, through 
which he views the 
pictures without the 
slightest discomfort. 
The Eskimos have 
used similar glasses 
for years in prevent- 
ing snow blindness. 
When a person looks 
at a motion picture 
with the naked eye, he 
receives the intense rays 
through a comparatively 
large area of the eye. 
Less than one-half of 
these rays are necessary. 
The other half simply 
tax the eye. They add 
nothing to the clearness 
of the picture and pro- 
duce the intense glare. 

Potash from California Sea Kelp 

Subterranean reapers harvest the product 

The harvester 
waiting for the 
tide to come in 
before it con- 
tinues its un- 
dersea kelp-cut- 
ting operations 

THE potash 
problem has 
been successfully 
solved. Our supply of 
raw material for its manu- 
facture costs little and is practically inex- 
haustible. Near San Diego, California, un- 
dersea reapers are harvesting kelp, from 
which potash equal to about three times our 
annual importation from Germany previous 
to the war, is made by one concern; a 
second plant of about equal capacity has 
been established in the same vicinity, and a 
smaller plant installed by the Government 
is in operation. Just now, the manufacture 
of munitions requires all that can be pro- 
duced, but we can obtain all that is re- 
quired for ourselves and our allies. 

The reaper cuts the weed four feet below 
the water surface when empty and six 
feet when loaded, the depth having been 

made a Government regulation for conserv- 
ing the supply. Each of the three boats 
in the Hercules fleet takes about five hun- 
dred tons every working day, which means 
practically every day in California. The 
cut kelp is carried aboard the harvester 
on a continuous belt elevator to a mill, 
where it is crushed. The resultant sticky, 
gelatinous mass, deposited in the storage 
hopper, contains about eighty per cent 
water. This is pumped through a six-inch 
pipe. As soon as a capacity load is ready 
it is transferred by pumps to barges and 
thence into digestive tanks on the wharf, 
each of 50,000 gallons capacity. Subsequent 
processes deal with evaporation. 



Popular Science Monthly 

The seats are fast- 
ened to pivoted 
pipe uprights 

At right: The truck carry- 
ing thirty-eight soldiers 

the body are slatted and are hinged along 
their lower edges so that they may be 
swung down to permit of easy access to the 
seats from both sides of the truck. The 
novel body was invented by P. Landes, of 
Chicago. Except for the body, the motor 
truck shown is of the conventional type, 
with no changes necessary for the body 
mounting. It is considered by 
experts who are giving their 
attention to the question of 
transportation of troops 
to be a solution of one 
phase of the problem. 
The seats are so con- 
structed as to allow of 
equal distribution of the 
weight over the wheels. 
This gives necessary bal- 
ance and increases the carry- 
ing capacity. 

Lift Three Floor-Planks and this Motor- 
Truck Carries Thirty-Eight Soldiers 

EQUIPPED with a new type of body in 
which three of the floor planks may be 
raised to form seats, the novel motor-truck 
shown in the accompanying illustrations is 
capable of carrying thirty-eight soldiers 
sitting astride the three seats. By this 
method of seating, the soldiers are carried 
much more comfortably than would be the 
case were they obliged to stand on their 
feet on long overland journeys. It also 
permits every available inch of body floor 
area to be utilized and practically in- 
creases the seating capacity one 
hundred per cent over that of 
the ordinary type of body. 

The three seats are car 
ried on pivoted pipe up- 
rights which can be locked 
in a vertical position 
when the seats are to be 
used. When not em- 
ployed, they can be 
dropped in three min- 
utes in such a manner 
that the top boards of 
the seats are flush with 
the other boards of the 
floor and form a flat 
platform or stake body 
which can be used for 
the transportation of • 
freight, baggage or other 

As shown, the sides of 

bait carrier 
clamped to the rod near the reel 

Carrying Your Hook and Bait Where 
They Won't Drag 

ONE of the fisherman's' troubles, the 
snagging of the hook when walking 
through grass or brush, is eliminated by 
means of a protector which is attached to 
the pole near the reel. The hook with its 
bait is placed in the wooden carrier until 
the fisherman again reaches a place where 
there is space enough to cast his line with- 
out getting it entangled in the brush. The 
minnow or other bait is perfectly protected 
from mutilation, and catching the hook in 
the clothing is also avoided. The 
protector is light, and helps to 
balance the reel on the pole, 
which may |be either of 
steel or wood. The pro- 
tector is attached se- 
curely to the pole by 
a clamp which can be 
tightened by hand. 

So far as casting 
goes, the fisherman 
may probably be in- 
convenienced a trifle at 
first by the additional 
weight of the carrier, but 
he will soon become ac- 
customed to it. The 
carrier is large enough to 
accommodate a plentiful 
supply of bait and hooks 
of all sizes, even those 
used for deep-sea and 

salt-water fishing. 

Popular Science Monthly 



Inflating Huge "Pillows" as Targets 
for Airplane Practice 

TN the days when balloons 

Taking Photographs with a Concealed 
Buttonhole Camera 

lNE of the quaintest and # 

most ingenious detective A^^gg&m^' mn l - fh< \T ^ were more °f a novelty- 
cameras ever devised has been / jfjUBBm*! ICf>ae tnan tne Y are now, gas-bags 
invented by A. A. Ciani, of East (dm y\ were often made in the form 

Orange, New Jersey. It resem- J^ SpVffV Wk* °f animals and human beings. 
bles other cameras in only one J- -U B^ The "pillows" which are shown 

feature, the lens, but even .that Wff in the photograph below may be 

feature is distinctive, so that it \ %W regarded as a relic of that time; 

might be said Mr. Ciani 's camera <S ^JL ^ J \^ S but they are used for a far 

is without a counterpart. It is , f~ ~**\ , more practical purpose than 

designed to be worn concealed / •. were the old man and animal- 

under the coat, in the manner AW Bl shaped balloons, 

shown in the illustration. The fl j Nowadays, the heaviest naval 

protruding lens can be H * ^B guns are the only weapons 

placed in the top button- ^^^,^K - : /*-^fc aD ^ e to decide battles. 

hole of the coat and photo- 4(RHP ^^B m^r ^P^P ^ there were no airplanes, 
graphs taken without any- ^-xm^***^ these guns, too, would be 

one knowing it, by pulling Ja J^^ <*mm\XL powerless; they could not 

a string hidden in the Mw M V mmX. ^ * 4l\ direct their fire tellingly 

pocket. ^^S^A Mm \ J | without aid from a watch- 

Look carefully at the mm\jmv' feb~ a& ^ man m an airplane, 

illustration showing the Ml W— Hence, the fortunes of 

interior of the camera and ■ I H H modern battles rest not 

you will see the shutter, H Sr m5 B only with sixteen-inch 

partly operated, in a ^Hy|M V" B guns but in the last 

sector shape. The shut- ^B ^ jB B^ analysis with airplanes. 

ter appears on either side \nm\ H H H* That explains the stern 

of the lens, in the opening Th e detective camera is worn struggle which is being 

just below the stem. Over concealed under the coat It is wa ^ f supremacy of 

•;, , , . operated by pulling a cord which jt ° . ^ J 

the brass centerpiece, but is led fron ; *£ into the pocket the air. 

not visible in the photo- The "pillows" shown 

graph, are two rubber bands which come herewith are really balloons roughly shaped 

into contact with the sensitized plate, like rectangular wings. Fighting in the air 

By operating a knob on the front side of requires so much skill in an entirely new 

the camera, the centerpiece is turned and sort of marksmanship that the practical 

with it the plate. Four photographs can be British have hit upon the scheme of 

taken on a plate, as there are only four systematically training their air fighters 

teeth on the centerpiece. Every time a in shooting from speedy airplanes at these 

picture is taken the plate is revolved one- odd-shaped balloons. The balloons are 

quarter turn. The shutter is operated by not inflated with gas, as they rest on the 

pulling the floor, but 

string con- + - with air from 

cealed in the a big electric 

pocket. blower in the 

The coat 9 A 71 center of the 

can be but- room. Such 

toned over "im^-i -•#• • # ' - # & a blower 1S 

without in- ft*2feA2l »* J -mvCmnVl' \ every balloon 

convenien- fvT^ll mm mm^m\ factory for 

c i n g the 1 ( nk/^ -A^T jft| ** l ^*dfli Ik*- use * n var " 

wearer and Blta^SL*-— -v^.W- ^' nishing; for 

without ox- 9v^^^^^3K only dis- 

citing the tended bag 

suspicion of ) ™ e "" - ■ - ' _J can be var- 

the one to The balloons are inflated and floated at the end of ropes. nished or in- 

be snapped. British aviators fire down upon them with machine guns Spected. 

Popular Science Monthly 



This Airplane-Camera Takes 750 
Exposures with One Loading 

THE greatest work of the airplane is to 
locate the enemy's strongholds and 
batteries and then map them. 
The multiple airplane-camera 
which the Allies are using — an 
American invention, by the 
way-^-can map the 
German lines with 
truly marvelous pro- 
ficiency. Where, 
in the first part 
of the war, artist- 
observers were 
used to make pencil 
sketches as accu- 
rately and as quick- 
ly as they could, 
now cameras such 
as this one are em- 
ployed to take 
thousands of pho- 
tographs at the rate of one a 
second, if necessary. 

One multiple airplane- 
camera alone is capable of 
seven hundred and fifty ex- 
posures with a single loading. 
The secret of this great 
capacity lies in its use of 
ordinary motion picture film. It is con- 
structed much like the ordinary film 
camera, with the exception that the turning 
of the film for a new exposure is accom- 
plished automatically by the action of a 
set of gears. 

The camera is placed on 
the airplane so that it will 
have an unobstructed view 
downward and slightly for- 
ward. One pull on the flexi- 
ble cable, connected with the 
operating lever of the gears, 
winds up the previously ex- 
posed film, sets the shutter, 
makes the new exposure, and 
registers its number. A 
spring instantly brings the 
lever back into normal posi- 
tion ready for the next pic- 
ture. This happens so swift- 
ly that it is possible to make 
a continuous record of a 
flight. In bomb-dropping 
the camera is capable of tak- 
ing pictures of the bomb in 
the air and at the very in- 
stant of explosion. 


The camera that takes 750 
exposures with one loading 

The Electric Stevedore. It Saved 
$18,000 in Labor Costs in a Year 

BELOW is pictured an electric floor- 
truck that does the work of ten man- 
propelled trucks. The pull- 
ing effort of the single front 
power-wheel is such that a 
railroad flat car weighing 
33,900 pounds is hauled over 
sandy soil, carrying several 
interested observers. 

The truck is the in- 
SHj vention of J. E. Haschke, 
of Los Angeles, the man 
at the wheel. 

The truck weighs but 
1500 pound;?. The mo- 
tor is mounted on the 
yoke of a caster wheel, 
which permits the truck 
to revolve within its 
own wheel base; hence 
its peculiar usefulness 
upon congested floors. 
The wheels are rubber- 
A striking feature is em- 
braced in the two levels of 
the truck, one but twelve 
inches from the floor. Any 
level of platform desired or 
demanded by warehouse needs can be 
provided. The truck will carry a ton on 
its back and tow several tons more on 
trailers; or it will carry several tons of iron, 
for instance, at a time over good streets. 


It would take ten man-oper- 
ated hand trucks to do the 
work of this electric truck 

Popular Science Monthly 


Above: The two hundred sound-proof rooms 
were finished in five days by using a quickly- 
appl'ed, ready-to-put-up composition board 

At right: Putting up the sound-proof board 
material. Standard lengths were used and 
practically unskilled workmen employed 

Two Hundred Sound-Proof Rooms and 
How They Were Built in Record Time 

WITH only five working days in which 
to erect two hundred sound-proof 
rooms in the large Coliseum in Chicago, 
the management of the National Music 
Show was confronted with an extraordinary 
problem. The difficulty was made all the 
greater by the impossibility 
of getting a sufficient force 
of workmen on account of 
the unusual war demands. 
The problem was solved 
by the use of a composition 
board material which proved 
highly efficient in deadening 
sound. In fact, although the 
walls were very thin, as is shown 
in the photographs, no sound of 
the numerous musical instru- 
ments or of voices penetrated 
from one room to the next. 
The rooms also made a very 
handsome appearance. The 
auditorium built for concerts 

had much the appearance of a real audi- 
torium built to stay. 

The rapid construction work was made 
possible by the lightness of the material, 
and the fact that comparatively unskilled 
workers could put it in place. 

A Paper-Disk Flipper for the 
Youthful "Cut-Up/' 

GI RLS and boys alike derive 
endless amusement from a 
new device which throws a 
paper disk larger than a 
"\ silver dollar from a hundred 
, to a hundred and fifty feet 
into the air. The device is 
very simple in its opera- 
tion, but flips the disks to a 
surprising height. You 
simply hold it in your right 
hand, with the thumb on the 
trigger member in the position 
shown in the illustration, then 
remove the thumb suddenly, 
and up or out the disk shoots. 

By removing the thumb 
suddenly from the trigger 
the disk is shot up into 
the air or out, as desired 

In the Grottoes Under the 

While the battle line sways back and 
forth over Verdun, in France, the 
military authorities live underground 
and carry on their business as usual 

At left: The composing room and press 
of "L'Echo de Paris." Underground 
France must have its daily newspapers 

French Official Photos 

An underground fortress from which many a battle has been directed. There are numerous 
telephone connections and the commanding officer follows on his map the movements of the troops 

In spite of their cellar quarters strict records 
of all affairs are kept by the city officials 

From this subterranean office all permits 
are issued for travel on the city streets 


The Trench Farms of the Philippines 

Notwithstanding the fact that rice grows best in valleys where the soil is rich and 
where it is kept flooded almost continuously until the grain matures, the Filipinos, 
who are as dependent upon rice as are the Japanese and Chinese, have succeeded 
in growing it upon mountainsides. There is of course a variety called "upland 
rice," which requires less water than that grown in the valleys, but even this is 
grown in marshy soil, kept wet by a trench system which holds back the rain and 
the irrigating streams preventing the water from flowing down the mountain and 
holding it in grooves in which the rice is planted. Huge water buffaloes are used 
to drag the plows and harrows through the mud. Sometimes these animals are 
blindfolded and made to turn wheels which elevate the water from the streams to 
the trench-fields. After the rice sprouts are set out, the water must be let off from 
time to time to permit weeding and cultivation, but it never destroys the ledges 


Remote from Man the Eagle Builds — But Alas! 

A pair of young eagles, two 
months old, in captivity. 
They have just been cap- 
tured from a nest on 
distant mountain. Note the 
wild look in their eyes. 
This is never entirely lost 

Bringing a young one to earth from its 
aerial roost. When two months old, 
eagles are ungainly creatures. They 
have not sufficient strength to use 
their wings and hence are helpless 

At right: A searching party and mo- 
tion picture operator returning to 
earth after a successful hunt. In 
addition to the danger of breaking 
their necks the hunters face the risk of 
being attacked by the mother bird 

Bungalows on the Roof of a Post-Office 

The post-office occupies the ground floor, and the bungalows take up the space that 
would otherwise be the second floor. The nine bungalows rent for $25 a month each 

Above: The top 
of the post- 
office bungalow 
colony. The 
windows seen on 
the second floor 
as one looks at 
the building 
from the street 
are the windows 
of the bungalows 

The bungalow 
residents have 
the advantage 
of being down- 
town and at the 
same time of 
living in an at- 
mosphere far re- 
moved from that 
of an ordinary 
apartment house 


And the Inventors Never Cracked a Smile 

Rockers more than ordinarily 
accommodating. The one at left 
above is a veritable rocking horse. 
The other has an additional 
rocker to prevent it from rocking 

One of the fountain 
pens above was. in- 
vented in 1847. The 
ink was contained 
in the bulb section 
and sent down to 
the point by pres- 
sure on the piston 
rod. Note the two- 
pointed pen and 
the pen with 
leather finger loops 

The chair below is a 
life - saving device 
made of zinc. When 
the ship sinks you 
float off into the 
water still seated 
and enjoying your 
paper and cigar 

Patented 'way back 
in '57, for floating 
horses across 
streams. Four 
bladders, inflated 
with air, are strap- 
ped to the 
to buoy him up 

To get those 
highboots of '61 
off, bootjacks 
were used. The 
chair has a kind 
of oarlock for 
this purpose and 
the shoe has a 
brass projection 
which slips back 
into a groove in 
the leather heel 
when not in use 


France's Tank Contribution to the War 

The tank all 
France is talking 
about. It is fitted 
with heavier guns 
than the British 
tanks, but it has 
not made any par- 
ticular name for 
itself in the fighting 
so far. The usual 
type of caterpillar 
drive is used 

Major Bossut and 
Lieut. Boucheron 
and the new tank. 
The photograph 
was taken just be- 
fore the tank broke 
down inside the 
German lines. 
Rather than see it 
fall in enemy hands 
Major Bossut 
blew up the tank 
killing himself 

Photos (g) Underwood and Underwood 


They Earn Their Living Simply by Seeing, 

Contrary to expectation tobacco 
is sampled by .the sense of 
touch. If the leaf does not feel 
right to the sensitive finger-tips 
of the expert it is rejected 

The coffee taster is a half brother 
in trade to the tea taster. He 
never drinks coffee; he tastes it. 
His beverage is made a sip at 
a time in a porcelain coffee 
pot on the French drip method 


Hearing, Smelling, Tasting and Feeling 

The motion-picture director 
holds his job on the strength 
of his eyes plus his imagina- 
tion. Every time he examines 
a film visually he imagines 
himself to be a hundred thou- 
sand picture fans all in one 

With ears trained to detect 
errors, some men are expert 
listeners. Singers as well 
known as Caruso are some- 
times obliged to abide by the 
verdict of a listening jury, 
such as the one shown above 

Tea tasters are employed by 
every first-class tea concern 
and by the customs officers of 
all the Governments. Some 
of the tea experts chew the 
leaf, some judge by smell 
and some sip the beverage 

555353 Q 


Cats? Demons? No; Just Chunks of Wood 

Some of the curious images appear just as Mr. Ogden found them in the woods. Others suggestive 
of the hapless creatures that Dante saw in the Inferno have been shaped with the penknife. 
There are no particular names for these dignitaries and no special uses except as "ornaments" 


There Is Pleasure as Well 

as Profit in Skunks. Your 

Next Year's Fur Coat May 

Come from a Farm 

Like This 

Above: Skunks make admirable 
pets when they are young. They 
are as playful and as harmless 
as kittens. Only the older ones 
need to be handled with care 

The striped skunk is the only 
one that makes money for the 
breeder. In return for good care 
and feeding its fur becomes ex- 
ceptionally thick and glossy 

The skunks are given as much freedom as possible in wire pens. They are great diggers, 
consequently they have to be watched continually and the pen walls constantly renewed 

The New Eagles of the Western Front 

The latest Nieuport "Avion de Chasse," or fighter, mounts three machine guns. Two 
on top of the plane fire over the propeller and one beneath the upper plane fires through 
the propeller. The perfect streamline body, the small wings and rudders and the big 
propeller with a hood in front enable the machine to travel at 120 miles an hour 

Machine gun showing How it is airtcooled by 

violent slipstream, of propeller * * 

The new fast armored Farman 
fighting plane. Only one ma- 
chine-gun can be carried because 
of the armor's weight. Another 
view of this machine appears 
at the top of the next page. 
The armor over the cylinder 
heads of the engine is perforated 
so that cooling drafts may enter, 
the strong slipstream from the 
propeller entering through the 
circular opening in front, passing 
through the radiator and finally 
emerging through these holes 

The three machine guns of the "Avion de Chasse" are aimed by pointing the whole 
machine straight at the enemy. They are fired simultaneously by the single pilot. 
Ordinary machine guns are used, evidenced by the useless rear handles and pistol grips 


Armor Appears on the Airplane 

On this and the preceding page we present pictures of the newest French airplanes — 
an unarmored fast fighting Nieuport "Avion de Chasse," a fast armored Farman 
biplane, and a heavy weight-carrying Caudroa, all of which are in active service 

Freucti Ollicial 

In the new armored Farman biplane the exhaust is carried far behind the pilot through 
a perforated tube. A certain amount of muffling is also thus attained. The machine 
gun is obviously cooled by forced draft produced by the violent slipstream of the 
front propeller. The armor leaves much of the really vital portions of the 
machinery necessarily exposed, such as part of the radiator; still it increases safety 

Either one of the pilots of the two-motored Caudron may stand up in turn and fire 
the machine-gun, the man in front rearwards, and the man behind either ahead or abeam 


What's Your Hurry? Here's Your Army Hat— and the 

Below: Sewing the 
sweat band on a 
finished hat. A 
machine does the 
sewing in one-half 
the time required 
by hand operators 

The first process in 
making an army 
hat is shown above. 
The metal shaping 
cone is placed over 
the fur and revolv- 
ed at great speed 

At right: Making 
the crown and 
brim smooth by 
putting the hat 
through a series of 
grinding rollers cov- 
ered with fine emery 

The inspection ta- 
ble. After the hats 
are shrunk and 
dyed they are ex- 
amined before be- 
ing sent on to 
the forming room 

Below: The cone 
of fur as it is re- 
moved from the 
blowing machine. 
It is very soft and 
delicate requiring 
careful handling 

which stretches the 
edge of the hat 
until it resembles 
a brim. Shellac 
gives the stiffening 


Processes Through Which It Passed in the Making 

Two stages in the molding of a 
kat are shown below. In the 
man's left hand is a hat which 
has just come from the pressing 
mold. The hat in his right hand 
is the "before pressing" model 

Forming the hat in 
a steam-heated 
press. A steel die 
in the lower part of 
the mold gives the 
finished hat its size 
and desired shape 

Above: Cutting the 
brim of the hat to a 
uniform width. As 
the work is done by- 
machine there is no 
chance for error 

The hats are dipped 
in shellac, then 
passed upward 
through rollers 
which wring out 
the surplus liquid 


Wood Carving by Machinery -A Novice Can Do It 

The original carv- 
ing shown here was 
made in plaster of 
Paris. The repro- 
ductions in wood 
were made by a 
machine which con- 
sists of a battery of 
four rotating drills 
and a stationary 
rod which the ope- 
rator moves over 
the outline of the 
pattern. Every 
movement of the 
master rod is dupli- 
cated by the four 
repeating drills 

When a very large 
number of repro- 
ductions are to be 
made of a certain 
design, the original 
is generally made in 
wood. With this 
machine one novice 
can do the work 
of five skilled men 


New Fashions in Gas Masks 

The mask which is in use at 
the present time by the English 
and the French. To the sol- 
dier in the trenches the gas 
mask is as important as his rifle 

Worn for gases which are 
poisonous but which do 
not affect the eyes. The 
mouth and nose are pneu- 
matically sealed by a 
rubber-faced cushion 

Impervious to smoke and flame, 
the mask is made of asbestos 
and is worn by rescue squads in 
fires and explosions. An entire 
suit of asbestos accompanies it 

Mask used by our submarine 
sailors when salt water 
reaches the electric storage 
batteries and chlorine gas 
is generated in consequence 

Worn for protection against 
chlorine gas by workmen who 
are constantly exposed to the 
gas in chlorinating plants 


Like a dentist he removes all de- 
cayed matter from a cavity 

THE science of tree surgery is but 
twenty years old. Yet it has already 
become of inestimable value. It is 
saving thousands of shade trees and fruit 
trees each year. All trees, and sweet- 
sapped trees especially, are liable to fungus 
disease. The fungus is a parasite by 
nature and sends 
little, thread-like 
tentacles into the 
woody tissue. 
These travel 
from cell to cell, 
the internal 
structure of the 
tree. The result 
is what we call 
"rot." When 
fungus starts in a 
tree it never 
stops unless ar- 
rested by human 
skill. The tree 
surgeon alone 
can destroy the 

The accom- 
panying illustra- 
tions show how 
useful tree sur- 
gery can be. In 
one of the illus- 
trations is shown 
steel cables 
strung between 

the upper a sick tree on the way to 

branches so that filling reaches almost to 

Operating Upon Trees 

When trees get sick or are dam- 
aged they need the tree surgeon 

the weakened trunk would not be unduly 
strained under the action of the wind. 
This was a comparatively easy task, but 
real tree surgery is not simple. It is a diffi- 
cult and exacting art. Some trees require a 
combination of bolts and lock-nuts, rein- 
forcing rods and cross-bolts with lock-nutr; 
above the crotch. Others need a combina- 
tion of bolts and criss-cross bolts with lock 
nuts, tortion rods and chains, and still 
others call for iron straps, tortion rods, 
iron backbone and ribs in addition to 
chains and la*g-hooks higher up. 

Another illustration shows large cement 
fillings built up in separate block sections to 
allow swaying of the tree. In a very short 
time, the edges of the cut "heal" to the 
cement. That is, the soft living tissue 
solidifies upon the cement, making a tight 
joint which is waterproof. Often the bark 
at the sides of the patch gradually grows to- 
gether closing 

health. The cement 
the heart of the tree 

over the cement. 
Young trees are 
not so difficult to 
doctor. One of 
their chief ene- 
mies is the bore 
worm. The tree 
surgeon, upon 
discovering a 
worm hole in the 
tree drills into it 
with a stiff wire, 
kills the worm 
and fills up the 
hole with tar. 

But tree sur- 
gery is not merely 
a matter of filling 
cavities. Unless 
the work is scien- 
tifically accurate 
and mechanical- 
ly perfect, it fails. 
Since decay de- 
stroys the struc- 
tural strength of 
the tree, this 
strength must be 
restored by me- 
chanical means. 


Tree Surgeons at Work 

Above : Healing soon takes place 
and the cambium (new growth of 
bark) rolls gradually over the 
cement filler, sometimes com- 
pletely concealing the patch 

Left: A tree whose trunk 
split asunder. The doctor has 
inserted eyebolts and has drawn 
the branches together again 
by means of wire cables 



Popular Science Monthly 

The food barrows of London serving meals ready prepared 
and hot or cold to patrons of the community kitchen 

A Kitchen on Wheels — the School 
Children Serve the Meals 

IN St. John's Wood, London, the com- 
munity service idea has been worked 
out to a nicety in relation to the kitchen 
and the serving of meals. Not only are 
housewives and others relieved of the duty 
of cooking the meals, but 
school children of the locality 
are pressed into service as 
cooks and waiters. 

Every day the food is sent 
out from the community 
kitchen in what are called 
food barrows. These are 
wheeled through the 
streets and are stopped 
upon demand at the 
doors of prospective 
customers or old pa-j 
irons. The food is 
carried in big alum- 
inum pots and ves- 
sels which fit into a 
metal container 
filled with water 
which may be boiling 
hot or ice-cold, ac- 
cording to whether the 
food is to be served hot 
or cold. 

Soup, coffee, and vege- 
tables of all kinds, meats 
and desserts are served 
in any desired amounts, 
in individual portions, or 

enough for an entire The kerosene passes drop by drop 

family repast. into the pipes over the flames 

Change Your Coal Stove 
Into a Gas Range 

WHEREVER kerosene oil 
is to be had, it is possible 
to convert your coal stove 
quickly into the decidedly more 
convenient gas range. A new 
attachment put on the market 
for this purpose is sufficiently 
simple for the least initiated to 
operate. A kerosene tank is 
screwed to the wall and the 
clamps on the burners are at- 
tached in the stove's fire box. 
From then on you will forever 
be free of the bother of both 
the coal bucket and its col- 
league, the ash pan ! 

The attachment is in reality a 
miniature gas plant. After fill- 
ing the tank with kerosene oil, the valve 
is opened until the oil begins to trickle 
from the burners. The valve is then closed 
and -the little oil previously placed in 
the iron pan under the burners is lighted. 
The heat from the burning of this oil 
causes that in the pipes above it to 
evaporate. As soon as this happens, the 
gas issues from the burners and it is ignited 
also. The intensely hot flames then given 
out can be directed on to whatever parts 
of the stove they are needed. 
Having once started the 
evaporation of the pipe 
oil, the tank valve can 
be again opened. What- 
ever oil thereafter flows 
from the tank will evap- 
orate in the red-hot 
:pipes over the burners 
and be converted 
into gas. One drop 
of oil will produce 
an immense amount 
of gas; obviously, 
then, the tank will 
be exhausted very 
slowly. The fact is 
that not more than 
two cents' worth of 
oil need be used up 
in an hour, according 
to the inventor, who 
also emphatically de- 
clares that there is posi- 
tively no element of 
danger in the device. 
"A little child can man- 
age it," he says. 

Popular Science Monthly 


Did You Hit the Target? 
This Target Answers 

ONE of the objections to rifle shooting 
from the standpoint of the spectator is 
that you can't see what is going on — the 
results of the shot, as you can when you 
watch shotgun shooters smash clay 
birds. To make the game more inter- 
esting to the spectator and to mark the 
target for the shooter without 
the necessity for walking out 
and retrieving the target or 
hauling it in on its carrier, 
Frank C. Reed, of Springfield, 
Ohio, has designed and put on 
the market what he terms the 
"spot shot" target. He takes 
advantage of the fact 
that if you ex- 
tinguish all front 
lighting on 
a paper and 
put a strong 
light be- 
hind it, any 
will show 
plainly in 

In a strong iron box he puts front lights of 
suitable strength and arrangement to best 
light up the small cardboard indoor minia- 
ture rifle target, and protects these as usual 
by a steel plate. 

Behind the target, which slides into 
grooves formed in the box, is a funnel- 
shaped passage leading back from the 
target to a movable plate at the end of an 
arm that con- 
trols a circuit 
breaker for I ; 
light circuit 
and for the 
normally ex- 
light behind 
the target. 
This arm also 
operates a 
dash-pot or 
air-jacket that 
slowly draws 
the arm and 
its plate down 
to place again, 
breaking the 
circuit for the 
backlight as it 

does so, and again lighting the front lights. 
When the bullet passes through the card- 
board target in the holder, it continues on 
down the funnel, striking the steel plate and 
driving it and its arm into the air. The 
bullet then continues into a curved bullet- 
stopper of heavy steel 

5fop to break impact and comes to 


ly, by the 
action of 
the arm 
driven vi- 
upward by 
the bullet, 
the front 
lights are 
put out 
a n d a 
light from 
the rear 

At left : A circle of light shows __. . _ _ i c ^ i_ _ 
the bullet hole. Above: The reveals t tic 
details of the lighting device target hole. 

Before dropping it into the "Long Tom" the washers toss 
the sand high in the air to catch the glitter of the gold 

Washing for Gold in the Clayey Soil 
of the Guianas 

IN working for gold in the Guianas, where 
sluices are impossible because the soil is 
clayey, the ground is worked with a "Long 
Tom," a puddling-box about eight feet 
long. The torn is filled with the gold- 
containing mass by a spade-man and a hoe- 
man. The larger stones collect against the 
perforated iron plate at the end of the box 
fitted with 
riffles through 
which the dirt- 
bearing water 
flows. The 
worker throws 
the stones high 
in the air, 
watching for a 
glitter of gold. 
To make sure, 
he catches 
them again 
and perhaps 
repeats the 
trick, w h i c h 
seems simple 
but really de- 
mands the 
highest skill. 


Popular Science Monthly 

The latest fashion 
in helmets — the 
screen-like visor 
which protects 
the eyes. It can be 
raised and lowered 

A Screen Visor Is Added to the 
French Helmet of Steel 

A REVERSION to primitive methods 
has been one of the remarkable fea- 
tures of this war. In our school days we 
learned that soldiers gave up the use of 
armor because they could fight better 
without it, and because it afforded no ade- 
quate protection after firearms became 
available. Now we must change our minds 
all over again, for trench helmets of steel 
are considered absolutely indispensable and 
even chain armor is used. 

The French were perhaps the first of the 
warring nations to actually equip their 
men with bullet-proof headgear, and they 
are the first to attach a screen-like visor of 
steel to the helmet for the protection of the 
eyes, as the photographs above show. 
The visor can be raised and lowered 
and when in the latter position it af- 
fords the eyes protection against shrap- 
nel and shell splinters. Judging by the 
size of the-perf orations, the visor would 
hinder rather than assist 
the soldier when he is 
required to take accurate 
aim in firing. 

Creating a Vacuum to Induce 
Artificial Respiration 

ANEW type of resuscitating device 
which commands attention because of 
its novelty if for nothing else, has been in- 
vented by H. E. Acklen, of Memphis, 
Tenn. A rubber cup which creates a 
vacuum when operated after the fashion of 
a pump is the inventor's method of 
methodically raising and lowering 
the patient's diaphragm to induce 
breathing. Whether the rubber 
cup is strong enough to raise 
the chest and lower it, is the 
question upon which the 
practicability of the 
apparatus rests. At first 
thought it would seem as if 
the cup would have all it 
could do to raise the leather 
pad and the skin, to say 
nothing about the chest. 
But if there is a question 
regarding the raising capabili- 
ties of the device, there is no 
question but what it is suffi- 
ciently strong to depress the chest. 
The handle enables the operator to 
exert a considerable pressure on the in- 
strument. The vacuum device is secured 
against the chest by straps which are held 
to the floor under the operator's feet, as 
the illustration shows. The up and down 
movement of the device may be regulated 
by the straps under the feet of the operator. 
They also hold the patient down. 

If the apparatus proves practicable it will 
doubtless be the quickest method yet devised 
for resuscitating the all-but-drowned. The 
pressure on the abdominal walls will force 
the water out of the stomach. 

Raising and lowering the 
chest with the rubber cup 

Popular Science Monthly 

U-:washed Sponges Are Fifty 
Per Cent Dirt 


quantities of sponges have found that 
in buying them at a fixed rate per pound, 
they were paying too much for plain earth. 
They now require every carload of sponges 
to be analyzed. Samples are taken from 
each car and weighed. They are then put 
through a standard washing process and 
weighed again. Fifty per cent impurities 
have been found in many cases. 

Using Live Steam or Vapor to 
Save Gasoline 

THE device shown below is designed to 
reduce the consumption of gasoline 
by introducing live steam or vapor into the 
intake manifold of an automobile engine, 
especially on -those carburetors which are 
difficult to adjust properly. The apparatus 
consists of a small cylindrical chamber 
screwed into the exhaust manifold, which 
contains a rotary valve controlled by a 
cable from the driver's seat. Hot exhaust 
gas is introduced into the chamber through 
a port in the rotary valve, where it meets 
a small amount of water drawn through a 
pipe tapped into the water-circulating sys- 
tem. Meeting the hot gas, the water is 
turned into steam and thence fed to the in- 
take manifold through another pipe where 
it mixes with the fuel from the carburetor 
to form a more economical mixture. The 
amount of v.a- „ ,. 


ter entering 
the rotary 
valve is con- 
trolled by a 
small needle 
valve at the 

Besides pro- 
ducing a more 
econom ic al 
mixture, the 
presence of a 
small amount 
of water vapor 
in the cylinders 
tends to soften 
the deposit of 
carbon and 
retard addi- 
tional forma- 

ater circulation 

The evaporation-cooled refrigerator is the Cali- 
fornian's answer to the desert's blistering heat 

The Imperial Valley Is Off the Ice-Man's 
Route: Hence the Burlap Cooler 

YOU can fry an egg on a rock in the 
Imperial Valley of California by 
letting the sun do the cooking, but a 
Rockefeller couldn't afford the price of a 
tumbler of cracked ice. But this does not 
mean that the Californians have to do 
without food refrigerators and various 
cooling devices. J. G. Hill, of Mecca, near 
the Salton Sea, has contrived an evapora- 

Control wire to steering 

The principle of the gas-saver involves moist air heated 
from exhaust gases and introduced into the manifold 


which requires 
no ice. 

It has a 
wooden frame- 
work, and in- 
cludes numer- 
ous shelves. 
Several layers 
of burlap cover 
it. A perfo- 
rated tin can 
at the top is 
connected with 
hose which 
sprinkles water 
over the entire 
burlap surface. 
The evapora- 
tion keeps the 
interior cool. 


Popular Science Monthly 

Surveyors climbing to the top of a precipi- 
tous cliff in Alaska to take observations 

Risking Lives for the Sake of Pre- 
cision in Government Surveys 

ONE of the most difficult and exacting 
tasks of an extensive land survey 
made by the United States Coast and 
Geodetic Survey, is the selection of points 
from which observations may be taken. In 
heavily wooded country it is necessary to 
climb the tallest trees or to raise poles 
taller than the trees, from which the distant 
horizon can be seen and such observations 
made as may be practicable. In 
mountainous country such as Alaska 
the surveyors have to face death 
for the sake of precision, 
climbing the highest peaks in 
order to obtain an unob- 
structed view of the hori- 

Why risk one's neck to 
make a simple survey " 
Because when great pre- 
cision is desired it is im- 
possible with chain or 
tape to survey a region 
in which there are bays, 
rivers, mountains and 
other natural obstruc- 

tions. To overcome these difficulties the? 
method called "triangulation" is employed. 
It rests upon the simple proposition taught 
in every school that if one side and the 
angles of a triangle are known the remain- 
ing sides can be computed. It is to obtain 
the first side of a triangle, or base line, that 
the surveyors climb the highest trees and 
mountains. So painstaking is their work 
that in a survey of one hundred miles the 
error is often less than five feet. 

The accompanying photograph shows a 
Government surveying engineer climbing a 
steep cliff in Alaska, prior to establishing 
a base line. On his back he carries the 
necessary surveying instruments. On the 
top of the cliff stands a companion engineer 
who undoubtedly scaled' the cliff without 
assistance. The feat is made safer' for the 
second man because of the rope which has 
been lowered to guide him in his ascent of 
the nearly perpendicular^ surface. 

If he is to measure a great distance from 
the top of the cliff the only instruments the 
engineer will use will be heliotropes (not 
helioscopes) by day and powerful lights by 
night. The heliotrope is a small mirror so 
arranged that it reflects the sunlight in a 
long line toward the observer. 

Keeping School Desks Presentable 
with Cardboard Covers 


The cardboard cover keeps the 
school desks always presentable 

JANITOR of a school in 
Pasadena, Cal., has found 
way to keep the desks in 
his classrooms looking 
bright and presentable 
without subjecting them to 
frequent planing and var- 
nishing. He slips over the 
desk tops a pressed-card- 
board cover, which he calls 
an envelope. The enve- 
lopes are made to conform 
with the general shape of 
the desk tops, and the 
outer edges are bent down 
and back and riveted, so 
that the cover will slip on 
over the desk top and will 
remain in position after it 
has been adjusted. 

There is a groove in- 
dented at the top of the 
cover to receiye pencils and 
pens, and a circular open- 
ing is provided through 
which the inkwell shows. 

Popular Science Monthly 


The More Fruit You Eat the Less 
Water You Need Drink 

MOST fruits contain from 75 to 95 per 
cent water, and a balance of woody 
fiber, or cellulose, fruit sugar and minerals. 
Thus the free use of fruit daily, insures a 
greater supply of water to the body. 

The cellulose of the fruit supplies bulk 
and a mechanical stimulation which pro- 
motes waste elimination. Acid fruits, such 
as oranges, lemons, limes, and most ber- 
ries, contain a certain chemical compound 
called "vitamines," in a very stable form. 
These vitamines are believed to purify the 
blood and to prevent scurvy and various 
skin diseases. 

Do Your Telephoning While Riding 
On a Trolley-Car 

WHAT an advantage to be able to 
telephone from a moving train ! Sup- 
pose you want to warn your wife that 
you are bringing a friend home 
dinner. How easy, if you could 
take down a receiver in the 
trolley-car and break the 
news to her while you are 
yet afar off. Or, maybe you 
are a detective and have 
spotted a long-sought crim- 
inal. A telephone would 
enable you to communicate 
with headquarters at once. 

At any rate, L. Zsitovs- 
zky of Philadelphia, has 
shown that this can be 
done by inventing an ap- 
paratus attachable to an 
ordinary trolley-car. In 
addition to the regular 
feed wire above are two 
other parallel wires for the 
transmission of messages. 
Contact is effected by small 
trolleys similar to the large 
trolley. The two wheels 
are mounted on arms con- 
necting with a split collar, 
attached to the end of a 
metal pole on the top of 
the car. 

The wires pass down 
through the pole and enter 
the telephone instruments 
in the ordinary way. They 
are arranged below the 
feed wire as a means of 

The train - telephone. The 
telephone wire is arranged 
below the trolley feed wire 

The lock fits over the porcelain terminal 
that extends from the magneto case 

A Lock Which Makes the Ford Car 
Thief Proof 

POLICE statistics show that 
thieves are constantly steal- 
ing Fords. There are plenty 
to select from and they are 
easy to dispose of. The 
lock illustrated bids fair to 
reduce to a marked extent 
the get-aways. It shuts off 
the ignition at its source. 
The design and location 
of the Ford magneto lends 
itself readily to the posi- 
tioning of the device. The 
lower end of the cartridge 
fits over the porcelain ter- 
minal that extends from 
the magneto case, while the 
top of the lock extends 
through a hole in the floor 
of the car which places the 
device conveniently under 
the coil box on the dash. 

By pressing the small 
lever down with the foot, 
the engine is shut off and 
the ignition system locked. 
A special serial key is re- 
quired to unlock and place 
the system in operation. 
When locked it is impossi- 
ble to make a new connec- 
tion with the magneto, 
since forcing the lock from 
its support will destroy 
the connections and render 
the magneto inactive. 


Popular Science Monthly 

The bottles contain inks of different colors. 
Each pen acts as a guard for its bottle 

Don't Drench a Plant: Water It 
Drop by Drop 

LUCIEN [DANIEL, a French botanist, 
j has discovered that young hothouse 
plants and slips of vegetables, as well as 
flowers, thrive far better by a system of 
continuous watering than by drenching the 
soil at stated periods. The new method 
depends upon the law of capillary attrac- 
tion. Near each plant is placed a jar con- 
taining water, into which is dipped one 
end of a strip of linen or cotton, whose 
other end lies near the plant. With this 
uninterrupted supply of water, drop by 
drop, the plants thrived, greatly outdistan- 
cing other plants, which were submitted to 
an intermittent drenching. 

Using a Dozen Different Inks With- 
out Making a Mistake 

MECHANICAL draftsmen, architects 
and map makers often use as mani- 
as ten inks of different colors in making a 
complicated drawing. Sometimes it hap- 
pens that the engrossed artist thrusts his 
pen into the wrong bottle of ink and draws 
a blue instead of a red line. Then follows 
an effort to erase the wrong line, with 
consequent loss of time. 

Frank B. Gilbreth, the well-known effi- 
ciency engineer, overcomes this 
difficulty very simply and ef- 
fectively. He has devised a 
special stand, to hold both 
the ink bottles and their 
pens. As the accom- 
panying photograph 
shows, each pen is 
thrust vertically into 
a hole directly in 
front of its bottle. 
The pens thus con- 
stitute a barrier in 
front of the bottles. 

When a green line 
is to be drawn, the 
draftsman picks up 
the proper pen and 
thus clears the way 
for the green-ink bot- 
tle; only that bot- 
tle and no other can 
be reached. It is 
impossible to thrust 
the pen into the 
red-ink bottle, be- 
cause that is guarded 

The Sailors and Marines Sleep On 
Their Life-Preservers 

IT MUST afford considerable consolation 
to the Navy recruit to realize that the 
mattress on which he sleeps so comfortably 
at night will stand him in good stead in 
case of an accident to the ship. In fact the 
very buoyancy which makes it such a 
comfortable bed is also the quality which 
makes it possible for it to be converted at a 
moment's notice into a life- 

The mattresses are 
stuffed with kapok, a light- 
er-than-cork material 
which is imported from 
the West Indies in bales 
similar to bales of cot- 
ton. It is made from 
the seeds and silk of a 
tree not unlike the 
cotton-wood tree, but 
instead of being in 
puffy balls, the kapok 
is in slender threads, 
which when compressed 
make a mass that is 
six times more buoyant 
than cork. 

Thin layers of the 
kapok are enclosed in 
strong ticking for the 
mattresses. Each mat- 
tress is provided with 
tapes long enough to tie 
around the body and 
over the shoulders, as 
shown in the illustration. 
It requires only a minute 

by its pen. 

tion in their life-preserver mattresses to adjust them. 

Hurling Barbed Wire at the Enemy 

A projectile is used from which barbed wire is 
uncoiled after it is shot at the onrushing troops 

When the projectile explodes, the caps containing the barbed wire shoot out 
like bullets in all directions distributing the wire in great tangled masses 

/%FTER a murderous ar- 

r\ tillery fire has swept away 
the ordinary barbed wire 
entanglements in front of a 
trench, there is nothing to 
impede the onrush of 
troops except machine-gun 
and infantry fire, accom- 
panied, at certain times, 
by well-placed barrage fire 
from the rear. Under 
most conditions this re- 
sistance is sufficient to 
deplete the ranks of an in- 
vading force but the fact 
that the first, second and 
third line of trenches may be captured in a 
single charge is proof that gun fire alone 
cannot dissipate a body of troops. There 
have been numerous occasions in this war 
where troops of both sides have deliberately 
plunged through a heavy barrage fire to 
carry a line of trenches. 

Accordingly, Enid S. Wales, of Detroit, 
Michigan, has invented a novel projectile 
which shoots barbed wire instead of bullets. 



Four hollow caps con- 
tain the barbed wire coils 

His idea is to first impede 
the progress of an onrushing 
body of troops by spreading 
coils of barbed wire in front 
of them and then to attack 
them with infantry and 
machine-gun fire. The in-