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FIRST             edition,  published  in  three            volumes,  1768 — 1771. 

SECOND                                          ten  1777—1784. 

THIRD                                                eighteen  1788 — 1797. 

FOURTH                                          twenty  1801—1810. 

FIFTH                                                 twenty  1815—1817. 

SIXTH                                                 twenty  1823 — 1824. 

SEVENTH                                          twenty-one  1830—1842. 

EIGHTH                                           twenty-two  1853 — 1860. 

NINTH                                                   twenty-five  1875—1889. 
(ninth  edition  and  eleven  supplementary  volumes),      1902 — 1903. 

ELEVENTH               published  in  twenty-nine  volumes,  1910 — 1911. 

TWELFTH                 (eleventh  edition  and  three  new  volumes),  1922. 


in  all  countries  subscribing  to  the 
Bern  Convention 


All  rights  reserved 










THE  PERIOD  1910  TO  1921   INCLUSIVE 







Copyright,  in  the  United  States  of  America,  1922 


The  Encyclopaedia  Britannica,  Inc. 













IF  it  had  not  been  for  the  World  War,  there  would  not  have  been  any  occasion,  so  early 
as  1922,  for  a  Supplement  to  the  Eleventh  Edition  of  the  Encyclopaedia  Britannica, 

as  published  in  1911.  But  for  the  exceptional  situation  so  created,  the  original  inten- 
tion not  to  take  in  hand  anything  equivalent  to  a  Twelfth  Edition  until  a  much  later  date 
would  undoubtedly  have  been  maintained. 

So  colossal  a  convulsion,  however,  as  that  of  the  war,  with  consequences  shown  in  so 
many  unexpected  directions  and  radically  changing  the  world-outlook  under  the  new 
conditions,  made  the  need  for  this  prompt  addition  to  universal  history  absolutely  impera- 
tive, as  a  record  and  illumination  of  so  peculiarly  dark  and  complex  a  period.  The  gap 
between  1911  and  1921  is  all  the  more  noticeable  because,  from  the  middle  of  1914  onwards, 
authentic  history  could  not  be  written  at  all,  as  had  been  practicable  normally  under 
earlier  peace  conditions,  in  such  periodical  publications  as  have  usually  served  the  require- 
ments of  the  public  for  purposes  of  reference  on  contemporary  affairs.  The  very  nature 
of  the  war,  and  of  the  war  conditions  which  persisted  even  after  the  Armistice,  not  only 
involved  the  imposition  of  secrecy,  the  cutting  off  of  intercommunication,  and  even  an 
interested  perversion  of  fact  in  much  that  was  given  out  for  belief,  but  also  led  to  a  state  of 
paralysis  and  aphasia  in  the  spheres  where,  before  the  war,  independent  observation  and 
judgment  were  to  be  found.  Attention  was  monopolized  everywhere  by  conditions  of 
urgency  and  emergency,  and  concentrated  upon  the  immediate  conduct  of  life,  while 
almost  every  expert,  whether  in  scholarship  or  in  science,  was  living,  so  to  speak,  from 
hand  to  mouth,  with  his  accustomed  intellectual  activities  interrupted,  suspended,  or 

In  such  circumstances  there  arose  inevitably  a  clear  call  for  the  publication  of  a 
Supplement  to  the  Encyclopedia  Britannica  at  as  early  a  date  as  was  practicable  after  the 
war,  conformably  with  the  arrival  of  a  stage  in  post-war  reconstruction  which  would 
once  more  enable  its  Editor  to  secure  a  reasonable  modicum  of  the  disinterested  inter- 
national cooperation  on  which  the  value  of  the  Encyclopedia  Britannica,  as  a  critical 
record  of  world-history,  has  so  long  depended. 

These  New  Volumes  of  the  Encyclopedia  Britannica  accordingly  follow  precedents 
established  during  the  154  years  since  it  made  its  first  appearance  in  1768.  Between  its 
Third  (1788-97)  and  Fourth  (1801-10)  Editions,  a  two-volume  Supplement  (1801)  to  the 
Third  Edition  was  published;  and  while  the  Fifth  Edition  (1815-7,  a  reprint  of  the  Fourth) 
was  still  current,  and  the  reedited  Sixth  (1823-4)  was  nearly  ready  for  issue,  a  "Supple- 
ment to  the  Fourth,  Fifth  and  Sixth  Editions,"  edited  by  Macvey  Napier,  appeared  in 
'six  volumes  during  1816-24.  In  1902  again,  by  way  of  supplement  to  the  Ninth  Edition 
(1875-89),  there  were  published  eleven  New  Volumes,  forming  in  combination  with  it  the 
Tenth  Edition,  for  the  general  editorship  of  which  the  present  writer,  taking  over  the  task 
early  in  1900  from  the  late  Sir  Donald  Mackenzie  Wallace,  was  responsible.  Incidentally 



those  eleven  New  Volumes  set  a  new  precedent  in  publications  of  this  kind  by  being 
prepared  and  issued  simultaneously,  and  the  same  method  was  subsequently  adopted  in 
the  preparation  of  the  Eleventh  Edition  (1911). 

Had  it  not  been  for  the  war,  the  twenty  years  between  the  average  date  of  the  Ninth 
Edition  (25  Volumes,  1875-89)  and  the  date  of  its  supplementary  New  Volumes,  which 
were  added  to  form  the  Tenth  Edition  (1902),  may  be  regarded  as  indicating  the  length 
of  interval  which  might  well  have  been  expected  to  follow  the  publication  of  the  Eleventh 
Edition  before  it  in  turn  had  a  supplement  added  to  it,  to  form  in  combination  with  it  the 
Twelfth  Edition.  The  course  now  taken,  however,  is  directly  in  line  with  Macvey  Napier's 
great  Supplement  (1816-24)  to  the  Fourth,  Fifth  and  Sixth  Editions.  The  extent  of 
that  Supplement  exhibited,  indeed,  a  notable  advance  in  the  whole  standard  of  the 
Britannica  as  a  work  of  original  scholarship  and  expert  authority — the  result  of  the  copy- 
rights having  recently  passed  into  the  hands  of  the  enterprising  publisher  Constable: 
but  its  interest  in  this  particular  connexion  lies  in  the  fact  that  it  was  conceived  as  a 
response  to  the  pressing  demand  for  a  comprehensive  survey  of  the  situation  resulting 
from  the  Great  War  which  had  just  ended  at  Waterloo  in  1815.  In  1816,  when  the  first 
volume  of  Macvey  Napier's  Supplement  appeared,  the  same  need  was  felt  for  an  authori- 
tative record  and  reconsideration  of  the  new  developments  during  the  convulsions  of 
1793-1815  as  has  arisen  now  in  respect  of  the  decade  ending  with  1921,  and  for  very 
similar  reasons.  Anyone  who  still  cares  to  examine  that  remarkable  Supplement  of  1816-24 
will  find  that  the  ideals  of  public  service  in  education  set  before  themselves  by  Constable 
and  Macvey  Napier  (as  expressed  by  the  latter  in  his  Preface  to  the  Sixth  Volume)  were 
identical  with  those  which  animate  the  Encyclopedia  Britannica  to-day.  The  present 
writer,  having  made  this  examination,  with  knowledge  of  the  many  difficulties  of  his  own 
task  a  hundred  years  later  (on  the  first  subsequent  occasion  of  an  engrossing  conflict 
having  upset  the  world),  is  bound  to  testify  to  the  admirable  way  in  which,  amid  evidence 
of  similar  obstructions  and  complications,  Macvey  Napier  carried  out  his  scheme.  His 
Supplementary  Volumes,  organized  at  the  conclusion  of  the  Great  War  of  1793-1815, 
formed  the  only  critical  and  universal  survey  then  available  of  the  period  just  ended. 
They  brought  together  a  mass  of  valuable  material  which  was  afterwards  incorporated  in 
later  editions;  indeed  much  of  this  information,  fresh  from  the  sources,  could  only  have 
been  placed  on  record  by  being  obtained  at  that  time — a  consideration  which  is  encourag- 
ing to  the  Editor  of  the  present  New  Volumes  in  regard  to  the  permanent  value  of  the 
material  embodied  in  them  also. 

In  one  respect,  possibly,  Macvey  Napier  may  appear  to  have  had  an  advantage  over 
the  present  Editor,  or  a  somewhat  easier  task,  in  that  he  had  eight  years  over  which 
to  spread  the  publication  of  his  volumes — first  issued  in  parts.  But  his  successor  a 
hundred  years  later  is  too  conscious  of  the  real  advantage  given  to  the  public  by  imme- 
diate and  simultaneous  production,  and  indeed  of  the  superior  quality  which  such  a  work 
possesses  when  the  whole  of  it  has  been  under  editorial  control  at  one  time,  to  take  this 
superficial  view.  Having  himself  organized  the  production  of  these  New  Volumes  within 
a  single  year — a  year,  moreover,  characterized  by  post-war  unrest  and  unsettlement — 
he  may  perhaps  make  this  difference  of  method  some  excuse,  however,  for  any  imperfec- 
tions in  them  which  may  be  found  in  the  light  of  later  events  or  of  knowledge  undisclosed 


while  they  were  in  the  making.1  The  generous  reader  may  pardon  some  incidental  defects 
or  omissions,  in  consideration  of  his  having  the  use,  practically  at  once,  of  the  full  Supple- 
ment, as  complete  as  it  could  reasonably  be  made,  and  not  having  to  wait  several  years 
for  a  succession  of  volumes  with  long  intervals  between  them.  In  the  latter  case  each 
volume  would  be  apt  to  exasperate  him  by  cross-references  from  its  articles  to  others  in 
a  volume  still  inaccessible;  each  earlier  one,  furthermore,  would  become  relatively  out-of- 
date  as  soon  as  the  next  one  appeared;  and  the  whole  must  lack  organic  unity,  because 
the  subject-matter,  as  distributed  in  one  volume  or  another,  must  necessarily  have  been 
dealt  with  at  different  dates  from  dissimilar  viewpoints. 

These  New  Volumes,  systematically  arranged,  in  accordance  with  the  traditional 
standards  of  the  Encyclopaedia  Britannica,  so  that  the  articles  may  be  adapted  either  for 
continuous  reading  or  for  occasional  reference,  have  been  planned  as  a  guide  to  an  appre- 
ciative understanding  of  contemporary  affairs.  The  reader  has  before  him  what  may  be 
described  as  an  international  stock-taking,  by  carefully  selected  authorities,  of  the  march 
of  events  all  over  the  world  from  1909-10  to  1920-1,  and  of  the  nature  and  critical  value 
of  such  advances  as  were  made  in  the  principal  branches  of  knowledge  during  that  period. 
In  this  respect  the  New  Volumes  aim  at  giving  a  key  to  the  problems  of  to-day,  so  far  as 
these  contemporary  problems  are  bound  up — as  indeed  they  are  to  an  unprecedented 
extent — with  the  new  social  and  economic  issues  which  only  began  to  emerge  in  their 
present  magnitude,  or  to  impress  themselves  on  the  public,  as  the  result  of  the  tremendous 
upheaval  caused  by  the  World  War.  Yet  it  is  necessary,  in  the  interests  of  a  publication 
which  is  essentially  educational,  to  add  one  proviso.  It  remains  as  true  as  ever  that  con- 
temporary human  life  and  interests  are  organically  related  not  only  to  the  immediate 
developments  of  one  preceding  decade  but  to  those  of  a  succession  of  earlier  decades  and 
epochs,  back  to  the  abysses  of  time.  The  great  Drama  is  of  the  Ages,  and  can  only  be 
appreciated  with  all  its  Acts  on  record.  The  eye  which  looks  only  at  the  passing  scene  is  too 
often  colour-blind.  The  roots  of  the  Post- War  World  go  down  into  the  Pre-War  World. 
Its  proper  interpretation  can  be  found  only  in  the  light  of  all  that  earlier  history  on  which 
we  can  look  back — as  we  cannot  do  on  contemporary  affairs — with  assurance  that  it 
is  seen  in  perspective  and  in  ordered  values,  as  the  result  of  an  accumulation  of  disinterested 
criticism.  The  Post- War  World  is  the  residuary  legatee  of  the  Pre-War  World,  from  which 
it  inherits  the  whole  basis  of  its  intellectual  equipment.  The  present  survey  of  recent 
happenings,  indispensable  though  it  may  be  as  an  account  of  the  Post- War  World,  can 
only  therefore  be  utilized  perfectly  when  it  is  regarded  as  an  integral  part  of  the  unitary 
library  of  education  represented  in  all  the  thirty-two  volumes  now  forming  the  complete 
Twelfth  Edition.  The  structure  of  that  great  edifice,  with  its  contents,  is  not  substantially 
affected  by  the  fact  that  it  has  been  built  with  an  Annexe  for  housing  more  recent 

1  It  may  be  noted  here  that,  though  bibliographical  references,  representing  a  selection  of  the  most  authoritative  books 
or  documents  published  since  1910,  are  plentifully  made  in  the  New  Volumes,  it  was  impossible,  merely  by  way  of  supplement 
to  the  bibliographies  attached  to  articles  in  the  Eleventh  Edition,  to  include  them  systematically,  except  in  appropriate  cases 
where  this  course  was  demanded  by  the  nature  of  the  supplementary  articles.  No  attempt  has  been  made,  when  otherwise 
there  was  no  substantial  reason  for  adding  a  supplementary  article  at  all  to  the  account  given  of  a  subject  in  the  Eleventh 
Edition,  to  add  a  list  of  later  books  published  about  it.  Nor,  indeed,  in  the  Editor's  judgment,  would  it  have  been  in  accord- 
ance with  the  objects  of  the  Britannica  to  give  the  cachet  of  "  authority  "  in  this  way  to  many  contemporary  publications 
which  can  hardly  be  said  to  have  earned  that  title.  The  bibliographical  references  in  the  Britannica  are  especially  valuable  as 
critically  directing  the  reader  to  the  best  sources,  outside  its  own  articles,  for  more  detailed  information;  but  the  very  nature  of 
many  of  the  articles  in  the  New  Volumes,  as  being  the  latest  (or  even  the  only  available)  authoritative  accounts  of  purely 
contemporary  developments,  made  it  unnecessary — if  indeed  it  would  not  be  misleading — to  direct  the  reader  to  com- 
paratively ephemeral  publications  by  less  responsible  writers. 


acquisitions,  in  the  shape  of  these  New  Volumes.  They  are  designed  as  having  behind  or 
beside  them  the  main  body  of  the  work — the  earlier  Volumes  of  the  Eleventh  Edition  which 
were  constructed  in  the  closing  years  of  the  Pre-War  World. 

It  may  be  pardonable  for  the  present  writer,  at  the  end  of  the  twenty-first  year  of  his 
occupancy  of  the  position  of  Editor  of  the  Encyclopaedia  Britannica,  to  emphasize  in  retro- 
spect one  specially  valuable  characteristic  of  the  Eleventh  Edition,  in  supplying  to-day 
an  authoritative  digest  of  world  history  and  the  progress  of  knowledge  up  to  the  last  few 
months  before  it  was  originally  published  in  1911.  Its  value  does  not  merely  depend  on 
the  benefit  secured  to  the  reader  of  these  New  Volumes  by  its  having  also  been  produced 
as  a  whole  at  one  date,  so  that  its  accounts  of  every  subject,  organically  distributed  under 
appropriate  headings,  represent  uniformly  a  single  editorial  policy  (identical  with  that 
of  to-day),  a  common  terminus  of  time  in  the  facts  dealt  with,  and  a  common  standard  of 
criticism  in  the  viewpoints  of  its  contributors — so  far  .as  expert  opinion  at  any  one  moment 
is  ever  in  agreement.  This  in  itself  is,  no  doubt,  a  great  convenience  in  the  linking  up  of  the 
later  information  provided  in  the  New  Volumes.1  But  there  is  a  still  more  important 
quality  attaching  to  the  Eleventh  Edition,  of  which  indeed  its  Editor  was  not  himself  fully 
aware  during  the  critical  years  of  its  preparation.  It  required  the  experience  obtained 
during  the  gestation  of  these  New  Volumes  to  teach  the  Editor  how  much  simpler  a 
matter  it  is  to  create  such  a  "  Library  of  Education"  when  the  world  is  at  peace  and  is 
progressing  normally,  as  it  was  in  the  years  preceding  1911,  than  when,  as  recently,  it  is 
everywhere  in  convulsion,  nobody  being  able  to  tell  from  week  to  week  what  he  would  be 
doing  next,  or  where  some  new  complication  or  even  revolution,  political,  economic,  indus- 
trial or  scientific,  might  break  out,  to  the  upsetting  of  any  attempt  at  orderly  statement  of 
the  progress  of  events  and  the  crystallization  of  opinion.  Though  it  was  not  so  realized  at 
the  time,  it  is  now  evident  that  the  maximum  service  which  the  Encyclopedia  Britannica 
could  have  performed  for  the  public  of  to-day  was  the  production  of  the  Eleventh  Edition 
in  1911,  before  the  war  of  1914-9  cut  a  Grand-Canyon  gash  in  the  whole  intellectual  struc- 
ture of  the  world.  For  what  would  have  happened  if  the  complete  new  edition  which  would 
follow  the  Tenth  Edition  had  not  been  undertaken  until  several  years  later — say,  after 
the  Armistice?  In  that  case  it  would  still  have  been  necessary,  in,  some  way,  to  keep 
what  may  roughly  be  divided  as  the  Pre-War  and  Post- War  Worlds  distinct.  The  account 
of  the  Post-War  World  would  then  substantially  be  what  appears  in  the  present  New 
Volumes;  for  this  must,  in  any  case,  start  at  a  convenient  point  before  the  war,  in  order  to 
make  the  break  intelligible,  and  it  must  differ  in  scope  and  perspective  from  the  part 
devoted  to  the  Pre-War  World,  in  proportion  as  its  new  problems  require  a  different  sort  of 
discussion  according  to  their  bearing  on  the  future  rather  than  as  continuations  of  past 
history.  But  so  far  as  the  Pre-War  World  is  concerned — everything,  that  is  to  say,  except 
the  contemporary  developments  of  the  decade  preceding  1921 — it  may  be  asserted,  with- 
out fear  of  contradiction  from  anyone  who  can  appreciate  the  responsibilities  of  an  Editor 
of  the  Encyclopedia  Britannica,  that,  if  the  task  had  not  been  undertaken  till  after  1914, 
it  would  have  been  absolutely  impossible  to  produce  to-day  anything  so  comprehensively 
authoritative  or  critically  complete  as  is  actually  available  in  the  shape  of  the  Eleventh 
Edition  owing  to  its  having  been  produced  just  before  the  war. 

'Reference  by  volume  and  page  (e.g.  "see  2.493")  is  accordingly  made,  as  a  rule  immediately  after  the  headings  of 
articles  in  the  New  Volumes  (but  also  elsewhere  in  their  course,  as  seemed  useful),  to  places  in  the  earlier  volumes  where 
accounts  of  the  same  subjects,  leading  up  to  the  point  where  the  account  is  now  resumed,  may  be  found. 


In  the  present  writer's  judgment  it  is  very  remarkably  the  fact  that,  however  care- 
fully the  contents  of  the  Eleventh  Edition  are  tested,  as  representing  the  highest  standards 
of  international  research  and  criticism,  whether  in  Science  or  in  Art  or  in  historical  informa- 
tion, up  to  1911,  nothing  substantial  has  occurred  since  to  diminish  its  value  or  alter  its 
perspective.  The  reason  is  that  it  was  fortunately  produced  at  a  quiet  period,  when  there 
was  every  opportunity  for  obtaining  sure,  authoritative  and  orderly  surveys,  in  a  world- 
society  which  was  evolving  along  known  lines  of  "normalcy" — to  use  President  Harding's 
favourite  expression — fairly  calculable  in  advance  in  accordance  with  well-informed 
expectations,  and  permitting  of  a  reasonably  final  judgment  on  the  sequence  of  con- 
temporary progress  in  relation  to  the  past.  To-day,  on  the  other  hand,  the  whole  atmos- 
phere of  scholarship  and  thought  has  temporarily  been  vitiated  by  the  world  upheaval, 
and  the  cooperation  enlisted  for  the  Eleventh  Edition  is  unattainable  under  present 
conditions.  It  is  not  too  much  to  say  that  the  service  done  by  the  Encyclopedia  Britannica 
for  the  public,  by  bringing  together  in  the  Eleventh  Edition  its  unique  combination  of  the 
world's  ripest  judgments  on  every  sort  of  subject,  could  not  have  been  rendered  to  this 
generation  at  all  if  that  Edition  had  not  been  completed  before  the  war.  As  the  composition 
of  the  present  New  Volumes  shows,  it  has  still  been  possible  for  the  Editor  to  enlist  the 
most  highly  qualified  experts,  and  writers  officially  connected  with  Government  Depart- 
ments or  Services,  for  dealing  with  matters  familiar  to  them  (and  often  known  only  to 
them)  in  the  course  of  the  past  decade.  But  the  writing  of  contemporary  history  by  persons 
who  have  been  chief  agents  or  eye-witnesses  is  one  thing;  it  is  quite  another  to  recreate  the 
whole  drama  of  the  far-reaching  past.  To  do  that,  as  it  was  done  in  the  Eleventh  Edition, 
needs  a  type  of  mind  and  will  which  for  the  present  has  largely  ceased  to  function  along 
the  pre-war  ways. 

Irrespectively,  indeed,  of  the  question  whether  as  good  a  complete  edition  as  the 
Eleventh  could  have  been  produced  de  novo  now,  it  would  cost  in  any  case  at  least  twice 
as  much  to  make  as  it  did  in  1911,  and  it  would  have  to  be  sold  at  a  far  higher  price.  But, 
from  the  editorial  point  of  view,  the  important  fact  is  that  it  could  not  be  made  to-day  so 
as  to  have  anything  like  the  scholarly  value  of  the  work  produced  before  the  war  by  the 
contributors  to  the  Eleventh  Edition.  Neither  the  minds  nor  the  wills  that  are  required  for 
such  an  undertaking  are  any  longer  obtainable  in  any  corresponding  degree,  nor  probably 
can  they  be  again  for  years  to  come.  This  is  partly  due  to  sheer  "  war-weariness,"  which 
has  taken  many  forms.  A  shifting  of  interest  has  taken  place  among  writers  of  the  academic 
type,  so  that  there  is  a  disinclination  to  make  the  exertion  needed  for  entering  anew  into 
their  old  subjects — a  necessary  condition  for  just  that  stimulating,  vital  presentation  of 
old  issues  in  the  light  of  all  the  accumulated  knowledge  about  them,  which  was  so  valuable 
a  feature  of  the  Eleventh  Edition;  the  impulse  has  temporarily  been  stifled  by  the  pressure 
of  contemporary  problems.  Many  of  the  pre-war  authorities,  moreover,  have  died  without 
leaving  any  lineal  successors,  and  others  have  aged  disproportionately  during  the  decade, 
while  the  younger  generation  has  had  its  intellectual  energies  diverted  by  the  war  to  work 
of  a  different  order.  Again  (a  most  essential  factor),  it  would  have  been  impossible  to 
attain  the  same  full  measure  of  international  cooperation,  among  representatives  of 
nations  so  recently  in  conflict,  and  in  a  world  still  divided  in  1921  by  the  consequences 
of  the  war  almost  as  seriously  as  while  hostilities  were  actually  raging. 


It  is  with  some  satisfaction  that  the  Editor  has  been  able  to  make  a  fresh  beginning  in 
these  New  Volumes  toward  a  revival  of  this  cooperation,  by  including  German,  Austrian 
and  Hungarian  contributors,  in  addition  to  those  from  the  countries  allied  or  associated 
with  the  British  Empire  and  the  United  States  during  the  war.  In  the  material  structure 
of  the  New  Volumes,  and  their  sub-editing,  the  same  note  of  Anglo-American  solidarity  is 
struck  as  in  the  Eleventh  Edition;  and  this  is  again  emphasized  by  their  being  dedicated 
jointly  to  the  two  Heads  of  the  English-speaking  peoples,  by  express  permission  of  King 
George  V.  and  President  Harding.  Nowhere  except  in  Great  Britain  and  the  United  States 
would  it  have  been  possible,  under  the  world-conditions  of  1921,  to  find  the  standard  of 
poise  and  perspective  required  in  their  construction.  Any  other  assumption,  throughout 
these  New  Volumes,  than  that  the  terrible  war  of  1914-9  was  won  by  those  who  had  right 
and  justice  for  their  cause,  would  manifestly  be  impossible  in  the  Encyclopedia  Britannica; 
and  historical  justification  for  this  belief  is  indeed  given  in  the  proper  articles.  On  the  other 
hand,  many  of  the  more  violent  criticisms  of  German  action  current  during  the  war  are 
now  shown,  in  the  Anglo-Saxon  spirit  of  fair  play,  to  have  been  exaggerated  for  "  propa- 
ganda" purposes.  Opinion  on  the  incidents  and  issues  of  the  war-period  will  probably 
continue  to  be  revised  by  succeeding  generations  over  and  over  again,  as  the  weight  of 
evidence,  so  much  of  it  still  undisclosed,  increases;  but  a  start  is  made  here  toward  the 
acceptance  of  such  conclusions  as  already  represent  a  judicial  view,  expressed  without 
favour  or  malice,  free  from  any  conscious  bias,  and  backed  by  a  presentation  of  the  relevant 
facts  on  authority  that  is  either  admittedly  unimpeachable  or  so  far  unchallenged.  It  was 
an  integral  part  of  the  editorial  policy  to  put  aside  any  war-prejudice  in  inviting  the 
assistance  of  contributors  from  among  the  nations  which  had  fought  against  the  Allies,  so 
far  as  might  be  practicable  without  the  intrusion  of  "  propaganda,"  especially  for  nar- 
ratives of  the  domestic  history  of  the  enemy  countries,  about  which  so  little  informa- 
tion had  penetrated  outside  during  the  war-period.  The  list  of  writers  of  ex-enemy  national- 
ity, and  of  the  articles  contributed  by  them,  shows  that  a  considerable  section  of  the 
contents,  including  the  military  history  of  the  war  itself  (to  which  British,  American, 
French,  Italian,  Belgian,  German,  and  Austro-Hungarian  soldiers  have  contributed),  is 
derived  from  such  sources;  and  this  fact  alone  gives  these  Volumes  a  special  interest.  Con- 
sistently with  this  policy,  the  Editor  has  encountered  only  very  rare  disappointments  in 
carrying  out  his  plan  of  obtaining  the  best  contributors  available  from  all  foreign  countries, 
including  Germany  and  Austria,  in  order  to  provide  the  most  authoritative  information 
on  their  own  affairs  according  to  their  own  respective  standpoints.  In  this  connexion 
it  will  be  noted  that,  for  the  first  time  in  the  history  of  the  Britannica,  the  article  on  Japan  is 
contributed  by  a  Japanese.  The  Editor  is  glad  here  to  acknowledge  the  help  of  the  dis- 
tinguished historian,  Prof.  A.  F.  Pribram,  of  Vienna,  in  organizing,  with  the  collabora- 
tion of  Dr.  Redlich,  the  eminent  Austrian  jurist,  the  whole  series  of  articles  dealing  with 
Austro-Hungarian  subjects.  He  had  also  the  valuable  assistance  of  Mr.  George  Saunders, 
formerly  The  Times  correspondent  in  Berlin,  in  obtaining  the  cooperation  of  German 
contributors  and  in  supervising  the  translation  and  editing  of  their  articles;  while  Mr. 
George  Adam,  The  Times  correspondent  in  Paris  during  1913-9,  performed  the  same 
function  in  respect  of  France.  In  the  case  of  Russia,  the  Editor  was  fortunately  able  to 
rely  on  the  great  authority  of  Sir  Paul  Vinogradoff .  The  Editor's  thanks  for  useful  advice 


and  assistance  with  regard  to  the  articles  on  other  foreign  countries  are  due  to  Presi- 
dent Masaryk  (Czechoslovakia),  Prof.  H.  Pirenne,  Rector  of  Ghent  University  (Belgium), 
Prof.  L.  V.  Birck  of  Copenhagen  (Denmark),  Mons.  M.  Beza,  of  the  Rumanian  Legation 
in  London  (Rumania),  Mons.  D.  Caclamanos,  the  Greek  Minister  in  London  (Greece), 
Mons.  H.  N.  Bronmer,  of  the  Netherlands  Legation  in  London  (Holland),  Baron  Alstro- 
mer,  the  Swedish  Charge  d' Affaires  in  London  (Sweden),  and  Mons.  Erik  Colbran,  of 
the  League  of  Nations. 

So  many  individuals  have,  in  one  way  or  another,  smoothed  the  Editor's  path,  either 
by  suggesting  the  best-qualified  contributors  or  by  giving  helpful  advice  on  the  subject- 
matter  of  articles,  that  he  can  only  make  a  rather  arbitrary  selection  here  in  naming  some 
of  the  more  conspicuous.  Practically  every  national  Government,  either  directly  or 
through  its  accredited  representatives,  has  aided- his  attempt  to  give  international  author- 
ity to  the  New  Volumes,  by  encouraging  the  use  of  its  own  sources  of  information;  and 
British  official  cooperation,  as  also  American,  has  been  generously  sanctioned  and  utilized. 
By  the  courtesy  of  the  Naval  Intelligence  Department  of  the  British  Admiralty,  the 
editorial  staff  had  access  to  all  the  historical  materials  it  had  collected  from  various  parts 
of  the  world  for  secret  service  during  the  war,  including  the  handbooks  of  statistical  and 
general  information  which  had  been*  privately  printed  by  the  Government  for  the  use  of 
British  officers  and  political  agents  while  the  war  was  still  in  progress,  and  which  were 
only  partially  "released"  for  publication  afterwards.  In  this  connexion  acknowledgment 
may  be  made  here,  once  for  all,  of  the  permission  .accorded  by  the  Geographical  Section 
of  the  British  War  Office  (supplemented  by  that  of  the  Controller  of  H.M.  Stationery 
Office),  and  by  the  French  Service  Geographique  de  I'Armee,  to  reproduce  British  and  French 
staff-maps,  and  also  by  the  Librairie  Militaire  Berger-Lerrault,  of  Paris,  to  reproduce  some 
of  their  maps  of  the  battle  areas.  In  different  specialist  spheres,  the  following  acted  as 
technical  consultants:  on  Biology  and  Zoology,  Dr.  Chalmers  Mitchell,  secretary  of  the 
Zoological  Society  of  London;  on  Botany,  Prof.  F.  W.  Keeble,  of  Oxford  University;  on 
Mathematics,  Prof.  G.  H.  Hardy,  of  Oxford  University;  on  Aeronautics,  Lt.-Col.  Mervyn 
O'Gorman;  on  Medicine  and  Surgery,  Dr.  R.  McNair  Wilson;  on  Civil  Engineering 
generally,  Mr.  H.  M.  Ross,  editor  of  the  Times  Engineering  Supplement;  on  Electrical 
Science  and  Engineering,  Prof.  J.  A.  Fleming,  of  University  College,  London.  Each  of  the 
above  was  responsible  for  suggesting  contributors  on  the  subjects  named,  and  assisted 
in  coordinating  their  contributions.  On  military  matters  Maj.  C.  F.  Atkinson  acted  for 
the  Editor  in  obtaining  the  cooperation  of  a  large  number  of  expert  advisers,  at  home 
and  abroad,  and  he  was  responsible  for  organizing  all  the  articles  dealing  with  military 
history  and  equipment.  On  naval  affairs  useful  advice  was  given  by  Rear-Adml.  Sir  W. 
Reginald  Hall,  M.P.,  and  Rear-Adml.  H.  W.  Richmond.  Mr.  Humbert  Wolfe,  of  the 
British  Ministry  of  Labour,  and  Mr.  R.  Page  Arnot,  of  the  unofficial  Labour  Research 
Department  (the  intelligence  office  of  the  British  Labour  movement),  assisted,  from 
different  points  of  view,  in  planning  the  articles  dealing  with  Labour  developments, 
while  valuable  advice  was  received  on  their  economic  aspects  from  Sir  Hubert  Llewellyn 
Smith  and  Mr.  Sidney  Webb.  The  Editor's  thanks  are  due  to  all  these  counsellors;  and 
also  to  Lord  Stamfordham,  for  material  in  connexion  with  the  biographical  article  on 
King  George  V.,  to  Sir  Godfrey  Thomas  as  regards  that  on  the  Prince  of  Wales,  to  Sir 


Hercules  Read  for  suggestions  as  to  the  treatment  of  Archaeology,  and  especially  to  Lord 
Justice  Sir  William  Younger  and  Lord  Newton,  jointly  and  severally,  for  their  help  in 
securing  the  undertaking,  by  their  colleague  Sir  Reginald  Acland,  K.C.,  of  the  article 
on  "  Prisoners  of  War,"  which  represents  the  first  judicial  review  of  the  evidence  officially 
taken  by  Sir  William  Younger's  committee  on  that  subject. 

In  crediting  the  editorial  staff  as  a  whole  with  a  loyal  fellowship  which  alone  rendered 
possible,  by  the  cooperation  of  its  various  departments,  the  production  of  the  New  Volumes 
in  so  short  a  time  from  their  inception,  the  Editor-in-chief  must  express  his  warmest 
acknowledgment  of  the  services  of  the  three  principal  assistant-editors  in  London — Dr. 
Henry  Newton  Dickson,  D.Sc.,  formerly  professor  of  Geography  at  University  College, 
Reading,  and  Literary  Director  of  the  Naval  Intelligence  Department  of  the  Admiralty 
during  the  war;  Professor  Walter  Alison  Phillips,  Lecky  Professor  of  Modern  History  at 
Trinity  College,  Dublin  (who  was  able  to  follow  up  his  previous  association  with  the 
Eleventh  Edition,  as  principal  assistant-editor,  by  devoting  his  vacations,  and  such  other 
time  as  he  could  spare,  to  this  work) ;  and  Mrs.  W.  L.  Courtney  (Janet  E.  Hogarth),  who, 
with  an  efficient  lieutenant  in  Mrs.  Guy  Chapman,  was  in  charge  of  the  work  done  by  the 
ladies  who  formed  part  of  the  staff.  Apart  from  a  general  participation  in  headquarters 
control,  Dr.  Dickson  was  especially  concerned  with  the  subject-matter  of  geography  and 
statistics,  and  with  the  selection  of  maps  and  illustrations,  Prof.  Alison  Phillips  with 
political  and  constitutional  history,  and  Mrs.  Courtney  with  the  biographical  articles  and 
those  dealing  with  the  Women's  Movement,  and  with  the  making  of  the  Index,  which  thus 
supplements  the  Index  to  the  Eleventh  Edition  under  the  same  guiding  hand  which  had 
been  responsible  for  the  great  Index  to  the  main  body  of  the  work.  As  Editor's  Secretary, 
keeping  touch  with  all  departments,  Mr.  Arthur  Bollaert  Atkins  also  resumed  his  former 
r61e,  with  an  efficiency  which  was  invaluable  to  the  editorial  organization.  The  New  York 
branch  of  the  editorial  staff,  under  Mr.  Franklin  H.  Hooper,  as  American  Editor,  with 
Mr.  H.  R.  Haxton  and  Dr.  G.  C.  Scoggin  as  his  principal  assistants,  acted  in  concert 
throughout  with  the  London  office,  more  particularly  in  arranging  for  articles  by  American 
contributors  or  dealing  with  American  affairs.  The  Editor-in-chief  was  assured  before- 
hand of  the  sympathetic  and  experienced  collaboration  he  enjoyed  in  this  respect  by  the 
fact  that  his  editorial  association  with  Mr.  F.  H.  Hooper  for  such  purposes  had  already 
been  continuous  since  the  year  1900.  In  seeing  the  New  Volumes  finally  through  the  press, 
he  had  the  advantage  of  having  the  combined  force  of  the  British  and  American  editorial 
staffs  brought  to  bear  on  the  critical  revision  of  the  work  as  a  whole. 

As  architect  both  of  the  Eleventh  Edition  and  of  the  superstructure  which  now  converts 
it  into  the  Twelfth  Edition,  it  has  been  the  present  writer's  privilege  to  be  served  by  an 
international  company  of  practical  builders,  supplying  the  world's  best  available  materials 
and  masonry;  and  he  has  been  inspired  by  the  ambition  of  cementing  and  adorning,  in  the 
completed  edifice,  that  great  movement  for  Anglo-American  cooperation,  on  whose  progress 
from  strength  to  strength  the  recovery  of  civilization  after  the  World  War  of  1914-9 
must  so  largely  depend. 

Christmas  1921. 



A.A.G.  = 

A.B.C.  = 

ac.  = 
A.C.  = 

A.C.I.  = 
A.C.  ofS. 
A.D.  = 

Adml.  = 
A.E.F.  = 

A.F.  = 
A.F.E.F.  = 

A.F.  of  L.  = 

A.I.D.  = 

A.I.F.  = 
A.L.  = 

A.L.A.M.  = 

A.L.G.P.  = 


A.  M.S.  = 
ANZAC.  = 

A.  O.K.  = 

A.P.C.  = 

Ariz.  = 
Ark.  = 

Anti-Aircraft;  Army  Act 
(British)  ;  Automobile 

Assistant  Adjutant-  G  e  n- 

Argentina,  Brazil,  Chile. 

sub-unit  (German  Army). 
acre  or  acres. 
Artillerie  de  Campagne,  Ar- 

tillerie   de  Corps  =  Field 

artillery,  Corps  artillery 

—  followed    by    numeral 
Army   Council   Instruction 

Assistant  Chief-of-Staff 

Anno  Domini  =  In  the  year 

of  our  Lord  (Latin);  Ar- 

tillerie   divisionnaire  — 

Divisional    artillery  (fol- 

lowed  by    numeral) 

American  Expeditionary 


Air  Force  (British). 
Air  Force  Cross  (British). 
Anglo-French     Expedition- 

ary Force. 

Air  Force  Medal  (British). 
American      Federation     of 


Aircraft  Inspection  Depart- 

ment (British). 
Australian  Imperial  Force. 
Artillerie   Lourde  =  Heavy 

artillery  (French). 
Association  of  Licensed  Au 

tomobile  Manufacturers. 
Artillerie  Lourde   a   grande 

puissance  =  Super-heavy 

artillery  (French). 
Artillerie    Lourde    5     voie 

ferree  =  Heavy  railway  ar- 

tillery (French). 
Army  Medical  Service. 
Australian  and   New    Zea- 

land Army  Corps. 
Army       Ordnance      Corps 

(since  1918  R.A.O.C.). 
Armee-0berkommando  = 

SupremeArmy  Command 


Headquarters  of  an  army, 

with  numeral,  e.g.  A.O.K. 

2  (German). 
Army    Pay     Corps;     since 

1918  R.A.P.C.  (British). 
Army  Pay   Department 

Army  Service  Corps;  since 

1918  R.A.S.C.  (British). 

A.S.E.=  Amalgamated  Society  of 


A.T.  =  A  rtillerie  de  tranc  hee  = 

Trench  artillery  (French). 

A.V.C.=  Army  Veterinary  Corps; 

since  1918  R.A.V.C. 

A.V.S.  =  Army   Veterinary   Service. 

Az.  =  Aufschlagziinder  =  Percus- 

sion fuze  (German). 


b.=  born. 

Balk.Penin.=  Balkan  Peninsula. 

bar.  =  barrel  or  barrels. 

Batt.  =  Battery;  battalion. 

Bav.  =  Bavarian. 

B.C.=  Before  Christ. 

Bde.  =  Brigade. 

Beds.  =  Bedfordshire. 

B.E.F.  =  British  Expeditionary  Force 

(in  particular  in  France 
and  Belgium). 

Berks.  =  Berkshire. 

E.G.  =  Brigadier-General,  General 

Staff  appointment  (Brit- 

B.H.P.  =  Brake  Horse-power. 

B.L.  =  Breech-loading  (artillery;  as 

distinct  from  Q.F.). 

B.M.=  Brigade-Major  (British). 

B.M.A.  =  British  Medical  Association. 

Bn.  =  Battalion. 

Brig.-Gen.  =    Brigadier-General. 

Bucks.  =  Buckinghamshire. 

bus.  =  bushel  or  bushels. 

Bz.  =  Brennziinder  =  'Time  fuze 



C.  =  circa  =  round  about  (Latin). 

C.A.  =  Corps  d'A  rmee=A  rmy 

Corps  (French). 

C.A.C.=  Corps  d'Armee  Colonials  = 

Colonial  Army  Corps 

Cal.  =  California. 

Cambs.=          Cambridgeshire. 

Capt.  =  Captain. 

C.Asia  =  Central  Asia. 

Cav.  =  Cavalry. 

C.B.E.  =  Commander  of  the  Order 

of  the  British  Empire. 

C.C.=  Corps  de  Cavalerie  =  Caval- 

ry Corps  (French). 

CE.  =  Contre-Espionnage  =  A  n  t  i  - 

spy  service  (French). 

C.E.=  Tetronitromethylaniline 

(Tetryl)  (Chemical  Ex- 

C.F.=  Chaplain  to  the  Forces 


cf.  =  confer  =  compare  (Latin). 

C.G.S.=  Chief  of  the  General  Staff 


C.H.  =  Companion  of  Honour. 

Ches.=  Cheshire. 

C.G.T.  =  Confederation  Generale  du 

Travail =General  Federa- 
tion of  Labour  (French). 

C.-in-C.=  Command  er-in-Chief 

C.I.D.  =  Criminal  Investigation  De- 

partment (British). 

C.I.G.S.=  Chief  of  the  Imperial  Gen- 
eral Staff  (British). 

C.M.=  Court-martial. 

C.M.B.  =          Central  Midwives  Board. 

C.N.  =  Comite  Nationale  de  Secours 

el  d 'Alimentation  =  Na- 
tional Committee  for  Re- 
lief and  Feeding  (Bel- 

co.  =  county. 

Co.=  Company. 

C.O.=  Commanding  Officer  (Brit- 


C.  of  S.  =         Chief  of  Staff  (U.S.A.). 

Col.  =  Colonel. 

Colo.=  Colorado. 

Comm.  =          Commander. 

Conn.  =  Connecticut. 

Corn.  =  Cornwall. 

C.O.S.=  Charity  Organization  SocU 

ety  (British). 

C.P.  =  Centre-pivot  (artillery). 

C.R.A.  =  Commanding  Royal  Artil- 

lery, i.e.  commanding  a 
formation  or  station 

C.R.A.  =  Commission  regulatrice  au-- 

tomobile  =  Motor  regula- 
tion staff  (French). 

C.R.B.=  Commission  for  Relief  in: 


C.R.E.=  Commanding  Royal  Engi- 

neers, i.e.  commanding  a 
formation  (British). 

C.r.h.  1   _          Calibres-radius  of  head  or- 

C.r.o.  /  "  ogive  (artillery). 

cub.  ft.  =          cubic  feet. 

Cumb.  =  Cumberland. 

C.W.S.=  Cooperative  Wholesale  So- 


cwt.=  hundredweight. 

d.=  died;  also  penny  or  pence. 

D.=  Director  (e.g.  D.M.O.=  Di- 

rector of  Military  Opera- 
tions); as  prefix  of  office- 
abbreviations  =  Deputy 
(e.g.  D.D.M. I.  =  Deputy 
Director  of  Military  In- 

D.A.=  Detachement  d'A  rmee  = 

Army  group  (French); 
Direct  Action  (fuze); 
Direction  de  I  'A  rriere 
=  Directorate  of  the 
Rear  Zone  (French). 
Equivalent  to  British  L. 
of  C.  and  American  S.O.S. 

D.A.Q.M.G.=  Deputy  Assistant  Quarter- 

D.B.E.=  Dame  of  the  Order  of  the 

British  Empire. 

D.C.=  Division  de  Cavalerie  =  Cav- 

alry Division  (French); 
District  of  Columbia. 

D.C.A.=  Defenses  Centre  Avians  (or 

Aeronefs)=  Anti-Aircraft  -. 
Defence  (French). 



D.C.M.=  Distinguished  Conduct 
.Medal  (British). 

DeL=  Delaware. 

de?:.  -  department. 

D.E.S.=  Direction  f Stapes  et  de 

Services  =  Directing  staff 
of  a  line  of  communica- 
tions  of  an  army 

I>eT.=  Devonshire. 

D  J.C.=  Distinguished  Flying  Cross 


D  J.M.=  Distinguished  Flying  Medal 

D.G.=  Director-General  (e.g.  D.G. 

A.M.S.  =  Director-Gen- 
eral Armv  Medical  Serv- 

D.G.V.O.=  Director-General  of  Volun- 
tarv  Organizations. 

DI.=  LH*ia»n  d'lnfanterie  =  In- 

fantry Division  (French). 

DIC.=  Dirision  d'lnfanterie  Colo- 

niale  =  Colonial  Infantry- 
Division  (French). 

Dir.=  Division. 

Dopp.Z.=  Doppflc*ndfr  =  Time  and 
percussion  fuze  (German  I. 

D.OJUL=  Defence  of  the  Realm  Act 

D.O.R-E.=  District  Officer  Royal  Engi- 
neers (British). 

Dorset.  =          Dorsetshire. 

D.Q.M.G.=  Deputy  Quart  ermaster- 

DR-=  Dirision  de  Res*rte=Re- 

serve  Division  (French). 

D-R-F.=  Depression  Rangefinder. 

D.S.C.  =  Distinguished  Service  Cross 

(U.S.A.  and  British). 

D.S.M.=  Distinguished  Service  Med- 

al (UJSA.  and  British). 

D.S.O.  =  Distinguished  Service  Order 


Dur.  =  Durham. 

E.=  East. 

Ed.  =  Editor. 

E.E.F.  =  Egyptian  Expeditionary 


e.g.  =  exempli  gratia  =  for  example 


E.M.F.  =          Electro-motive  force. 

E  .N  .E.  =  Elements  non  mdirision- 

nies =Troops  not  included 
in  divisions  ("corps 
troops"  or  "army 
troops  ")  (French). 

Ess.=  Essex. 

Esth.  =  Esthonia. 

et  seq.  =  et  sequfntio=*zad  the  follow- 
ing (Latin). 

FAJf.T5-=   First  Aid  Nursing  Yeoman- 
ry Service  (British). 

FEKA.  =  FemkampfartiUerie  =  Super- 

heavy  artillery  (G  e  r  - 

fig.  =  figure    or   figures  (illustra- 

tion . 

FU.=  Florida. 

Flugalnctkrkanone  =  A  n  t  i  - 

aircraft  gun  (German). 
Field    Marshal:   Fusil  Ui- 
traiiieur  =  French    light 

F. Mi.  =          Field  -  Marshal  -  Lieutenant 

f .o.b.  —  free  on  board. 

r.=      French  Equatorial  Africa. 
Field    Service    Regulations 

ft.=  foot  or  feet. 

ft.*  =  square  feet. 

ft.'  =  cubic  feet. 

fur.  =  f urlong  or  furlongs. 

F.WJ>.=         Four-wheel  Drive. 

MGW=  General  Staff  branch  of  the 

Staff,  and  its  functions 

G.=  Gold. 

G».  =  Georgia. 

G.A.  =  Croupe     d  'A  rmfes  =  Group 

of  Annies  (followed  by 
E=£rf.  N  =  Aorrf.  etc.) 

gal.  =  gallon  or  gallons. 

G«l.=  Galicia. 

G-AJl-  =  Grand  Army  of  the  Re- 
public (UlS.A.). 

Gii.=  Grand  Cross  of  the  Order 

of  the  British  Empire. 

G.dJL  =  General  der  A  rtiUerie 

G.dJ.  =  General  der  Infanierie    \ 

G.tLK.  =  General  der  Kavallerie  J 

=  "  full "  general  (German 
and  Austro-Hungarian). 

Gen.=  Generai 

G.H.Q.  =  General  Headquarters 
(British  and  U.S.A.). 

GI,GII,Gin.=  Maintenance,  Intelligence 
and  Operation  branches; 
General  Staff  (U.SJV.). 

G.Kdo.  =  General- Kommando  =  Army 
corps  headquarters  (Ger- 

Glos.  =  Gloucestershire. 

G.M.T.  =         Greenwich  Mean  Time. 

G.O.  =  Generaloberst  =  General    in 

Command  (German). 

G.O.C.=  General  Officer  Command- 
ing (British). 

GOT.  =  Governor. 

G.Q.G.  =  Grand  Quartier-Giniral  - 
General  Headquarters 
(French  Field  Armies). 

gr.  =  gramme  or  grammes. 

G.R.  =  Care   rfgulatriee  =  Regulat- 

ing station — rail  trans- 
port (French). 

G.S,  =  General  Staff    (British  and 

U.S.A.);  General  Service 

G.S.G.S.  =  Geographical  Section  Gen- 
eral Staff  (British). 

G.S.O.=  Gas-SchHtsOJfiaer  =  Ant  i- 
gas  Officer  (German). 

G.S.O.i,2j=  General  Staff  Officer,  ist, 
2nd  and  3rd  grade  (Brit- 

G.V.C.=  Gardes  des   Votes   de  Com- 

munication =  Line-of-Com- 
munication  defence  troops 

H.  =  Honred  (as  prefix  in  Aus- 

tro-Hungarian designa- 
tions); "  Heure"  =Zero 
hour,  hour  set  for  attack 

HJL=  Heavy  Artillery;  less  fre- 

quently, horse  artillery; 
high-angle  (gun). 

Hants.  =  Hampshire. 

H.E.  =  High  Explosive. 

Hereford.  =      Herefordshire. 

Herts.  =  Hertfordshire. 

H.G.  =  Heeresgr*ppe**Group  of 

armies  (German). 

hhd.  =  hogshead  or  hogsheads. 

H.M.S.=  His  Majesty's  Ship  (Brit- 

H.O.=  Headquarters  (British  and 


H.Ou.  =  Hauptquartier  =  Headquar- 

ters (German). 

H.P.  =  Horse- power. 

HJl.=  Hors  rang  =Supernuraer- 

ary  (French  Army). 

Hunts.  =          H  unt  ingdonshire. 
H.T.=  Horse  Transport. 

H.V.=  High  Velocity  (gun). 

L  =  Instantan/e  =  I  nstantaneous 

(in  French  fuze  designa- 
tions); Island. 

Ia.=  Iowa. 

LA.=  im  A*ftrage  =  B\  order,  on 

behalf  of  (German). 

LA.=  Indian  Army. 

ib.  or  ibid.  =  ibidem  =  in  the  same  place 

LD.  =  Infanterte-Difiiion  =  Infan- 

try Division  (German). 

i.e.=  «i«/=that  is  (Latinl. 

I.HJ>.=  Indicated  Horse-power. 

Dl.=  Illinois. 

LLJ>.  Independent  Labour  Partv 


in.  =  inch  or  inches. 

in.s=  square  inches. 

in.'  =  cubic  inches. 

Ind.  —  Indiana. 

Inf.  =  Infantry. 

Is.  =  Islands. 

I.W.W.=  Industrial  Workers  of  the 

"  J"  =  "Jour"  ="  Zero  day  "  fixed 

for  attack  (French). 

J.C-A.=  Jewish  Colonization  Asso- 


K.  =  Koniglic k  =  Royal,  or  Kai- 

serlick  =  Imperial  (Ger- 

Kan.  =  Kansas. 

K.B.E.  =  Knight  Commander  of  the 
Order  of  the  British  Em- 

K.D.  =  KatuUerie-Division  =  Ca  val- 

•  ry  Division  (German). 

kgm.  =  kilogram  or  kilograms. 

K  K.  Kaiseriich-Koniglich  =  Im- 

perial-Royal (Austrian 

km.  =  kilometre  or  kilometres. 

K.R.  =  King's  Regulations  (British 


K.T.D.=  KavaJlerie  -  Tntppendirision 

=  Cavalry  Division 

K.u.K.  =  Kaiserlich  und  Koniglich  = 

Imperial  and  Royal  (Aus- 
trian and  Hungarian  des- 
ignation of  common 

kw.=  kilowatt  or  kilowatts. 

Ky.=  Kentucky. 

L.  =  Landicehr  (German  and 


La.=  Louisiana. 

Latv.  =  Latvia. 

Ib.  =  pound  or  pounds. 

Lanes.  =  Lancashire. 

L.C.C.=  London  County  Council. 

Ldst.=  Landiturm  (Austro-Hun- 

garian and  German). 

Lith.  =  Lithuania. 

L.M.G.  =  Leifhtes  Afaschinengetcehr  = 
Light  machine-gun 

L.  of  C.  =  Line  of  Communications 

Leics.  =  Leicestershire. 

Lines.  =  Lincolnshire. 

Lt.  =  Lieutenant. 

Lt.-Comm.  =    Lieutenant- Commander. 

Lt-Gen.  =        Lieutenant-General. 




m.  =  mile  or  miles. 

Maj.  =  Major. 

Maj.-Gen.  =     Major-GeneraL 

M.B.E.=          Member  of  the  Order  of  the 

British  Empire. 

M.C.=  Military    Cross    (British); 

Master  of  Chemistry. 

Md.  =  Maryland. 

Mdi.=  Middlesex. 

Me  Maine. 

Mebu.  =  Maschinengewckr-Eisenbeto*- 

unlerstand  =  Reinforced 
concrete  machine-gun 
emplacement  (German). 

M.E.F.  =  Mediterranean  Expedition- 
ary Force  (British 

Mesop.  =          Mesopotamia. 

M.G.  =  Machine-gun    (heavy    im- 

plied, as  a  rube). 

M.G.A.  =  Major-General  in  charge  of 
administration,  regional 
commands  (British;. 

M.G.C.  =          Machine-gun  Corps. 

M.G.G.S.  =  Major-General,  General 
Staff  of  anAriny  (British). 

M.g.H.=  Mit  gcschrankter  Haftung  = 

With  limited  liability 

M.G.K.=  Maschinengewekr-Kompa- 
nie  =  Machine-gun  Com- 
pany (German). 

M.G.O.=  Master-General  of  the 
Ordnance  (British). 

MJ.=  Military    Intelligence;    for- 

merly also  .Mounted  In- 
fantry (British;. 

Mich.  =  Michigan. 

Minn.  =  M  innespta. 

Miss.  =  Mississippi. 

M.L.=  Muzzle-loading. 

M.M.  =  Military  Medal  (British). 

M.  ofM.=  Ministry'  of  Munitions 

Mo.  =  Missouri. 

Mons.  =  Monmouthshire. 

Mont.  =  Montana. 

M.S.=  Military  Secretary. 

M.T.  =  Mechanical  Transport. 

m-V.  =  mil     Verzogenmg  =  Delay- 

action  fuze  (German). 

MW.  =  Minenwerfer  =  Trench  Mor- 

tar (German). 


N.  =  North. 

N.A.C.B.  =        Navy  and   Army   Canteen 

Board  (British). 
N.Af.  =  North  Africa. 

N.Am.  =  North  America. 

N.C.  =  North  Carolina. 

N.C.T.=  Nitro-cellulose,  Tubular. 

NJ).=  North  Dakota. 

Neb.  =  Nebraska. 

Nev.  =  Nevada. 

N.H.=  New  Hampshire. 

N.H.P.=          Nominal  Horse-power. 
N.I.D.  =  Naval  Intelligence  Division 


N.J.  =  New  Jersey. 

N.M.=  New  Mexico. 

Nor.  =  Norway. 

Norf .  =  Norfolk. 

Northants.  =    Northamptonshire. 
Northumb.  =    Northumberland. 
N.O.T.  =          Netherlands     Overseas 


Notts.  =  Nottinghamshire. 

N.S.=  Gregorian,  or  new  style, 

Calendar  (see  4.994). 
N.U.R.=          National   Union    of    Rail- 

waymen  (British). 
N.TJ.S.E.C.  =   National  Union  of  Societies 

for  Equal  Citizenship 

N.TJ.W.S.S.  =  National  Union  of  Women's 
Suffrage  Societies  (Brit- 

N.TJ.W.W.=  National  Union  of  Women 
Workers  (British). 

N.Y.=  New  York. 




Ore.  = 


oz.  = 

P.  = 



P.  etO.= 


pop.  = 

Pres.  = 
Prof.  = 
pt.  = 


Officer  of  the  Order  of  the 

British  Empire. 
Officer  Commanding  (Brit- 


preme   Army 

Ordnance  Survey  (British); 

Julian,  or  old  style.  Cal- 

endar (see  4-994). 
Officers'  Training  Corps. 
ohae     Vcrzogentng  =  Direct- 

action  fuze  (German). 
ounce  or  ounces. 

Percussion  (fuze). 


Pour  ampliation  =  Author- 
ized for  issue  of  docu- 
ments (French  Army). 

Paste  <fe  Cammaniement 
(French  Army);  Post  of 
Command  (U.S.A-)  = 
battle  or  advanced  head- 
quarters (British). 

Pares  O.  Comois  —  Trains 
and  columns  (French 

Par  ordre  =  By  order;  by 
command  (French);  Post 



Paste-retard  =  Delay-action 
fuze  (French). 

Pounder  (Gun  designation). 



pint  or  pints. 

Pigeon  Toyaffur  =  Carrier- 
pigeon  (French). 

QJULMJf.S.  Queen  Alexandra's  Im- 
perial Military  Nursing 
Service  (British). 

QJLMJ.N.S.  Queen  Alexandra's  Military 
Families  Nursing  Service 

QJULN.N.S.  Queen  Alexandra's  Royal 
Naval  Nursing  Sen-ice 

QJ.=  Quickfiring   (artillery). 

Q.G.=  Quarticr  General  =  Head- 

quarters (French). 

Q.G.A2=  Headquarters  of  the  II. 
Army  (French). 

Q.M .AJLC.  =  Queen  Mary's  Army  Auxil- 
iary Corps  O\;XA.C.) 


Q.M.G.  =         Quartermaster-General. 
Q.M.N.G.=     Queen  Mary's  Needlework 

Guild  (British). 

qr.  =  quarter  or  quarters, 

qt.  =  quart  or  quarts. 

q.v.=  quod    vide  =  which       see 

(Latin),  for  reference. 

R-=  Reserve  (in  troop  designa- 


RJL=  Royal  Artillery  (British). 

RJLC.=  Royal  Automobile  Club 









ILL  = 





KJf.VJL  = 







Salop  = 




Royal  Air  Force  (British). 
Royal  Army  Medical  Corp* 

Royal  Army  Ordnance 

•-:-    :  -  •  -- 
Royal  Army  Service  Corn 

Royal  Corps  of  Signals, 
ance  1919  (British). 

Roe  Droite= Right  bank  (of 
a  river)  (French). 

r       '--     ':--.-  -  ._-=     :  -  •  -- 


Becen  t 
Royal  Field-   Artillery 

Ro>alFl>-ing  Corps  (Brit- 

Sae  Ga«£fc=Left  bank  (of 
a  river)  (French). 

Royal  Garrison  Artillery 
L-::>-  . 

Royal  Horse  Artillery  (Brit- 
Rhode' Island. 

Royal  Institute  of  British 

Royal  Irish  Constabulary. 

Royal  Maiw«  (British). 

Royal  Military  Academy 
(Woohrich);  Royal  Ma- 
rine Artillery  (British). 

Royal  Mfljtar>  College 

Royal  Marine  Light  In- 
fantry (British). 

Royal  Navy  (British). 

Royal  Ka'val  Air  Force 

Royal  Naval  Air  Service 

Royal  Naval  Reserve  (Brit- 

Royal  Naval  Volunteer  Re- 
serve (British). 



Railway  Operating  Division 
(British  Army  in  France). 

Rules  of  Procedure  (British 
Military  Law). 

Railway  Transport  Officer 
(British  and  U.S.A.). 


Royal  Warrant  (for  pay, 
etc.)  (British). 


shilling  or  ! 

Society  of  Automobile  En- 


South  Carolina. 

South  Dakota. 

seqmens,  tequcmtia  =the  fol- 
lowing (Latin). 


Senior  Medical  Officer  of  a 
formation  or  station 

Senior  Mechanical  Trans- 
port Officer  of  a  forma- 
tion (British). 


Sen-ices  of  Supply,  Rear 
Zone  (U.S-A.),  equivalent 
to  British  L.  of  C;  also 
wireless  call  for  life-sav- 

Society  for  Psychical  Re- 

Society  for  Prevention  of 
Venereal  Disease. 


square  feet. 

Sans  retard  =  Direct -action 
(of  fuze). 



S.S.  =  Secret  Service. 

S.S.F.A.  =  Soldiers'  and  Sailors'  Fami- 
lies Association  (British) . 

S.S.S.E.=  Societe  Suisse  de  Surveil- 
lance £conomique=Sviiss 
Society  for  Economic  Su- 

Staffs.  =  Staffordshire. 

Stellv.  =  Stellvertreter,  stellvertre- 

tend=  Substitute,  acting 
deputy  (German  Army). 

Suff.=  Suffolk. 

Sur.  =  Surrey. 

Sus.  =  Sussex. 


T.  =  Territorial   (British  Army) 

T.=  Time  (fuze). 

T.A.=  Territorial  Army  (British, 

since  1919). 

T.B.D.=  Torpedo-boat  destroyer. 

T.C.  =  Trains  de  Combat  ="  Com- 

bat trains,"  "first-line 
transport"  (French). 

T.D.  =  Territorial  Officers'  Decora- 

tion (British). 

Tenn.=  Tennessee. 

Tex.  =  Texas. 

T.F.=  Territorial  Force  (British, 

till  1919). 

T.F.N.S.  =  Territorial  Force  Nursing 
Society  (British). 

T.M.=  Trench  Mortar. 

T.M.G.  =  Temps  Moyen  de  Green- 
wich =  Greenwich  Mean 
Time  (French). 

T.N.T.=  Trinitrotoluene  (High  Ex- 

T.P.S.=  Telegraphie  par  le  50/  = 

Earth  telegraphy  (Power 
buzzer,  etc.)  (French). 

T.S.F.=  Telegraphie  sans  fl  =  Wire- 

less telegraphy  (French). 


Ukr.  =  Ukraine. 

U.S.  =  United  States. 

U.S.A.  =  United  States  of  America; 

United  States  Army. 
U.S.N.  =          United  States  Navy. 
U.S.S.  =  United  States  Ship. 

Va.  =  Virginia. 

V.A.D.=  Voluntary  Aid  Detachment; 

nursing  service,  Terri- 
torial Force  (British). 

V.C.=  Victoria  Cross  (British). 

V.D.  =  Volunteer  Officers'  Decora- 

tion (British). 

Verst.  =  Verstarkl  =  R  ei  n  forced, 

chiefly  of  formations 
temporarily  provided 
with  artillery  (German). 

viz.=  videlicet  =  namely. 

Vt.  =  Vermont. 

V.T.C.=  Volunteer  Training  Corps 



W.  =  West. 

W.A.A.C.=       Women's  Army    Auxiliary 

Corps    (Q.M.A.A.C.) 

W.A.F.F.  =      West  Africa  Frontier  Force. 

Wash.  =  Washington. 

W.D.=  War  Department  (British 

and  U.S.A.). 

Westm.  =         Westmorland. 

WUts.=  Wiltshire. 

Wis.  =  Wisconsin. 

WM.  =  Werfmme=Shell  of  Minen- 

werfer  (German). 

W.O.=  War  Office  (British Gov't.). 

Worcs.  =          Worcestershire. 

W.R.A.C.=  Women's  Reserve  Ambu- 
lance Corps  (British). 

W.R.A.F.  =  Women's  Royal  Air  Force 

W.R.N.S.=  Women's  Royal  Naval 
Service  (British). 

W.S.P.U.  =  Women's  Social  and  Politi- 
cal Union  (British). 

Wumba.  =  Waff  en-  und  Munitions- 
Beschaffungs-Ami  =  W  a  r 
Office  for  Munitions 

W.U.S.L.  =      Women's    United    Service 

League  (British). 
W.Va.  =  West  Virginia. 

W.V.R.  =          Women's  Volunteer  Service. 
Wyo.=  Wyoming. 

yd.  =  yard  or  yards. 

Y.M.C.A.  =  Young  Men's  Christian  As- 

Yorks.  =  Yorkshire. 

Y.W.C.A.=  Young  Women's  Christian 




A.  B. 
A.  C.  D. 

A.  D.  H. 
A.  E.  Ev. 
A.  Fl. 

A.  F.  Pr. 

A.  G.  L. 
A.  G.  W. 

A.  H.  Br. 

A.  H.  C.* 
A.  H.  Ch. 
A.  H.  Gi. 


f  Austrian  Empire : 

\      Literature  and  Drama. 

Administration : 

ALFRED  C.  DEWAR,  CAPT.  R.N.  (RET.),  B.Lrrr.  (Oxon.). 

Gold  Medallist,  Royal  United  Service  Institution.  Late  of  the  Historical  Section,  (  Biocka(je.  Convov 

[  Coronel;  Dogger  Bank. 

Naval  Staff,  Admiralty. 


Chief  Scientific  Adviser  and  Director-General  of  the  Intelligence  Department, 
Ministry  of  Agriculture  and  Fisheries.  Author  of  The  Soil;  Fertilisers  and 
Manures;  A  Pilgrimage  of  British  Farming;  Agriculture  after  the  War;  etc. 



Joint-author  of  The  Natural  Organic  Colouring  Matters  (Perkin  and  Everest).  J  Botany:   Chemistry  of  Sap 
Author  of  various  papers  on  Colouring  Matters,  etc.,  in  Proc.  Roy.  Soc.,  Journ.  1       Pigments  of  Plants. 
Chem.  Soc.,  etc. 


Director  of  the  Department  of  Systematic  Bacteriology  in  St.  Mary's  Hospital, 


Professor  of  Modern  History  in  the  University  of  Vienna. 
Vienna  Academy  of  Science;  etc. 

Member  of  the  « 


Physician  to  the  City  of  London  Hospital  for  Diseases  of  the  Chest. 



Austrian    Empire:     Austro- 
Hungarian  Foreign  Policy; 
Berchtold,  Count  L. ; 
Burian,  R.  S.  von; 
Charles  (Emperor  of  Austria) ; 
Czernin,  Count. 


ADAM  GOWANS  WHYTE,  B.Sc.,  A.I.E.E.  ( 

Editor  of  the   Electrical  Press  Limited.    Author  of   The  Electrical  Industry;  <  Electricity  Supply:  United 
Electricity  in  Locomotion;  The  All-Electric  Age.  {     Kingdom. 

ALFRED  H.  BROOKS,  B.Sc.,  D.Sc. 

Geologist,  U.S.  Geological   Survey.     In   charge  of  geologic  and   topographic  i  ..    . 
surveys  and  investigations  of  mineral  resources  of  Alaska.   Vice-Chairman  of 
the  first  Alaska  Railroad  Commission. 


Late  Director,  Westminster  Technical  Institute. 


University  Lecturer  in  Botany,  Oxford. 


Professor  of  Engineering,  University  of  Manchester;  late  Professor  of  En- 
gineering, St.  Andrews  University.  Member,  Board  of  Trade  Water  Power 
Committee;  Hon.  Secretary,  Conjoint  Board,  Water  Power  Committee.  Member 
of  the  Air  Ministry  I.C.E.  Committee.  President,  British  Association,  Section 
9,  1921. 

Arts  and  Crafts  (in  part). 
Botany:  General  Morphology. 

Aeronautics:  Aero- Engines. 

1A  complete  list,  showing  all  contributors  to  the  New  Volumes  (arranged  according  to  the  alphabetical  order  of  their  surnames)  with 
the  articles  signed  by  them,  appears  at  the  end  of  Volume  XXXII. 



A.  H.  McM. 

A.  J.  G. 
A.  J.  M. 

A.  L.  Bo. 
A.  L.  C. 
A.  P. 

A.  S.  D. 

A.  S.  E. 

B.  B.-H. 
B.  E.  P. 

B.  K.  L. 

B.  W.  D. 

C.  A.  D. 

C.  Br. 
C.  B.  C. 

C.  C.  H. 
C.  E.  C. 
C.  E.  W.  B. 


F.S.A.,  F.L.S.,  etc. 

Foreign  Secretary  to  the  Government  of  India,  1911-4.  British  High  Com- 
missioner in  Egypt,  1914-6.  See  biographical  article:  M'MAHON,  SIR  ARTHUR 


Principal  and  Professor  of  Systematic  Theology  in  the  Scottish  Congregational 
College,  Edinburgh.  Assistant  Editor  of  Peake's  Commentary  on  the  Bible. 


Design  Branch,  Directorate  of  Research,  Air  Ministry,  in  charge  of  Seaplane 
Development.  Assistant  Director,  Air  Department,  Admiralty,  June  1915  to 
June  1916;  Senior  Flying  Officer  Naval  Air  Station,  Felixstowe,  August  1916  to 
June  1917. 


See  the  biographical  article:  AUFJENBERG-KOMAROW,  MORITZ. 


Church  History :   Free 
Churches:  Presbyterian 
Church  of  Scotland. 

Aeronautics:  Seaplanes. 

Army:   Austro- Hungarian 

(in  part); 
Beck,  Graf  von; 
Conrad  von  Hotzendorf. 


Professor  of  Statistics  in  the  University  of  London. 
Statistics;  Wages  in  the  United  Kingdom;  etc. 

Author  of  Elements  of  <  Cost  of  Living. 

Army:    United  States; 
Champagne,  Battles  in 

(in  part). 


Education:  United  States 
(in  part). 


Army :   British. 

Champagne,  Battles  in 

(in  part). 


Distinguished  Service  Medal  (U.S.A.),  C.M.G.  Legion  of  Honour.  Formerly 
co-editor  of  The  Military  Historian  and  Economist.  • 

SIR  ARTHUR  PEARSON,  BT.,  G.B.E.  (died  1921). 

Chairman  of  the  Blinded  Soldiers  and  Sailors  Care  Committee.  President  of 
the  National  Institute  for  the  Blind.  Author  of  Victory  over  Blindness;  The 
Conquest  of  Blindness.  See  the  biographical  article:  PEARSON,  SIR  ARTHUR. 


Assistant  Commissioner  for  Higher  Education  and  Director  of  Professional 
Education,  University  of  the  State  of  New  York. 


Plumian  Professor  of  Astronomy  and  Experimental  Philosophy  and  Director 
of  the  Observatory,  Cambridge.  Author  of  Stellar  Movements  and  the  Structure 
of  the  Universe;  Space,  Time  and  Gravitation. 

Director-General  of  Mobilization  and  Recruiting,  War  Office. 


Late  French  Army.  Commanded  a  Division  1915-6.  Author  of  La  Grande 
Guerre  sur  le  front  Occidental;  Les  Batattles  d'Arlois  et  de  Champagne;  and,  under 
the  pseudonym  "  Pierre  Lebaut  court,"  of  La  Defense Nationale,  1870-1  and  other 
works,  including  a  general  bibliography  of  1870-1. 


Editor  of  the  Cape  Times.   Formerly  Foreign  Editor  of  The  Times. 


Fellow  and  Lecturer  in  Mediaeval  and  Modern  Languages  and  English,  Christ's 
College,  Cambridge. 


President  of  Colorado  College,  Colorado  Springs,  Colo.  Author  of  Freedom  of 
the  Press  in  Massachusetts. 


Professor  of  the  Science  of  Administration  in  the  University  of  Vienna. 

WING    COMMANDER    T.   R.    CAVE-BROWNE-CAVE,    C.B.E.,    R.A.F.,    F.R.AE.S., 

A.M.I.MECH.E.,  A.M.I.N.A. 

In  charge  of  Airship  Experiments  and  Research  at  the  Admiralty  and  the  Air 
Ministry.  Lecturer  in  Airship  Engineering,  Imperial  College  of  Science.  Airship 
Member  of  the  Aeronautical  Research  Committee.  Formerly  Engineer  Officer, 
R.N.  Airship  Pilot,  1913.  In  charge  of  Non-rigid  Airship  Design  and  Con- 
struction at  Kingsnorth,  1914-8. 

CHARLES  CAESAR  HAWKINS,  M.A.,  M.I.E.E.,  Assoc.  AMERICAN  I.E.E.  f  _.    ^    .  _     . 

Author  of  The  Dynamo.    Joint-author  of  Papers  on  the  Design  of  Alternate  {  ^'ectncal  Engineering 
Current  Machinery.  \      <*»  *"')• 


Director  of  Military  Operations,  War  Office,  1914-6.  Author  of  Small  Wars; 
Military  Operations  and  Maritime  Preponderance;  The  Dardanelles;  etc. 


Gloucestershire  Regiment.  Inspector  of  Grenade  Training,  G.H.Q.,  Great  Brit- 
ain, 1915-8.  Experimental  Officer  for  Grenades  and  Trench  Stores,  Ministry 
of  Munitions,  1915-9.  Control  Officer,  Inter-Allied  Commission  of  Control,  1919. 

|  Botha,  General. 


/  Austrian  Empire  (in  part) ; 
( Badeni,  K. 

Aeronautics:  Airships. 

Dardanelles  Campaign. 

Dogs,  War  (in  part). 



C.  F.  A. 

C.  F.  C. 
C.  H.  H. 

C.  H.  T. 
C.  J.  M. 
C.  L.  C. 

C.  LI.  M. 

C.  M.  E.  M. 
C.  O.  B. 

C.  R.  W. 

C.  T.  A. 
C.  T.  G. 


T.D.  Late  East  Surrey  Regiment.  Distinguished  Service  Medal  (U.S.A.),  Order 
of  Saint  Anne  (Russia).  Formerly  Scholar  of  Queen's  College,  Oxford.  Staff 
Officer  for  Trench  Warfare  Research,  1915-7.  British  Instructor  in  Intelligence, 
American  Expeditionary  Force,  1918.  Editorial  Staff  of  the  nth  edition  of  the 
Encyclopedia  Britannica.  Author  of  Grant's  Campaigns;  The  Wilderness  and 
Cold  Harbor;  etc. 


Analytical  and  Consulting  Chemist.  Member  of  the  firm  of  Cross  &  Bevan. 
Joint-author  (with  E.  J.  Bevan)  of  Researches  on  Cellulose;  Text-Book  of 

CLARENCE  HENRY  HARLNG,  B.LiTT.  (Oxon.),  PH.D.  (Harvard). 

Associate  Professor  of  History  in  Yale  University.  Author  of  The  Buccaneers 
in  the  West  Indies  in  the  XVII.  Century;  Trade -and  Navigation  between  Spain 
and  the  Indies  in  the  Time  of  the  Habsburgs;  etc. 


Past-Master  of  the  Art  Workers'  Guild.   Late  Member  of  Council  of  the  Royal  I  £elcljler>  J> 
Institute  of  British  Architecture.   Cantor  Lecturer  on  Mosaic.  [  Bentley,  J.  i>. 


Financial  Editor  of  The  Times. 

Air  Bombs  (in  part) ; 
Ammunition  (in  part) ; 
Army:   Russian  (in  part) ; 

German ;  Artillery  (in  part) ; 
Balkan  Wars  (in  part); 
Bombthrowers ; 
Cordonnier,  General; 
Eastern  European  Front 
Campaigns  (in  part). 




Member  of  the  Staff  of  the  Deutsche  Allgemeine  Zeitung. 

<  English  Finance. 

f  Allenstein-Marienwerder; 
I  Ballin,  A. ;  Berlin;  Bernstorff, 
|     Count;  Dresden; 

Author  of  {  Behaviourism. 


Curator  of  South  American  History  and  Literature  in  the  Harvard   College   I  Argentina; 
Library.   Manager  of  the  Foreign  Commercial  Department  of  the  Corn  Exchange   |  Buenos  Aires. 
National  Bank  of  Philadelphia.   Author  of  Inter- American  Acquaintances. 


Emeritus  Professor  of  Psychology  in  the  University  of  Bristol. 
Animal  Life  and  Intelligence;  Instinct  and  Experience;  etc. 

See  the  biographical  article:  MANGIN,  C.  M.  E. 


Reader  in  Malay  in  the  University  of  London  and  in  the  School  of  Oriental 
Studies,  London  Institution. 


Attorney-at-Law.   Hon.  Secretary,  National  Municipal  League.   Vice-President, 
American  Civic  Association.  President,  Civil  Service  Commission  of  Philadelphia. 


Historical  Section,  Committee  of  Imperial  Defence. 

/  Champagne,  Battles  in 

\       (in  part). 

Austric  Family  of  Languages. 

City  Government. 

Artois,  Battles  in  (in  part). 


Referee-in-Bankruptcy,  U.S.  District  Court,  Southern  District  of  Ohio.    Secre-  {  Cincinnati, 
tary  to  the  Trustees  of  the  Sinking  Fund  of  Cincinnati,  Ohio. 

D.  A. 


DOUGLAS  AINSLIE,  B.A.  (Oxon.).  f 

Translator  of  Benedetto  Croce's  works.   Author  of  John  of  Damascus;  The  Song  <  Croce,  Benedetto  (in  part), 
of  the  Stewarts;  and  other  poems. 


Colonel  Commandant,  Royal  Artillery.  Secretary,  Member  and  President  of  the 
Ordnance  Committee.  President  of  the  Committee  on  Explosives.  Formerly 
on  the  Experimental  Staff  at  Shoeburyness. 


President  of  the  University  of  California.  Professor  of  Education,  University  of 
California,  1910.  President,  Board  of  Trustees,  Mills  College,  California,  1910-7. 
Author  of  the  Ethno-Botany  of  the  Coahuilla  Indians;  A  History  of  the  Philip- 
pines; etc. 


Professor  of  History  and  Political  Science  in  the  University  of  Arkansas.  Author 
of  A  History  of  Military  Government  in  Newly  Acquired  Territory  of  the  United 
States.  Joint-author  of  The  South  in  the  Building  of  the  Nation;  Studies  in  South- 
ern History  and  Politics.  Associate  Editor  of  the  Southwestern  Political  Science 


Commander  of  the  Legion  of  Honour.   General  in  Command  of  the  London  Air  <  Air  Raids. 

Ammunition  (in  part). 

California,  University  of. 




E.  C.K. 
E.  F.  B.  G. 

E.  F.  L. 
E.  G.-H. 


E.  J.  F. 
E.  J.  G. 

E.  J.  R. 

E.  J.  S. 

E.  M.  Ho. 
E.  N.  S. 
E.  S. 

E.  S.  H. 

E.  S.  H.* 
E.  S.  S. 
E.  V.  V. 

E.  v.  W. 
E.  W.  MacB. 


Late  Dean  and  Emeritus  Professor  of  Dental  Pathology  and  Therapeutics, 
Dental  School,  University  of  Pennsylvania.  Editor  of  The  Dental  Cosmos. 

ELINOR  F.  B.  GROGAN  (Lady  Grogan). 

Wife  of  Colonel  Sir  Edward  Grogan,  Bart.,  C.M.G.,  D.S.O.  Travelled  and  lived 
for  some  years  in  the  Balkans.  Author  of  articles  on  Balkan  subjects  in  the 
Nineteenth  Century;  New  Europe;  etc. 


Consulting  Engineer.  Formerly  of  the  Armour  Plate  Department,  Armstrong 
Whitworth  &  Co. 


Late  General  Staff,  Austro-Hungarian  Army.  Now  of  the  Kriegsarchiv,  Vienna. 
Formerly  Staff  Officer  to  Field-Marshal  Conrad  von  Hotzendorf. 


Late  General  Staff,  Austro-Hungarian  Army.  Now  of  the  Kriegsarchiv,  Vienna. 
Part-author  of  the  Austrian  Official  War  Chronology  Tables,  etc. 


Assistant  in  the  Department  of  Greek  and  Roman  Antiquities  in  the  British 
Museum.  Editor  of  the  Journal  of  Hellenic  Studies. 


Professor  of  Biblical  and  Patristic  Greek,  and  Secretary  to  the  President,  Chicago 
University.  Author  of  the  Story  of  the  New  Testament;  Index  Patristicus;  and 
Contributor  to  the  Atlantic  Monthly. 


Director  of  the  Rothamsted  Experimental  Station.  Author  of  Soil  Conditions 
and  Plant  Growth;  The  Fertility  of  the  Soil;  Lessons  on  Soil;  Manuring  for  Higher 
Crop  Production;  etc. 


Lecturer  in  Botany  and  Fellow  of  University  College,  London.  Hon.  Secretary, 
British  Ecological  Society.  Author  of  An  Introduction  to  the  Study  of  Plants;  etc. 

EDMUND  KNECHT,  Pn.D.  (Zurich),  M.SC.TECH.,  F.I.C. 

Associate  Professor  of  Applied  Chemistry,  Manchester  University  and  College 
of  Technology. 

President  of  Dartmouth  College,  Hanover,  N.H. 

Royal  Engineers. 


Secretary  to  the  Lord  Mayor  of  Birmingham.    Joint-author  (with  R.  H.  Brazier)]  Birmingham. 
of  Birmingham  and  the  Great  War. 


Member  of  Education  Authority  for  Perthshire.  Vice-Chairman,  Territorial 
Force  Nursing  Service  Committee.  On  Royal  Commission  on  the  Civil  Service. 
Member  of  the  Scottish  Universities  Committee.  Author  of  The  Life  of  Des- 
cartes; etc. 



Armour  Plate. 

Austria,  Republic  of: 
History;  Eastern  European 
Front  Campaigns  (in  part) . 

Army:  Austro-Hungarian  (in 

Brest  Litovsk,  Battles 

round,  1915; 
Dunajec-San,  Battles  of  the^ 

Archaeology :  Greece. 

Chicago,  University  of. 

Botany:  Soil  Sterilization* 

Botany:    Ecology. 

Dyeing :  United  Kingdom- 

Dartmouth  College. 

<  Bridging,  Military. 

Child  Welfare: 

United  Kingdom. 

Army:    British,    Demobiliza- 
Dogs,  War  (in  part). 

F.  A.  Cl. 


Late  Royal  West  Kent  Regiment.  Formerly  Mobilization  Directorate,  War 
Office.  Member  of  Gray's  Inn. 


Reader  in  Economic  Mycology,  University  of  London.   Mycologist  to  the  South-  {  Botany:   Mycology. 

Eastern  Agricultural  College,  Wye,  Kent. 

Professor  of  History  in  the  University  of  Delaware.   Author  of  The  Origin  and 

Early  Development  of  the  English  Universities  to  the  Close  of  the  ijth  Century; 

English  Trading  Expeditions  into  Asia  under  Authority  of  the  Muscovy  Company, 


Emeritus  Professor  of  History  in  the  University  of  Pressburg. 

ERNEST  WILLIAM  MACBRIDE,  D.Sc.  (Lond.),  M.A.  (Cantab.),  HON.  LL.D.  (McGill), 


Vice-President  of  the  Zoological  Society  of  London.  Vice-Chairman  of  the 
Eugenics  Education  Society.  Formerly  Professor  of  Zoology  in  McGill  Univer- 
sity, Montreal.  Professor  of  Zoology  in  the  Imperial  College  of  Science  and 
Technology,  London.  Author  of  Textbook  of  the  Embryology  of  the  Invertebrata; 


Professor  of  United  States  Citizenship,  Maxwell  Foundation,  Boston  University.  (  Boston. 
Author  of  Organized  Democracy;  First  Lessons  in  Finance;  etc. 


Andrassy,  J.  J. 




F.  A.  L. 
F.  C.-O. 
F.  C.  E. 

F.  G.  B. 
F.  G.-T. 

F.  H.  Br. 


F.  J.  C.  W. 

F.  Ke.* 
F.  L.  N. 

F.  M.  R. 
F.  R.  C. 

F.  W.  E.-G. 

F.  W.  P. 

F.  Y. 


G.  A. 

G.  Ab. 

G.  A.  Y. 
G.  C. 
G.  E.  B. 


Professor  of  Experimental  Philosophy  in  the  University  of  Oxford. 

Director,  Admiralty  Compass  Department. 


Major,  late  General  Staff,  Turkish  Army.  Author  of  a  Life  of  M  alike;  Die  Ruine 
des  Orients;  etc.  Member  of  Committee,  German  League  of  Nations  Union. 

FRANK  Fox,  O.B.E. 

Author  of  Australia;  Problems  of  the  Pacific;  "G.H.Q."    Served  in 
War  as  Artillery  officer  and  as  Staff  officer. 


Superintendent,  Homerton  Residential  School  for  the  Deaf. 
The  Teacher  of  the  Deaf.   Officer  of  the  French  Academy. 


Chief  Secretary  to  the  Danish  Extraordinary  Commission  on  Regulation  of 
Prices.  Secretary  to  the  General  Director  of  the  Great  Northern  Telegraph 
Company  (Store  Nordiske). 


On  the  Staff  of  The  Times  for  Indian  Affairs.  London  Correspondent  of  The 
Times  of  India.  Formerly  Assistant  Editor  of  the  Bombay  Gazette  and  Editor  of 
the  Indian  Daily  Telegraph,  Lucknow. 


Author  of  The  Complete  Auction  Player;  Master- Auction;  etc. 

MAJOR  F.  J.  C.  WYATT,  O.B.E.,  M.C. 

Royal  Engineers.  Organizer  and  Controller  of  Camouflage,  British  Expedition- 
ary Force,  France,  1916-8. 


Sherardian  Professor  of  Botany  in  the  University  of  Oxford. 


Late  Royal  Artillery.  Department  of  Scientific  and  Industrial  Research.  Director 
of  Alcohol  Section,  Fuel  Research  Board. 


Royal  Artillery.    Chief  Instructor,  Artillery 
Instructional  Staff,  Artillery  College). 

I  Einstein,  i 
\  Compass. 

Army:    Turkish; 
Balkan  Wars  (in  part). 

Formerly  Editor  of  {  Deaf  and  Dumb. 

Denmark  (in  part). 

}  Aga  Khan ; 

]  Bikaner,  Maharaja  of. 

Bridge,  Auction. 
Camouflage:  Military. 

\  Botany:  Introductory. 

College,  Woolwich    (assisted   by  <  Ammunition  (in  part) . 


Editorial  Staff,  nth  edition  of  the  Encyclopedia  Bntannica.  Editorial  Staff  of 
The  Times.  Author  of  South  Africa  from  the  Great  Trek  to  the  Union;  Problems 
of  Exploration;  Africa;  The  Sahara  in  1915;  The  Great  War  in  Europe;  etc. 


Special  Examiner  and  Adviser  to  the  Board  of  Trade  on  Colour  Vision  and  Eye- 
sight. Author  of  The  Physiology  of  Vision.  Inventor  of  the  Colour  Perception 
Spectrometer  and  Colour  Perception  Lantern — used  as  the  Official  Test  of  the 
British  Navy. 


Founder  and  former  Editor  of  The  Coal  Age. 


Editor  of  the  Saturday  Review.  Author  of  With  the  Battle  Cruisers;  Master- 
singers;  Ireland  at  the  Cross  Roads;  Christopher  Columbus  and  the  New  World; 
The  Sands  of  Pleasure;  When  the  Tide  Turns;  etc. 




Formerly  Correspondent  of  The  Times  in  Paris. 


Chief  of  the  Children's  Bureau,  U.S.  Department  of  Labor.  Formerly  Director 
Child  Labor  Division,  U.S.  Children's  Bureau,  and  Executive  Secretary, 
Illinois  Immigrants  Commission,  Chicago. 


Lieutenant-Colonel,  Corps  of  Engineers,  Assistant  to  the  Chief  of  Engineers, 
U.S.  Army. 


Author  of  Introduzione  allo  studio  delle  opere  di  B.  Croce  (1920). 


Formerly  Scholar  of  New  College  and  Fellow  of  All  Souls  College,  Oxford. 
Editor  of  The  Times,  1884-1912.  Author  of  Life  of  Disraeli  (vols.  3, 4,  5,  and  6). 
See  biographical  article :  BUCKLE,  GEORGE  EARLE. 

Abyssinia;  Africa;  Angola; 
Belgian  Congo;  Cairo; 
Cameroon;  Cape  Province; 
Dahomey;  Delagoa  Bay; 
East  African  Military 

Operations ;  Egypt  (in  part). 

Colour  Vision  and 
Colour  Blindness. 

Coal:    United  States. 

Beatty,  Lord. 

|  Denmark  (in  part). 

/  Briand,  A. 

\  Deschanel,  P. 

Children,  Laws  Relating  to : 

United  States; 
Child  Welfare:  United  States. 

Engineers,  Military: 

United  States. 

/  Croce,  Benedetto 
\      (in  part). 

Asquith,  H.  H.;  Balfour, 
A.  J.;  Carson,  Sir  Edward; 

Cecil,  Lord  Hugh;  Cecil, 
Lord  Robert;  Churchill, 
Winston;  Cromer,  Lord; 

English  History:   1913-21. 

G.  £.  M. 

G.  E.  S. 
G.  K.  S.-M. 



Secretary  of  the  Prudential  Assurance  Company,  Limited.    Manager  to  the 
Dollar  Securities  Committee. 


Professor  of  Anatomy  in  the  University  of  London.    Author  of  The  Ancient  \   .     , 
Egyptians;  The  Royal  Mummies;  Migrations  of  Early  Culture;  Evolution  of  the  }  An"lropology. 
Dragon;  etc. 

G.  S.  F. 

G.  T.* 
H.  A.  B. 

H.  A.  H. 
H.  Ch. 

H.  Cl. 

H.  Cr. 
H.  E.  A. 

H.  E.  A.  C. 
H.  E.  B. 
H.  E.  E. 

H.  E.  Wi. 
H.  G.  J. 


Barracks  and  Hutments; 
Engineers,  Military: 
United  Kingdom. 

Conservation  Policy. 


C.I.E.,  HoN.M.lNST.C.E.,  LATE  R.E. 

Director  of  Fortifications  and  Works,  War  Office,  1911-8.  Author  of  The  Water 
Supply  of  Barracks  and  Cantonments;  The  Principles  of  Structural  Design;  etc. 

GIFFORD  PTNCHOT,  A.B.  (Yale),  HON.  A.M.  (Yale  and  Princeton),  Sc.D.  (Michigan 

Agricultural  College),  LL.D.  (McGill). 

Professor  of  Forestry,  Yale  University.  U.S.  Forester,  1898-1910.  President  of 
the  National  Conservation  Association.  Pennsylvania  Commissioner  of  Forestry. 
Author  of  The  Adirondack  Spruce;  The  Training  of  a  Forester;  The  Fight  for 
Conservation;  etc.  , 

GEORGE  SAUNDERS,  O.B.E.,  B.A.  (Oxon.),  HON.  LL.D.  (Glasgow).  [  Bethmann  Hollweg,  T.  von; 

Correspondent  of  the  Morning  Post  in  Berlin,  1888-97;  and  of  The  Times  in  I  Biilow,  Prince  von ; 
Berlin,  1897-1908,  and  in  Paris,  1908-14.  ]  Delbruck,  Hans; 

{ Eisner,  Kurt. 

Guv  STANTON  FORD,  PH.D.  [ 

Professor  of  History  and  Dean  of  the  Graduate  School,  University  of  Minnesota.  J 

Director  of  Division 
Public  Information. 

of  Educational  and  Civic  Publications,  Committee  on 

Censorship :  United  States. 


Scholar  and  Exhibitioner,  Royal  College  of  Music.   Author  of  Experance  Morris  {  Dancing. 
Dance  Book,  No.  2.    Conductor,  Philharmonic  Societies,  London  and  Liverpool. 


Late  Royal  Field  Artillery.  Author  of  Modern  Guns  and  Gunnery;  Modern 
Artillery  in  the  Field. 


Associate  Professor  of  History  and  Social  Science  in  the  University  of  Arizona. 


Formerly  Scholar  of  Corpus  Christi  College,  Oxford.  Editor  of  the  toth,  nth 
and  1 2th  editions  of  the  Encyclopedia  Britannica.  Financial  Editor  of  The 
Times,  1913-20.  See  the  biographical  article :  CHISHOLM,  HUGH. 


Governor  of  Nigeria.  In  the  Federated  Malay  States  Civil  Service, 
1883-1903;  in  the  West  Indies,  1903-7;  in  Ceylon,  as  Colonial  Secretary,  1907-12. 
Governor  of  the  Gold  Coast,  1912-9.  Administered  the  British  Sphere  of  Occu- 
pation in  Togoland  throughout  the  World  War.  Author  of  Studies  in  Brown 
Humanity;  Furtlier  India;  The  German  Colonies;  etc. 


Author  of  How  Motion  Pictures  Are  Made. 


Emeritus  Professor  of  Chemistry  at  the  City  and  Guilds  College,  South  Kensing- 
ton. Davy  Medallist  of  the  Royal  Society,  1911. 


Formerly  Scholar  of  Jesus  College,  Oxford,  and  Advocate  of  the  High  Court  at 
Calcutta.  Author  of  Calcutta  Old  and  New.  Late  Editor  of  India. 


Professor  of  History  in  Western  Reserve  University,  Cleveland,  Ohio.  Author  of  (  Cleveland. 
The  Revolutionary  Period  in  Europe;  The  Teaching  of  History  and  Civics;  etc.       [ 


Sometime  Beit  Professor  of  Colonial  History,  Oxford.  Fellow  of  All  Souls 
College,  Oxford.  Author  of  A  Short  History  of  British  Colonial  Policy;  Origin 
and  Growth  of  the  English  Colonies;  "  Canada"  (Part  II.)  in  Sir  Charles  Lucas's 
History  and  Geography  of  the  British  Colonies;  etc. 

MAJOR  H.  E.  WIMPERIS,  O.B.E.,  M.A.,  M.I.E.E.,  A.M.I.C.E.,  F.R.AE.S. 

Superintendent  of  the  Air  Ministry  Laboratory.  Lecturer  on  Air  Navigation  at 
the  Imperial  College  of  Science.  Served  in  Royal  Air  Force. 


Professor  of  Government  in  the  University  of  Texas.  Author  of  Principles  of 
Prussian  Administration;  Applied  City  Government;  A  Handbook  of  Civic  Im- 
provements; Municipal  Functions;  etc. 


Assistant  Keeper  of  Egyptian  and  Assyrian  Antiquities,  British  Museum. 

Artillery  (in  part). 

English  History: 



j  Cinematograph. 
<  Chemistry 

Banerjea,  Sir  S. 

British  Empire. 

Aeronautics :  A  ir  Navigation. 


/Archaeology:    Egypt 
\      and  Western  Asia. 




Associate  Professor  of  Mexican  History  and  Librarian  of  the  Bancroft  Library, 
University  of  California.  Author  of  Jose  de  Gdlvez,  Visitor-General  of  New 
Spain]  etc. 

H.  J.  W.          H.  J.  WILSON,  C.B.,  C.B.E. 


Professor  of  Constitutional  Law  at  the  University  of  Vienna. ' 

H.  Lu.  H.  LUND,  M.A. 

H.  L.  H.  S.      HARRY  L.  H.  SCHUTZE,  M.D. 

Bacteriologist  at  the  Lister  Institute,  London. 

H.  L.  T.  HENRY  LETHEBY  TIDY,  M.A.,  M.D.  (Oxon.),  F.R.C.'P.  (Lond.). 

Assistant  Physician  to  St.  Thomas's  Hospital.  Physician  to  the  Great  Northern 
Hospital,  London. 

H.  M.  L.          HAROLD  MAXWELL  LEFROY,  M.A.,  F.Z.S. 

Professor  of  Entomology  in  the  Imperial  College  of  Science  and  Technology, 
South  Kensington.  Author  of  Indian  Insect  Pests;  Indian  Insect  Life;  etc. 

H.  N.*  CAPTAIN  HOFFMAN  NICKERSON,  B.A.,  M.A.  (Harvard). 

Late  U.S.  Army.  Member  of  New  York  State  Legislature,  1916.  In  the  World 
War  served  in  G.H.Q.  Intelligence  Staff,  American  Expeditionary  Force,  France. 


Rector  of  the  University  of  Ghent.  Member  of  the  Royal  Academy  of  Belgium 
and  of  the  Institute  of  France.  Corresponding  Member  of  the  Royal  Historical 
Society.  Author  of  Histoire  de  Belgique;  etc. 

H.  P.  W.          HENRY  PARKER  WILLIS,  PH.D. 

Professor  of  Banking  in  Columbia  University.  Director  of  Research,  Federal 
Reserve  Board.  Author  of  American  Banking;  The  Federal  Reserve;  etc. 

H.  R.  M.          HUGH  ROBERT  MILL,  D.Sc.,  LL.D. 

Gold  Medallist  of  the  Royal  Geographical  Society.  Author  of  The  Siege  of 
the  South  Pole;  etc.  See  the  biographical  article:  MILL,  HUGH  ROBERT. 

H.  Tk.  HANS  TIEKE,  PH.D. 

Professor  of  Art  History  in  the  University  of  Vienna. 


Late  General  Staff,  German  Army.  Director  in  the  Archives  of  the  Reich. 
Formerly  member  of  the  Historical  Section  of  the  Great  General  Staff.  During 
the  World  War  a  General  Staff  Officer  with  troops.  Representative  of  the 
Supreme  Command  at  the  Foreign  Office,  1918. 


Editor  of  the  Financial  Supplement  of  the  Saturday  Review.  Formerly  Editor  of 
The  Economist.  Author  of  The  Meaning  of  Money;  Case  for  Capitalism;  etc. 


H.  W.  M.        HENRY  WILLIAM  MARDON,  F.R.G.S. 

Commander  of  the  Mejidieh.  Formerly  Lecturer  in  Geography  and  Education 
in  the  Tewfikieh  and  Dar  el  Ulum  Colleges,  Cairo.  Author  of  A  Geography  of 
Egypt  and  the  Anglo-Egyptian  Sudan;  etc. 

H.  W.  M.*       HAROLD  WOOD  MILNER,  M.Sc.,  A.M.I.C.E. 

Executive  Engineer,  Public  Works  Department,  Government  of  India. 

I.  B.  B.  SIR  ISAAC  BAYLEY  BALFOUR,  K.B.E.,  M.D.,  LL.D.,  M.A.,  F.R.S. 

Regius  Keeper  of  the  Royal  Botanic  Garden,  Edinburgh.  Fellow  of  Magdalen 
College,  Oxford. 

I.  F.  IRVING  FISHER,  A.B.,  PH.D. 

Professor  of  Political  Economy  at  Yale  University.    Author  of  The  Nature  of 
Capital  and  Income;  The  Purchasing  Power  of  Money;  The  Rate  of  Interest;  etc. 
See  the  biographical  article:   FISHER,  IRVING. 

J.  A.  G.  JAMES  ALISON  GLOVER,  O.B.E.,  M.A.,  M.D.  (Cantab.),  D.P.H. 

Medical  Officer,  Ministry  of  Health.  Late  Officer  in  Charge  Cerebro-Spinal 
Fever  Laboratory,  London  District. 

J.  A.  T.*          JOHN  AITON  TODD,  B.L.  f 

Lecturer  in  Economics,  Balliol  College,  Oxford.   Author  of  The  World's  Cotton  {  Cotton  and  Cotton  Industry. 
Crops;  etc. 

J.  B.  C.  K.       JOHN  BAKER  CANNINGTON  KERSHAW,  F.I.C.,  F.S.S. 

Consulting  Chemist  and  Chemical  Engineer.  Author  of  The  Electric  Furnace 
in  Iron  and  Steel  Production;  Electrometallurgy;  Electrothermal  Methods  of  Iron 
and  Steel  Production. 

Costa  Rica. 

I  Arbitration  and  Conciliation: 
I       United  Kingdom. 

!  Austria,  Republic  of: 

<      Constitution  and 
{     Administration. 

|  Denmark  (in  part). 
<,  Bacteriology:  Medical. 

Encephalitis  Lethargica. 
Economic  Entomology. 
Artois,  Battles  in  (in  part). 

Belgium:    History  (in  part). 

Banking:  United  States. 

Antarctic  Regions. 
Austrian  Empire :  Art. 

Champagne,  Battles  in 

(in  part) . 


f  Demobilization  and 

|      Resettlement:    United 

[      Kingdom. 



Botany :    Horticultural 

Dollar  Stabilization. 

Cerebro-Spinal  Fever. 



I  Electrochemistry  and 

]      Electrometallurgy. 


J.  C.  M.* 

J.  C.  Mo. 
J.  E.  W. 
J.  H.  D. 

J.  Mo.* 
J.  M.  M. 

J.  O.  P.  B. 


J.  P.-B. 
J.  R.  Co. 

J.  R.  J-  J- 
J.  R.  R. 

J.  SI. 

J.  S.  Ba. 

K.  M. 

K.  P. 

L.  C.  W. 


Jo  VAN  Cvijic. 

Patron's  Medallist  of  the  R.G.S.  Officer  of  the  Legion  of  Honour.  Professor  of 
Geography  in  the  University  of  Belgrade.  Author  of  Das  Karstphaenomen; 
Grundlinien  der  Geographic  und  Geologic  lion  Mazedonien  und  Altserbien;  La 
Peninsiile  Balkanique. 


Deputy  Chief  Engineer,  Southern  Command.  Formerly  Chief  Instructor  in 
Fortification,  School  of  Military  Engineering,  Chatham.  Fortification  Adviser  to 
the  Chilean  Government.  Member  of  the  Belgian  Coast  Defences  Commission, 
1919,  and  of  the  Heligoland  Commission,  1920. 

JAMES  CECIL  MOTTRAM,  M.B.  (Lond.),  D.P.H.  (Cantab.). 

Director  of  the  Research  Department,  Radium  Institute.  Late  Experimental 
Officer,  Camouflage  School,  G.H.Q.  Author  of  Controlled  Natural  Selection. 

'JAMES  E.  WEST,  LL.B.,  LL.M. 

Chief  Scout  Executive,  Boy  Scouts  of  America.  Formerly  Secretary  of  Presi- 
dent Roosevelt's  White  House  Conference  on  Care  of  Dependent  Children. 


Late  6oth  Rifles.   Member  for  Fareham  Division  of  Hampshire.   Served  through-   ,  A  _     . 

out  South  African  War.    Instructor  in  Staff  Duties  at  the  Staff  College.    On  the  1  A"018.  Ba 
General  Staff  in  France,  1914-8. 

RT.  REV.  MGR.  J.  MOVES,  D.D. 

Canon  of  Westminster  Cathedral. 

Balkan  Peninsula  (in  part). 

Coast  Defence. 

I  Camouflage:    Natural; 
I  Colours  of  Animals. 


Boy  Scouts :    United  States. 

Domestic  Prelate  to  H.  H.  Pope  Benedict  XV. 

Formerly  Editor  of  the  Dublin  Review, 


Roman  Catholtc- 


Head  of  the  Department  of  Chemistry  and  Dyeing,  Philadelphia  Textile  School,  _  .  rr  .  , 
1898-1007;  Consulting  Chemist  and  Expert  in  Textile  Chemistry  and  Dyestuffs  Dyem8:  Umtea 
since  1910.  Editor  Colour  Trade  Journal  since  1917. 


Author  of  China;  Japan  and  Korea;  Houseboat  Days  in  China.   Joint-author  of  J  rjjjna 
China  under  the    Empress   Dowager.    Served  in  Chinese  Maritime   Customs, 
1883-96.  Shanghai  Correspondent  for  The  Times,  1897-1910. 

Professor  of  History  to  Prince 


Avocat  at  the  Court  of  Appeal  of  Belgium. 
Leopold  of  Belgium,  Duke  of  Brabant. 

Editor  of  The  Guardian. 


Professor  of  Economics,  University  of  Wisconsin.  Author  of  Documentary 
History  of  American  Industrial  Society;  History  of  Labor  in  the  United  Slates; 
Principles  of  Labor  Legislation;  etc. 


Late  Royal  Artillery.    Gold  Medallist  of  the  Royal  Artillery  Institution. 


Grand  Cross  of  St.  Maurice  and  St.  Lazarus.  Commander  of  the  Osmanieh. 
Grand  Cross  of  Polar  Star.  Late  Ambassador  to  the  Court  of  Italy.  Member  of 
Lord  Milner's  Mission  to  Egypt,  1920.  Special  Envoy  to  King  Menelek  II.,  1897. 
Author  of  Customs  and  Lore  of  Modern  Greece;  Poems  in  Many  Lands;  etc. 

JOHN  SLATER,  B.A.  (Lond.),  F.R.I.B.A. 

Formerly  President,  Architectural  Association,  and  Vice-President,  Royal 
Institute  of  British  Architects,  1900-4.  Member  of  Appeal  Tribunal  under  the 
London  Building  Acts.  Author  of  a  Short  History  of  The  Berners  Estate; 
Joint-author  of  Classic  and  Early  Christian  Architecture. 


Author  of  "The  Future  of  the  Albanian  State"  (R.G.S.  Journal,  July  1918). 

Late  General  Staff,  Austro-Hungarian  Army.   Now  of  the  Kriegsarchiv,  Vienna. 

Author  of  various  monographs  on  the  World  War. 


Professor  in  the  University  of  Vienna. 


Professor  of  Aerodynamics  at  the  Imperial  College  of  Science  and  Technology, 
South  Kensington.  Author  of  Applied  Aerodynamics. 


First  Assistant  Librarian,  Enoch  Pratt  Free  Library,  Baltimore.  Author  of 
Parson  Weems:  A  Biographical  and  Critical  Study,  etc. 


Author  of  cytological  papers  in  the  Annals  of  Botany;  Archiv  fiir  Zellforschung; 

Albert,  King  of  the  Belgians; 
Belgium:  History  (in part). 

/  Church  History : 
\     Church  of  England. 

Arbitration  and  Conciliation: 

United  States. 

Air  Bombs  (in  part). 

Egypt :  History. 

Architecture :  British. 


Carpathians,  Battles  of. 

Austrian  Empire:  Economic 
Conditions  (in  part); 

Austria,  Republic  of:  Eco- 
nomic Conditions  (in  part). 

Aeronautics:    Aerodynamics. 



Botany:  Cytology. 



Secretary,    Canadian    Section,    International    Joint    Commission.     Formerly  I  Canada:  English 

Librarian  of  the  Ottawa  Public  Library.    Author  of  Bibliography  of  Canadian  }        Canadian  Literature. 
Fiction;  A  Little  Book  oj  Canadian  Essays;  Century  of  Canadian  Sonnets;  etc. 

L.  J.  S.  LEONARD  JAMES  SPENCER,  M.A.,  Sc.D.,  F.G.S. 

Assistant  Keeper  in  the  Mineral  Department,  British  Museum  Natural  History.  \  Crystallography. 
Editor  of  the  Mineralogical  Magazine.   Author  of  The  World's  Minerals. 

L.  Va.  LALLA  VANDERVELDE.  /  T>  i  • 

Secretary  of  the  Institut  des  Hautes  Etudes,  Brussels  University.  \  "Ogam'.  Literature. 

I  Austrian  Empire : 

L.  v.  M.  LUDWIG  VON  MISES,  DR.  JURIS.  J      Finance  and  Banking; 

Professor  of  Political  Economy  in  the  University  Vienna.  ]  Austria,  Republic  of: 

(      Finance  and  Banking. 


Sometime  Scholar  of  Trinity  College,  Cambridge.   Author  of  Empire  and  Com-  J  „  . . 

merce  in   Africa;  International  Government;    Cooperation  and  the  Future  of  In-  1  ^°°Pel     on- 

duslry;  etc. 

M.  B.  E.          MIRA  BURR  EDSON.  .        f 

Editor  of  the  Arts  and  Crafts  Magazine  and  Arts  and  Crafts  Bulletin.    Charter  {  **T/*r°  t/ratts: 
Member  of  the  National  Society  of  Craftsmen  and  of  the  Art  Alliance.  {      ^tates- 

M.  C.  S.  MARIE  CARMICHAEL  STOPES,  D.Sc.  (Lond.),  PH.D.  (Munich). 

Fellow  of  University  College,  London.    Sometime  Lecturer  in  Palaeobotany, 
Universities  of  Manchester  and  London.    Author  of  Catalogue  of  Cretaceous 

Botany:   Anatomy  and 

Plants  in  the  British  Museum,  etc. 

M.  Fl.  WING  COMMANDER  MARTIN  FLACK,  C.B.E.,  M.A.,  M.B.  f 

Director  of  Medical  Research,  Royal  Air  Force.    Author  of  papers   on  the  <  Aerotherapeutics. 
medical  aspect  of  flying,  etc. 

M.  K.  DR.  M.  KRISTIANSEN.  <  Denmark  (in  part). 

M.  M.  W.        MERTON  M.  WILNER.  /  u  «  i 

Editorial  Writer  on  the  Bu/alo  Express.  \  Bufial0- 


Formerly  Superintendent  of  the  Royal  Aircraft  Factory,  Farnborough.    Con- 

sultant to  the  Director-General  of  Military  Aeronautics.  Chairman  of  the  Royal 
Aeronautical  Society,  and  of  the  Accidents  Investigation  Committee  of  the  Air 

Aeronautics:  Introductory. 

Air  Defence. 


Conseiller  d' Etat.   Colonial  Editor  of  Le  Temps.  \  Alger 

M.  St.  L.  S.     MAJOR  AND  BREVET  COLONEL  M.  St.  L.  SIMON,  C.B.E.,  R.E. 

Assistant  Director,  Engineering  Services,  Canada,  1908-10.  Staff  Captain,  War 
Office  (Fortifications  and  Works),  1911-5.  Anti-Aircraft  Defence  Commander, 
London,  1916-8.  Anti-Aircraft  Defence,  Independent  Force,  R.A.F.,  1918. 
Anti-Aircraft  Defence,  Leeds,  1919.  Commander  of  Northern  Air  Defences, 
1919.  General  Staff,  War  Office,  1920-1. 

N.  M.  B.          NICHOLAS    MURRAY    BUTLER,    PH.D.,    LL.D.    (Cantab.),     JUR.D.,    HoN.D.Lrrr.   f  Columbia  University; 

(Oxon.).  {  Education:    United  States 

See  the  biographical  article:   BUTLER,  N.  M.  (      (in  part). 

N.  W.  NORMAN  WILKINSON,  O.B.E.,  R.I.  [ 

Marine  Painter  and  Etcher.    Originator  of  Dazzle  Painting  (Naval  Camouflage)   <  Camouflage:    Naval. 
as  used  by  the  Allied  Powers  in  the  World  War.   Author  of  The  Dardanelles. 

O.  Kr.  OTTO  KRIEGK,  PH.D.  (Gottingen).  /„ 

Member  of  the  Staff  of  the  Weser  Zeitung,  Berlin  Office.  1 


Parliamentary  Secretary  (Private)  to  Mr.  Austen  Chamberlain  as  Chancellor  of  J  rtiatnViariain    T  Anctpn 
the  Exchequer-  and  as  Leader  of  The  House  of  Commons.   Author  of  The  Great     *" 

Preference  Debate.  ( 

lKAMemberKof  the  Berlin  Staff  of  the  Frankfurter  Zeitung.  {  Bavaria:    Political  History- 

O.  v.  K.  BARON  OTTO  VON  KLIMBERG,  DR.  JURIS.  j  Bosnia  and  Herzegovina. 

P.  B.  PAUL  BOURSON.  f  . .         T 

Member  of  the  Commissariat  General  of  the  French  Republic  at  Strasbourg.  \  Alsace-lx>n 

P.  Vi.  SIR  PAUL  VINOGRADOFF,  M.A.,  D.C.L.,  LL.D.,  DR.  HIST.,  DR.  JURIS. 

Corpus  Professor  of  Jurisprudence,  Oxford.  Author  of  Villainage  in  England; 
The  Growth  of  the  Manor;  Outlines  of  Historical  Jurisprudence;  etc.  See  the 
biographical  article:  VINOGRADOFF,  SIR  PAUL. 

Benckendorff,  Count; 
Denikin,  Anton. 



Censorship  (in  part). 


Vice-Chairman  of  the  Newspaper  Proprietors'  Association.  Chairman  of  the 
Weekly  Newspaper  and  Periodical  Proprietors'  Association.  Represented  the 
British  Press  at  the  Peace  Conference,  1919-21.  See  the  biographical  articl ;: 

R.  A.  C.  RALPH  ADAMS  CRAM,  LITT.D.  (Princeton),  LL.D.  (Yale),  F.R.G.S. 

Fellow  of  the  American  Institute  ctf  Architects  and  of  the  North  British  Academy 
of  Arts.  Hon.  Corresponding  Member  of  the  Royal  Institute  of  British  Architects. 
Associate  of  the  National  Academy.  Member  of  the  American  Institute  of  Arts 
and  Letters.  Supervising  Architect,  Princeton  University.  Lecturer  on  the 
Philosophy  of  Architecture,  Massachusetts  Institute  of  Technology.  Member  of 
the  firm  of  Cram,  Goodhue  &  Ferguson.  Author  of  Church  Building;  The  Ruined 
Abbeys  of  Great  Britain;  etc.  See  the  biographical  article:  CRAM,  RALPH  ADAMS. 

R.  B.-P.  LiEUTENANT-GENERALSmRoBERTBADEN-PowELL,BART.,K.C.B.,K.C.V.O.,LL.D.  /  Boy  Scouts:  United 

Chief  Scout.  \       Kingdom. 

R.  DeC.  W.     ROBERT  DECOURCY  WARD,  A.M.  f 

Professor  of  Climatology,  Harvard  University.    Author  of  Climate  Considered  \  Climate  and  Climatology. 
Especially  in  Relation  to  Man. 

Architecture:  United  States. 

R.  F.  T. 
R.  H.  G. 



Statistician  to  the  Ministry  of  Mines. 

Coal:    United  Kingdom. 


Assistant  Professor  of  History  in  Yale  University.   Author  of  The  Evolution  of  <  Connecticut. 
Long  Island,  etc. 


Late  General  Staff,  Austro-Hungarian  Army.  Now  of  the  Kriegsarchiv,  Vienna.   ]      Campaigns  (in  part). 

R.  K.  B.-W.     BRIGADIER-GENERAL    RALPH    KIRBY    BAGNALL-WILD,    C.M.G.,    C.B.E.,    R.A.F.,   f 


Director  of  Aircraft  Inspection.    Fellow  and  Past  Chairman  of  the  Royal  Aero- 
nautical Society.    Commission,  Royal  Engineers,  1893.    Inspector  of  Aircraft, 

Aeronautics : 

Materials  and  Methods  of 

R.  K.  H. 
R.  M.  H. 

R.  M.Wi. 

R.  McK.  W. 
R.  N.  R.  B. 

R.P.  D. 

R.  Si. 

R.  T.  T. 

R.  van  O. 


Royal  Field  Artillery.  Superintendent  of  External  Ballistics,  Ordnance  Com- 
mittee. Author  of  Nomography;  Interior  Ballistics;  etc. 

SQUADRON  LEADER  R.  M.  HILL,  R.A.F.,  M.C.,  A.F.C. 

Associate  Fellow  of  the  Royal  Aeronautical  Society.  Formerly  in  charge  of  the 
Experimental  Flying  Department,  Royal  Aircraft  Establishment.  Author  of 
paper  to  the  Royal  Aeronautical  Society:  A  Comparison  of  the  Flying  Qualities  of 
Single-  and  Tivin-Engined  A  eroplanes;  Aeronautical  Research  Committee  Reports 
and  Memoranda  No.  678;  The  Influence  of  Military  and  Civil  Requirements  on 
the  Flying  Qualities  of  Aeroplanes. 

R.  McNAre  WILSON,  M.B.,  Cn.B. 

Fellow  of  the  Royal  Society  of  Medicine.   Editor,  Oxford  Medical  Publications.  J  Bilharziosis  ; 
Late  Research  Worker  in  Cardiology,  Medical  Research  Committee.  Consultant  1  Burns  and  Scalds  ; 
to  the  Ministry  of  Pensions  in  Trench  Fever.  [  Cancer. 

Ballistics  (in  part). 

Aeronautics :    Performance 
of  Aeroplanes. 

RONALD  McKiNNON  WOOD,  B.A.  (Cantab.),  A.M.I.C.E.,  F.R.AE.S. 
Head  of  Aerodynamics  Department,  Air  Ministry.  • 

/  Aeronautics :  Development 
\      of  Aeroplane  Design. 


Member  of  the  Scottish  National  Antarctic  Expedition,  1902-4,  and  of  the  Scottish  J  Aland  Islands ; 
Arctic  Expeditions,  1909,  1912  and  1914.  Lecturer  in  Geography,  University  of  ]  Arctic  Regions. 
Sheffield.  Author  of  Spitsbergen,  etc.  Joint-author  of  The  Voyage  of  the  Scotia. 


Late  Scholar  of  Balliol  College,  Oxford.    Author  of 
Editor  of  The  Labour  International  Handbook. 

The  Two  Internationals.  {  Communism. 


Professor  of  Geography,  University  of    Graz;  Member  of    the  Academy  of 
Science,  Vienna. 


Secretary  of  the  Industrial  District  Commission. 


Barrister-at-Law.   Author  of  Digest  of  Law;  Husband  and  Wife;  etc. 


Administrator  of  Danzig  and  High  Commissioner  of  the  League  of  Nations, 


Aide-de-Camp  to  H.  M.  The  King  of  the  Belgians.   Graduate  of  the  Staff  College. 
Order  of  Leopold.   D.S.O.   Legion  of  Honour. 

Austria,  Republic  of: 

{      Economic  Conditions. 

/  Austrian  Empire :    Economic 
\      Conditions  (in  part). 

(  Children,  Law  Relating  to: 

<       United  Kingdom; 

(  Divorce:    United  Kingdom. 


Antwerp :   Siege  of  1914 ; 
Army:    Belgian. 


S.  B.  W.  S.  B.  WILLIAMS.  /  Electricity  Supply: 

Assistant  Managing  Editor  of  Electrical  World.  \       United  States. 

S.  G.  P.  SYDNEY  GROSS  PAINE,  D.Sc.,  F.I.C.  f  „ 

Assistant  Professor  of  Bacteriologv,  Imperial  College  of  Science  and  Technology,  {  "actenology: 

London  1      General  and  Agricultural. 

St.  J.  E.  ST.  JOHN  GREER  ERVINE.  f 

Dramatic  Critic  of  The  Observer.    Author  of  The  Magnanimous  Lover;  Mixed  {  Drama. 
Marriage;  Jane  Clegg;  and  other  plays.  [ 

S.  P.  S.  STANLEY  PARKER  SMITH,  D.Sc.,  M.I.E.E.,  A.M.I. C.E.  /Electrical  Engineering 

Joint-author  of  Papers  on  the  Design  of  Alternate  Current  Machinery.  \      (in  part). 

S.  R.  W.  REV.  STAGEY  R.  WARBURTON,  B.A.  f  Cmircjj  j 

Editor  of    Year  Book  of  the  Churches.    Secretary  of  Literature  of  the  General  <       ~. 
Board  of  Promotion  of  the  Northern  Baptist  Convention,  U.S.A.  [ 

S.  V.  SWALE  VINCENT,  LL.D.,  D.Sc.,  M.D.,  F.R.S.E.,  F.R.S.C.  f 

Professor  of  Physiology  in  the  University  of  London.  Author  of  Internal  Secretion  {  Ductless  Glands. 
and  the  Ductless  Glands.  { 

T.  C.  McC.      THOMAS  CHALMERS  McCoRVEY,  M.A.,  LL.D. 

Professor  of  History  and  Political  Science  in  the  University  of  Alabama.  Author  J 
of  The  Government  of  the  People  of  the  Stale  of  Alabama.  Contributor  to  The  1 
Library  of  Southern  Literature  and  The  South  in  the  Building  of  the  Nation,  etc.  [ 

T.  G.  M.         THOMAS  GARRIGUE  MASARYK.  / 

President  of  the  Czechoslovak  Republic.  \ 




Entered  Rifle  Brigade,  1913.    Served  in  France,  1914-5.     G.H.Q.,  1916.    Aide-  j  Aeronautics:    Control 

de-Camp  to  Governor-General  of  Canada,  1916-8.    Officer  of  the  War  Cabinet,  }      of  Air  Traffic. 
1918-9.    Air  Ministry,  1919-21. 

V.  H.  B.  VERNON  HERBERT  BLACKMAN,  Sc.D.,  F.R.S.  f 

Professor  of  Plant  Physiology  and  Pathology  in  the  Imperial  College  of  Science  <  Botany:    General  Physiology. 

and  Technology.  [ 

V.  L.  E.  C.        GENERAL  VICTOR  Louis  SMILIEN  CORDONNIER.  /  Argonne,  Battles  of  the; 

See  the  biographical  article:    CORDONNIER,  V.  L.  E.  \  Army:  French. 

W.  A.  P.  WALTER  ALISON  PHILLIPS,  M.A.  (Oxford  and  Dublin).  f 

Lecky  Professor  of  Modern  History  in  the  University  of  Dublin.    Member  of  J  _.  . 

the  Royal  Irish  Academy.     Author  of  Modern  Europe;  The  Confederation  of  } 

Europe;  etc.  1 

W.  B.  A.          W.  BROUGHTON  ALCOCK.  /  Dvsenterv 

Director  Central  Laboratory,  Ministry  of  Pensions.  \     * 


Examiner  in  Banking,  Currency  and  Foreign  Exchange  to  various  public  bodies. 

Author  of  Foreign  Exchange  and  Foreign  Bills  in  Theory  and  in  Practice;  Eastern 

Banking:  British. 

Exchange;  Currency  and  Finance;  etc.    Sometime  Editor  of  the  Statist  British 
Banking  Supplement  and  International  Banking  Supplement. 

W.  G.  C.*         WILLIAM  GEORGE  CONSTABLE,  M.A. 

Fellow  of  St.  John's  College,  Cambridge.    Barrister-at-Law.    Lecturer  at  the  :~r 

Wallace  Collection.  Be      rd> 


Editor-in-Chief  of  the  Medical   History  of  the  Great  War.    Formerly  Deputy  J  Army  Medical  Service : 
Director-General,  Army  Medical  Service.   Author  of  Handbooks  of  the  Medical  ]      British. 
Services  of  Foreign  Armies,  etc. 


Gladstone  Professor  of  Political  Theory  and  Institutions  in  the  University  of  {  Education:  United  Kingdom. 

W.  H.  T.          COLONEL  W.  H.  TSCHAPPAT  (U.S.  Army).  f  Ammunition  (in  part); 

Author  of  Ordnance  Treatise,  U.S.A.  \  Ballistics  (in  part). 

W.  J.  C.          W.  J.  CHILDS.  f 

Late  of  the  Intelligence  Department  of  the  Admiralty  (Geographical  Section).  \ 

W.  K.  McC.     WILLIAM  KIDSTON  McCmRE,  M.A.  (Oxon).  f  Asiago,  Battle  of; 

Late  Correspondent  of  The  Times  in  Rome.    Correspondent  of  The  Times  on  J  Cadorna,  General; 

the  Italian  Front,  1915-7-    Author  of  Italy's  Part  in  the  War;  Italy  in  North  1  Caneva,  Carlo; 

Africa;  Chapters  on  Italy  in  The  Times  History  of  the  War;  etc.  (  Caporetto,  Battle  of. 

AJ0Rrd^anceADepartmtnt  of  the  U.S.  Army.  1  Ammunition  (in  part). 

W.  L.  G.*        WILLIAM  L.  GRIFFITH.  f  ... 

Permanent  Secretary*  Office  of  the  High  Commissioner  for  Canada,  London.  J  2f      It,  ,      .. 
Author  of  The  Dominion  of  Canada;  article  on  "  Canada,"  Oxford  Survey  of  the  ]  °nus%  ^°"       lia» 
British  Empire.  ( Lanada- 


American  Literature. 

I  Cornell  University. 

Army  Medical  Service: 

United  States. 


W.  L.  P.          WILLIAM  LYON  PHELPS,  M.A.,  PH.D.,  LITT.D. 

Lampson  Professor  of  England  Literature  at  Yale  University.  Author  of  Essays 
on  Modern  Novelists;  Essays  on  Russian  Novelists;  Essays  on  Modern  Drama- 
tists; The  Twentieth  Century  Theatre;  The  Advance  of  English  Poetry;  etc. 


Secretary  of  Cornell  University. 

W.  P.  C.          WESTON  P.  CHAMBERLAIN. 

Colonel,  Army  Medical  Corps,  U.S.  Army. 


Consulting  Mining  and  Metallurgical  Engineer,  New  York. 
of  Zinc  and  Cadmium. 

W.  R.  Ma.       WILLIAM  R.  MANNING,  Pn.D. 

Economist,  Latin-American  Division,  U.S.  Department  of  State.  Author  of 
Nootka  Sound  Controversy  (Justin  Winsor  Prize  Essay  of  American  Historical 
Association,  1904);  Early  Diplomatic  Relations  Between  the  United  States  and 
Mexico  (Albert  Shaw  Lectures,  Johns  Hopkins  University,  1913);  etc. 

W.  St.  WILLIAM  STOCKING,  M.A.  (Yale). 

Newspaper  Editor,  1865-1900.  Historian  and  Statistician,  Detroit  Board  of 
Commerce,  1903-21.  Author  of  Under  the  Oaks;  History  of  the  Republican 
Parly;  etc. 

W.  S.  Ro.         WILLIAM  SPENCE  ROBERTSON,  Pn.D. 

Professor  of  History  in  the  University  of  Illinois.  Author  of  Francisco  de  Mi- 
randa and  the  Revolutionizing  of  Spanish  America;  Rise  of  the  Spanish  American 
Republics;  etc. 


Professor  of  Law  in  the  University  of  Tubingen.  Author  of  Familienrecht  des 
Burgerlichen  Geselzbuchs;  Erbrecht  des  Burgerlichen  Geselzbuchs.  Cooperated  in 
the  drafting  of  the  Constitution  of  Wurttemberg,  1919. 


Reserve  of  Officers,  Canadian  Army.  Coordinating  Officer  of  the  Canadian 
Special  Mission  at  the  Naval  and  Military  Fronts,  1917.  Formerly  President 
of  English  Section  of  Royal  Society  of  Canada  and  of  Historic  Landmarks  Asso- 
ciation. Author  of  The  Fight  for  Canada ;  The  Logs  of  the  Conquest  of  Canada ; 
Folk  Songs  of  New  France;  etc. 

X.  Initial  used  for  anonymous  contributors. 


American  Distinguished  Service  Cross.  Knight  of  the  Legion  of  Honour.  Lectur-  J  »,„,._  D__    _..  /  • 
er  in  the  University  of  Belgrade.  Author  of  "  L1  Emigration  Vendeenne,"  Annales     H 
de  Geographic,  1917,  "La  Yougo-Slavie,"  Annales  de  Geographic,  1921. 

Y.  D.  GENERAL  YOURI  DANILOV.  Army:   Russian  (in  part) 

Author  of  Metallurgy  <  Copper. 







Bavaria  (in  part). 

Canada:    Literature, 
French  Canadian. 




ABBE,  CLEVELAND  (1838-1916),  American  meteorologist,  was 
born  in  New  York  Dec.  3  1838.  He  studied  astronomy  under 
Briinnow  and  A.  B.  Gould,  and  spent  a  year  at  the  Pulkovo 
Observatory,  1865-6,  under  Struve.  He  was  assistant  at  the 
U.S.  Naval  Observatory,  1867-8,  and  Director  of  the  Cincinnati 
Observatory,  1863-73.  His  success  there  in  forecasting  the 
weather  from  meteorological  observations  telegraphed  from 
various  points  led  to  his  being  called  to  the  U.S.  Signal  Serv- 
ice in  1871.  Thereafter  with  Government  aid  he  was  enabled 
to  extend  the  field  of  his  forecasts  and  became  the  "  Father 
of  the  Weather  Bureau."  The  bureau  was  formally  estab- 
lished in  1891  under  the  Department  of  Agriculture,  and  Abbe 
remained  its  head  until  his  death  Oct.  28  1916.  To  his 
initiative  is  largely  due  the  introduction  of  the  system  of  stand- 
ardized time. 

He  was  the  author  of  Report  on  Standard  Time  (1879);  Report  on 
the  Solar  Eclipse  of  July  1879  (1881);  An  Account  of  Progress  in 
Meteorology  and  Allied  Subjects  in  the  Years  1879-81  (1883); 
Treatise  on  Meteorological  Apparatus  and  Methods  (1888);  Prelim- 
inary Studies  in  Storm  and  Weather  Prediction  (1889);  Recent 
Progress  in  Dynamic  Meteorology  (1890);  The  Mechanics  of  the 
Earth's  Atmosphere  (3  vols.  of  translations,  1891-1910);  The  Physi- 
cal Basis  of  Long-Range  Forecasting  (1902);  The  Progress  of  Science 
as  Illustrated  by  the  Development  of  Meteorology  (1908);  Notes  on 
Balloons  and  on  Waterspouts  from  the  Voyage  of  La  Perouse  (191^) 
and  The  Introduction  of  Meteorology  into  Courses  of  Instruction  in 
Mathematics  and  Physics  (1915). 

ABBEY,  EDWIN  AUSTIN  (1852-1911),  American  painter 
(see  i.n),  died  in  London,  Aug.  i  1911.  The  last  years  of 
his  life  were  devoted  to  mural  paintings  for  the  Capitol  at 
Harrisburg,  Pa.,  his  native  state.  He  completed  "  The  Apothe- 
osis of  Pennsylvania,"  which  stands  behind  the  Speaker's  chair 
in  the  House  of  Representatives,  also  "  The  24  Hours  "  for  the 
ceiling  of  the  dome;  but  for  the  Senate  chamber  he  finished 
only  one  painting  —  "  Von  Steuben  Training  the  American 
Soldiers  at  Valley  Forge."  In  igro  there  was  completed 
under  his  supervision  the  decoration  -of  the  Peers'  corridor  of 
the  Houses  of  Parliament.  He  left  bequests  of  his  works  to 
the  Metropolitan  Museum  of  Art  in  New  York,  to  the  Boston 
Museum  of  Fine  Arts  and  to  the  National  Gallery  in  London. 
In  1912,  the  Old  Masters'  Exhibition  of  the  Royal  Academy, 
held  at  Burlington  House,  London,  included  over  300  works  of 
Abbey's  loaned  for  this  special  occasion  as  a  memorial  to  him. 

ABBOTT,  LYMAN  (1835-  ),  American  divine  and  author 
(see  1.26),  continued  after  1910  as  editor  of  The  Outlook,  and  in  a 
less  degree  as  a  public  speaker,  to  take  an  active  part  in  the  dis- 
cussion of  important  public  questions.  After  the  outbreak  of 
the  World  War  he  supported  the  cause  of  the  Allies,  and  on  the 
sinking  of  the  "  Lusitania  "  in  1915  urged  that  America  break 
off  diplomatic  relations  with  Germany.  He  was  the  author  of 

The  Spirit  of  Democracy  (1910);  America  in  the  Making  (1911, 
being  the  Yale  lectures  on  the  responsibilities  of  citizenship); 
The  Four  Anchors  (1911);  Letters  to  an  Unknown  Friend  (1913); 
Reminiscences  (1915,  containing  in  the  preface  an  admirable 
summary  of  his  liberal  views)  and  The  Twentieth  Century 
Crusade  (1918). 

'ABDUL  HAMID  II.  (1842-1918),  ex-Sultan  of  Turkey  (see 
1.35),  died  Feb.  10  1918.  On  his  deposition  in  April  1909  he 
was  sent  to  Salonika  as  a  state  prisoner,  but  when  that  town 
capitulated  to  the  Greeks  during  the  Balkan  War  (1912)  he 
was  brought  back  to  Constantinople.  In  1915  it  was  judged 
prudent  to  exile  him  from  Turkey  in  Europe  and  he  was  removed 
to  Smyrna. 

British  politician  (see  1.43),  who  served  as  High  Constable  of 
Ireland  at  the  coronation  of  King  George  V.  (1911),  died  in 
London  Jan.  3  1913.  He  was  succeeded  as  3rd  duke  by  his 
eldest  son,  James  Albert  Edward  Hamilton,  born  Nov.  30  1869. 

ABERCROMBIE,  LASCELLES  (1881-  ),  English  poet,  was 
born  at  Ashton-upon-Mersey,  Ches.,  Jan.  9  1881,  and  educated 
at  Malvern  and  Victoria  University,  Manchester,  where  he 
studied  science.  His  first  work,  Interludes  and  Poems,  appeared 
in  1908,  and  his  other  works  include:  Mary  and  the  Bramble 
(1910);  The  Sale  of  St.  Thomas  (1911);  Emblems  of  Love  (1912); 
Deborah  (1912);  Speculative  Dialogues  (1913)  and  The  Epic 
(1914),  besides  a  critical  study  of  Thomas  Hardy  (1912).  He  was 
in  1919  appointed  lecturer  in  Poetry  at  the  university  of 

IST  MARQUESS  OF  (1847-  ),  British  politician  (see  1.47), 
retained  his  office  as  Lord-Lieutenant  of  Ireland  until  1915.  On 
his  retirement  he  was  created  Marquess  of  Aberdeen  and  Temair, 
the  latter  title  being  a  form  of  the  place-name  Tara,  chosen 
for  its  connexion  with  the  history  of  Ireland.  His  wife,  Ishbel 
Maria  (b.  1857) — daughter  of  Dudley  Marjoribanks,  ist  Baron 
Tweedmouth— whom  he  married  in  1877,  took  a  prominent 
part  in  charitable  work  during  her  residence  in  Ireland,  becoming 
president  of  the  Irish  Industries  Association  and  other  societies. 
She  did  excellent  work  in  increasing  the  number  of  nurses  and 
establishing  committees  for  the  improvement  of  sanitary  con- 
ditions and  combating  the  spread  of  tuberculosis  in  Ireland. 
She  published  in  1908  Ireland's  Crusade  against  Tuberculosis. 

ABINGDON,  WILLIAM  LEPER  [PILGRIM]  (1859-1918),  English 
actor,  was  born  May  2  1859  at  Towcester,  Northants.  He 
began  life  as  a  bank  clerk,  but  soon  went  on  the  stage,  first  ap- 
pearing at  Belfast  in  1881.  His  chief  successes  were  in  melo- 
drama, with  Wilson  Barrett's  travelling  companies  and  later  at 
the  Adelphi  theatre,  London,  where  he  played  in  The  Harbour 
Lights  (1889)  and  many  similar  pieces.  Between  1903  and  1911 


he  appeared  often  in  America.  In  1905  he  played  Monks  in 
Oliver  Twist  at  His  Majesty's  theatre,  London.  He  died  in  New 
York  May  20  1918. 

English  chemist,  was  born  at  Derby  July  24  1843  and  edu- 
cated at  Rossall  school,  obtaining  a  commission  in  the  R.E. 
1861.  In  1876  he  became  C.B.,  D.Sc.,  D.C.L.  and  F.R.S. 
and  from  1893  to  1897  he  was  successively  president  of  the 
Royal  Astronomical  Society  and  of  the  Physical  Society.  In 
1899  he  became  assistant  secretary  to  the  Board  of  Education; 
in  1903  he  was  appointed  advisor  to  the  science  department  of 
the  Board,  and  the  same  year  became  a  member  of  the  Advisory 
council  for  education  to  the  War  Office.  In  1900  he  was  knighted 
and  in  1904  became  chairman  of  the  Society  of  Arts.  His  con- 
tribution to  science  was  mainly  in  the  furtherance  of  photo- 
graphic chemistry  and  especially  of  colour  photography  and 
colour  printing  (see  16.661;  21.489,  498,  531,  532;  25.631; 
6.729).  His  publications  on  these  subjects  include  Instruction 
in  Photography  (1870);  Colour  Vision,  Colour  Measurement 
and  Mixture  (1893);  and  Trichromatic  Theory  of  Colour  (1914). 
He  also  wrote  Thebes  and  its  Five  Great  Temples  (1876),  and, 
with  C.  D.  Cunningham,  The  Pioneers  of  the  Alps  (1888).  He 
died  at  Folkestone  Dec.  3  1920. 

ABRUZZI,  DUKE  OF  THE  [Luici  AMEDEO]  (1873-  ), 
Italian  vice-admiral  and  explorer,  son  of  Amedeo,  late  Duke  of 
Aosta  and  sometime  King  of  Spain,  was  born  at  Madrid 
Jan.  29  1873.  He  entered  the  navy  as  a  cadet  and  followed 
a  regular  naval  career  in  which  he  achieved  great  distinc- 
tion; but  he  also  became  well  known  as  an  eminent  traveller 
and  mountaineer.  He  was  the  first  to  ascend  Mt.  St.  Elias  in 
Alaska  (1897),  and  in  1899  he  organized  an  expedition  with  the 
object  of  reaching  the  North  Pole;  although  he  himself  was 
disabled  by  frostbite  early  in  1900  and  forced  to  remain  on  his 
ship,  the  "  Stella  Polare,"  Comm.  Cagni  pushed  on  with  a  part 
of  the  expedition  and  reached  the  lat.  of  86°  34',  at  that 
ti«ie  the  record  of  northern  exploration.  In  1906  he  was  the 
first  to  ascend  Mt.  Ruwenzori  in  East  Africa,  reaching^the  twin 
summits  (16,800  ft.),  which  he  named  Margherita  and  Alexandra, 
and  also  the  other  chief  peaks  of  the  range;  he  made  the  first  de- 
tailed map  of  the  Ruwenzori  and  collected  much  scientific  in- 
formation about  it.  In  1909  he  explored  the  Central  Karakoram 
in  the  Himalayas  and  by  ascending  peak  K.2  achieved  the  record 
for  height ;  among  other  scientific  work  the  expedition  completed 
the  map  of  the  great  Baltoro  glacier.  During  the  Libyan  War  he 
commanded  a  naval  squadron  in  the  Adriatic  and  had  various 
successful  engagements  with  Turkish  warships.  During  the 
World  War  he  was  commander-in-chief  of  the  Italian  naval 
forces,  and  showed  very  high  qualities  of  seamanship,  strategy 
and  organization  in  the  extremely  difficult  operations  in  the 
Adriatic.  He  had  British  and  French  warships  under  his  orders. 
He  relinquished  his  command  in  1917  owing  to  disagreements 
with  Adml.  Thaon  di  Revel,  chief  of  the  Naval  Staff,  and 
retired  from  the  service.  Afterwards  he  undertook  an  important 
colonization  and  agricultural  development  scheme  in  Italian 
Somaliland.  He  was  made  a  Knight  of  the  Order  of  the  Annun- 

ABYSSINIA  (see  1.82). — Since  1910  boundary  commissions 
have  delimited  in  part  the  Sudan-Abyssinia  and  the  Italian- 
Abyssinian  frontier.  No  change  was  made  in  the  international 
status  of  the  country  between  1910  and  1921.  The  conquests  of 
Menelek  had  been  retained  and  the  independence  of  the  empire 
maintained.  The  Spanish  protectorates  excepted,  Abyssinia  was 
the  only  country  of  Africa  neutral  throughout  the  World  War. 

Recent  History. — From  1899,  a  year  which  marked  the  end  of 
an  era  of  conquest  and  civil  war,  the  Emperor  Menelek  (see 
18.128)  had  maintained  internal  peace  and  had  cautiously  en- 
couraged commercial  relations  with  Europeans.  But  in  1910 
Menelek  was  stricken  by  a  malady  which  incapacitated  him  from 
rule,  although  until  his  death,  in  Dec.  1913,  and  for  years 
afterwards  (e.g.  in  1919),  his  name  was  invoked  by  the  people  as 
that  of  the  highest  authority  in  the  country.  A  regency  was 
formed  in  1910,  consisting  of  Lij  Yasu — Menelek's  grandson, 

whom  he  had  nominated  his  heir  in  1908 — and  Ras  Tesamma, 
Lij  Yasu  being  then  only  fourteen.  Menelek's  wife,  the  Empress 
Tartu,  a  princess  of  Tigre,  opposed  the  regency,  called  to  her  aid 
the  Tigrian  chiefs,  and  usurped  authority.  She  refused  to  see  the 
representatives  of  foreign  powers  and  stopped  the  building  of 
the  railway  from  Jibuti  (see  1.95)  to  the  capital,  Addis  Abbaba. 
After  maintaining  her  position  about  a  year  Taitu  was  over- 
thrown by  a  palace  revolution.  She  took  no  further  part  in  the 
government  and  died  Feb.  n  1918. 

Not  long  after  the  regency  was  established  Ras  Tesamma,  a 
capable  man  of  moderating  influence,  died,  April  1911.  Lij 
Yasu  then  attempted  to  reign  uncontrolled.  He  was  strongly 
opposed;  but  with  the  help  of  his  father  Ras  Michael,  chief  of  the 
Wollo  Galla,  Yasu  made  good  his  authority  and  on  Menelek's 
death  was  acknowledged  negus  negusti  (king  of  kings,  emperor). 

At  that  time,  the  beginning  of  1914,  the  condition  of  the 
country  was  not  without  promise.  The  building  of  the  railway 
from  Jibuti  had  been  resumed;  in  1912  it  had  reached  the 
Hawash  river,  and  was  then  (1914)  being  carried  up  the  steep 
escarpment  to  the  Abyssinian  plateau.  Even  in  its  incomplete 
state  it  carried  in  1913  merchandise  valued  at  over  £1,600,000. 
A  considerable  trade  between  the  Galla  provinces  (western 
Abyssinia)  and  the  Sudan  had  also  developed.  Both  Abyssinians 
and  Gallas  showed  a  distinct  appreciation  of  foreign  products; 
it  needed  only  good  government  and  the  provision  of  better 
means  of  communication  to  have  brought  about  a  great  develop- 
ment of  the  very  rich  natural  resources  of  the  country.  Lij 
Yasu,  however,  was  a  youth  of  depraved  morals,  his  adminis- 
tration was  both  weak  and  tyrannical,  and  the  result  was  in  the 
south  anarchy,1  and  in  the  north  the  alienation  of  the  Tigrians, 
always  jealous  of  Shoa  (Menelek's  hereditary  kingdom).  The 
maintenance  of  a  large  standing  army  was  another  cause  of 
poverty  and  discontent.  Out  of  a  total  population,  according  to 
trustworthy  estimates,  of  from  10,000,000  to  12,000,000,  about 
500,000  were  in  the  army.  (Detailed  figures  for  1916  gave  a  total 
of  571,000  as  the  strength  of  the  Abyssinian  forces.)  In  the 
Galla,  Somali  and  Shankalla  (i.e.  negro)  provinces  these  men 
lived  largely  by  plunder. 

Such  was  the  situation  when  the  World  War  broke  out. 
Lij  Yasu  had  already  come  very  much  under  German  and 
Turkish  influence,  the  chief  agent  in  the  propaganda  of  the 
Central  Powers  having  been  Herr  K.  Schwemmer,  consul  for 
Austria-Hungary.  (Schwemmer,  owing  to  Italian  pressure,  was 
recalled  to  Vienna  and  left  Abyssinia  in  Oct.  1914.)  Yasu  had 
already  given  offence  to  the  Abyssinians,  whose  attachment  to 
their  own  form  of  Christianity  is  strong,  by  his  neglect  of  the 
observances  of  the  national  church,  and  in  June  1914  had  caused 
his  father,  Ras  Michael,  to  be  crowned  negus  (king)  of  Wollo, 
the  only  province  of  Abyssinia  proper  inhabited  by  Moslems 
(Galla  intruders).  Michael  remained  nominally  a  Christian; 
Yasu,  at  first  secretly  and  later  openly,  embraced  Islam,  and, 
inspired  by  Turco-German  policy,  set  himself  to  unite  all  the 
Moslems  of  the  empire.  He  married  the  daughters  of  several 
Danakil  and  Galla  chiefs,  and  betrothed  himself  to  the  daughter  of 
Aba  Jiffar,  King  of  Jimma,  the  most  powerful  Moslem  prince  in 
the  empire.  He  also  made  political  alliances  with  Moslems  out- 
side the  Abyssinian  dominions,  among  others  with  the  "  Mad  " 
Mullah  of  Somaliland,  then  at  war  with  the  British.  His  policy 
was  summed  up  as  (i)  Moslem  as  opposed  to  Christianity;  (2) 
Galla  as  opposed  to  Abyssinian;  (3)  Turco-German  as  opposed 
to  the  Entente. 

In  April  1916  Yasu  officially  placed  Abyssinia  in  religious 
dependence  on  the  Sultan  of  Turkey  as  Caliph  and  sent  to  the 
Turkish  consul-general  at  Harrar  an  Abyssinian  flag  bearing  the 
crescent  and  a  confession  of  faith  in  Islam.  About  this  time  he 
informed  his  Moslem  confederates — who  had  been  told  that 
Germany  and  Austria  had  embraced  Islam  and  had  imposed 
that  faith  upon  France — that  he  would  lead  them  against  the 
Allies  as  soon  as  a  great  German  victory  should  be  announced. 

*One  result  was  raiding  into  the  Sudan  and  adjacent  territories 
by  Abyssinians.  These  raids  the  central  Government  did  not  or 
could  not  prevent. 


His  anti-Christian,  anti-Abyssinian  attitude  led  to  Yasu's 
downfall.  The  Allied  representatives  at  Addis  Abbaba,  in 
particular  the  Hon.  W.  G.  Thesiger,  then  the  British  minister, 
did  much  to  counteract  Turco-German  propaganda  and,  except 
Ras  Michael,  all  the  Abyssinian  chiefs  were  opposed  to  the 
Emperor's  proceedings.  They  had  the  support  of  the  people,  the 
Shoans  as  well  as  the  men  of  Tigre  and  Gondar,  and  they 
determined  to  end  an  intolerable  situation.  On  Sept.  27 
1916 — the  Feast  of  the  Cross — by  a  public  proclamation  of  the 
Abuna  (the  head  of  the  church)  Lij  Yasu  was  declared  dethroned, 
on  the  specific  ground  of  his  apostasy.  His  aunt,  the  Princess 
Zauditu  (Judith),  who  had  been  a  prisoner  in  the  palace  since 
Menelek's  illness  in  1910,  was  proclaimed  empress.  Dejaz 
(general)  Taffari  Makonnen,  a  cousin  of  Zauditu,  was  appointed 
heir  to  the  throne  and  regent  with  the  title  of  Ras  (prince). 
The  new  regime  was  at  once  accepted,  practically  unopposed, 
by  the  chiefs  and  people  of  Shoa  and  by  the  imperial  army  (a 
force  of  50,000  kept  in  the  neighbourhood  of  the  capital). 

Lij  Yasu  was  then  at  Harrar,  a  Moslem  centre,  arming  the 
Somalis.  On  receipt  of  the  news  of  his  deposition  he  showed  the 
weakness  of  his  character  by  publicly  renouncing  Islam,  a  step 
which  gained  him  no  credit  either  with  the  Abyssinians  or  the 
Somalis.  The  garrison  of  Harrar  (Abyssinians),  sent  by  Yasu  to 
oppose  the  Shoan  troops  which  the  new  rulers  had  dispatched 
against  him,  joined  his  enemies.  On  Oct.  8  Yasu  fled  secretly 
from  Harrar,  making  for  the  Danakil  country.  On  the  gth 
Harrar  was  occupied  by  the  Shoans,  who  killed  some  400  un- 
resisting Somalis  before  the  slaughter  was  stopped  through 
the  intervention  of  the  British  consul. 

Ras  Michael  was  made  of  sterner  stuff  than  his  son;  moreover, 
the  Wollo  Galla  remained  faithful  to  him  and  he  was  able  to  put 
some  80,000  men  in  the  field.  Wollo  lies  on  the  eastern  edge  of 
the  Abyssinian  plateau,  with  Gondar  and  Tigre  N.  and  N.W. 
and  Shoa  to  the  S.  Leaving  20,000  to  30,000  men  to  guard  his 
northern  frontier,  Ras  Michael  marched  S.,  hoping  to  capture 
Addis  Abbaba  by  a  rapid  blow.  Meantime  the  new  Government 
had  prepared  to  advance  N.,  fixing  on  Shano,  40  m.  N.E.  of  the 
capital,  as  the  place  of  concentration.  Michael,  who  was  first  in 
the  field,  had  an  engagement  with  the  advanced  force  of  the 
Shoans  under  Ras  Lul  Seged  Oct.  17,  before  whom  he  gave  way. 
But  on  the  igth  Michael  surrounded  and  destroyed  Lul  Seged's 
force  in  a  furious  battle  in  which  over  12,000  men  perished. 
Lul  Seged  himself  was  slain,  but  his  resolute  defence  had  de- 
layed Michael's  advance;  it  gave  time  to  the  Shoans  to  complete 
their  concentration.  By  Oct.  21  they  had  60,000  men  at  Shano, 
and  a  great  superiority  in  artillery  over  Michael.  On  the  22nd 
Shoan  cavalry  under  Ras  Kassa1  seized  a  position  in  the  rear  of 
Michael's  army;  the  same  day  his  force  on  the  northern  frontier 
was  attacked  and  defeated  by  the  Ras  of  Gondar  (Waldo  Giorgis). 
Cut  off  from  his  base,  almost  enveloped  and  with  supplies  running 
short,  Michael's  only  alternative  to  being  starved  into  surrender 
was  to  attack.  The  King  chose  the  latter  course  and  gave  battle 
at  Shano  on  Oct.  27.  The  fighting  was  desperate  and  the 
slaughter  great.  The  Shoans  were  at  first  hard  pressed  but  the 
timely  arrival  of  Ras  Kassa's  cavalry  decided  the  issue.  The 
Wollo  army  was  utterly  routed,  Michael  was  taken  prisoner  and 
all  his  artillery  captured.  This  ended  the  campaign,  in  which 
in  three  weeks  over  60,000  lives  are  said  to  have  been  lost,  the 
casualties  of  the  Shoans  alone  exceeding  20,000.  The  Fitaurai 
Hapti  Giorgis,  Minister  of  War,  who  had  commanded  in  chief  the 
Shoan  forces,  made  no  attempt  to  occupy  Wollo  or  to  pursue 
Lij  Yasu  and  thus  effectively  pacify  the  country.  He  returned 
to  Addis  Abbaba  where  the  Empress  Zauditu  reviewed  the 
victorious  troops,  the  ceremony  ending  with  the  parade  of  Ras 
Michael,  a  fine-looking,  dignified  man  of  about  65,  chained  to 
the  chief  who  had  captured  him. 

Profiting  by  the  inactivity  of  the  Government,  Lij  Yasu 
gathered  together  the  remnants  of  his  father's  army.  He  man- 
aged to  keep  his  footing  in  the  Wollo  country  for  the  greater  part 
of  1917  and  finally  took  refuge  in  Magdala.  Closely  besieged, 
Magdala  surrendered  in  Dec.  1917.  Lij  Yasu  escaped,  and 

'Abyssinian  envoy  to  London  for  the  coronation  of  George  V. 

thereafter  appears  to  have  led  a  wandering  life  among  the 
Danakil  and  Somali.  In  Oct.  1918  he  was  appealing  to  the 
Turks  in  Arabia  for  help,  and  making  attempts  to  raid  the 
Jibuti  railway.  At  the  close  of  1920  Yasu  appeared  in  Tigre, 
apparently  hoping  to  gain  over  that  province,  but  in  Jan. 
1921  he  was  captured  by  Government  forces. 

The  Government  of  the  Empress  Zauditu  and  Ras  Taffari 
was  pro- Ally  and  in  the  summer  of  1919  missions  were  sent  to 
London,  Paris,  Rome,  Brussels  and  Washington  to  congratulate 
the  Allies  on  their  victory.  These  missions  received  good  advice 
as  to  the  necessity  of  an  amelioration  of  social  conditions  in 
Abyssinia,  the  suppression  of  slavery — Menelek's  conquests  had 
given  a  great  impetus  to  the  slave  trade — and  the  development 
of  commerce  and  agriculture. 

•  Economic  Conditions  and  Trade. — Two  great  hindrances  to  the 
economic  development  of  the  country  have  been  stated — internal 
disturbances  and  lack  of  adequate  means  of  communication.  After 
the  close  of  the  World  War,  and  with  the  railway  from  the  Gulf  of 
Aden  to  Addis  Abbaba  completed,  an  improvement  was  anticipated. 
A  British  company,  the  Abyssinian  Corporation,  was  formed  in 
Dec.  1918,  with  the  approval  of  the  Foreign  Office,  but  owing  to 
restriction  of  shipping,  the  fluctuations  of  exchange  and  the  fall 
in  the  price  of  coffee  its  first  two  years'  operations  were  unsatisfac- 
tory. Nevertheless  the  total  trade  of  Abyssinia  increased.  Valued 
at  about  £1,000,000  in  1905,  it  had  more  than  doubled  by  1910; 
and  in  1920,  in  the  absence  of  any  official  statistics,  was  roughly 
estimated  at  between  £3,500,000  and  £4,000,000.  Hides  and  skins, 
coffee  and  beeswax  are  the  chief  exports.  The  chief  imports  are 
cotton  goods  and  Maria  Theresa  dollars  (minted  at  Trieste  and  an 
exact  reproduction  of  the  1780  issue).  The  external  trade  of  northern 
Abyssinia  is  with  Massawa  via  Asmara;  that  of  Shoa  and  Harrar 
with  Jibuti  and,  to  a  small  extent,  with  Zeila  and  Berbera  (British 
Somaliland).  These  are  all  ancient  routes  to  the  sea-coast;  to  the 
old  trade  routes  to  the  Sudan  by  the  Blue  Nile  has  been  added  that 
by  the  Baro-Sobat  rivers.  Gambela,  on  the  Baro  and  60  m.  within 
the  Abyssinian  frontier,  was  leased  to  the  Sudan  Government  in 
1907,  and  in  the  Sobat  flood  season  (June-Nov.)  a  steamer  serv- 
ice is  maintained  with  Khartum.  Although  the  road  from  the 
Baro  river  to  Gore,  on  the  highlands,  was  and  remained  very  bad, 
Gambela  became  an  important  transport  centre.  The  value  of  its 
trade,  £43,000  in  1910,  was  £103,000  in  1913  and  was  estimated  at 
about  £200,000  in  1919.  Much  of  the  trade  in  the  country  is  in  the 
hands  of  Greeks,  Syrians  and  Arabs.  The  agricultural  and  mineral 
wealth  of  the  country  remain  as  yet — if  the  cultivation  of  coffee  be 
excepted — scarcely  tapped,  and  its  water-power  unutilized. 

See  L.  de  Castro,  Nella  Terra  del  Negus,  2  vols.  (1915);  Capt. 
Stigand,  To  Abyssinia  through  an  Unknown  Land  (1910);  G.  Mon- 
tandon,  Au  Pays  Ghimirra  (1913) ;  Major  C.  W.  Gwynn,  "A  Jour- 
ney in  S.  Abyssinia"  (with  map),  Geog.  Jnl.,  Aug.  1911;  Major 
F.  L.  Athill,  "  Through  S.  W.  Abyssinia  to  the  Nile,"  ibid.,  Nov. 
1920;  C.  H.  Armbruster,  Mitia  Amharica,  Part  III.  Amharic- 
English  Vocabulary,  Vol.  I.  (1920).  (F.  R.  C.) 

ACHENBACH,  ANDREAS  (1815-1910),  German  painter  (see 
1.142),  died  in  1910. 

ACHURCH,  JANET  [MRS.  C.  CHARRINGTON]  (1864-1916), 
English  actress,  was  born  in  Manchester  Jan.  17  1864.  She 
married  Charles  Charrington  June  1889.  She  first  appeared  at 
the  Olympic  theatre,  London,  Jan.  8  1883,  with  Genevieve 
Ward  in  the  farce  of  Betsy  Baker.  Two  years  later  she  joined 
Frank  Benson's  company  and  played  Shakespearean  heroines; 
but  her  chief  success  was  gained  as  Nora  Helmer  in  Ibsen's  A 
Doll's  House,  when  that  play  was  first  produced  in  England  in 
1889.  She  appeared  later  in  other  Ibsen  plays  and  in  those  of 
Bernard  Shaw.  She  died  at  Ventnor  Sept.  n  1916. 

ADAM,  JULIETTE  (1836-  ),  French  writer  (see  1.172), 
whose  volumes  of  reminiscences  of  distinguished  contemporaries 
numbered  seven  by  1910,  subsequently  published  Impressions 
franQaises  en  Russie  (1912)  and  Chretienne  (1913),  as  well  as 
various  writings  in  pursuit  of  her  lifelong  policy  of  revanche, 
L'heure  vengeresse  des  crimes  bismarckiens  (1915),  Guillaume  II. 
jSpo-0  (1917),  and  a  volume  of  war  sketches,  La  vie  des  dmes 

ADAM,  PAUL  (1862-1920),  French  novelist  (see  1.72), 
published  in  his  later  years  various  novels,  including  Le  Trust 
(1910)  and  Stephanie  (1913).  He  was  active  in  propaganda  work 
during  the  World  War,  and  shortly  before  his  death  published 
Reims  devasteea.nd.Le Lion  d' Arras.  He  died  in  Paris  Jan.  7  1920. 

ADAMS,  HENRY  (1838-1918),  American  historian  (see  1.175). 
died  in  Washington,  D.C.,  May  27  1918.  In  1910  his  Letter  to 


American  Teachers  of  History  appeared,  and  in  1911  his  Life  of 
George  Cabot  Lodge.  In  1913  his  Mont  Saint  Michel  and  Chartres 
(privately  printed  in  1904)  was  published  by  authority  of  the 
American  Institute  of  Architects,  a  scholarly  interpretation  of 
the  architecture  and  literature  of  the  mediaeval  Church.  In  1918 
his  autobiographical  The  Education  of  Henry  Adams  (privately 
printed  in  1906)  was  issued  for  the  public.  No  book  of  its 
decade  evoked  more  discussion  in  America.  In  1919  The  Deg- 
radation of  the  Democratic  Dogma  (consisting  of  several  essays 
previously  published  together  with  one  hitherto  unpublished) 
was  issued,  with  an  introduction  by  his  brother,  Brooks  Adams. 
His  brother,  CHARLES  FRANCIS  ADAMS  (see  1.175),  died  in 
Washington,  D.C.,  March  20  1915-  In  1911  he  published  Studies 
Military  and  Diplomatic,  1775-1865,  and  in  1913  Trans- Atlantic 
Historical  Solidarity  (lectures  delivered  at  Oxford). 

In  1916  Worthington  C.  Ford  edited  Charles  Francis  Adams,  an 
Autobiography,  from  papers  deposited  in  1913  with  the  Massachu- 
setts Historical  Society.  See  also  the  same  editor's  A  Cycle  of 
Adams  Letters,  1861-1865  (1920). 

ADAMS,  MAUDE  (1872-  ),  American  actress,  was  born  in 
Salt  Lake  City,  Utah,  Nov.  n  1872.  Her  family  name  was 
Kiskadden,  but  she  adopted  the  maiden  name,  Adams,  of  her 
mother,  an  actress.  She  early  played  child's  parts,  and  at  the  age 
of  16  went  to  New  York.  From  her  appearance  in  Hoyt's  A  Mid- 
night Bell,  in  1889,  her  popularity  grew  steadily.  In  1897  she 
was  first  starred  by  Charles  Frohman  as  Lady  Babbie  in  The 
Little  Minister;  and  in  many  of  Barrie's  other  plays  she  won 
applause.  She  introduced  Rostand  to  the  American  stage, 
taking  the  title-role  in  L'Aiglon  (1901),  and  in  Chantcclcr  (1911). 
Other  plays  in  her  repertory  were  Romeo  and  Juliet  (1900); 
The  Pretty  Sister  of  Jose  (1903);  The  Jesters  (1908)  and  As  You 
Like  It  (1910). 

ADAMSON,  WILLIAM  (1863-  ),  British  Labour  politician, 
was  born  at  Halbeath,  Fife,  April  2  1863.  When  very  young 
he  began  to  work  in  the  pits,  and  for  many  years  led  the  life 
of  a  miner.  In  1902  he  became  assistant  secretary  of  the  Fife 
and  Kinross  Miners'  Association,  and  in  1908  its  general  secre- 
tary. He  stood  for  Parliament  unsuccessfully  in  Jan.  1910, 
but  in  Dec.  was  elected  for  West  Fife.  On  the  reorganiza- 
tion of  the  Labour  party  in  1917,  Mr.  Adamson  succeeded 
Mr.  Arthur  Henderson  as  its  chairman,  and  in  1918  he  was  sworn 
of  the  Privy  Council.  In  1919  the  Labour  party,  as  the  second 
strongest  combination  in  the  House  of  Commons,  decided  to 
assume  the  position  of  the  official  Opposition,  and  Mr.  Adamson 
became  its  leader,  taking  his  seat  on  the  front  Opposition 
bench.  As  an  Opposition  leader  he  also  congratulated  the 
Speaker  upon  his  reelection.  He  took  part  in  the  debate  on  the 
King's  speech,  pointing  out  the  views  of  the  Labour  party  on  the 
industrial  situation.  Mr.  Adamson  took  a  prominent  part  in  the 
various  trade-union  discussions  in  1919,  1920  and  1921,  particu- 
larly in  the  numerous  debates  on  the  coal  industry  in  these  years. 

ADDAMS,  JANE  (i86cr-  ),  American  sociologist  (see 
1.183),  published  Twenty  Years  at  Hull  House  (1910),  with  much 
autobiographical  comment;  A  New  Conscience  and  an  Ancient 
•Evil  (1911)  and  The  Long  Road  of  Women's  Memory  (1916). 
She  did  much  to  promote  the  cause  of  woman  suffrage,  and  in 
1912  was  an  active  worker  in  behalf  of  the  short-lived  National 
Progressive  party.  After  the  outbreak  of  the  World  War  in 
Europe  she  attended  the  International  Congress  of  Women 
held  at  The  Hague  in  1915,  and  was  elected  president.  She  was 
also  appointed  chairman  of  the  International  Committee  of 
Women  for  Permanent  Peace.  She  was  an  avowed  pacifist 
after  America  had  entered  the  World  War. 

ADDISON,  CH  RISTOPH  ER  ( 1 860-  ) ,  English  politician  and 
medical  practitioner,  born  June  19  1869  at  Hogsthorpe,  Lines., 
was  educated  at  Trinity  College,  Harrogate,  and  received  his 
medical  training  at  St.  Bartholomew's  hospital.  He  graduated 
at  London  University,  taking  the  M.B.  (Honours  in  For.  Med.) 
and  the  B.S.  in  1892,  and  the  M.D.  in  1893.  He  was  elected 
F.R.C.S.  in  1895.  He  became  lecturer  in  Anatomy  both  at 
his  own  hospital  and  at  Charing  Cross  hospital;  professor 
of  Anatomy  at  University  College,  Sheffield;  and  Hunterian 

professor  at  the  Royal  College  of  Surgeons  in  1901.  Besides  the 
private  practice  of  his  profession,  he  contributed  largely  to 
medical  knowledge  by  the  publication  of  several  books,  mainly 
on  the  anatomy  of  the  pancreas  and  the  abdominal  viscera,  by 
papers  in  the  Proceedings  of  the  Royal  Society  and  in  professional 
journals,  and  by  editing  for  a  time  the  Quarterly  Medical  Journal. 
He  took,  moreover,  a  leading  part  in  medical  education  in 
London  University.  In  1910  he  entered  Parliament  as  Liberal 
member  for  Hoxton.  He  immediately  became  active  in  the 
House.  In  conjunction  with  Sir  George  Newman  he  was  mainly 
instrumental  in  securing  the  medical  treatment  of  school  children 
and  State  provision  for  medical  research;  and  he  was  one  of  the 
few  doctors  of  distinction  who  supported  Mr.  Lloyd  George  in  his 
struggle  with  the  profession  over  the  Insurance  Act  (1912). 
The  valuable  support  he  then  gave  to  Mr.  Lloyd  George  in 
reconciling  the  doctors  to  his  proposals  created  a  firm  bond 
between  him  and  the  future  Prime  Minister.  When  in  1914 
Mr.  Charles  Trevelyan,  on  the  outbreak  of  war,  resigned  the 
Parliamentary  Secretaryship  of  the  Board  of  Education, 
Dr.  Addison  was  appointed  in  his  place.  But  his  principal  work 
during  the  war  was  effected  at  the  Ministry  of  Munitions,  where 
Mr.  Lloyd  George  obtained  his  assistance  as  Parliamentary 
Secretary  when  the  office  was  created  under  the  first  Coalition 
Ministry  in  1915.  So  long  as  Mr.  Lloyd  George  was  Minister, 
Dr.  Addison  was  his  right-hand  man  in  the  strenuous  labours 
of  the  office,  resulting  in  the  enormous  multiplication  of  engines 
of  war,  and  in  the  redeeming  of  many  vital  industries,  fertilizers, 
tungsten  and  potash  from  German  control;  and  when  Mr.  Lloyd 
George  formed  a  Government  himself  in  December  1916,  he 
placed  him  at  the  head  of  the  department.  Dr.  Addison  had  to 
deal  with  various  labour  troubles,  and  in  particular  with  a 
serious  strike  of  engineers  in  May  1917.  In  July  he  left  the 
Ministry  of  Munitions  to  become  Minister  of  Reconstruction 
without  portfolio.  In  this  new  but  very  important  work  his 
policy  was  apparently  influenced  by  a  rather  idealistic  vision  of 
a  "  new  world  "  after  the  war.  One  result  was  the  unemploy- 
ment dole,  at  first  a  necessity,  but  afterwards  a  hindrance  to  a 
return  to  normal  life.  To  promote  national  health  had  always 
been  his  main  object  in  politics,  and  when  Mr.  Lloyd  George 
reconstructed  his  Ministry  in  the  beginning  of  1919,  he  entrusted 
the  Local  Government  Board  to  Dr.  Addison,  that  he  might  com- 
plete Lord  Rhondda's  work  and  transform  it  into  a  Ministry  of 
Health.  This  was  accomplished  in  June.  He  also  carried  through 
Parliament  an  important  Housing  and  Town-Planning  bill 
compelling  local  authorities  to  provide  housing  schemes,  and 
obtained  parliamentary  sanction  to  an  arrangement  for  the  issue 
by  such  authorities  of  housing  bonds.  The  ambitious  medical 
establishment  created  by  him  was  subjected  to  a  good  deal  of 
criticism  on  the  score  of  economy  during  1920;  and  on  the 
reconstruction  of  the  Ministry  in  March  1921  he  was  transferred 
from  the  new  department  to  become  once  more  a  minister  without 
portfolio.  This  position  he  resigned  on  July  14.  He  married 
in  1902  Isobel  Gray,  and  had  two  sons  and  two  daughters. 
ADEN  (see  1.190). — The  territory  comprises  the  peninsulas  of 
Aden  proper  and  Little  Aden,  a  strip  of  mainland  including  the 
villages  of  Sheikh  'Othman,  6  m.  inland,  'Imad  and  Hiswa,  and 
Perim  Island.  The  town  of  Aden  and  its  port  Tawahi,  4  m. 
westward,  are  connected  by  a  good  carriage-road  with  the 
Somali  settlement  of  Ma'la  about  midway.  The  harbour — 
known  as  Bandar  Tawiya  or  Aden- West  Bay — lies  between  the 
main  and  Little  Aden  peninsulas  (Jebel  Ihsan  or  Hasan);  it 
extends  8  m.  from  E.  to  W.  and  3  m.  from  N.  to  S.  and  is  divided 
into  a  western  and  an  inner  bay  by  a  spit  of  land.  The  depth  of 
water  at  the  main  entrance  is  45  to  5  fathoms  and  in  the  western 
bay  3  to  4  fathoms.  For  lack  of  docks  and  quayage,  large  vessels 
lie  off  Steamer  Point  and  all  cargo  is  handled  by  means  of 
lighters,  the  labour  being  either  Somali  or  Arab.  Sailing  and 
small  craft  load  and  unload  at  Ma'la.  The  population  of  Aden 
proper  in  1915  was  36,900  and  of  the  whole  settlement  46,000, 
of  whom  about  23,000  were  Arabs  and  a  large  part  of  the 
remainder  Somalis.  European  residents  and  Christians  numbered 
2,000  to  3,000,  Mohammedans  about  34,000  and  Jews  3,700. 


On  March  I  1921  the  administration  of  Aden  was  transferred 
from  the  India  Office  to  the  Colonial  Office,  which  also  exer- 
cises political  influence,  in  varying  degrees,  over  the  confederations 
of  tribes  inhabiting  the  interior  as  far  as  the  Yemen  frontier  and 
over  certain  tribes  of  the  Hadhramaut.  The  revenue  in  1914-5 
amounted  to  87^  lakhs  of  rupees  (approx.  £580,000),  derived  mainly 
from  the  Aden  Port  Trust  Fund  (£34,000),  Aden  Settlement  Fund 
(£28,000),  Local  Supply  Bills  (£257,000),  imperial  and  municipal 
receipts  (£215,700),  Post  Office  (£34,000),  excise,  customs  and 
income  tax.  The  expenditure  in  the  same  year  was  £556,000. 

The  value  of  the  total  trade  (including  specie)  amounted  to 
£8,526,000  (1913-4),  and  had  increased  to  £10,045,000  in  1918-9 
and  £13,641,000  in  1919-20.  Of  the  last  amount,  £7,124,000 
represented  exports  and  £6,517,000  imports.  A  very  large  propor- 
tion represents  simple  transhipment ;  but  Aden  is  also  the  centre  of 
the  exporting  and  importing  business  of  the  Red  Sea  commercial 
region  made  up  of  the  Hejaz,  Asir,  Yemen,  Hadhramaut,  Eritrea, 
Abyssinia  and  British  and  French  Somaliland.  The  principal  arti- 
cles of  import  in  1919-20  were:  cotton  piece-goods  and  yarn 
£2,180,000,  hides  and  skins  £1,291,000,  coal  £626,000,  grain  and 
flour  £541,000,  coffee,  sugar,  tobacco,  hardware,  petroleum  and 
provisions.  The  exports  were:  hides  and  skins  £2,123,000,  cotton 

foods  £2,112,000,  coffee  £456,000,  grain  and  pulse  £329,000,  tobacco 
213,000  and  salt  £151,000.  Local  products,  including  kat,  fire- 
wood, live  animals,  ghi,  dates,  honey,  wax,  gums  and  sesame  oil, 
to  the  value  of  about  £125,000,  were  exported  in  1919-20.  1,065 
steam  vessels  of  aggregate  tonnage  2,736,391  and  sailing  craft  of 
tonnage  365,569  cleared  in  the  year  ending  March  1919.  The  port 
is  free  except  for  a  small  duty  on  alcoholic  liquors  and  intoxicating 
drugs.  Licenses  are  required  for  the  importation  of  petroleum  and 
small  arms  and  ammunition. 

The  water  supply,  formerly  very  uncertain  and  unsatisfactory, 
is  mainly  from  reservoirs  and  from  condensation.  The  reservoirs 
have  a  storage  capacity  of  8,000,000  gal.  but  the  most  effective  sup- 
ply is  obtained  by  condensation  of  sea  water.  Six  condensers  yield 
52,000  gal.  daily. 

Aden  produces  no  foodstuffs.  The  only  local  industries  are  the 
preparation  of  salt  (Italian  and  Indian  concessions,  with  an  out- 
put of  124,000  tons  in  1916-7),  the  unhusking  of  Arabian  coffee 
berries  and  the  making  of  cigarettes  from  tobacco  imported  from 
Egypt.  The  main  trade  routes  are: — to  San'a,  via  Lahej,  227  m.; 
to  Mocha  and  Hodeida,  via  Ta'izz,  299  m.;  and  to  Makalla,  via 
Nisab,  413  m. 

During  the  World  War,  Turkey  brought  pressure  to  bear  on  cer- 
tain of  the  tribes  of  the  Aden  Protectorate  (see  ARABIA)  and  in 
July  1915  a  Turkish  army  several  thousand  strong  advanced  on 
Lahej,  the  'Abdali  capital  (21  m.  N.).  A  small  British  force  sent 
to  assist  in  its  defence  proved  altogether  inadequate  and  had  to 
retreat  to  Aden.  The  Turks  occupied  Sheikh  'Othman,  but  were 
unable  to  threaten  Aden  itself.  The  loyal  Sultan  was  killed.  On 
July  20  of  the  same  year  reinforced  Aden  troops  surprised  the 
Turks  at  Sheikh  'Othman,  inflicted  on  them  considerable  loss  and 
they  retired  to  Lahej.  In  Oct.  and  in  Dec.  cavalry  had  small 
affairs  with  enemy  reconnoitring  parties  in  which  the  latter 
were  driven  off.  In  Jan.  1916,  owing  to  the  Turks  again  des- 
patching troops  to  coerce  the  tribes  in  the  east  of  the  Protectorate, 
a  demonstration  in  support  of  the  latter  was  made  by  the  Aden 
column.  It  located  the  enemy  force  near  the  village  of  Subar  (4  m. 
S.S.E.  of  Lahej),  inflicted  considerable  loss  on  it,  and  the  Turkish 
pressure  was  relieved.  In  Dec.  1917  the  defensive  line  at  Aden 
described  an  arc  of  about  1 1  m.  radius  and  there  had  been  constant 
patrol  skirmishes  and  small  actions  which  continued  until  the 

ADLER,  VIKTOR  (1852-1918),  Austrian  politician,  was  born 
at  Prague  June  24  1852,  the  son  of  a  well-to-do  business  man, 
who  moved  with  his  family  to  Vienna  when  the  son  was  three 
years  old.  Here  he  studied  at  the  Schotten-gymnasium,  where 
he  gathered  round  him  a  circle  of  fellow-students  who  thus  early 
began  to  occupy  themselves  with  political  and  social  questions, 
their  interest  having  been  aroused  by  the  works  of  Lassalle  and 
by  the  events  of  1866  and  1870.  It  was  at  this  time,  too,  that  the 
Social  Democratic  Labour  movement  first  began  to  affect 
Austria.  On  the  basis  of  the  new  law  respecting  combinations, 
passed  during  the  era  of  Liberal-bourgeois  reform,  arose  the  first 
proletarian  organizations,  and  the  battles  between  the  adherents 
of  state  assistance  (Lassalle)  and  of  self-help  (Schultz-Delitzsch) 
were  being  publicly  fought  out.  At  the  university  Adler  entered 
the  German  national  students'  association,  "  Arminia,"  became 
a  member  of  the  committee  of  the  German  Reading  Union,  and 
belonged  to  the  national  and  democratic  group  of  intellectuals 
who,  since  the  middle  of  the  'seventies,  had  grouped  themselves 
around  the  deputy  Schonerer,  and  had  formulated  the  so-called 
Linz  programme  (see  also  PERNERSTORFER).  He  studied  medi- 
cine, attaching  himself  especially  to  the  psychiatrist  Meynert, 

and  in  addition  to  his  medical  practice  occupied  himself  with 
industrial  hygiene.  In  his  later  career  he  continued  to  take 
special  interest  in  public  health  questions.  Intending  to  adopt 
factory  inspection  as  a  career,  he  went  in  1883  to  study  in 
Switzerland  and  in  London,  where  he  came  into  close  touch  with 
Engels.  On  his  return  to  Vienna,  however,  he  turned  entirely  to 
politics.  The  Workmen's  party,  weakened  by  the  general 
economic  depression,  by  internal  dissensions  and  by  police 
prosecutions,  had  sunk  into  political  insignificance.  In  the 
'eighties  the  "  Radicals  "  (Most,  Peukert)  and  the  "  Moderates  " 
were  at  daggers  drawn.  The  Government  of  Count  Taaffe,  on 
the  other  hand,  supporting  itself  on  the  lower  middle  classes, 
which  held  the  balance  of  votes  in  Austria  and  especially  in 
Vienna,  introduced  legislation  for  the  organization  of  industry 
on  the  guild  system.  It  attempted,  indeed,  to  conciliate  the 
working  classes  by  social-political  legislation  on  the  German 
model,  but  at  the  same  time  used  the  excuse  given  by  the 
methods  of  violence  advocated  by  the  Radicals  to  suspend  the 
ordinary  law  in  Vienna  and  certain  other  districts,  as  a  pre- 
liminary to  anti-Socialist  and  anti-Anarchist  legislation.  The 
ground  being  thus  prepared  by  the  Government,  Adler  under- 
took to  restore  unity  in  the  ranks  of  Labour.  In  1886  appeared 
his  paper  Gleichheit  (Equality),  eventually  succeeded  by  the 
Arbeiterzeitung,  the  principal  organ  of  the  Social  Democratic 
party,  which  Adler  continued  to  conduct  till  his  death.  His 
object  was  to  organize  the  workmen  as  a  political  party,  and 
the  best  methods  seemed  to  him  to  be  those  of  public  propaganda 
and  open  political  warfare.  The  united  Labour  party  (Arbeiter- 
partei)  was  to  keep  the  socialistic  ideal  constantly  in  view,  but 
was  not  to  despise  small  gains.  By  his  sound  judgment,  and  his 
exceedingly  clever  handling  of  men,  he  succeeded,  in  spite  of 
difficulties  within  and  without  the  party,  in  reaching  the  first 
stage  in  the  path  he  had  marked  out  by  carrying  the  whole  party 
with  him,  in  the  last  days  of  the  year  1888,  on  the  basis  of  a 
carefully  weighed  programme  at  the  party  meeting  held  at 
Hainfeld,  Lower  Austria.  He  was  able  to  appear  in  July  1889  at 
the  first  congress  of  the  Second  International  (of  which  he  was 
from  that  time  an  official)  as  the  representative  of  the  united 
Austrian  party;  and  the  first  May  Day  celebration  (1890),  the 
first  of  those  imposing  demonstrations  by  which  he  sought  to  give 
a  striking  proof  of  the  will  and  the  power  of  the  working  classes, 
showed  that  a  new  epoch  had  dawned  for  Austrian  Social 
Democracy.  Adler,  who  was  repeatedly  involved  in  legal 
proceedings  and  condemned  to  terms  of  several  months'  im- 
prisonment for  political  offences,  was  from  that  time  the  acknowl- 
edged leader  of  the  party. 

In  consequence  of  the  ever-increasing  extension  of  its  industrial 
and  political  organization,  in  which  Adler  took  an  energetic  part, 
the  party  obtained  an  increasing  influence  in  public  life,  which 
was  further  increased  by  the  division  of  the  bourgeois  parties  on 
the  nationality  question.  Adler  understood  how  to  make  the 
best  of  these  conditions.  He  regarded  it  as  his  first  task  to  secure 
for  the  workmen  representation  in  Parliament.  After  the  three 
years'  struggle  for  electoral  reform  (1893-6),  which  followed 
the  proposals  for  the  modification  of  the  franchise  put  forward 
by  the  prime  minister,  Count  Taaffe,  some  measure  of  electoral 
reform  was  secured.  But  it  was  insufficient,  and  it  was  only  when 
the  Government  had  decided  that  an  extension  of  the  franchise 
was  the  sole  means  by  which  the  monarchy  could  be  protected 
against  the  centrifugal  forces  of  nationality,  that  Adler  was  able 
to  use  the  impression  made  by  the  confusions  in  Hungary  and  the 
Russian  revolution  of  1905  to  interpose  with  all  his  weight  and 
help  to  secure  the  triumph  of  universal  and  equal  suffrage  (1907). 

The  Social  Democratic  party  increased  their  representation 
from  ii  deputies  to  87.  Adler  himself  entered  the  Diet  of  Lower 
Austria  in  1902,  and  in  1905  was  elected  to  the  Reichsrat,  where 
until  his  death  he  played  an  important  part  as  chairman  of  the 
committee  of  the  Social  Democratic  party  and  of  the  Social 
Democratic  Deputies'  Club,  taking  part  in  all  important 

New  dangers,  due'to  the  nature  of  the  Austrian  State  with  its 
rival  nationalities,  more  than  once  threatened  the  unity  of  the 


party.  Adler  had  always  been  a  Pan-German,  but  regarded  the 
disruption  of  Austria  and  the  union  of  German  Austria  with 
Germany  as  a  distant  goal  which  had  no  place  in  the  practical 
politics  of  the  moment.  He  aimed  therefore  at  establishing  a 
friendly  relation  between  the  nations  on  the  basis  of  democracy. 
When  the  Austrian  Germans  were  threatened  by  the  language 
ordinance  of  Count  Badeni,  and  Parliament  itself  by  a  coup 
d'etat,  Adler  made  an  alliance  with  the  German  parties,  rallied 
the  working  classes,  and  overthrew  the  Polish  prime  minister 
(1897).  At  the  party  congresses,  Adler  tried  to  accommodate  the 
conflicting  national  standpoints  on  the  basis  of  the  principles 
laid  down  in  the  Briinn  programme  (equal  rights  and  national 
autonomy).  But  the  unified  organization  of  the  trade  unions  and 
the  union  of  the  Social  Democratic  parties  were  destroyed  in 
consequence  of  these  differences,  more  especially  by  the  in- 
transigeance  of  the  Czechs.  No  general  party  congress  of  the 
different  Austrian  nationalities  has  taken  place  since  1905. 

In  the  congresses  and  in  the  secretariat  of  the  International 
Adler,  with  Jaures  and  Bebel,  played  the  most  prominent  part, 
whether  as  leader,  adviser,  or  mediator.  He  took  part  in  the 
great  peace  demonstration  of  the  International  at  Basel,  and  in 
the  meeting  of  the  secretariat  in  Brussels  immediately  before  the 
outbreak  of  the  World  War.  In  spite  of  bad  health,  which  for 
many  years  in  succession  had  compelled  him  to  spend  much  time 
on  the  Riviera  and  at  Nauheim,  he  travelled  in  the  spring  of  1917, 
immediately  after  the  trial  of  his  son  Friedrich,  to  Stockholm  to 
the  proposed  Socialist  congress.  After  the  collapse  of  Austria  in 
1918,  at  the  constituent  session  of  the  provisional  German- 
Austrian  National  Assembly,  which  was  formed  by  the  meeting 
of  all  the  German  deputies,  he  read  the  declaration  of  the  Social 
Democrats,  in  which  they  expressed  their  willingness,  in  associa- 
tion with  the  other  German-Austrian  parties,  to  build  the  new 
State  on  the  basis  of  democracy  and  the  self-determination  of 
their  own  and  other  nationalities,  without  prejudice  to  a  possible 
association  with  the  German  Empire. 

In  his  opening  words  Adler  said:  "  You  will  permit  an  old  man 
to  say  that  at  last  we  see  the  accomplishment  of  what  we  have 
longed  for  since  our  youth."  He  did  not  long  survive  that  day. 
He  held  for  a  few  days  the  office  of  Foreign  Minister,  entrusted  to 
him  by  the  new  State  Council  (Staatsrat),  but  in  spite  of  his  iron 
determination  he  was  not  able  to  bear  the  strain.  He  broke  down 
on  Nov.  ii  and  died  on  the  lath,  1918,  the  day  on  which 
the  State  Council  had  decided  to  proclaim  German  Austria 
a  democratic  republic  and  an  integral  part  of  the  German  Reich. 

His  works  include  articles  scattered  in  various  newspapers,  in 
the  Neue  Zeit,  Kampf,  Deutsche  Worte,  in  addition  to  those  in  the 
Arbeiterzeitung;  pamphlets,  among  which  are  Die  Fabrikinspektion, 
insbesondere  in  England  und  der  Schweiz  (1884);  Die  Arbeiterkam- 
mer  und  die  Arbeiter  (1886);  Das  allgemeine,  gleiche  und  direkte 
Wahlrecht  und  das  WMunrecht  in  Oesterreich;  Alcoholismus  und 
Gewerkschaft  (many  editions).  See  also  Die  Gleichheit  vor  dem  Aus- 
nahmegericht  (1889);  Schwurgerichtsprozess  gegen  Doktor  Viktor 
Adler  wegen  Verbrechens  der  Storung  der  offentlichen  Ruhe  (1894). 

His  son,  FRIEDRICH  ADLER  (1879-  ),  Austrian  politician, 
was  born  at  Vienna  July  9  1879.  He  was  educated  at  the  Real- 
gymnasium  in  Vienna,  and  studied  philosophy  at  the  uni- 
versity of  Zurich.  He  was  privatdozent  (lecturer  by  diploma) 
in  physics  at  the  university  of  Zurich  from  1907  to  1911,  editor 
of  the  Social  Democratic  daily  Volksrechl  from  1910  to  1911, 
and  from  1911  to  1916  secretary  of  the  Austrian  Social  Demo- 
cratic party  and  editor  of  the  monthly  Kampf.  During  the 
World  War  he  was  in  sympathy  with  the  conclusions  reached 
at  the  conferences  of  the  Socialists  of  the  Left  at  Zimmerwald 
and  Kienthal.  In  despair  over  the  break-up  of  the  International, 
he  shot  (Oct.  21  1916)  the  Austrian  prime  minister,  Count 
Stiirgkh,  in  the  expectation  that  the  deed  would  be  a  signal  for 
the  rising  of  the  proletariat  against  the  war.  After  a  speech  in 
his  own  defence  which  aroused  much  attention  he  was,  on  May 
19  1917,  condemned  by  a  special  tribunal  to  death,  a  sen- 
tence commuted  to  18  years'  imprisonment.  During  the  chaos 
of  the  autumn  of  1918  he  was  amnestied  (Nov.  i).  In  1919 
he  was  elected  to  the  National  Assembl^,  and  became  vice- 
president  of  the  committee  of  the  Social  Democratic  party  and 

of  the  Union  of  the  Social  Democratic  deputies.  As  president 
of  the  Austrian  National  Workmen's  Council  and  of  the  Vienna 
District  Workmen's  Council  he  exercised  great  influence  in  the 
party.  On  his  initiative  was  founded  the  International  Labour 
Association  of  Socialist  Parties,  of  which  the  first  meeting  was 
held  in  Vienna  in  Feb.  1921.  He  made  the  opening  state- 
ment, and  became  secretary  of  the  Association. 

His  works  are:  Die  Erneuerung  der  Internationale  (1918);  Ernst 
Mack's  Ueberwindung  des  mechanischen  Materialismus  (1918); 
Ortszeit,  Systemszeit,  Zonenzeit  und  das  ausgezeichnete  Bezugssystem 
der  Electrodynamik,  eine  Untersuchung  ilber  die  Lorentzische  und  die 
Einstein' sche  Kinematik  (1920).  See  also  Friedrich  Adler  iior  dem 
Ausnahmegericht  (1919). 

ADMIRALTY  ADMINISTRATION  (see  1.195).— The  history 
of  the  British  Admiralty  during  the  World  War  of  1914-8  is  the 
history  of  the  evolution  of  the  naval  staff  and  of  a  great  expan- 
sion of  the  technical  and  administrative  departments.  All  de- 
partments expanded  during  the  war,  but  the  evolution  of  the 
naval  staff  was  more  than  mere  expansion,  for  it  represented 
the  adoption  of  definite  principles  of  staff  work  which  were  in- 
tended to  prevent  those  responsible  for  the  conduct  of  naval 
operations  being  crushed  under  a  load  of  administrative  business. 

This  was,  indeed,  no  new  trouble.  It  had  been  experienced 
ashore  and  afloat  in  peace  and  war.  Kempenfelt  and  Tryon 
had  commented  strongly  on  it.  "  We  are  every  day,"  wrote 
the  former  to  Middleton  in  1770,  "plagued  and  puzzled  with 
minutiae  from  morning  to  night  whilst  essentials  are  neglected." 
"  It  cannot  be  right,"  wrote  Tryon  in  1890,  "  that  the  Com- 
mander-in-Chief  should  find  himself  devoting  his  time  to 
coaling  and  watering,  provisioning,  storing  and  repairing." 
They  were  seeking  after  a  solution  of  the  difficulty  which  lay  in 
a  clear  distinction  between  fighting  and  supply,  between  the 
use  of  the  weapon,  and  its  supply  and  maintenance  in  an  efficient 
state.  This  principle  had  been  introduced  into  the  British  army 
by  Lord  Haldane,  and  is  equally  applicable  to  naval  work. 
It  is  a  principle  vital  to  war,  for  on  the  outbreak  of  war  the  whole 
rhythm  of  work  changes.  Work  expands  tenfold  in  extent  and 
an  hundredfold  in  urgency,  and  without  some  clear  distinction 
of  this  sort  it  is  impossible  to  give  to  the  conduct  of  operations 
the  attention  it  deserves. 

The  principle  was  not  to  be  found  in  the  British  Admiralty  at 
the  beginning  of  the  war.  •  The  First  Sea  Lord  was  just  as  in- 
terested in  the  design  of  ships  as  in  operations,  and  the  Wai 
Staff  lacked  some  of  the  most  important  elements  of  staff  work. 
The  important  distinction  between  fighting  and  supply  was 
not  to  be  found;  the  Chief  of  the  War  Staff  had  no  seat  on  the 
Board,  and  the  methods  of  conducting  the  work  of  a  large  staff 
had  not  been  studied.  Up  to  1909  the  Intelligence  Department 
had  to  some  extent  filled  the  place  of  a  staff.  It  had  gradually 
grown  from  the  Foreign  Intelligence  Branch  or  Committee 
instituted  in  1883,  and  had  developed  into  the  Naval  Intelli- 
gence Department,  consisting  of  four  divisions — foreign,  trade, 
mobilization  and  war— of  which  the  two  latter  were  evidently 
tentative  efforts  towards  an  Operations  Division.  In  Sept.  1909 
it  split  into  two  separate  departments,  intelligence  and  mobiliza- 
tion, of  which  the  latter  was  clearly  the  beginning  of  an  Opera- 
tions Division,  but  was  killed  by  its  name,  for  it  soon  became 
immersed  in  the  task  of  manning  and  mobilization,  which  be- 
longs wholly  to  the  sphere  of  supply.  The  Intelligence  Depart- 
ment sank  more  and  more  into  the  position  of  a  mere  handmaid 
for  the  collection  of  data  and  translations  from  the  foreign 
press.  Its  development  was  hampered  by  the  intense  suspicion 
with  which  most  flag  officers  regarded  anything  that  seemed  to 
trespass  on  their  prerogative  of  command.  The  idea  of  a  staff 
was  held  in  great  disfavour.  The  word  was  anathema  at  the 
Admiralty  and  not  allowed  to  be  used  in  War  College  publica- 
tions, and  it  is  no  secret  that  the  most  distinguished  flag  officers 
were  opposed  to  the  institution  of  a  staff  in  1912. 

The  naval  staff  really  dates  from  the  Memorandum  of  Jan. 
1912  issued  by  Mr.  Churchill,  after  the  breakdown  of  the  old 
system  at  the  Agadir  crisis,  but  it  had  not  had  sufficient  time 
to  develop  before  the  World  War  broke  on  it  and  broke  it  up. 
It  consisted  of  three  small  divisions — operations,  intelligence 


and  mobilization.  Its  deficiencies  may  be  briefly  summarized: 
Firstly,  the  Chief  of  the  War  Staff  was  not  a  member  of  the 
Board,  and  could  not  act  with  Board  authority;  his  function 
was  merely  advisory.  Secondly,  there  was  a  great  insufficiency 
of  trained  staff  officers,  and  the  War  Staff  proved  quite  inad- 
equate in  numbers  and  training  to  deal  with  the  business  of  war. 
Thirdly,  the  principles  of  staff  work  had  not  been  studied,  and 
the  vital  distinction  between  fighting  and  supply  was  not  to  be 
found.  Fourthly,  the  system  found  little  support  either  at  White- 
hall or  in  the  fleet  at  sea.  There  was  no  clear  conception  of  con- 
ducting the  work  of  a  staff,  or  of  grafting  it  on  to  the  business 
system  of  the  Admiralty.  On  the  first  day  of  war  a  number  of 
sections  were  bundled  into  one  big  room  in  order  to  be  as  close 
as  possible  to  one  another  to  the  serious  dislocation  of  their 
work.  The  Operations  Division  was  divided  on  the  basis  of 
types  of  ships  rather  than  of  areas.  It  soon  became  absorbed  in 
current  work,  and  had  no  time  for  the  examination  of  large 
plans,  which  might  require  three  months'  work  merely  to  reduce 
to  terms  of  time  and  supply.  The  enormous  importance  to  a 
staff  of  an  operations  chart  clearly  and  continuously  visualizing 
the  situation  was  not  appreciated.  An  operations  chart  was 
started,  but  gradually  over-centralization  and  the  obsession  of 
secrecy  came  down  on  it  like  a  thick  fog  and  turned  it  into  a 
fiasco.  The  movements  of  transports  were  kept  a  profound 
secret,  and  news  of  them  was  withheld.  Secret  telegrams  (pink 
telegrams)  were  started  about  Nov.  1914  but  were  not  passed 
to  the  War  Room  to  be  plotted  on  the  chart,  which  degenerated 
into  a  paltry  record  of  reports  of  mines  sighted  round  the  coast. 
Up  to  1917  there  was  no  chart  to  which  a  staff  officer  could  go 
and  see  at  a  glance  the  actual  situation  at  the  moment  in  any 
and  every  area. 

The  work  which  ought  to  have  been  done  by  the  staff  was 
done  by  a  small  group  of  two  or  three  flag  officers  acting  in  an 
advisory  capacity  to  the  Board,  and  the  system  seemed  to  be 
designed  for  the  special  purpose  of  making  it  as  difficult  as 
possible  to  obtain  information.  The  Intelligence  Division  was 
expanding  and  developing  under  Capt.  (later  Adml.  Sir)  William 
R.  Hall,  but  its  sections  had  to  fight  hard  to  obtain  information  as 
to  British  movements.  The  flag  officers  worked  for  the  Board, 
not  for  the  staff,  and  no  one  quite  knew  what  they  did  or  where 
they  did  it. 

Let  us  consider  the  constitution  of  the  Admiralty  Board 
when  the  war  broke  out.  Under  a  patent  of  Dec.  i  1913  it  con- 
sisted of  the  First  Lord,  Mr.  Winston  Spencer  Churchill  (since 
Oct.  24  1911),  Adml.  Prince  Louis  of  Battenberg  (ist  S.L., 
since  Dec.  9  1912),  Vice-Adml.  Sir  Frederick  Hamilton  (2nd 
S.L.),  who  had  succeeded  Vice-Adml.  Sir  John  Jellicoe  (July 
30  1914),  Rear-Adml.  Archibald  G.  H.  Moore  (3rd  S.L.,  since 
May  29  1912),  Capt.  Cecil  F.  Lambert  (4th  S.L.,  since  Dec.  i 
1913),  Mr.  George  Lambert,  M.P.  (Civil  Lord,  since  Dec.  21 
1905),  Sir  Francis  J.  S.  Hopwood  (Parliamentary  and  Financial 
Secretary  since  Jan.  18  1912,  later  created  Lord  Southborough), 
with  Sir  Graham  Greene  as  Permanent  Secretary.  Its  business 
was  governed  by  an  Order  in  Council  of  Aug.  10  1904,  which 
made  the  First  Lord  responsible  to  His  Majesty  and  Parliament 
for  all  the  business  of  the  Admiralty,  and  from  time  to  time  with 
his  sanction  various  memoranda  were  issued  regulating  the 
distribution  of  business.  The  distribution  of  business  had  re- 
mained materially  the  same  for  many  years,  though  the  memo- 
randum actually  in  force  at  the  outbreak  of  war  was  dated 
Jan.  1914. 

The  First  Sea  Lord  was  responsible  for  advising  on  prepara- 
tions for  war,  for  the  fighting  and  sea-going  efficiency  of  the  fleet, 
and  for  the  superintendence  of  the  War  Staff.  The  2nd  Sea  Lord 
was  responsible  for  personnel;  the  3rd  Sea  Lord  for  materials; 
the  4th  Sea  Lord  for  transport  and  stores,  full  and  half  pay, 
salvage  and  collisions.  No  one  was  specially  responsible  for 
the  conduct  of  all  operations  of  war,  and  though  this  pre- 
sumably rested  with  the  Chief  of  the  War  Staff  he  was  not  a 
member  of  the  Board,  and  at  least  two  flag  officers  senior  to 
him  were  acting  in  an  advisory  capacity  to  the  Board.  The 
First  Sea  Lord  was  responsible  for  the  "  fighting  efficiency  of 

the  fleet,"  a  phrase  covering  an  immense  technical  scope  and 
opening  out  an  endless  vista  of  all  sorts  of  considerations. 

It  is  interesting  to  observe  that  the  distinction  between 
fighting  and  supply,  which  lies  at  the  basis  of  modern  staff 
organization,  existed  in  a  simpler  form  in  the  organization  of 
Henry  VIII.,  which  continued  in  force  in  the  British  navy  down 
to  1832.  In  this  organization  the  Lord  High  Admiral  or  Com- 
missioners of  the  Admiralty  exercised  the  function  of  general 
control  and  was  responsible  for  the  conduct  of  a  war,  while  the 
actual  supply  services  were  performed  by  four  principal  officers, 
namely,  the  Treasurer,  Comptroller,  Surveyor  and  Clerk  of  the 
Acts,  responsible  respectively  for  finance,  supervision  of  accounts, 
building  and  upkeep  of  ships,  and  record  of  business.  These 
officials  came  to  be  known  as  the  Navy  Board,  and  the  organiza- 
tion of  the  Admiralty  f rom  1 546  to  1832  was  roughly  as  follows : — 

Lord  High  Admiral 

Commissioners  for  executing  his  office 



Navy  Board 





Sick  and  Hurt 

Pay,  Stores  (other  than 

Ordnance  and  Victual- 
ling) Manning,  Ship- 
building, Dockyards 

Here  the  work  of  supply  is  kept  distinct  from  the  business  of 
fighting,  and  it  was  under  this  dual  organization,  in  which  the 
Navy  Board  was  responsible  for  the  multifarious  requirements 
of  war,  that  the  earlier  wars  were  fought. 

Unfortunately,  the  supply  system  was  often  bad  and  in- 
sufficient and  corrupt,  though  its  defects  were  due  just  as  much 
to  limitations  of  the  time  as  to  the  system.  The  work  was  not 
closely  coordinated,  with  the  result  that  Sir  James  Graham  in 
1832  merged  the  functions  of  the  Navy  Board  and  the  Admiralty, 
an  amalgamation  which  was  regarded  as  a  master  stroke  at 
the  time  and  had  distinct  advantages,  but  unfortunately 
neglected  to  retain  the  principle  of  distinction  between  the 
Admiralty  and  supply,  with  the  result  that  it  was  not  the  Ad- 
miralty that  swallowed  the  Navy  Board  but  the  Navy  Board 
that  swallowed  the  Admiralty.  The  general  constitution  of 
the  Board,  though  it  varied  from  time  to  time,  may  be  repre- 
sented as  follows: — 

Board  of  Admiralty 
First  Lord 


First  Sea  Lord: 

Preparation  for 

war,  fighting 



and  Sea 






3rd  Sea        4th  Sea 
Lord :  Lord : 

Material     Transport 
and  Stores 
Permanent  Secretary 
Financial  Secretary 
Note. — According  to  the  Order  in  Council  of  Aug.  1904  the  First 
Lord  is  practically  supreme  as  being  responsible  to  the  King  and 
Parliament,  but  according  to  the  terms  of  the  Patent  "  two  or  any 
more  of  you  "  can  exercise  the  office. 

In  1860  commenced  that  vast  multiplication  and  develop- 
ment of  technical  crafts  and  branches  which  began  with  the 
steam  engine  (the  last  sailing  ship  of  the  time,  the  Ganges,  was 
paid  off  in  1861),  and  exercised  an  enormous  influence  on  the 
navy  and  naval  thought.  The  result  in  conjunction  with  Sir 
James  Graham's  amalgamation  was  inevitable.  Between  1860 
and  1900  the  study  of  strategy  and  of  staff  work,  which  is  the 
business  side  of  war,  was  practically  ignored.  All  the  talent  and 
brains  of  the  navy  flowed  to  the  great  technical  schools.  The 
whole  trend  of  thought  for  forty  years  was  exclusively  technical. 
It  was  supposed  that  war  and  the  conduct  of  war  was  quite  a 
simple  matter  for  any  flag  officer  and  needed  no  study.  This 
simple  creed  received  a  rude  shock  at  the  time  of  the  Agadir 
crisis  when  the  Admiralty  plans  for  war  were  torn  to  shreds  by 
the  General  Staff.  A  War  Staff  was  then  instituted.  But  the 
War  Staff  had  hardly  been  weaned  and  had  not  yet  found  its 



feet  when  the  World  War  broke  out.  It  laboured  under  a  further 
handicap:  practically  all  senior  officers  were  opposed  to  it. 
They  were  wedded  to  centralization.  Centralization  had  become 
engrained  in  their  bones  from  boyhood,  and  their  whole  outlook 
was  necessarily  opposed  to  a  staff.  The  deficiencies  of  the  system 
could  be  seen  in  the  conduct  of  the  Dardanelles  campaign.  It 
is  clear  that  there  was  no  machinery  for  the  intensive  investiga- 
tion of  a  big  strategical  question.  The  First  Lord  was  impressed 
with  an  exaggerated  estimate  of  the  Queen  Elizabeth's  guns, 
and  the  War  Staff  could  neither  supply  a  sufficiently  trenchant 
criticism  of  the  project  nor  could  they  grip  the  problem  and 
transform  it  into  a  workable  proposition  by  segregating  a  force 
and  training  it  as  the  Zeebrugge  force  was  afterwards  trained. 

Enough  has  been  said  to  show  that  the  war  staff  lacked  the 
staff  spirit,  and  a  knowledge  of  the  principles  of  staff  organiza- 
tion and  of  the  conduct  of  staff  work.  One  bright  spot,  however, 
shone  in  it.  While  the  operations  side  became  more  and  more 
narrowly  centralized,  the  intelligence  side,  under  Sir  William 
Hall,  summoned  a  vast  reserve  of  civilian  talent  to  its  aid.  Very 
early  in  the  war  a  system  of  special  intelligence  based  on  wireless 
directionals  had  begun  to  develop,  and  though  cramped  and 
restricted  by  the  obsession  of  secrecy  had  proved  of  great 
value.  In  Dec.  1916,  when  Adml.  Sir  John  Jellicoe  came  to  the 
Admiralty,  he  instituted  an  anti-submarine  division,  which 
was  no  more  than  a  belated  plans  division  directed  to  a  special 
purpose,  but  it  was  not  till  1917  that  the  staff  was  thoroughly 
reorganized  and  really  began  to  function  as  a  staff.  In  Dec. 
1916  it  was  organized  as  follows: — 

Chief  of  War  Staff 




Signal  Section  Mobilization 
Apr.  1916 

Trade  Division        Anti-submarine 
Aug.  23  1914      Division  Dec.  1916 

Sir  Eric  Geddes  gave  an  immense  impetus  to  the  system, 
which  was  forced  upon  the  Government  by  the  exigencies  of 
war,  and  in  its  main  outlines  was  merely  the  system  of  Moltke, 
Lord  Haldane,  and  every  modern  army,  adapted  to  naval  needs. 
These  can  be  briefly  summarized  as  follows.  The  work  of  a 
staff  follows  three  lines  of  practical  cleavage:  (a)  operations 
(or  direction),  (6)  administration,  and  (c)  technical.  Operations 
(or  direction)  enshrines  the  main  purpose  of  a  business;  admin- 
istration is  responsible  for  its  maintenance  and  equipment  in  an 
efficient  state;  technical  control  deals  with  the  scientific  aspect 
of  applied  sciences  associated  with  the  business.  Finance  and 
the  Secretariat  interpenetrate  the  whole.  Operations  (or 
direction)  is  the  premier  function,  and  splits  into  two  main 
divisions,  operations  (minor)  and  intelligence.  It  is  the  special 
task  of  operations  to  appreciate  the  situation  continuously,  to 
assist  the  Command  in  the  consideration  of  requirements  and 
with  the  preparation  and  conduct  of  operations,  and  to  convert 
the  intentions,  policy  and  decisions  of  the  Command  into  orders 
and  instructions.  It  is  its  business  to  visualize  the  situation 
continuously  on  an  operations  chart  and  to  furnish  all  branches 
and  technical  services  with  timely  information  of  all  require- 
ments. The  function  of  intelligence  is  to  collect,  sift  and  dis- 
tribute information  of  the  enemy,  and  by  the  cumulative  in- 
telligence arising  out  of  its  work  to  help  operations  to  appreciate 

the  situation.  Administration  and  technical  comprise  all  the 
great  services  of  supply  and  technical  work,  including  personnel, 
pay,  victualling,  stores,  transport,  and  the  crafts  of  hydrography 
and  surveying,  navigation,  marine  engineering,  naval  con- 
struction, gunnery,  torpedoes,  mine-laying,  mine-sweeping  and 
signals.  Each  service  is  responsible  for  its  internal  efficiency, 
and  the  Chief  of  the  Staff  is  responsible  for  the  coordination  of 
all,  while  to  assist  him  in  this  a  training  and  staff  division  is 
required  which  acts  as  the  trustee  of  staff  principle  and  organiza- 
tion and  is  also  responsible  for  staff  training,  principles  of 
training,  staff  history  and  manuals  of  war.  No  one  of  the  three 
great  branches  is  more  important  than  another.  Like  the  brain, 
heart  and  lungs,  all  are  complementary  to  each  other.  If  there 
are  no  ships  there  can  be  no  operations;  if  the  operations  are 
badly  conducted,  the  best  ships  will  be  useless;  a  new  technical 
invention  may  revolutionize  operations,  and  the  whole  service 
must  rest  on  a  basis  of  good  discipline  and  sound  financial 

The  first  step  towards  these  principles  was  really  taken  in 
May  1917,  when  the  term  "  War  Staff  "  was  altered  to  "  Naval 
Staff  "  and  the  office  of  Chief  of  the  Naval  Staff  was  merged 
in  the  First  Sea  Lord  (Admiral  Jellicoe),  while  a  Deputy  Chief 
of  the  Naval  Staff  (Vice-Admiral  Oliver)  and  an  Assistant  Chief 
(Rear-Admiral  Duff)  were  appointed  with  seats  on  the  Board. 
This  gave  the  naval  staff  direct  representation  on  the  Board, 
and  the  presence  of  three  members  ensured  the  necessary 
authority  to  carry  through  any  operation  of  war.  The  D.C.N.S. 
directed  all  operations  and  movements  of  the  fleet,  while  the 
A.C.N.S.  was  responsible  for  mercantile  movements  and 
anti-submarine  operations. 

The  office  of  Controller  was  revived,  and  Sir  Eric  Geddes 
appointed  to  fill  it,  with  the  rank  of  Honorary  Vice'Admiral, 
all  questions  of  supply  being  thus  practically  merged  in  his 
hands;  but  he  had  barely  filled  the  office  two  months  when  he 
took  Sir  Edward  Carson's  place  as  First  Lord  July  20  1917. 
On  Sept.  6  1917  a  Deputy  First  Sea  Lord,  Sir  Rosslyn  Wemyss, 
was  added  to  the  Board  to  control  operations  abroad  and 
questions  of  foreign  policy.  Sir  Oswyn  Murray  too  had  suc- 
ceeded Sir  Graham  Greene  as  Permanent  Secretary  in  Aug.  1917. 

In  Oct.  1917  the  development  of  the  staff  was  carried  one 
step  further  by  the  formation  on  Oct.  19  of  two  Committees  of 
the  Board — the  Operations  Committee  and  the  Maintenance 
Committee.  The  First  Lord  was  chairman  of  both,  and  the 
former  consisted  of  the  First  Sea  Lord  and  C.N.S.,  the  Deputy 
ist  S.L.,  D.C.N.S.,  A.C.N.S.,  and  sth  Sea  Lord.  The  latter 
consisted  of  the  Deputy  ist  S.L.  (representing  the  operations 
committee),  2nd  S.L.  (personnel),  3rd  S.L.  (material),  4th  S.L. 
(transport  and  stores),  Civil  Lord,  Controller  and  Financial 

The  direction  of  operations  was  finally  handed  over  to  the 
C.N.S.  by  an  order  in  Council  of  Oct.  1917,  under  which  he 
became  responsible  for  the  issue  of  orders  affecting  war  opera- 
tions to  the  fleet.  It  empowered  such  orders  to  be  issued  in 
his  own  name  as  C.N.S.,  and  not  as  previously  by  the  secretary 
in  the  name  of  the  Board. 

These  measures  were  accompanied  by  the  institution  of 
further  divisions  of  the  staff,  including  a  plans  division,  and  by 
Oct.  1917  the  Board  and  naval  staff  had  assumed  the  following 
form: — 

Board  of  Admiralty 
ist  L. 

Pi!  I 

istS.L.     D.C.N.S.      A.C.N.S.        sth  S.L.       Deputy  istS.L. 

Operations  Committee 

(Deputy  ist  S.L.)        2nd  S.L.         3rd  S.L.         4th  S.L.        Civil  L. 

Parl.  and  Finance  Secretary 

Maintenance  Committee 

Permanent  Secretary 


Naval  Staff 
C.N.S.  and  1st  S.L.  (Adml.  Jellicoe) 



(Acting  V.A.  Oliver) 

A.C.N.S.   (R.A.  Duff) 



(R.A.  Hope) 

Aug.  18  1917 
(Comm.  R.  L. 


Oct.  8  1917 
(R.A.  Roger  Keyes) 

Dec.  16  1916  (Capt. 
W.  W.  Fisher) 

Trade  (Capt. 
Alan  G.  Hothan) 

May  23  1917  (Capt. 
Lionel  Preston) 

.  Mercantile  Movements 
Oct.  I  1917  (Capt. 
Fred  Whitehead) 

(R.A.  Wm.  Hall) 

One  of  the  most  important  divisions  of  the  naval  staff  was 
the  mercantile  movements  division,  which  had  been  started  as 
a  convoy  section,  under  the  management  of  Paymaster  Capt. 
H.  W.  Manisty.  It  was  here  in  May  1917  that  an  operations 
chart  came  into  use  for  the  direction  of  convoys,  on  which  the 
movements  of  submarines  derived  from  wireless  directionals  and 
other  reports  were  plotted,  day  and  night.  Operations  divisions, 
troubled  like  Martha  over  many  things,  had  never  been  able  to 
deal  in  big  plans,  and  this  work  was  undertaken  by  the  plans 
division  which  drew  up  plans  for  the  mining  of  the  Bight,  the 
Great  Northern  Barrage  (in  conjunction  with  the  U.S.  navy), 
the  Dover  Barrage,  the  Otranto  Barrage  and  numerous  smaller 

The  ease  with  which  the  distinction  between  operations  and 
administration  can  be  applied  is  illustrated  in  the  submarine 
and  auxiliary  patrol  services.  In  both  these  services  the  ad- 
ministrative work  (such  as  regulations,  conditions  of  entry, 
stores,  personnel)  was  dealt  with  by  a  centre  which  had  very 
little  or  nothing  whatever  to  do  with  operations  (Commodore 
(S)  in  the  one  case  and  the  Auxiliary  Patrol  Office  in  the  other), 
and  the  system  worked  very  successfully  from  first  to  last. 
The  reorganization  of  staff  work  was  not  limited  to  the  Ad- 
miralty. It  extended  to  every  command,  and  in  April  1918 
the  First  Lord  and  Rear-Adml.  Sir  W.  R.  Hall  proceeded  to 
Malta  and  made  arrangements  for  the  entire  reorganization  of 
the  C.-in-C.'s  staff,  leading  to  a  great  reduction  in  shipping 
losses  in  the  Mediterranean. 

With  the  advent  of  peace  the  naval  staff  was  greatly  reduced, 
and  some  divisions  naturally  disappeared.  A  change  of  some 
importance  has  taken  place  in  the  function  of  the  A.C.N.S., 
who  has  become  responsible  for  all  staff  questions  relating 
to  technical  branches  and  crafts  such  as  gunnery,  torpedoes 
and  mining.  Gunnery  and  torpedo  divisions  have  been  introduced 
into  the  staff  to  deal  with  questions  of  the  tactical  use  of  these 
weapons  and  the  training  of  personnel.  The  plea  for  this  lies 
in  the  close  connexion  between  the  use  of  the  weapon  and 
operations.  There  can  be  no  doubt  that  training  and  the 
tactical  aspects  of  weapons  constitute  a  sphere  common  to  the 
naval  staff,  the  great  technical  departments  and  the  fleet, 
but  though  they  certainly  require  to  be  in  close  touch  with 
the  naval  staff  it  still  remains  a  moot  point  whether  all  technical 
crafts  with  the  training  that  belongs  to  them  should  not  be 
segregated  from  the  naval  staff. 

The  distribution  of  the  naval  staff  in  1921  was  as  follows: — 

nal  organization  and  general  direction  of  the  work  of  the  naval  staff 
and  cooperation  of  the  naval  staff  with  the  material  side  of  the 

D.C.N.S. — Operations  and  movements,  naval  intelligence, 
strategy,  policy  and  plans.  Sea-borne  trade  and  international  law. 

A.C.N.S. — Methods  of  fighting  at  sea.  Design  in  relation  to 
policy  and  tactics.  Staff  questions  of  research.  Air  development  in 
relation  to  naval  warfare. 

Little  has  been  said  here  of  the  civil  side  of  the  Admiralty 
because  it  runs  through  and  interpenetrates  every  branch. 
The  more  essentially  civilian  branches,  such  as  naval  stores  and 
victualling,  were  among  the  most  efficient  of  the  war.  There 
is  sometimes  a  tendency  to  talk  of  the  Admiralty  as  a  place 
where,  through  civilian  agency,  the  best  naval  plans  "  gang 
aft  agley."  This  is  a  complete  fallacy.  Admirals  have  played 
a  great  part  in  the  Admiralty  and  in  its  history,  past  and  present, 
and  cannot  dissociate  themselves  from  its  work.  If  the  Ad- 
miralty in  the  war  made  mistakes,  the  navy  and  its  admirals 
must  share  the  blame,  and  in  the  final  victory  a  portion  of  the 
laurels  belong  to  the  Admiralty  and  the  civil  servants  of  the 

The  strength  pf  the  naval  staff  divisions  and  departments  in 
the  British  Admiralty  is  shown,  as  for  the  crucial  dates  under 
the  war  reorganization,  in  the  table  on  p.  10.  (A.  C.  D). 

UNITED  STATES. — After  1909  various  measures  providing 
for  a  reorganization  of  the  U.S.  Navy  Department  were  brought 
forward,  but  for  several  years  Congress  failed  to  take  any 
action,  though  certain  proposals,  notably  the  recommendations 
of  the  board  appointed  by  President  Taft  in  1909,  were  strongly 
urged.  The  organization  .of  the  Department  as  then  con- 
stituted had  been  the  subject  of  criticism  by  a  number  of 
secretaries  of  the  navy  as  well  as  by  others;  the  chief  defect 
was  the  lack  of  some  agency  to  perform  the  functions  of  a  general 
staff  in  the  conduct  of  naval  operations.  It  is  true  that  since 
1900  the  secretary  had  had  the  deliberations  and  reports  of  the 
general  board  to  guide  him,  but  this  board  had  no  executive 
powers,  and  in  the  last  analysis  the  responsibility  for  coordinat- 
ing the  activities  of  some  eight  different  bureaus  rested  solely 
on  the  secretary  of  the  navy.  In  default  of  legislation,  Secretary 
Meyer  made  an  effort  in  1913  to  remedy  this  condition  by  the 
issuance  of  regulations  providing  for  the  appointment  of  an 
aid  for  operations,  an  aid  for  personnel,  an  aid  for  material, 
and  an  aid  for  inspections,  who  were  to  be  officers  of  the  navy 
on  the  active  list  not  below  the  grade  of  captain  and  who  were 
to  constitute  an  advisory  council  charged  with  the  duty  of 

1st  S.L.  and  C.N.S. 









The  duties  of  the  C.N.S.  and  principal  officers  are  as  follow: — 

C.N.S. — All  large  questions  of  naval  policy  and  maritime  war- 
fare organizations,  distribution,  and  fighting  sea-going  efficiency  of 
the  fleet.  Advice  as  to  general  direction  of  operations  of  war.  Inter- 


Secretariat  and  Staff  Registries. 


•Air  Sec- 



promoting  effective  cooperation  in  the  work  of  the  Depart- 
ment. Under  Secretary  Daniels,  who  succeeded  Secretary  Meyer 
in  1913,  the  offices  of  aid  for  personnel  and  aid  for  inspections 
were  discontinued,  but  there  was  created  the  office  of  aid  for 




(An  asterisk  denotes  divisions  and  departments  in  existence 
April  1921.) 

Naval  Staff:  — 


Nov.  1918 

"Operations  .        .        .        . 



"Intelligence          .        .        .     "   . 
Mobilization        .... 



140  (45  unpaid) 
to  maintenance 




Anti-submarine  )  merged  in 


Mine-sweeping  f  rjifence 


"Signals  (now  Signal  Dept.) 




Mercantile  Movements  (lapsed) 


"Training  and  Staff  Duties 


"Local  Defence  Div'n  (post  war) 


"Gunnery  Division 


"Torpedo  Division  (post  war) 


Total       .... 



Secretarial:  — 



80  (2  unpaid) 

Chief  Censor          .... 




"Statistics        .... 


Total       .        .'       . 



Personnel:  — 

"Mobilization        .... 

\aval  Staff 




"Royal  Marine  Office   . 



"Paymaster  Director  General 
"Admiral  of  Training  (post  war) 


Physical  Training  and  Sports    . 

"Naval  Education 



"Chaplain  of  the  Fleet 

2     , 


"Medical  Director  General 

10        . 


Total       .... 



Technical:  — 

"Hydrographer     .... 



"Navigation  ..... 



"Naval  Construction    . 



"Naval  Engineer-in-Chief   . 



"Electrical  Engineering 


"Naval  Ordnance 

53  (and 



"Torpedoes  and  Mining 


"Naval  Equipment 



"Compass  Department 
"Dockyards  and  Shipbuilding     . 
(Director  of  Dockyards) 



Warship  Production  . 


Auxiliary  Vessels 


"Armament  Production 

(now  Armament  Supply) 


Airship  Production     . 


Finance  Division 


Costings  Division        .        .        . 


General  Merchant  Shipbuilding 


Admiralty  Labour  Dept.    . 
Materials  and  Priority 

1  06 

"Research  and  Experiment 


"Works  . 



Total       .... 



Supply:  — 






3°  , 



116  (4  unpaid) 

Total       .... 



Finance:  — 

"Accountant  General   . 


297  (i  unpaid) 

"Contract  and  Purchase 



"Greenwich  Hospital    . 



Total      .... 



Summary:  — 

Naval  Staff  






Personnel  *| 



Technical  >  Maintenance 



Supply      j 






Grand  Total  . 



education,  whose  duties  were  concerned  with  the  Secretary's 
programme  for  furnishing  free  instruction  to  enlisted  men. 

The  outbreak  of  the  World  War  gave  new  force  to  the  pro- 
posals for  reorganizing  the  naval  administration,  and  by  the 
Act  of  March  3  1915  Congress  created  the  office  of  chief  of  naval 
operations,  the  incumbent  of  which  by  the  subsequent  Act 
of  Aug.  29  1916,  was  promoted  to  the  rank  of  admiral  and 
assigned  15  officers  above  the  rank  of  lieutenant-commander  of 
the  navy  or  major  of  the  marine  corps  as  assistants.  The  chief 
of  naval  operations  was  "  charged  with  the  operations  of  the 
fleet  and  with  preparation  and  readiness  of  plans  for  its  use 
in  war."  By  regulation  his  duties  were  defined  as  including 
the  direction  of  all  strategic  and  tactical  matters,  organization, 
manoeuvres,  target  practice,  drills  and  exercises  and  the  training 
of  the  fleet  for  war.  Under  his  direction  were  also  placed  the 
Naval  War  College  at  Newport,  the  office  of  naval  intelligence, 
the  office  of  gunnery  exercises  and  engineering  performances, 
the  operation  of  the  radio  service  and  other  systems  of  com- 
munication, the  aeronautics  service,  the  division  of  mines  and 
mining,  the  naval  defence  districts  and  the  coastguard  when 
operating  with  the  navy.  The  duties  of  the  previously  existing 
bureaus  were  limited  to  activities  subordinate  to  military 
operations.  By  the  Act  of  June  30  1914,  these  bureaus  had  been 
reduced  to  seven,  the  bureau  of  equipment  having  been  abolished 
and  its  duties  distributed  among  the  other  bureaus.  The  value 
of  the  new  method  of  organization  became  almost  immediately 
apparent;  within  10  months  after  the  passage  of  the  first  Act 
(1915)  plans  for  the  mobilization  of  the  U.S.  naval  force  were 
approved  and  ready  to  put  into  effect.  Thus,  when  the  United 
States  entered  the  World  War  the  Navy  Department  was, 
from  the  administrative  standpoint,  well  prepared  to  undertake 
its  new  duties  and  responsibilities.  In  his  report  for  1918  Secre- 
tary Daniels  stated  that  the  war  had  necessitated  no  change  in 
the  organization  of  the  Department,  which  had  easily  expanded 
to  meet  the  emergency.  During  the  war  the  Navy  Department 
had  the  assistance  of  the  War  Industries  Board,  the  Council 
of  National  Defense,  the  National  Research  Council,  the 
Aircraft  Production  Board  and  the  Naval  Consulting  Board. 

The  Naval  Consulting  Board,  composed  of  civilian  inventors 
and  engineers,  •  was  first  established  in  1915  with  Thomas  A. 
Edison  as  chairman.  It  was  a  voluntary  body  whose  function 
was  to  give  expert  advice  when  called  upon.  Secretary  Daniels 
also  established  an  advisory  council  composed  of  the  Assistant 
Secretary  of  the  Navy,  the  chief  of  naval  operations,  the  chiefs 
of  bureaus,  the  major-general  commandant  of  the  marine  corps 
and  the  judge-advocate  general  of  the  Navy  Department. 

Secretary  Daniels'  interest  in  education  for  enlisted  men  has  al- 
ready been  noted.  An  order  issued  by  the  Navy  Department  in 
Dec;  1913  provided  for  instruction  of  enlisted  men,  petty  officers  and 
warrant  officers  serving  on  board  ship,  the  purpose  being  partly  to 
supply  deficiencies  in  school  training  and  partly  to  fit  them  for  pro- 
motion. Training  was  also  instituted  at  the  various  naval  stations, 
and  schools  for  assistant  paymasters,  yeomen,  cooks,  bakers,  com- 
missary stewards,  hospital  apprentices,  machinists'  mates,  musicians, 
mess  attendants,  painters,  plumbers,  electricians,  blacksmiths,  and 
carpenters  were  maintained.  Thus  enlisted  men  could  prepare 
themselves  to  engage  in  civil  trades  at  the  end  of  their  period  of  navy 
service.  With  the  outbreak  of  the  war  much  of  this  educational 
work  was  temporarily  suspended.  By  the  Act  of  Dec.  20  1917  the 
number  of  midshipmen  at  the  U.S.  Naval  Academy  was  fixed  as 
follows — five  for  each  senator,  representative  and  delegate  in 
Congress,  one  for  Porto  Rico,  two  for  the  District  of  Columbia,  15 
appointed  each  year  at  large,  and  100  appointed  annually  from 
enlisted  men  of  the  navy.  As  a  war  measure  the  President  was 
authorized  in  1918  to  reduce  the  course  of  instruction  at  the  Academy 
from  four  to  three  years;  in  1919,  however,  the  fulj  four-year  course 
was  resumed.  During  the  participation  of  the  United  States  in  the 
World  War  three  training  camps  for  officers  of  the  marine  corps  were 
held.  In  accordance  with  the  Naval  Militia  Act  of  1914  various 
states  organized  divisions  known  as  the  U.S.  Naval  Volunteers,  to 
which  were  assigned  naval  officers  as  instructor-inspectors  of  the 
militia.  A  later  Act  (Aug.  29  1916)  created  the  U.S.  Naval  Reserve 
force,  with  which,  in  1918,  the  naval  militia  was  amalgamated.  The 
Act  of  1916  also  provided  for  a  Naval  Flying  Corps,  for  special 
engineering  officers,  for  Naval  Dental  and  Dental  Reserve  Corps, 
and  for  taking  over  the  lighthouse  service  in  time  of  war. 

The  Naval  Appropriations  Act  of  1915  repealed  section  9  of  the 
Personnel  Act  of  March  3  1899,  which  authorized  the  retiring  of 


1 1 

officers  in  certain  circumstances  for  the  purpose  of  accelerating  pro- 
motion. As  a  result  there  were  no  means  of  promotion  in  the  com- 
missioned personnel  of  the  navy  except  through  vacancies  created 
by  death  or  statutory  age-limit  retirements.  In  1917,  however,  a 
new  law  changed  promotion  by  seniority,  so  that  line  officers  above  the 
rank  of  lieutenant-commander  were  promoted  by  selection,  the  ques- 
tion of  proved  ability  being  the  controlling  consideration.  Much 
comment  was  aroused  in  1919  when  a  new  fleet  organization  was  put 
into  effect,  by  which  two  divisions  of  practically  equal  strength, 
the  Atlantic  fleet  and  the  Pacific  fleet,  each  having- a  commander- 
in-chief  of  the  rank  of  admiral,  were  created.  Some  critics  regarded 
this  as  a  violation  of  the  principle  enunciated  by  Admiral  Mahan 
that  the  fleet  should  never  be  divided.  Secretary  Daniels  stated  that 
with  the  Panama  Canal  open  the  two  fleets  could  effect  a  junction  in 
either  ocean  and  "  carry  out  the  plans  already  formulated  for  opera- 
ting as  one  fleet  before  any  enemy  could  try  conclusions  with  us." 

ADOR,  GUSTAVE  (1845-  )>  Swiss  statesman,  a  member  of 
a  family  of  Vaud,  which  in  1814  obtained  the  burghership  of 
Geneva,  and  grandson  of  Jean  Pierre  Ador,  who  first  obtained 
this  right,  was  born  at  Geneva  Dec.  23  1845.  He  studied 
law  at  the  academy  (now  the  university)  of  Geneva  and  in 
1868  became  an  advocate.  In  1871  he  started  his  political  career 
as  member  of  the  communal  council  of  Cologny,  and  was 
twice  mayor,  in  1878-9  and  1883-5.  He  was  a  member  of 
the  cantonal  Parliament  1874-6,  and  continuously  from  1878 
to  1915  save  for  a  short  break  in  1902.  In  1878-9  he  represented 
Geneva  in  the  Swiss  Conseil  des  Etats.  Then  he  became  a 
member  of  the  executive  of  the  canton  of  Geneva,  being  put  in 
charge  of  the  Department  of  Justice  and  Police.  He  resigned 
after  an  unfavourable  election  in  1880,  but  once  more  became 
member  of  the  cantonal  executive  in  1885,  and  for  12  years  had 
charge  of  the  cantonal  finances.  In  1889  he  became  a  member  of 
the  Swiss  Conseil  National,  and  remained  so  till  1917,  being 
elected  its  president  in  1901.  He  was  president  of  the  cantonal 
executive  in  1890,  1892,  and  1896.  In  1894  he  became  lieutenant- 
colonel  in  the  Swiss  army.  In  1914  he  founded  in  Geneva  the 
association  for  facilitating  communications  between  prisoners-of- 
war  and  the  central  Geneva  agency,  and  succeeded  in  giving  this 
enterprise  great  importance  and  a  wide-spread  extension.  After 
the  enforced  resignation  of  Arthur  Hoffmann,  Ador,  in  order  to 
soothe  the  Entente,  became  a  federal  councillor  or  member  of  the 
Federal  Executive  in  June  1917  and  was  entrusted  with  the 
Department  of  Foreign  Affairs.  Towards  the  end  of  1918  he  was 
elected  by  Parliament  to  be  the  Swiss  President  for  1919,  but 
retired  from  the  Federal  Executive  at  the  end  of  his  year  of  office. 

ADVERTISEMENT  (see  1.235). — The  great  public  service 
rendered  by  advertising  during  the  World  War  was  one  of  the 
most  striking  features  of  the  progress  made  in  this  form  of 
business  during  the  decade  1910-20. 

Before  1915  no  Government  in  modern  times  had  attempted 
to  raise  subscriptions  to  a  loan  through  the  persuasive  methods 
of  commercial  advertising  on  a  large  scale.  The  custom  was 
merely  to  publish  the  prospectus,  and  leave  it  to  the  investor  to 
form  his  judgment  of  its  merits.  It  was  not  till  the  floating  of  the 
45%  War  Loan  in  1915  that  the  British  Government  took  any 
definite  steps  to  depart  from  precedent.  At  an  early  stage  in  its 
subscription,  when  it  was  feared  that  the  result  would  not  be  as 
good  as  had  been  hoped  for,  a  Treasury  official  asked  the  advice 
of  a  well-known  London  journalist,  and  at  his  suggestion  it  was 
decided  to  spend  £100,000  in  advertising  under  his  direction. 
A  little  more  than  £60,000  was  actually  spent  in  advertising, 
and  the  subscriptions  to  the  loan  eventually  realized  nearly 
£600,000,000.  Later,  this  new  departure  was  followed,  but  only 
after  stereotyped  official  methods  had  again  proved  inadequate, 
in  the  campaigns  for  National  War  Bonds  after  Dec.  1916, 
by  a  considerable  extension  of  advertising,  while  in  the  United 
States  it  was  freely  employed  in  the  raising  of  the  Liberty  Loans 

Before  this,  advertising  by  poster  had  been  employed  ef- 
fectively in  England  to  gain  enlistments  for  the  army.  In  this 
connexion,  and  in  the  loan  advertising  of  1915  and  following 
years,  both  in  Great  Britain  and  America,  advertising  reached  an 
effectiveness  and  power  that  had  never  been  imagined.  It  is 
true  that  the  subject  dealt  with  was  in  everyone's  mind;  the 
appeal  was  to  patriotism,  to  emotion  as  well  as  to  cold  reason 

and  self-interest.  The  interests  of  the  writer  and  of  the  reader 
of  the  advertisements  were  identical.  Even  so,  the  results  were 
amazing.  In  1917  a  leading  American  banker  said  it  was  im- 
possible to  float  a  loan  of  $3,000,000,000  because  there  were 
"  only  275,000  investors  in  the  country."  But  after  widespread 
advertising  there  were  more  than  6,000,000  individual  sub- 
scribers to  this  loan,  and  the  amount  was  greatly  over-subscribed. 
For  the  last  of  the  American  war  loans,  the  "  Victory  Loan  " 
floated  after  the  Armistice,  nearly  21,000,000  subscribers  were 
obtained — one  for  every  five  of  the  country's  population,  in- 
cluding women  and  children. 

War  advertising  enlisted  much  new  talent  in  writing  and 
illustrating.  The  foremost  artists  and  writers  on  both  sides  of 
the  Atlantic  volunteered  their  services  and  competed  for  the 
honour  of  having  their  productions  used.  With  professional 
advertising  men,  printers,  engravers  and  lithographers  all  giving 
their  best,  the  result  was  an  excellence  in  form  and  character 
that  had  never  been  achieved  before.  While  the  tide  of  patriotic 
emotion  raised  by  the  war  brought  new  resources  to  advertising, 
their  proper  application  would  not  have  been  possible  without 
the  knowledge  gained  in  advertising  for  ordinary  business 
purposes  during  previous  years  (see  PROPAGANDA). 

In  the  years  before  1915  remarkable  advances  had  been  made. 
The  number  of  articles  of  trade-marked,  advertised  merchandise 
had  increased  rapidly.  Stimulated  by  advertising  revenue,  scores 
of  weekly  and  monthly  publications  had  obtained  circulation 
running  into  hundreds  of  thousands,  and  some  had  passed 
the  million  mark.  Great  daily  newspapers  had  a  similar  growth 
and  could  afford  to  sell  their  copies  at  a  price  which  did  not  pay 
for  the  paper  on  which  they  were  printed.  Posters  and  advertising 
signs  had  passed  from  their  former  rude  state  to  a  high  degree 
of  attractiveness. 

At  the  same  time  came  a  remarkable  improvement  in  the 
character  of  advertising.  Misleading  advertisements  and 
advertising  of  questionable  merchandise  or  of  uncertain  financial 
offers  were  gradually  weeded  out.  Publications  found  it 
unprofitable  to  accept  advertising  that  was  offensive  to  their 
better  clients.  The  Association  of  Advertising  Clubs  of  the 
World  adopted  "  Truth  in  Advertising  "  as  their  slogan,  and 
vigilance  committees  were  appointed  to  eradicate  misleading  or 
untruthful  advertising  of  whatever  products.  Advertising  had 
become  a  business  of  high  principles  and  well-defined  ethics. 
One  of  the  most  powerful  influences  in  the  development  of 
advertising  along  sound  business  and  ethical  lines  was  the  ad- 
vertising agency.  Beginning  more  than  half  a  century  before  as 
an  agency  for  the  selling  of  space  in  publications,  the  modern 
advertising  agency  grew  into  a  service  institution,  acting  on 
behalf  of  its  clients  in  planning  advertising  campaigns,  selecting 
the  mediums  to  be  used,  preparing  advertisements,  attending 
to  all  the  details  of  engraving,  type-setting  and  plate-making 
and  performing  many  other  incidental  services.  The  advertising 
agency  attracted  well-educated  young  men  in  increasing  num- 
bers and  represented  a  recognized  field  for  the  employment  of 

All  advertising  is  more  or  less  a  competition  for  public  atten- 
tion. As  the  volume  of  advertising  increased  the  competition 
became  more  keen,  and  resulted  in  improvement  of  both  the 
writing  and  artistic  treatment  of  advertisements.  One  of  the 
most  notable  features  in  recent  years  has  been  the  use  of  illustra- 
tions in  colour,  made  possible  by  improved  processes  of  colour- 
engraving  and  by  the  perfection  of  high-speed  colour  printing 
presses.  One  popular  magazine  in  America,  with  a  circulation 
approaching  two  million;  has  contained  more  than  50  full-page 
advertisements  in  colour  in  a  single  issue.  Every  one  of  these 
pages  was  printed  by  four-colour  process,  and  gave  a  faithful 
reproduction  of  the  subject.  This  has  made  it  possible  to  display 
all  sorts  of  merchandise,  including  foods,  in  their  natural  tempting 
colours,  and  textiles  with  all  their  shades  and  patterns,  as  well  as 
to  reproduce  beautiful  paintings  for  their  attractive  value.  Per- 
haps as  a  result  of  this  achievement  in  colour  printing,  there 
has  been  a  remarkable  improvement  in  the  artistic  worth  of 
advertising  illustrations.  Celebrated  painters  and  illustrators  no 



longer  find  it  beneath  their  dignity  to  make  pictures  for  ad- 
vertising purposes,  especially  as  the  bids  for  their  services  run 
to  large  figures.  Similar  improvement  has  been  achieved  in 
typography,  engraving  and  lithography,  and  in  all  the  mechanical 
processes  of  reproduction. 

As  the  volume  of  advertising  expenditure  has  grown,  so  has 
the  number  of  publications  which  derive  their  chief  support  from 
advertising.  These  publications  have  been  divided  more  and 
more  in  recent  years  into  groups  or  classes,  each  with  an  appeal 
to  a  certain  class  of  the  population.  The  number  of  general 
publications  reaching  all  classes  has  been  correspondingly 
reduced.  The  most  prominent  class  publications  are  the  women's 
magazines,  chiefly  of  monthly  issue,  of  which  in  1921  there  were 
four  or  five  in  America  with  more  than  a  million  circulation. 
These  magazines  deal  with  home  problems,  dressmaking,  cook- 
ing, care  of  children  and  kindred  subjects,  and  are  the  most 
valuable  mediums  for  the  advertising  of  foods,  textiles  and  all 
household  commodities.  There  are  similar  class  publications 
devoted  to  business  interests,  the  world  of  books,  motion 
pictures,  the  theatre,  fashionable  society,  sports  of  one  kind  and 
another  and  all  classes  of  commercial  and  industrial  enterprises. 
The  significance  of  this  tendency  is  that  advertising  of  each  kind 
may  be  placed  before  the  readers  it  especially  interests,  with  a 
selected  audience  and  less  waste  of  circulation. 

Each  succeeding  year  has  seen  some  enlargement  of  the 
possibilities  of  advertising.  Paid  space  has  been  used  in  increas- 
ingly large  amounts  in  political  campaigns,  local  and  national, 
presenting  the  records  of  candidates  and  showing  photographs 
of  themselves  and  their  families.  It  is  used  more  and  more  to 
influence  public  opinion  on  behalf  of  one  cause  or  another. 
Industrial  disputes,  involving  strikes  or  lock-outs,  have  led 
employers  and  employees  alike  to  appeal  through  advertisements 
to  the  public  for  sympathy  and  moral  support.  Public  service 
institutions  have  used  advertising  to  put  themselves  in  a  better 
light  before  the  public  or  to  explain  the  necessity  for  increased 
revenue.  In  one  notable  case,  advertising  was  used  to  turn 
business  away.  The  American  Telephone  &  Telegraph  Co.  was 
seriously  affected  by  the  entry  of  the  United  States  into  the 
World  War.  It  could  not  obtain  the  supplies  it  needed;  the 
Government  took  thousands  of  its  highly  trained  workers;  and 
at  the  same  time  demands  on  its  service  increased  enormously. 
The  Company  was  wise  enough  to  advertise,  explaining  why  its 
service  was  deficient,  why  applicants  were  kept  waiting  for 
installations,  and  also  imploring  the  public  neither  to  conduct 
unnecessary  conversations  over  the  wires  nor  to  prolong  use 
beyond  the  time  required.  Similar  advertising  was  employed  by 
the  American  railways  in  the  period  immediately  following  their 
return  from  Government  control  to  private  management,  but 
in  this  case  the  explanation  of  inadequate  service  was  followed 
by  an  appeal  for  higher  passenger  and  freight  rates  to  provide 
revenue  for  rehabilitation.  During  the  same  period^  the  Chicago 
meat-packers,  facing  threatened  Federal  action  for  the  further 
regulation  of  their  activities,  entered  upon  an  elaborate  advertis- 
ing campaign  to  convince  the  public  of  their  blamelessness. 

All  these  varied  developments  of  advertising  have  been  of  the 
utmost  interest  to  students  of  economic  trends.  It  is  certain  that 
advertising  has  been  largely  instrumental  in  changing  buying 
habits  and  in  introducing  many  things  which  have  quickly 
become  a  part  of  everyday  life.  The  chief  function  of  advertising 
is  the  saving  of  time.  Information,  whether  as  to  merchandise 
or  controversial  or  public  issues,  can  be  placed  before  great 
numbers  of  the  population  almost  over  night.  Public  education 
on  any  subject  can  be  effected  in  days  or  weeks,  where  years 
were  required  by  old-fashioned  methods  of  canvassing.  For 
this  reason  it  has  been  possible  to  build  up  entire  new  industries 
on  advertised  products  within  a  short  period.  In  political  life, 
and  in  financial  operations,  advertising  has  served  to  eliminate 
the  secrecy  and  ignorance  which  invite  deceit  and  fraud.  The 
whole  tendency  is  to  take  the  public  into  confidence  and  play  the 
game  in  the  full  light  of  fair  and  frank  publicity.  Advertising  is 
no  weapon  for  dark  causes  and  no  advocate  for  unworthy  goods. 
To  be  effective  it  must  be  a  sincere  expression  of  the  character 

of  the  advertiser.  Unless  it  bears  the  stamp  of  truth  and  sincerity 
it  is  ineffective  and  defeats  its  own  purpose. 

This  individuality  of  a  business  house  as  well  as  the  conditions 
under  which  it  operates  and  the  field  from  which  it  may  seek 
custom  must  all  be  considered  carefully  before  embarking  on  an 
advertising  campaign..  It  is  well  to  seek  the  expert  assistance  of 
an  advertising  agency  of  established  reputation.  The  implements 
of  advertising  are  many,  including  newspapers,  weeklies, 
magazines,  trade  publications,  outdoor  displays,  cards  in 
railway  cars  and  the  sending  of  circulars  and  booklets  to  persons 
whose  names  have  been  selected  on  some  sound  principle. 
Each  is  more  efficient  for  one  purpose  than  another,  and  knowl- 
edge and  judgment  are  needed  to  plan  a  campaign  that  will 
achieve  results  at  economical  cost.  The  advertising  policy  of  a 
business  house  and  the  selection  of  an  advertising  agency  and 
advertising  manager  should  be  a  concern  for  the  executive 
heads  who  direct  the  permanent  interests  of  the  business.  For 
advertising,  once  entered  upon,  is  a  continuing  influence.  The 
advertising  for  any  one  week  or  any  one  month,  unlike  that 
week's  or  month's  buying  or  selling,  cannot  be  regarded  as  a 
completed  transaction.  Advertising,  it  already  has  been  said,  is 
an  expression  of  character.  It  reveals  the  character  of  the 
advertiser,  and  immediately  begins  to  form  a  consciousness  of 
the  particular  house  or  merchandise  advertised  in  the  mind  of 
the  public.  It  has  an  influence  also  on  the  advertiser's  own 
organization.  The  workman  in  the  factory  and  the  salesman  in 
the  shop  judge  from  the  advertising  their  employer's  sincerity 
and  desire  to  serve.  If  the  advertising  is  such  that  they  can  take 
pride  in  it;  if  it  is  attractive  in  appearance;  if  it  is  placed  in  the 
right  environment;  if  it  is  a  worthy  representation  of  the  purposes 
and  ideals  that  animate  the  business — then  the  advertising  will 
stimulate  every  employee  to  greater  efforts  and  enhance  the 
moral  of  the  organization.  Every  advertisement  tends  to 
create  or  destroy  the  one  great  business  asset,  reputation. 

The  steady  growth  of  advertising  is  assured.  While  there  are 
no  authentic  data  on  the  amount  spent  for  advertising,  it  has  been 
estimated  that  the  expenditure  for  all  forms  of  advertising  in 
America  in  1920  was  upwards  of  $1,200,000,000,  an  increase  of 
approximately  100%  in  five  years.  Individual  industrial  firms  in 
Great  Britain  spend  as  much  as  £200,000  a  year  on  advertising, 
and  the  total  expenditure  there  on  all  forms  of  publicity  is  esti- 
mated at  over  a  hundred  million  sterling  annually.  With  the 
growth  in  public  intelligence  and  the  realization  of  the  power  of 
advertising,  it  is  likely  to  be  still  more  widely  employed  in 
the  future.  The  modern  business  concern  is  adopting  advertising 
as  a  part  of  its  fixed  business  policy;  not  as  an  expedient  for 
occasional  use  but  as  an  element  of  business  to  be  constantly 

Austro-Hungarian  statesman  (see  3.25;  9.951),  was  born  at  Gross- 
Skal,  Bohemia,  the  son  of  Baron  (Freiherr)  Johann  Lexa  von 
Aehrenthal  and  his  wife  Marie,  nee  Countess  Thun-Hohenstein, 
and  began  his  diplomatic  career  in  1877  as  attache  to  the  Paris 
embassy  under  Count  Beust.  He  went  in  1878  in  the  same 
capacity  to  St.  Petersburg,  and  from  1883  to  1888  he  worked  at 
the  Foreign  Office  in  Vienna  under  Kalnoky,  with  whom  he 
formed  close  relations.  In  1888  he  was  sent  as  councillor  of 
embassy  to  St.  Petersburg,  where  he  exercised  considerable 
influence  with  the  ambassador,  Count  Wolkenstein.  Recalled  in 
1894  to  service  in  the  Foreign  Office,  he  undertook  important 
duties,  and  in  the  following  year  went  to  Bucharest  as  ambassa- 
dor. Here  he  succeeded  in  strengthening  the  relations  between 
the  courts  of  Vienna  and  Bucharest,  the  secret  alliance  which 
King  Charles  had  concluded  in  1883  with  the  Central  European 
Powers  being  renewed  on  Sept.  30.  In  1899  he  became  am- 
bassador in  St.  Petersburg,  where  he  remained  until  his 
appointment  as  Foreign  Minister  in  Oct.  1906.  Aehrenthal 
at  this  time  thought  that  Austria-Hungary  must,  even  at  the 
cost  of  some  sacrifice,  come  to  an  agreement  with  Russia.  In  this 
sense  he  endeavoured  to  continue  the  negotiations  successfully 
begun  by  his  predecessor,  Prince  Franz  Liechtenstein  (b.  1853), 
for  the  bridging  over  of  the  differences  on  Balkan  questions 


between  Vienna  and  St.  Petersburg,  in  order  to  create  a  basis  for 
a  permanent  friendly  relation  between  Austria-Hungary  and 
Russia.  He  played  a  principal  part  in  concluding  the  Miirzsteg 
Agreement  of  1903.  During  the  Russo-Japanese  War  he  took  a 
strong  line  in  favour  of  a  benevolent  attitude  on  the  part  of  the 
Vienna  Cabinet  towards  Russia.  When,  in  Oct.  1906,  he 
succeeded  Count  Goluchowski  as  Foreign  Minister  he  at  first 
maintained  the  views  which  he  had  professed  as  ambassador. 
He  was  determined  to  preserve  the  interests  of  Austria-Hungary 
in  the  Balkans,  but  also  showed  himself  prepared  to  meet  the 
Russian  wishes  in  the  Dardanelles  question.  Accordingly  he 
entered  into  negotiation,  after  the  outbreak  of  the  Young  Turk 
revolution  in  the  summer  of  1908,  with  Isvolski,  arranging 
with  him  Sept.  15  at  the  chateau  of  Buchlau,  in  Moravia, 
an  agreement  which  aimed  at  securing  for  Austria-Hungary 
the  annexation  of  Bosnia  and  Herzegovina  and  for  Russia 
the  opening  of  the  Dardanelles  to  Russian  warships. 

It  was  only  when  Isvolski's  proposals  were  wrecked  on  the 
opposition  of  England,  and  the  Russian  minister  protested 
against  the  annexation  of  Bosnia  and  Herzegovina,  which  had 
meanwhile  been  accomplished,  and  supported  the  Serbs  in  their 
opposition  to  Austria-Hungary,  that  Aehrenthal  abandoned  the 
idea  of  a  friendly  accommodation  with  the  Russian  Government. 
In  the  sharp  struggle  during  the  annexation  crisis,  not  only  with 
Russia  and  Serbia,  but  with  the  Western  Powers,  he  held  with 
tenacious  energy  to  his  purpose,  and,  powerfully  supported  by 
Germany,  succeeded  in  carrying  out  his  intentions  after  excited 
negotiations  which  threatened  to  lead  to  war.  The  annexation 
of  Bosnia  and  Herzegovina  was  acknowledged  by  the  Powers;  an 
agreement  was  reached  with  Turkey;  Serbia,  after  long  hesitation, 
was  obliged  to  submit.  For  this  achievement  Aehrenthal 
was  rewarded  by  his  master  by  elevation  to  the  rank  of  Count 
(Aug.  1 8  1909),  while  at  the  courts  of  his  opponents  he  was 
hated  but  respected. 

This  was  the  zenith  of  his  political  career.  Few  at  this  time 
realized  the  danger  which  arose  later  from  the  closer  adhesion  of 
Russia  to  the  Western  Powers,  especially  as  Aehrenthal  took  the 
greatest  pains  to  prove  in  all  quarters,  after  the  conclusion  of  the 
annexation  crisis,  that  Austria-Hungary  cherished  no  far- 
reaching  plans  of  conquest.  In  this  spirit  he  offered  the  most 
decided  opposition  to  those  circles  at  the  court  of  Vienna  which 
advocated  a  bloody  reckoning  with  Serbia.  He  held  fast  by  the 
Triple  Alliance,  for  he  saw  in  this  the  surest  bulwark  of  peace. 
He  sought  to  form  the  most  intimate  relations  with  the  German 
Empire,  but  insisted  on  the  independence  of  the  Habsburg 
Monarchy,  and  energetically  repulsed  all  efforts  on  the  part  of  the 
German  chancellery  to  set  limits  to  that  independence.  One  of 
his  most  difficult  tasks  was  to  adjust  the  ever-recurring  conflicts 
with  Italy,  who,  while  officially  supporting  the  political  action  of 
the  Triple  Alliance,  often  embarked  on  courses  directly  opposed 
to  the  interests  of  Austria-Hungary.  A  succession  of  agreements 
which  he  concluded  with  the  Italian  Foreign  Minister,  Tittoni, 
justified  his  efforts,  and  enabled  him  to  maintain  correct  relations 
with  the  Italian  Government.  Yet,  by  the  maintenance  of  his 
peace  policy,  which  had  the  full  approval  of  the  Emperor 
Francis  Joseph,  he  came  into  serious  conflict  with  the  party  led 
by  the  chief  of  the  general  staff,  Conrad  von  Hotzendorf,  which 
championed  a  policy  not  afraid  of  energetic,  warlike  methods. 
The  battle,  carried  on  on  both  sides  with  tenacious  endurance, 
ended  in  1911  with  the  victory  of  Aehrenthal  and  the  resignation 
of  Hotzendorf. 

In  the  solution  of  questions  of  internal  policy  Aehrenthal,  as 
Foreign  Minister,  only  took  part  in  so  far  as  they  seemed  to  him 
to  affect  the  interests  of  the  monarchy  as  a  whole.  With  the 
Czechs,  who  on  his  accession  to  office  had  shown  some  suspicion 
on  account  of  his  intimate  connexion  with  the  leading  members 
of  the  loyal  Bohemian  landed  aristocracy,  he  succeeded  in 
maintaining  reasonably  good  relations.  As  against  the  Magyars, 
he  upheld  the  view  that  the  unity  of  the  monarchy  must  not  be 
shaken,  and  he  therefore  offered  a  determined  resistance  to  the 
attempts  of  the  party  of  independence  to  intrench  on  the  rights 
of  the  Crown  in  military  matters.  He  realized  the  need  for  an 

increase  of  the  army  and  the  reorganization  of  the  army  and 
navy,  but  he  opposed  the  far-reaching  demands  of  the  War 
Minister  and  the  chief  of  the  general  staff. 

Aehrenthal  married  in  1902  Pauline,  Countess  Szechenyi. 
He  died  Feb.  17  1912. 

Even  during  his  lifetime  the  estimate  of  his  political  policy 
fluctuated  violently.  On  the  one  hand  it  was  blamed  as  pro- 
vocative, on  the  other  as  weak.  After  the  disastrous  result  of  the 
World  War,  bringing  with  it  the  downfall  of  the  Habsburg 
Monarchy,  it  is  still  more  difficult  to  answer  the  question 
whether  the  path  pursued  by  Aehrenthal  in  foreign  affairs  was 
the  right  one.  It  is  certain  that  the  Entente  Powers  were  drawn 
more  closely  together  by  the  active  part  played,  during  his 
period  of  office,  by  Austria-Hungary  in  Balkan  affairs.  It  is  true 
that  the  chances  of  success  for  the  Central  Powers  in  an  inter- 
national struggle  were  better  in  the  years  1909  and  1911  than  in 
1914.  But  the  question  remains  undecided  whether,  if  his 
activity  had  been  longer  continued,  Aehrenthal  would  have  been 
able  to  maintain  the  position  of  Austria-Hungary  as  a  great 
power  without  an  appeal  to  the  decision  of  arms.  There  is 
no  doubt  that  Aehrenthal  was  a  statesman  of  considerable  mark, 
a  man  of  wide  knowledge  and  well-ordered  intelligence;  he  was 
ambitious,  but  not  vain,  and  an  untiring  worker.  Moreover,  in 
moments  of  great  excitement  he  was  able  to  maintain  outward 
calmness.  He  was  convinced  of  his  own  value,  but  had  no  desire 
to  parade  it.  The  Emperor  Francis  Joseph  esteemed  him,  stood 
by  him  in  the  good  and  evil  hours  of  his  administration  of 
foreign  affairs,  and  repeatedly  refused  to  accept  his  tendered 

See  B.  Molden,  Alois,  Graf  Aehrenthal:  Seeks  Jahre  auswartiger 
Politik  Oesterreich-Ungarns  (1917);  and  the  article  "Aehrenthal" 
in  the  Deutsche  Nekrologen  (vol.  xviii.,  1917,  pp.  230  seq.). 

(A-  F.  PR.) 

AERONAUTICS  (see  1.260). — Between  1909  and  1921,  Aero- 
nautics, an  infant  to  start  with,  had  not  grown  as  a  child  grows, 
but  irregularly.  One  member  had  prospered  at  one  time  and  one 
at  another.  Thus  we  find  that  enterprize  in  flight  was  early  in  ad- 
vance of  all  appliances;  then  engines  developed  for  a  period; 
later,  structural  design.  Though  aerodynamic  theory  had  been 
far  ahead  it  was  badly  neglected  for  a  spell  and  was  once  again 
fostered;  with  this  study  secret  and  semi-magical  wing  shapes 
disappeared;  after  that  came  methodical  production,  first  in 
units  and  subsequently  in  bulk;  then  came  pilotage  and  the  ele- 
ments of  commercial  flying.  The  seaplane,  though  less  risky  than 
the  aeroplane,  advanced  even  more  fitfully  and  never  caught  it  up; 
the  airship,  which  was  earlier  and  safer,  still  lagged  behind  be- 
cause it  made  less  appeal  to  sensation  and  cost  much  more.  The 
engine,  though  once  in  advance,  fell  behind,  and  only  now  (1921) 
is  again  full  of  promise.  Landing-grounds  and  night  alighting 
facilities  have  advanced  but  little,  meteorology  progresses  slowly 
against  fog,  the  enemy,  but  aerial  navigation  is  at  last  appearing 
as  a  science. 

By  taking  such  of  these  elements  as  have  separate  stories  and 
keeping  them  distinct  in  the.  several  sections  which  follow,  it  is 
hoped  to  present  more  clearly  the  progress  and  prospects  of  aerial 
science  than  by  showing  a  series  of  moving  pictures  of  the  infant 
prodigy  in  motion  as  a  whole. 

Achievements  and  Performance  (see  Section  I.). — The  twelve  years 
of  labour  of  the  American  Wrights  culminated  just  before  1909  in 
the  birth  of  the  art  as  we  now  know  it.  Hazardous  flights  on  the 
straight  or  in  figures  of  eight;  a  circle  over  Paris;  the  crossing  of  24 
miles  of  sea;  the  excelling  of  the  speed  of  an  express  train,  a  velocity 
once  deemed  monstrous  and  now  insignificant;  the  scaling  of  the 
Alps;  looping  and  inverted  flying;  leaving  the  craft  by  parachute; 
releasing  the  first  i,ooo-lb.  weight;  firing  the  first  gun;  discovering 
how  to  get  out  of  a  spin;  alighting  by  night,  etc.— each  of  these 
was  an  experience  and  a  token  of  growth.  Each  seemed  perilous 
and  astonishing,  yet  they  had  become  so  common  by  1921  that  it 
was  already  difficult  even  to  remember  the  sense  of  wonder. 

Design  (see  Section  II.). — The  advance  of  design  occurred  away 
from  the  public  vision,  nor  were  its  milestones  of  progress  coincident 
with  the  landmarks  made  by  the  great  performers  who  relied  more 
on  their  own  tact  in  the  air  than  on  the  tested  and  thought-out  qual- 
ities of  their  craft.  They  chafed  under  the  cautions  of  those  who 
made  stress  calculations.  Each  "  stunt  "  was  performed  before  any 
human  being  knew  if  it  was  safe.  How  and  why  was  design  altered 


and  bettered  under  the  circumstances?  Yet  strength  factors  were 
introduced,  down  pressures  foreseen,  fine  lines  provided,  wing  shapes 
and  controls  improved,  alighting  gear  developed  and  instability 
cured.  This  is  the  subject  matter  of  Section  II.  which  is  closely  allied 
to  Section  III. 

Aerodynamics  (see  Section  III.). — Aerodynamic  theory  had  risen 
out  of  the  void  at  the  bidding  of  the  applied  mathematician  before 
1909,  but  it  developed  at  the  call  of  designers  who  would  have  been 
tied  to  the  repetition  of  old  methods  had  not  theory  justified  de- 
parture. Once  aerodynamic  theory  was  established  their  inspiration 
could  take  wing. 

The  deductions  l  from  wind  tunnel  experiments  on  models  2  ft. 
long  could  be  but  surmises  till  the  principle  of  dynamic  "  similarity  " 
emboldened  designers  to  transfer  the  wind  tunnel  results  to  the  4O-ft. 
machines.  "  Scale  effect,"  "  slipstream  effect,"  pressure  distribu- 
tion, phugoids,  and  the  like,  had  to  be  verified  on  the  full-sized 
aeroplane  and  measured  in  the  course  of  flight  with  the  cooperation 
of  a  few  keen  fliers,  at  a  time  when  pilots  at  large  were  almost  antag- 
onistic to  "  theory."  Mathematics  had  been  applied  to  the  motion 
of  aeroplanes  through  the  air  in  advance  of  even  the  earliest  flight, 
and  several  separate  starts  were  made.  England,  represented  by 
F.  W.  Lanchester,  was  easily  first.  Lanchester  made  great  strides, 
at  a  time  when  he  had  no  wind  channel  for  his  model  verifications. 
Bryan  came  independently;  L.  Bairstow  had  the  wind  tunnel,  of 
which  he  has  indicated  the  arrangement  in  Section  VI.  and  greatly 
advanced  the  problems.  It  was  E.  T.  Busk  who  in  1913  in  his  own 
person  as  flier  verified  the  theories  he  had  formed  and  achieved  stable 
flight  cm  "  RE  I  "  (see  Plate  I.,  fig.  l).  America  had  led  in  initiating 
practical  flight;  France  in  model  experiments,  rotary  engines  and 
speed  records;  Germany  in  length  of  aeroplane  flight  and  in  rigid 
airships;  but  in  the  matter  of  stability  and  of  scientific  analysis  on 
both  model  and  full  scale,  Britain  took  the  lead  before  the  war 
and  still  kept  it  in  1921.  Something  of  each  national  temperament 
is  disclosed  by  these  specializations. 

Construction  and  Materials  (see  Section  IV.). — Aircraft  con- 
structional methods  are  to  be  regarded  from  two  points  of  view — 
the  one  where  a  few  craft  are  to  be  made  as  perfect  as  possible,  and 
the  other  where  bulk  production  is  demanded. 

Before  1914  there  was  no  output  of  aircraft  in  Britain  other  than 
by  units;  in  France  there  was  some  manufacturing,  in  America  a 
little,  and  in  Germany  rather  more.  These  countries  had  factories 
proper  where  repetitive  processes  were  employed.  An  army,  small 
in  numbers,  was  deemed  in  Britain  to  need  correspondingly  few 
aircraft.  A  large  navy  neglected  them.  When  bulk  production 
came  it  came  with  a  will,  but  designs  that  were  admirable  for  unitary 
construction  were  found  ill  adapted  to  bulk  manufacture,  and  the 
British  story  of  changes  in  material  and  methods  which  is  outlined 
in  Section  IV.  is  typical  of  the  war  period  everywhere. 

The  tautening  of  fabrics  with  cellulose  acetate,  the  evolution  of 
the  fairshaped  strut  and  wire,  the  steerable  tail  skid,  sewing  the 
fabric  to  the  wing  ribs,  covering  the  wheel  spoke  with  fabric,  were 
among  the  step-by-step  advances  which  all  belong  to  the  period 
before  large  outputs  were  contemplated,  i.e.  the  period  when,  for 
example,  joints  were  machined  from  the  solid  steel  bar.  The  plywood 
body,  the  spars  of  built-up  wood,  the  standard  relation  of  radiator 
to  engine  size,  the  pressed  metal  turnbuckle  and  the  thorough  inter- 
changeability  of  detail  parts  belong  to  the  "  bulk  output  "  period,  as 
also  incidentally  much  speeding-up  of  processes  and  methods,  the 
evolving  of  glues  and  cements,  fine  castings,  new  alloys  and  the  wide- 
spread use  of  tests  not  hitherto  commercialized  but  known  to  be 
good  by  the  few.  It  would  be  truer  to  say  that  the  World  War  dis- 
seminated the  science  of  aeronautics  rather  than  that  it  fostered  it. 
The  war  did  foster  the  technics  of  quantity  production. 

Aero  Engines  (see  Section  V.). — Man  would  have  flown  long  before 
he  did  but  for  the  lack  of  a  light  engine.  One  cwt.  per  horse-power 
was  about  the  weight  of  the  commercial  gas  engine,  and  to  fly  he 
wanted  one  twenty  times  lighter.  The  French  rotary  engine  of 
1909-10  was  the  most  real  promoter  of  aerial  experience  of  its 
time,  for  it  weighed  4  Ib.  where  a  motor-car  engine  weighed  ten. 
How  and  by  what  grouping  of  parts,  increases  of  compression  and 
refinements  of  design  this  weight  has  been  cut  down  to  2  Ib.  with 
fuel  economy  on  a  similar  scale,  appears  in  Section  V.  Here  it  will 
only  be  noted  that  the  Germans  on  the  basis  of  airship  experience 
had  inclined  rather  earlier  than  others  to  big  powers  on  aeroplanes, 
and  their  aeroplane  successes  on  aerodynamically  inferior  craft 
were  due  to  big  engines.  Their  engines  were  water-cooled,  rather 
heavy  but  reliable.  The  radial  air-cooled  engine  of  the  French  has 
been  mentioned  above.  The  British  service  was  late  to  realize  how 
very  big  the  war  aero  engine  must  be,  and  developed  an  air-cooled, 
non-rotary  and  some  good  water-cooled  motors  eventually  of 
adequate  sizes.  The  Americans  made  good  use  of  the  experience 
poured  in  upon  them  from  Europe  when  they  began  in  1917  to 
tackle  the  Liberty  engine  of  450  H.P.  Apart  from  size,  the  advances 
in  view  to-day  are  considerable.  The  means  for  protecting  ourselves 
from  the  fire  risks  on  crash  due  to  petrol  are  also  being  evolved. 

Navigation  (see  Section  VI.). — Aerial  navigation,  as  distinct 
from  piloting  with  the  ground  in  view,  developed  tardily  everywhere, 
though  first  in  Britain.  It  was  a  surprise  to  find  that  raiding  airships 

1  See  "  Flight,"  1912,  pp.  32,  33. 

from  Germany  disclosed  no  up-to-date  navigating  apparatus  when 
they  were  brought  down,  nor  had  their  aeroplanes  any  turn  indicator 
to  guide  them  when  immersed  in  cloud  or  fog.  Even  after  seeing  the 
Lucas  compass  (see  Plate  I.,  fig.  2)  on  captured  aeroplanes  they  did 
not  appreciate  or  copy  it,  nor  its  principle  of  the  "space-damped" 
vertical  card,  spherical  bowl  and  long  period;  nor  was  there  any- 
where an  instrument  to  compare  with  the  British  apparatus  figured 
in  Section  VI.  The  air  speed  indicator  that  uses  the  principle  of 
Pilot  was  also  a  British  idea,  which  displaced  the  earlier  French 
flat  plate  pressed  back  by  the  wind  against  a  spring,  and  other 
such  speed-meters. 

Control  of  A  ir  Traffic  and  A  ir  Stations. — Air  stations  and  the  rules 
evolved  to  control  traffic  have  a  section  (VII.)  to  themselves.  The 
early  stations  were  fields  and  each  flier  a  law  to  himself.  When  the 
Air  Convention  of  Oct.  1919  is  ratified  all  aircraft  will  be  taboo  that 
have  not  a  specific  factor  of  strength  and  an  adequate  field  of  view 
for  the  flier.  As  we  progress  all  stations  will  give  wireless  warning 
to  those  approaching  them  when  they  are  immersed  in  fog  and  will 
afford  facilities  for  night  alighting.  The  movement  is  in  this  direc- 
tion. The  mobility  of  aircraft  makes  international  agreement  on  all 
rules  for  alighting,  racing,  and  signalling  warnings  very  important. 
Bodies  like  the  Royal  Aero  Club  in  Britain  exist  in  each  county  and 
meet  annually  for  these  purposes. 

Seaplanes  (see  Section  VIII.). — The  seagoing  seaplane  is  relatively 
backward.  To  make  a  craft  light  enough  to  fly  and  heavy  enough 
to  stand  the  buffets  of  the  open  sea  up  to  the  speed  needed  to  quit 
the  waves  in  flight  is  a  problem  which  was  not  fully  solved  even  under 
the  war  stimulus.  It  was  tackled  too  late — by  Britain  no  less  than 
the  others.  Even  the  high-speed  "  float  "  seaplane  was  neglected  in 
England  but  it  eventually  advanced  in  Germany  to  be  a  formidable 
offence  against  the  air  enemies  of  the  submarine.  Theirs  was  not, 
however,  a  craft  that  could  ride  out  a  sea.  The  American  NC3  made 
a  record  by  riding  on  the  water  for  150  miles  in  its  Atlantic  crossing. 
It  was  an  achievement  to  withstand  the  sea  so  long  even  though  the 
craft  was  travelling  backwards  all  the  150  miles.  Section  VIII. 
shows  that  scientific  work  is  being  applied  to  the  problem,  notably 
in  the  matter  of  stability  when  changing  from  waterborne  to  airborne 

Airships  (see  Section  IX.). — Airship  knowledge  gave  to  Germany 
technical  advantages  which  would  have  been  even  more  valuable  to 
Britain.  They  did  not  use  on  aeroplanes  the  identical  engines  of 
their  airships,  but  the  experience  of  large  aero  engines  of  the  utmost 
reliability  and  economy  was  there.  The  dominant  advantages  of 
airships  are  that  they  fly  for  long  hours,  carry  large  weights,  do  not 
descend  for  an  engine  failure  and  can  safely  fly  by  night.  In  con- 
sequence of  night  flying  they  are  able  on  long  journeys  to  outstrip 
the  aeroplane  in  speed  from  point  to  point.  High  cost  of  housing 
and  the  numbers  required  to  handle  them  on  the  ground  were  their 
chief  hampering  factors,  but  the  wonderful  development  of  the 
mooring  mast,  a  British  device,  has  improved  the  position.  The 
towing  of  airship  by  airship  and  by  submarine,  the  protection  of 
fabric  from  deterioration,  the  use  of  non-inflammable  gas  are  all 
landmarks  in  their  evolution.  The  kite  balloon  and  the  parachute 
also  need  mention,  though  opinions  differ  as  to  the  advisability  of 
giving  the  latter  to  the  commercial  aeroplane  as  a  life-belt  is  given 
to  the  liner.  It  is  of  little  use  unless  the  jump  is  made  over  200  ft. 
from  the  ground;  if  a  high  wind  is  blowing  the  parachutist  meets  the 
ground  with  the  sideways  speed  of  the  wind  and  it  absorbs  18%  of 
the  useful  (passenger)  load.  This  position  is,  however,  the  result  of 
great  advances  which  have  assuredly  not  ceased. 

Each  sectional  aspect  of  aeronautics  between  1909  and  1921 
divides  itself  into  three  periods:  before,  during  and  after  the  war. 
The  dominant  emotions  and  aspirations  of  those  periods  governed 
men's  thoughts  whether  they  were  flying,  designing,  calculating; 
experimenting  with  engines,  model  aeroplanes  or  safety  devices; 
evolving  navigational  instruments,  tests  for  pilots  against  gid- 
diness, or  parachutes  to  save  the  lookouts  on  kite  balloons. 
Before  the  war  the  aircraft  builder  starved  although  it  was  early 
accepted  that  frontiers,  rivers,  chasms,  forests  and  entrenched 
positions  could  be  crossed  by  anyone  brave  enough  to  fly,  but 
that  acceptance  was  half-hearted.  It  now  amazes  one  to  realize 
that  in  1911  the  speed  of  flight  was  regarded  as  a  defect  for  the 
military  aeroplane,  or  that  vulnerability  by  gun-fire  from  the 
ground  was  its  supposed  weakness.  The  Governments  demanded 
that  their  aeroplanes  should  be  transported  in  crates,  or  towed 
with  folded  wings  to  their  jumping-off  place  (see  Plate  I.,  fig.  3). 
An  aeroplane  was  a  mute  observer;  no  means  of  continuously  trans- 
mitting observations — say  of  artillery  fire  or  enemy  movements — 
or  for  malung  photographic  records  had  been  tried  out,  accepted 
as  good  or  prepared  in  quantity.  Imagination  is  greater  than 
fact  when  the  imagination  is  active:  all  these  effects  could  easily 
be,  and  were,  imagined  once  flight  was  admitted — but  the  state 
is  a  herd,  and  extends  its  imaginative  power  like  a  herd  to  the 
distance  of  the  next  meal  or  next  year's  crop.  All  nations  econo- 


mized  in  aircraft  research.  Only  individuals  in  any  army,  navy 
or  populace  appreciated  it.  Its  exponents  were  a  butt  for  attack. 

Still  it  was  war  or  the  fear  of  war  that  was  responsible  for  what 
there  was.  War  has  often  been  the  great  inciter  of  technical 
advances — it  accounted  for  the  Roman  roads  and  for  the  modern 
steel  industry  when  battleship  plates  were  founded  and  forged. 
Such  industries  have  in  the  past  made  some  compensation  to  the 
world  for  their  malignant  first  inspiration.  So,  too,  will  aircraft 
in  its  civilian  uses  and  in  many  indirect  ways. 

The  exact  calculation  of  stresses,  the  exact  adaptation  of  ma- 
terial to  meet  them,  the  most  radical  economy  of  avoidable 
weight,  all  of  which  are  in  the  essence  of  engineering  progress,  have 
been  enforced  upon  the  new  engineer  physicist  of  aerial  science, 
and  young  and  brilliant  aircraft  engineers  have,  since  the  Armis- 
tice, been  thrown  into  industry  generally,  imbued  with  the  exact- 
itude and  thrift  of  mechanical  material  learnt  under  the  grave 
penalty  attaching  to  small  errors  in  strength,  weight  or  quality 
or  design  for  aircraft  construction. 

The  introduction  of  the  scientific  idea  was  an  intense  uphill 
struggle.  Flying  was  first  in  the  hands  of  men  of  enthusiasm 
rather  than  of  precision;  the  pioneers  were  more  courageous  than 
scientific  or  critical.  Dynamic  similarity,  the  theorem  of  three 
moments  and  the  like  were  uninteresting  to  the  small  makers, 
and  all  makers  were  in  a  small  way.  The  data  for  the  calculation 
of  aeroplane  stresses  were  insufficient  to  move  the  larger  firms  to 
quit  the  imitative  methods  of  design  which  were  the  beginnings 
of  the  industry.  The  risks  from  obvious  misadventures,  from 
fliers'  errors,  from  bad  landing-grounds,  etc.,  were  so  great 
that  the  hazards  to  be  guarded  against  by  calculations  and  wind- 
tunnel  experiments  appeared  few  and  negligible  by  comparison. 

Before  the  war  public  pressure  had  a  rather  doubtful  directing 
influence.  If  it  was  not  explicitly  said  that  such  appliances  must 
be  frail  and  dangerous,  it  was  assumed.  In  one  country  after 
another  the  ministers  were  rather  upbraided  by  the  air  industry 
and  dismissed  eventually  for  failing  to  spread  themselves  on  large 
orders  than  urged  to  develop  the  basis  for  strength  and  balance,  by 
expenditure  now  proved  justifiable  on  precise  calculations,  labo- 
ratory work  and  mathematics,  finer  metallurgy,  woodcraft  and 
chemistry,  instruments  and  navigation  such  as  are  recorded  in 
the  succeeding  sections. 

The  main  efforts  made  on  the  scientific  side  have  been  individ- 
ual, and  for  those  individuals  are  mainly  unrequited.  Many  are 
dead — scarcely  heard  of — E.  T.  Busk;  K.  Lucas;  R.  M.  Groves; 
B.  Hopkinson;  Pilgrim;  Pinsent;  Usborne;  many  others  lived  on 
in  1921  to  see  the  result  of  their  work,  which  was  unparalleled 
in  brilliance  of  achievement.  Fortunately  the  names  of  the  per- 
formers of  heroic  flights  live  on,  and  many — unavoidably  there 
are  omissions  from  so  great  a  list — appear  in  Section  I. 

In  1911-2  the  compelling  necessity  for  providing  in  the  inter- 
ests of  fliers  a  margin  of  strength  for  aircraft,  calculated  upon 
the  stresses  induced  by  its  speed  and  by  its  manoeuvres,  was 
first  accepted.  So  far  as  we  know,  this  importation  of  an  engineer- 
ing standard  was  British,  and  was  imposed  upon  foreign  sup- 
pliers for  the  first  time.  ' 

The  various  nations,  each  wanting  to  know  how  the  other  was 
getting  on,  would  purchase  a  few  examples  abroad;  a  proceeding 
naturally  coupled  with  any  known  precautions  for  the  home 
flier  whose  person  would  be  risked  in  testing  them.  In  any  coun- 
try the  industrials  regarded  foreign  purchases  with  some  jealousy, 
since  a  tenuous  air  vote  was  seen  to  be  expended  elsewhere  than 
with  the  home  constructor;  still  an  informative  exchange  of  tech- 
nical knowledge  ensued. 

The  20  H.P.  engine  of  Wright  and  the  35  H.P.  engine  of  Green 
were  seen  to  be  too  small  by  any  who  knew  the  50  H.P.  Gnome 
in  flight.  The  speedy  monoplane  of  Nieuport  (French  1910) 
showed  Britain  the  value  of  smooth  external  lines  for  the  craft. 
The  Wright  biplane  (U.S.A.)  bore  only  2  Ib.  per  sq.  ft.  of  wing 
area,  and  Farman  followed  its  lead  in  France.  The  uses  of  heavy 
loading,  as  in  the  De  Haviland  craft,  appeared  later,  when  its 
demerits  were  envisaged  and  difficulties,  such  as  the  high  speed  of 
alighting,  overcome  simply  by  the  great  skill  and  courage  of 
fliers.  The  German  Zeppelin  taught  much  to  Britain.  The 

British  Avro  and  BE2  taught  the  possibility  of  a  wide  speed 
range  to  the  French  and  others,  and  generally  aircraft  lore  became 
international.  (M.  O'G.) 


The  Arena  of  Aeronautics  in  igog. — The  achievements  in 
1909  had  been  latent  in  the  effort  of  the  previous  40  years; 
that  which  appeared  sudden  was  the  outcome  of  protracted 
experiment  and  the  driving  force  of  great  personalities.  The  date 
recalls  the  names  of  Wright,  Voisin  and  Farman.  The  year  1908 
had  made  power-driven  flight  a  reality.  Farman  had  flown  from 
Chalons  to  Reims;  Orville  Wright  had  flown  for  over  an  hour  in 
America;  Wilbur  Wright  held  the  Michelin  Cup  with  a  flight  of 
124  km.  in  France. 

In  1909  man  little  knew  at  what  bitter  cost  he  would  maintain 
the  conquest  of  the  air;  yet  the  toll  of  life  served  but  as  a  stimulus. 
The  International  Conference  that  was  held  in  London  consoli- 
dated the  position  of  the  Aero  Clubs  of  the  various  countries  with 
a  view  to  the  advancement  of  aeronautics  as  an  organized  move- 
ment. The  great  natural  flying-ground  at  Pau  soon  made  it  the 
Mecca  of  aeronautics.  There  Wilbur  Wright  created  the  first 
flying-school,  and  among  his  pupils  were  names  now  famous.  At 
the  aero  show  in  London  the  public  inspected  and  handled  ma- 
chines that  really  flew.  At  Farnborough,  Cody  was  experimenting 
with  a  machine  that  was  to  glide  down  a  wire.  Bleriot,  who  had 
emerged  from  crash  after  crash  unscathed,  flew  from  Etampes  to 
Orleans,  25  miles.  His  little  machine  hopped  over  hedges  and 
trees,  its  diminutive  engine  humming  above  the  roar  of  the  Paris- 
Orleans  express,  the  windows  of  which  were  white  with  faces 
upturned  to  see  the  new  wonder.  On  a  memorable  Sunday 
morning  (July  25  1909),  Bleriot  set  out  from  France  without  a 
watch  or  compass  to  fly  the  Channel;  his  monoplane  was  lost 
in  the  haze;  but  he  emerged  triumphant  towards  the  cliffs  of 
Dover,  where  he  landed  on  a  slope  and  crashed.  His  feat 
eclipses  all  others  of  the  year,  and  is  the  forerunner  of  the  cross- 
ing of  the  Atlantic  10  years  later.  The  analogy  goes  further,  for 
Hawker's  failure  to  cross  the  Atlantic  is  reminiscent  of  that  other 
failure  of  Latham's  to  wrest  the  prize  from  Bleriot. 

The  year  is  memorable  for  flying  meetings  which  roused  public 
enthusiasm  in  many  countries:  at  Reims,  Brescia,  Berlin,  Co- 
logne, Blackpool  and  Doncaster.  At  Reims  Latham  covered  96 
m.,  while  later  in  the  year  Paulhan  climbed  to  600  metres,  a 
dizzy  height  in  those  days.  The  Comte  de  Lambert,  a  pupil  of 
Wright,  flew  from  Juvisy  round  the  Eiffel  Tower  and  back,  the 
first  flight  over  a  town.  In  Germany  Herr  Grade  won  a  £2,000 
prize  for  the  first  German  to  fly  a  figure  of  eight  round  two  posts 
placed  i  km.  apart.  At  the  close  of  the  year  Farman  held  the 
Michelin  Cup  with  a  fine  flight  of  234  km.,  made  at  Chalons. 

The  Flying  Qualities  of  the  Early  Aeroplanes. — So  rapid  has 
been  their  development  that  it  is  worth  recalling  what  these  early 
aeroplanes  were  like.  The  factors  which  govern  the  balance  of  an 
aeroplane  and  the  respective  functions  of  the  movable  and  fixed 
surfaces  used  for  its  control  during  flight  were,  in  1909,  ill 
understood.  The  probable,  possible  and  impossible  were  all  one. 
Aeroplanes  were  built  by  eye  and  developed  by  trial  and  error; 
the  light  aero  engine  was  in  its  infancy.  Wilbur  Wright  laid  the 
foundation  of  aeroplane  control  as  we  now  conceive  it,  but  ham- 
pered it  by  combining  the  movement  of  the  vertical  rudder  with 
the  warping  of  the  main  planes  for  turning  in  the  air.  The  pio- 
neers flew  almost  by  blind  instinct;  they  had  but  the  vaguest  idea 
of  how  to  remedy  a  loss  of  control;  some  were  even  inclined  to 
doubt  that  remedies  existed;  atmospheric  disturbances  and  so- 
called  "  air  pockets  "  were  referred  to  with  awe;  instruments 
which  now  assist  the  maintenance  of  balance,  attitude  and  flying 
speed  were  unknown,  and  when  suggested  were  objected  to;  it 
was  all  that  human  concentration  could  do  to  make  proper  use 
of  the  control  surfaces  to  maintain  equilibrium,  not  only  because 
the  equilibrium  was  essentially  of  an  unstable  kind,  but  because 
the  control  surfaces  themselves  were  often  incorrectly  designed 
and  thus  treacherous  or  inadequate.  It  was  on  such  machines 
that  the  early  pioneers  committed  themselves  to  the  air,  break- 
ing records  over  laud  and  sea. 



The  Pre-War  Years. — The  chief  flight  of  the  year  1910  was 
Paulhan's  from  London  to  Manchester,  by  which  he  won  the 
Daily  Mail  £10,000  prize  (April  27  and  28  1910).  The  race  was 
gallantly  contested  by  Grahame-White.  If  skill  and  tenacity  had 
been  the  determining  factor,  the  prize  would  have  been  hard  to 
award.  The  chances  of  the  race  aroused  the  greatest  enthusiasm 
and  to  the  many  incredulous  one  more  demonstration  was  thus 
given  of  the  possibilities  of  the  aeroplane. 

During  the  year  flying  meetings  were  held  at  Heliopolis, 
Wolverhampton,  Bournemouth,  Blackpool  and  Lanark,  the 
flying  performances  at  which  demonstrated  the  advance  that  had 
been  made  on  those  of  the  previous  year.  At  Bournemouth  Eng- 
land lost  one  of  her  best  fliers,  the  Hon.  C.  S.  Rolls,  who  had 
previously  made  the  double  journey  across  the  English  Channel. 
His  statue  stands  at  Dover,  gazing  out  over  the  waters  that  he 
crossed.  Most  British  pilots  were  flying  on  aeroplanes  that  were 
wholly  or  partly  French,  but  it  is  to  be  noted  that  Moore  Braba- 
zon  won  the  British  Michelin  Cup  with  a  flight  of  19  m.  on  an 
all-British  machine.  At  Lanark  Chavez  on  a  Bleriot  monoplane 
reached  a  height  of  1,794  metres,  a  prelude  to  his  magnificent 
flight  over  the  Alps,  the  tragic  sequel  to  which  was  his  fatal 
accident  on  landing.  Legagneux,  however,  created  a  record  by 
reaching  a  height  of  3,100  metres. 

Moisant  flew  from  Paris  to  London  but,  though  he  quickly 
reached  English  soil,  various  troubles  delayed  his  arrival  in 
London  till  three  weeks  later.  On  the  continent,  Leblanc  won 
the  £4,000  prize  for  the  Circuit  de  L'Est.  Grahame-White  went  to 
America  and  brought  back  the  Gordon  Bennett  Cup,  which 
Curtis  had  won  the  year  before.  The  contests  for  the  British 
Michelin  Cup  and  the  Baron  de  Forest  prize  brought  forward  new 
fliers.  Sopwith,  competing  for  the  former,  flew  100  m.  at  Brook- 
lands,  which  had  been  opened  as  a  flying-ground  the  year  before, 
thus  beating  Cody's  distance  of  97  m.  which  had  previously 
stood;  competing  for  the  latter  he  flew  from  Eastchurch  well 
into  Belgium. 

At  the  close  of  the  year  Cody,  after  an  exciting  contest  with 
Sopwith  and  Ogilvie,  held  the  British  Michelin  Cup  with  a  dis- 
tance of  185  m.  in  4  hours  47  minutes.  In  France  Tabuteau  held 
the  International  Michelin  Cup  with  a  distance  of  582  km.  in  7 
hours  48  minutes. 

It  was  in  1911  that  the  aeroplane  was  first  tried  in  warfare. 
Hamilton,  an  American,  carried  out  a  flight  over  the  town  of 
Ciudad  Juarez  during  a  Mexican  rebellion.  In  their  campaign  in 
Tripoli  the  Italians  also  realized  the  value  of  the  aeroplane  for 
reconnaissance.  In  England  the  idea  of  the  time  was  that,  for 
bombing,  aircraft  would  be  useless  and  contrary  to  international 
usage;  on  the  other,  hand,  the  first  British  attempt  was  made  to 
run  an  aerial  post  between  Hendon  and  Windsor. 

Capt.  Bellenger,  a  Frenchman,  flew  from  Paris  to  Bordeaux 
in  5  hours  10  minutes  net  time,  a  distance  of  690  km.,  while  later 
Fourny  remained  in  the  air  for  n  consecutive  hours,  covering  a 
distance  of  720  kilometres.  Garros  made  a  height  record  of 
3,910  metres.  London  was  linked  with  Paris  by  a  notable  non- 
stop flight  by  Prier,  which  foreshadowed  the  aerial  services  of 

The  year  1911  saw  many  races:  the  Paris-Madrid  race  won  by 
Vedrines  at  50  m.p.h.,  in  the  course  of  which  the  French  Minister 
of  War  met  his  death  and  the  premier  was  seriously  injured;  the 
European  Circuit,  divided  into  nine  stages,  with  the  recently 
opened  Hendon  flying-ground  at  the  end  of  the  seventh,  which 
was  won  by  Lt.  Conneau  flying  under  the  name  of  "  Beaumont  "; 
the  Daily  Mail  race  round  Great  Britain  of  1,010  m.,  also  won  by 
"  Beaumont  "  with  Vedrines  as  a  close  second. 

The  Gordon  Bennett  Cup  was  won  for  America  at  Eastchurch 
by  Weyman  flying  a  Nieuport  monoplane  at  79  m.p.h.,  and  the 
International  Michelin  Cup  for  France  at  Gidy-Lhumery  by 
Helen  with  a  distance  of  1,252  km.  in  14  hours  7  minutes  at  56  m. 
per  hour. 

The  increase  in  performance  over  the  previous  year  may  be 
referred  chiefly  to  the  development  of  the  aero  engine.  It  would 
be  difficult  to  say  that  fliers  were  more  skilful,  but  it  is  certain 
that  they  were  able  to  substitute  knowledge  and  experience  for 

pure  instinct,  and  thus  set  out  on  long  and  arduous  flights  with 
increased  confidence  in  their  own  powers  and  in  the  reliability  of 
the  aircraft  they  flew. 

One  of  the  most  prominent  features  of  the  year  1012  was  the 
active  part  that  the  British  and  French  Governments  took  in  the 
development  of  aircraft  for  war.  The  French  Minister  of  War 
held  a  great  review  of  military  fliers  and  aeroplanes,  and  British 
aircraft  took  a  conspicuous  part  in  naval  and  military  manoeu- 
vres. The  Cody  pusher  biplane  won  the  £4,000  prize  in  the  War 
Office  trials  on  Salisbury  Plain  in  the  summer,  during  which  the 
tractor  biplane  BE2  reached  a  height  of  9,500  feet.  In  Sept. 
four  army  fliers  lost  their  lives  in  two  accidents  in  monoplanes, 
which  led  to  close  restrictions  being  placed  on  their  method  of 
bracing  in  England.  In  March  the  French  Government  had  im- 
posed a  ban  on  certain  monoplanes  until  the  defects  were  removed 
as  the  result  of  a  report  by  Bleriot  on  their  structural  weakness. 

Garros  won  the  Grand  Prix  of  the  Aero  Club  de  France  for  the 
Anjou  Circuit  of  685  m.  at  45  m.p.h.;  Sopwith  the  first  Aerial 
Derby  at  59  m.p.h.,  a  race  round  London  of  81  m.;  Vedrines  the 
Gordon  Bennett  Cup  in  America  at  105  m.p.h.;  Audemars  flew 
from  Paris  to  Berlin;  the  two  British  Michelin  Cups  were  won  by 
Hawker  and  Cody,  the  first  with  a  duration  of  8  hours  23  minutes, 
and  the  second  with  a  flight  over  a  circuit  of  186  m.  in  3  hours  23 
minutes;  in  France  Daucourt  for  the  Pommery  Cup  flew  550  m. 
in  a  single  day  at  63  m.p.h.,  while  at  the  meeting  at  Leipzig 
Hirth  reached  a  height  of  4,100  metres.  World's  records  were 
made  in  height  by  Garros,  who  reached  5,610  metres;  in  dis- 
tance by  Fourny  with  1,010  km.;  and  in  speed  by  Vedrines  with 
174  km.  per  hour,  over  5  kilometres. 

In  the  spring,  flying  had  suffered  an  irreparable  loss  in  the 
death  of  Wilbur  Wright  from  typhoid  fever. 

Apart  from  the  establishment  of  the  fundamental  merit  of  the 
tractor  biplane  the  year  was  notable  rather  for  a  steady  improve- 
ment in  strength  and  detail  than  for  any  radical  departure  in 
type.  From  this  time  it  becomes  increasingly  difficult  to  single 
out  individual  performances.  Achievements  deemed  impossible 
three  years  before  became  commonplace  events. 

The  year  1913  was  one  of  great  progress.  Long  cross-country 
flights  were  proving  day  by  day  the  faith  that  fliers  had  in  the 
aero  engine.  Seguin  in  France  covered  1,021  km.,  Legagneux 
reached  a  height  of  6,120  metres,  while  Prevost  attained  the 
speed  of  203  km.  per  hour,  over  5  kilometres.  It  was  a  brilliant 
year  for  him;  he  won  the  Schneider  Cup  for  seaplanes  at 
Monaco,  covering  150  nautical  m.  in  3  hours  48  minutes,  and 
the  Gordon  Bennett  Cup  at  Reims  at  124  m.p.h.  Helen  won 
the  International  Michelin  Cup  with  a  distance  of  16,096  km. 
Captain  Longcroft  won  the  Britannia  Challenge  Trophy  by  a 
magnificent  flight  from  Montrose  to  Farnborough  via  Ports- 
mouth on  a  BE2  aeroplane  built  by  the  Royal  Aircraft  factory. 
Hamel  won  the  second  Aerial  Derby  at  76  m.p.h.,  while  Pegoud 
in  France  and  England  gave  some  of  the  most  marvellous  demon- 
strations in  the  new  art  of  aerobatics  that  the  world  had  ever 
seen,  including  looping,  inverted  flying  and  quitting  his  aeroplane 
in  a  parachute.  In  Dec.  1913  the  REi,  the  first  aeroplane  stable 
longitudinally  and  laterally,  was  flown  for  35  minutes  without 
hand  or  foot  control;  and  this,  which  may  be  regarded  as  the 
greatest  technical  advance  in  aerodynamics,  is  to  the  credit  of 
Busk,  an  Englishman,  who  both  made  the  flight  and  applied  the 
theory  on  which  the  aeroplane  was  designed.  The  last  previous 
attempt  of  the  kind  was  by  Dunne,  who  a  few  months  earlier 
had  flown  for  one  minute  with  "  hands  off." 

The  year  1914,  just  as  it  marked  a  turning  point  in  the  affairs 
of  nations,  altered  the  whole  character  of  flying.  For  seven  months 
the  ideas  of  safe,  stable  flying  and  safe  alighting  were  dominant ; 
then  the  World  War  came  down  like  a  curtain  and  blotted  them 
out  in  favour  of  widely  different  objects.  During  those  months, 
Sykorsky,  in  Russia,  had  been  proving  the  weight-carrying  possi- 
bilities of  the  aeroplane,  and  had  risen  to  300  metres,  carrying 
15  passengers.  At  Farnborough,  an  SE4  (see  Plate  I.,  fig.  4)  flew 
at  130  m.p.h.  and  climbed  1,400  ft.  in  a  minute.  Linnekogel  had 
reached  a  height  of  6,350  metres  in  Germany,  though  just  before 
the  war  Oelrich  beat  him  by  reaching  7,860  metres.  Landmann 


in  Germany  remained  in  the  air  for  21  hours  48  minutes,  while 
Boehm  further  improved  on  this  unofficially  with  a  time  of  just 
over  24  hours. 

The  Schneider  Cup  for  seaplanes  was  won  for  England  by 
Pixton,  who  covered  150  nautical  m.  in  two  hours  at  Monaco  on 
a  Sopwith  biplane  fitted  with  floats.  The  Aerial  Derby,  the 
London-Manchester-London  and  London-Paris-London  races 
were  all  won  by  Brock.  Notable  events  on  the  Continent  were  the 
Prince  Henry  Circuit  of  1,125  m-  in  Germany,  in  which  there 
were  40  competitors,  and  the  Security  competition  in  France; 
although  most  of  the  big  international  races  had  to  be  cancelled. 

The  World  War. — The  ingenuity  that  sought  for  speed  at  low 
heights  suitable  to  the  race-course  or  for  the  maximum  climb  was 
by  no  one  appreciated  as  vital  for  war  purposes,  either  in  France 
or  Germany,  and  least  of  all  in  Britain;  aeroplanes  were  for  re,- 
connaissance — they  should  fly  slowly — and  the  very  inferior 
anti-aircraft  guns  would  not  impede  their  flying  low;  it  was  not 
till  many  months  elapsed  that  the  margin  of  speed  and  climb  was 
found  to  be  decisive  as  to  who  should  be  the  victor  in  mortal  com- 
bat held  in  the  upper  air.  The  diverse  needs  of  war  stimulated 
the  development  of  specialized  types,  which  were  evolved  as 
fast  as  production  considerations  would  admit.  The  prime  use 
remained,  as  foreseen,  reconnaissance,  but  to  maintain  and  sup- 
port this  other  craft  were  called  into  being;  the  possibilities  of 
the  aeroplane  as  a  bomb-dropper  were  as  yet  hardly  called  for. 
The  early  war  pilot  went  into  battle  armed  more  as  a  sportsman 
than  as  a  soldier.  But  he  was  attacked,  and  had  either  to  be  made 
self-defensive  or  to  be  escorted  by  fast,  high-powered,  swift-climb- 
ing fighters. 

In  1915  the  artillery  on  the  ground  came  to  rely  almost  entirely 
on  aerial  "  spotting,"  and  the  small  single-seater  fighters  had  to 
sweep  hostile  aircraft  from  the  skies  to  allow  such  machines  fitted 
with  wireless  to  pursue  their  work  uninterrupted.  Bombing  was 
also  rapidly  developed.  The  first  time  a  i,ooo-lb.  weight  was  re- 
leased by  Goodden  from  an  aeroplane  was  an  event  calling  for 
a  special  communication  to  the  Secretary  of  State  that  by  big 
bombs  the  nerves  and  arteries  of  the  enemy  might  be  continually 
harassed  and  disorganized.  Owing  to  freedom  of  movement 
in  three  dimensions  air  supremacy  was  a  far  more  difficult  and 
comprehensive  thing  than  naval  supremacy.  It  was  never 
achieved  save  locally  and  for  brief  periods  by  any  Power,  and 
then  only  by  concentrating  organizations  of  the  greatest  mobility 
and  flexibility  at  some  place  and  time. 

The  requirements  of  quantity,  coupled  with  the  demands  for 
change,  came  so  rapidly  that  the  development  and  expansion  of 
the  aerial  arms  of  the  Great  Powers  are  difficult  to  grasp.  Of 
the  innumerable  acts  of  courage,  the  endurance  and  self-sacrifice, 
the  skill  of  the  pilot  in  war,  it  is  impossible  here  to  attempt  a 
record.  Here  and  there  the  names  of  great  pilots  stand  out.  But 
if  one  be  mentioned,  a  hundred  others  would  claim  justice.  Such 
were  the  changing  fortunes  of  war,  so  many  and  so  astounding 
were  the  feats  of  daring,  that  with  deeds  not  unworthy  of  a  Ball, 
a  McCudden,  a  Bishop,  a  Nungesser,  a  Garros,  a  Guynemer,  a 
Vedrines,  an  Immelmann,  a  Richthof  en,  a  Boelcke  or  a  Voss,  many 
a  flier  passed  through  the  war  without  fame  or  praise. 

It  was  only  during  1915  that  the  specialized  type  of  aeroplane 
began  to  appear.  The  two-seater  aeroplane  with  an  engine  of  up 
to  150  H.P.  was  used  promiscuously;  for  reconnaissance,  artil- 
lery "  spotting,"  any  bombing  there  was,  and  fighting  as  well. 
Types  in  use  by  the  British  were  BE2C's,  Avros  and  Bleriots, 
with  small  engines  below  100  H.P.;  by  the  French,  Caudrons, 
Breguets,  Farmans,  Voisins,  Bleriots  and  Moranes;  by  the 
Germans,  LVG's  and  Rumplers,  with  engines  over  120  H.P.  and 
up  to  160  H.P.;  the  maximum  speeds  seldom  exceeded  80  m.  per 
hour.  Later  in  the  year  the  single-seater,  originally  intended  as  a 
scout,  was  used  for  fighting.  The  80  H.P.  Bristol  scout  and  other 
tractors  used  by  the  British  were  handicapped  by  their  inability 
to  fire  forwards,  the  direction  of  best  aim;  the  various  models  of 
Nieuport  and  Morane  scouts  used  by  the  French  were  also 
adopted  by  the  British,  while  the  Albatross  and  Fokker  scouts 
were  used  by  the  Germans.  Engines  up  to  200  H.P.  were  coming 
in.  The  so-called  "  scout  "  became  a  real  fighter;  its  speed  and 

climb  became  truly  effective  when  firing  through  the  propeller 
was  devised  by  a  Frenchman,  adopted  by  Germany,  and  then  with 
feverish  haste  by  the  Allies.  The  French  and  Germans,  more 
zealous  about  bombing,  were  for  this  purpose  introducing  large 
twin-engined  aeroplanes  and  experimenting  with  armoured  ones. 
Speeds  rose  to  over  100  m.p.h.,  and  aeroplanes  flew  and  fought 
at  heights  of  15,000  ft.,  whither  they  were  driven  by  the  increas- 
ing intensity  of  the  anti-aircraft  fire  and  by  the  advantage  to  be 
derived  from  a  swift  descent  to  pounce  or  to  retract.  Night  flying, 
which  had  been  tentatively  practised  for  exhibition  before  the 
war,  was  taken  seriously,  as  its  potentialities  for  bombing,  for  the 
depositing  of  spies  and  for  other  conveyance  were  realized. 
Stable  aeroplanes  with  special  alighting  gear  and  a  clear  forward 
field  of  view  were  needed  for  the  repelling  of  airships  by  night. 
The  loading  of  war  aeroplanes  was  increased  and  was  only 
limited  by  the  absolute  necessity  of  reasonable  landing  speeds; 
even  then  fast  scouts  taxed  the  skill  of  most  pilots.  Seaplanes, 
whose  aerial  performance  was  always  poor  compared  with  that  of 
aeroplanes,  were  of  great  use  in  conjunction  with  naval  opera- 
tions, and  took  part  in  the  Gallipoli  campaign. 

In  1916  the  air  services  came  more  and  more  into  prominence. 
The  cry  for  higher  and  yet  higher  performance  was  insistent. 
The  French  Spad  flew  at  130  m.p.h.  and  reached  over  20,000 
feet.  The  German  Albatross  scouts  manoeuvred  magnificently 
at  great  heights,  and  high-flying  reconnaissance  Rumplers  with 
cameras  photographed  back  areas.  Bombing  flights  up  to  800  m. 
were  carried  out,  notably  by  the  French.  Night  bombing  and  even 
night  reconnaissance  became  general,  first  on  moonlight,  and  then, 
as  the  flier's  skill  increased,  on  dark  nights.  Accessories  for 
night  flying,  such  as  wing  tip  flares,  were  developed.  Airships 
had  already  proved  vulnerable  to  aeroplane  attack,  and  a  German 
airship  was  brought  down  in  flames  at  Cuffley  on  Sept.  3  1916 
while  engaged  in  raiding  England  by  night.  Kite  balloons  were 
attacked  and  brought  down  with  incendiary  rockets  and  bullets. 
Flying  became  organized,  and  aeroplanes  patrolled  in  larger  and 
larger  formations  and  in  layers,  each  unit  being  allotted  its  re- 
spective duties,  signals  being  made  by  coloured  lights.  Slower 
aeroplanes  were  escorted  by  fast  fighters;  other  fighters,  like 
hawks,  moved  on  mobile  offensive  patrols. 

As  peace  seemed  no  nearer  in  191 7,  redoubled  efforts  were  made 
in  the  air.  America  joined  in,  and  American  fliers  joined  British 
squadrons,  finally  forming  their  own;  the  Italians  had  developed 
large  twin-engined  Caproni  triplanes;  the  Austrians,  the  Turks, 
all  realized  what  air-power  meant.  The  British  used  large  twin- 
engined  flying-boats  against  the  submarine.  The  Germans 
eventually  attacked  with  big  float-seaplanes  of  remarkable  speed. 
Scouts  were  flown  off  lighters  at  sea  against  airships,  and  off  the 
decks  of  battleships  and  "  mother  "  ships.  Formation  flying  was 
developed  and  aerial  fighting  of  the  fiercest  intensity  was  the 
prelude  to  every  big  land  operation.  The  British  SEsA's  and 
Sopwiths,  the  French  Nieuports  and  Spads,  the  German  Alba- 
trosses, Rolands  and  Fokkers,  swept  the  sky  in  "  circuses  "  30 
strong,  and  the  effect  of  superiority  of  performance  was  hard  to 
distinguish  from  sheer  skill  in  handling. 

As  the  last  and  bitterest  struggles  of  the  World  War  were 
being  waged  in  1918,  aerial  activity  reached  its  zenith.  The 
deep  hum  of  aircraft  practically  never  ceased  by  night  or  day,  in 
fair  weather  or  foul.  Large  twin-engined  Handley  Pages  and 
German  Gothas  flew  farther  and  farther  afield  on  bomb  raids; 
retreating  armies  in  the  East  fled  before  the  onrush  of  death  from 
the  air.  Aeroplanes  flew  low  and  attacked  anything  they  could 
find  on  the  ground.  Large  flying-boats  patrolled  vast  expanses  of 
water.  The  night  was  full  of  the  attackers  and  the  attacked,  for 
fighting  scouts  had  learnt  to  seek  out  and  fight  the  night  bomber. 
Engines  had  become  more  and  more  powerful  and  had  reached 
400  horse-power.  The  height  at  which  an  aeroplane  could  fly 
was  limited  rather  by  the  physical  endurance  of  the  pilot,  even 
with  the  help  of  oxygen,  than  the  possible  "  ceiling  "  of  the  aero- 
plane. It  would  hardly  be  an  exaggeration  to  say  of  the  aero- 
planes used  in  the  first  and  last  phases  of  the  World  War  that 
their  relative  effectiveness  as  fighting  implements  was  commen- 
surate with  that  of  a  bow  and  arrow  and  a  modern  rifle. 



The  Art  of  Flying  in  War. — If,  in  war,  higher  performance  was 
the  prime  means  of  gaining  the  position  to  strike,  controllability 
was  essential  to  direct  the  blow.  Pegoud  had  given  a  glimpse  of 
the  possibilities  of  aerobatics  in  1913,  and  during  the  war  these 
possibilities  were  explored  to  the  uttermost.  Probably  owing  to 
temperament,  the  French  led  the  way.  The  pilot  of  a  fighting 
aeroplane  simply  came  to  regard  his  machine  as  a  mobile  gun 
platform,  whose  motion  must  be  in  sympathy  with  his  lightest 
touch  to  enable  him  to  get  his  sights  on  the  target.  In  fighting- 
scouts  the  guns  were  integral  with  the  aeroplane,  the  nose  of 
which  was  controlled  so  as  to  point  them  at  the  target.  With 
opposing  machines  of  equal  performance  the  striking  position 
had  to  be  gained  by  manoeuvre,  confidence  in  which  was  inspired 
by  a  good  view  of  the  opponent.  In  order  to  use  his  guns  effec- 
tively, the  pilot's  arcs  of  view  had  therefore  to  be  made  as  large  as 
possible.  Though  "  looping  "  itself  was  little  used,  half-loops  and 
"  Immelmann  "  turns  enabled  the  pilot  to  turn  rapidly  while 
gaining  height. 


FIG.  5. — Immelmann  Turn. 

Until  1916  spinning  nose-dives  had  merely  been  associated 
with  loss  of  flying  speed  and  control,  almost  always  with  fatal 
results.  A  courageous  demonstration  of  the  method  of  recovery 
from  a  spin  by  Goodden,  and  later  the  practical  application  of 
the  theory  by  Lindemann,  both  at  the  Royal  Aircraft  factory, 
did  much  to  prevent  future  accidents.  A  spin  came  to  be  regarded, 
not  with  fear,  but  as  a  means,  if  crippled,  of  eluding  attack. 

French  pilots  again  pointed  the  way  in  the  art  of  "  rolling,"  a 
manoeuvre  in  which  the  aeroplane  is  rolled  about  its  longitudi- 
nal axis.  In  1017  this  manoeuvre  was  widely  practised.  The 
development  of  an  aerial  combat  was  so  swift  that  the  first  few 
seconds  might  decide  the  fate  of  one  of  the  opponents.  It  was 
rather  in  a  brilliant  combination  of  the  manoeuvres  described 
above,  calculated  to  make  effective  striking  possible  while  pre- 
senting an  elusive  target,  than  in  the  use  of  any  single  manoeuvre, 
that  the  war  pilot  put  his  trust.  He  had  to  study  the  characteris- 
tics of  the  aeroplane  he  was  attacking,  single  or  two-seater  or 
large  bomber,  gauge  its  weakness,  divine  the  mentality  of  its 
pilot  and  pit  his  skill  against  it;  but  it  was  grit  and  the  will  to 
close  and  finish  it  that  alone  could  be  the  decisive  factor. 

To  make  possible  the  achievements  of  the  fighting  pilots, 
and  to  solve  aerodynamic  problems  continuous  experiments 
with  new  engines  were  carried  on  behind  the  scenes.  High  per- 
formance and  controllability  were  not  achieved  without  the 
incessant  labour  of  scientists  and  designers,  who  were  not  a  little 
baffled  by  the  conflicting  and  rapidly  changing  demands  often 
expressed  with  emphasis  rather  than  illuminating  precision;  by 
the  time  new  features  in  design  could  be  given  air  trial  the  original 
demand  had  changed  out  of  recognition. 

And  for  military  requirements  something  more  than  controlla- 
bility was  required;  for  besides  having  to  control  the  aeroplane 
the  pilot  had  to  examine  maps,  operate  wireless,  watch  many  in- 
struments, navigate,  care  for  his  guns,  and  keep  a  perfect  look-out. 
If  the  controls  were  temporarily  released  the  aeroplane  ought  in 
some  measure  to  look  after  itself;  in  other  words,  be  stable.  In 
1914  the  BE2,  and  later  the  FEz,  aeroplanes  were  altered  so  as 
to  be  stable  longitudinally  in  partial  conformity  with  Busk's 
REi  design.  They  were  thereupon  called  BEaC  and  FE2B ;  with 
these  the  flier's  hands  were  free,  and  with  them  no  less  than 
seven  airships  were  brought  down,  a  result  no  doubt  assisted 

by  the  confidence  which  stability  inspired  in  night  flying.  But 
it  then  seemed  that  stability  impaired  controllability.  By  1916 
so  strongly  did  war  pilots  desire  the  maximum  of  control  that  for 
some  time  many  looked  upon  stability  with  disfavour.  Gradually, 
however,  a  neutral  stability  was  found  to  be  compatible  with 
the  desired  control.  An  added  safety  was  that  stable  aeroplanes 
would  automatically  tend  to  recover  from  a  spin  after  loss  of 
control,  and  that,  unlike  unstable  aeroplanes,  they  would  tend  to 
return  to  a  normal  attitude  if  they  became  inverted  uninten- 
tionally or  during  the  course  of  violent  manoeuvres.  Great  as 
was  this  advance  in  aerodynamic  knowledge,  problems  equally 
great  remain,  the  solution  of  which  can  only  be  reached  by  con- 
stant and  arduous  experiment. 

The  Return  to  Peace. — Civil  aviation  was  mainly  restarted  by 
the  conversion  of  war  types,  which  were  not  so  well  suited  as  if 
designed  for  the  purpose.  Specialization  of  type  commenced  in 
two  directions:  aeroplanes  destined  for  travel  and  transport  and 
those  designed  for  racing. 

The  year  1919  saw  wonders  as  great  as  any  that  had  gone  be- 
fore. On  June  i4th-isth  Alcock  crossed  the  Atlantic  on  a 
Vickers-Vimy  with  twin  Rolls  engines  in  16  hours  12  minutes,  by 
which  he  won  the  Daily  Mail  £10,000  prize,  and  for  which  he  was 
knighted.  Of  Hawker's  plucky  attempt  and  descent  into  mid- 
Atlantic;  of  Alcock's  battle  with  driving  mist,  cloud  and  darkness; 
of  the  navigation  of  Whitten  Brown,  his  companion;  above  all,  of 
the  human  endurance  underlying  the  feat,  it  is  impossible  to 
speak  in  measured  terms.  Just  prior  to  Alcock's  achievement 
there  was  one  of  a  different  kind,  a  triumph  of  organization  for  the 
Americans;  for  Lt.-Comm.  Read  and  his  crew  came  from  America 
to  England  via  the  Azores  and  Lisbon,  including  the  remarkable 
passage  of  150  m.  under  power  on  a  rough  sea,  in  the  flying-boat 
NC4.  In  the  late  autumn  Ross-Smith  and  his  brother  flew 
another  Vickers-Vimy  to  Australia  in  28  days,  won  the  £10,000 
offered  by  the  Australian  Government,  and  were  both  knighted. 

High-powered  racing  aeroplanes  again  appeared.  Janello,  in 
an  Italian  seaplane,  put  up  a  fine  performance  for  the  Schneider 
Cup  at  Bournemouth  at  a  speed  estimated  at  140  m.p.h.,  but, 
though  virtual  winner,  had  unfortunately  to  be  disqualified. 
Gathcrgood  won  the  Aerial  Derby  at  129  m.p.h.  on  a  De  Havi- 
land  aeroplane.  Racing  machines  reached  speeds  of  170  and  180 
m.p.h.,  and  climbs  were  made  to  over  30,000  feet. 

In  1920  Van  Ryneveld  flew  from  England  to  Cairo,  and  thence 
after  many  adventures  to  the  Cape.  He  crashed  two  aeroplanes  on 
the  way,  and  arrived  at  his  destination  on  a  third  supplied  by  the 
South  African  Government;  but  considering  the  conditions  for 
flying  in  Central  Africa  his  achievement  is  of  the  first  rank. 

The  Schneider  Cup  and  the  Gordon  Bennett,  two  classic  races, 
were  won  respectively  for  Italy  by  Lt.  Bologna  in  a  Savoia  sea- 
plane at  Venice  with  an  average  speed  of  io(5  m.p.h.,  and  by 
Sadi  Lecointe  at  Etampcs  at  169  m.  per  hour.  Courtney  won  the 
fifth  Aerial  Derby  in  a  Martinsyde  racer  with  an  average  speed 
of  153  m.  per  hour.  At  Etampes  the  Farman  "  Goliath,"  a  large- 
passenger  machine,  remained  aloft  for  24  hours  19  minutes,  beat- 
ing all  duration  records.  In  America  Maj.  Schroeder  on  a  Le  Pere 
biplane  with  a  supercharged  engine  reached  a  height  of  33,000 
feet.  The  fast  American  and  French  racers  continually  raised  the 
speed  record,  until  Sadi  Lecointe  on  a  Nieuport  reached  313  km. 
per  hour  over  a  measured  kilometre.  By  the  end  of  1920  racing 
machines  had  reached  a  speed  of  nearly  200  m.p.h.,  a  military 
type  scout  had  climbed  to  20,000  ft.  in  15  minutes,  a  large  com- 
mercial machine  had  climbed  to  15,000  ft.  with  a  weight  equiva- 
lent to  26  passengers,  fliers  had  climbed  over  six  miles  into  the 
air,  and  an  aeroplane  had  remained  aloft  for  over  24  hours. 

To  promote  safety,  experiments  were  carried  out  to  reduce 
landing-speed  while  retaining  a  reasonable  top  speed  by  means  of 
wings  variable  in  flight,  a  problem  to  the  solution  of  which 
Handley  Page  offered  a  notable  contribution.  In  spite  of  these 
and  other  difficulties  so  little  risk  now  remains  that  the  number 
of  miles  flown  for  every  accident  is  something  like  35,000,  or  one- 
and-a-half  times  round  the  world. 

The  years  from  1909  to  1920  reveal  a  story  of  progress  that, 
even  allowing  for  the  extraordinary  stimulus  of  the  World  War, 


is  surely  without  parallel  in  the  annals  of  engineering.    And  in 
this  story  may  be  found  the  hint  of  a  tremendous  future. 

See  also: — The  Royal  Aero  Club  Year  Books  (1911-9);  Flight 
(Jan.  1909  to  Dec.  1920,  the  Official  Organ  of  the  Royal  Aero  Club) ; 
Captain  McCudden,  Five  Years  in  the  Royal  Flying  Corps  (1918). 

(R.  M.  H.) 


Design  of  Lifting  Surfaces. — The  determination  of  the  forces 
acting  upon  a  body  moving  through  a  viscous  fluid,  such  as 
the  atmosphere,  is  a  problem  so  far  not  amenable  to  mathematical 
solution,  and  design  must  therefore  be  based  upon  experiment. 
A  vast  mass  of  experimental  data  has  been  obtained  by  testing 
models  in  wind  tunnels  (by  Eiffel  in  Paris,  by  Prandtl  at 
Gottingen,  at  the  National  Physical  and  other  laboratories)  and 
by  experiments  upon  aeroplanes  in  flight,  principally  in  England 
at  the  Royal  Aircraft  Establishment,  Farnborough.  A  very  use- 
ful amount  of  information  had  been  acquired  before  the  war, 
but  this  has  been  greatly  extended  during  the  war  period. 

Lifting-surfaces  of  various  shapes  have  been  used  in  the 
design  of  aeroplanes,  disposed  in  a  variety  of  ways.  It  was 
immediately  evident  that  the  span  or  spread  of  the  wing  across 
the  line  of  flight  should  be  large  in  comparison  with  the  "  chord  " 
or  dimension  along  the  flight  path.  The  ratio  of  the  span  to  the 
chord  has  been  termed  the  "  aspect  ratio."  Aerodynamic 
efficiency  increases  with  increasing  aspect  ratio;  but  it  is  desirable 
to  limit  the  aspect  ratio  for  constructional  reasons  and  in  order 
to  reduce  the  room  required  for  housing.  The  greater  aerody- 
namic efficiency,  moreover,  becomes  neutralized  after  a  point  by 
the  head  resistance  due  to  the  additional  external  bracing  re- 
quired. A  compromise  must  be  made,  and  the  average  figure 
used  is  in  the  region  of  six  to  one.  It  was  also  evident  that 
the  wings  should  be  cambered  along  the  line  of  flight.  The 
early  aeroplane  wings  had  approximately  the  same  curvature 
of  upper  and  lower  surfaces.  Wind-tunnel  experiments,  however, 
showed  that  the  curvature  of  the  under  surface  had  but  small 
influence  compared  with  that  of  the  upper  surface,  a  result 
which  enabled  the  designer  to  increase  the  thickness  and  in- 
ternal strength  of  the  wings  and  reduce  external  bracing. 

Extensive  wind-tunnel  research  has  been  carried  out  to  find 
the  best  cross-section  shape  of  wings.  Greater  lift  can  be  ob- 
tained from  highly  cambered  wings,  but  thinner  wings  offer 
less  resistance  to  motion  at  small  angles.  An  aeroplane  should 
have  as  large  a  speed  range  as  possible.  While  a  wing  of  high 
lifting-capacity  is  required  to  fly  slow,  small  resistance  is  re- 
quired for  fast  flying,  that  is  at  fine  angles  of  attack.  A  greater 
speed  range  is  obtained  by  the  use  of  wings  of  small  curvature 
(about  i  in  15),  the  same  lower  limit  being  attained  by  the  use 
of  a  larger  area  to  carry  a  given  weight.  Wind-tunnel  experi- 
ments further  determined  the  extent  to  which  the  curvature 
should  be  greater  towards  the  leading  edge  of  the  wing. 

Early  writers  sometimes  stated  the  requirements  of  a  wing 
as  consisting  purely  of  a  high  ratio  of  lift  to  resistance  at  some 
angle  of  attack.  The  requirements  are  in  reality  more  complex. 
To  secure  a  wide  range  of  speed  a  high  ratio  of  lift  to  resistance 
is  required  at  fine  angles  (fine  in  comparison  with  the  angle  at 
which  the  wing  attains  its  greatest  lift  at  a  given  speed)  and  in 
addition  a  high  value  of  this  ratio  is  required  at  the  inter- 
mediate angle  at  which  the  aeroplane  climbs.  This  is  not  all. 
For  longitudinal  stability  the  travel  of  the  centre  of  pressure 
when  the  angle  of  attack  varies  should  be  small,  as  this  travel 
on  a  curved  surface  produces  instability.  The  wing  section  best 
meeting  all  these  requirements  is  probably  the  British  Royal 
Aircraft  Factory's  No.  15,  designed  early  in  1916. 

•-Length  of  Chord — •> 

Rear  Spar 

Front  Spar 

Leading  ; 


FlG.  6.—  Wing  Section  R.A.F.  15. 

The  resistance  of  a  wing  must,  however,  be  considered  in  rela- 
tion to  the  resistance  of  the  external  bracing  attendant  upon 

its  use.  It  has  bee'n  suggested  that  the  thick  wing,  in  spite  of 
greater  head  resistance  due  to  the  wing,  might  prove  superior 
by  making  possible  the  suppression  of  all  external  bracing,  and 

o  s          10        is         20 

FIG.  6b. — Variation  of  the  ratio 
of  lift  to  Resistance  for  the  wing 
alone  as  the  Angle  varies. 





0  5  10  15  2f 

FIG.  6a.— Variation  of  the  Lift  FIG.  6c.— Travel  of  Centre  of 
and  Resistance  of  awing  with  Pressure  as  Angle  of  Attack 
Angle  of  Attack.  varies. 

the  German  Junker  and  others  have  designed  aeroplanes  on 
these  lines. 

The  term  "  wing  "  is  commonly  used  of  the  half  of  a  lifting- 
surface  on  one  side  of  the  aeroplane,  the  whole  surface  con- 
stituting a  "  plane."  Thus  a  monoplane  has  one  pair  of  wings. 
A  tandem  aeroplane  has  two  or  more  pairs  of  wings  arranged 
as  the  name  implies.  The  terms  "  biplane,"  "  triplane,"  "  quad- 
ruplane  "  denote  that  two,  three,  or  four  planes  are  superposed. 
Langley's  "  aerodrome  "  is  an  early  example  of  the  tandem 
aeroplane.  This  type  is  inconvenient  structurally  and  aerody- 
namically  very  inefficient.  The  rear  plane  acts  upon  air  to  which 
a  downward  trend  has  been  imparted  by  the  plane  in  front.  The 
reaction  upon  the  rear  plane  is  therefore  inclined  backward  by 
the  angle  through  which  the  air  has  been  "  downwashed  " 
by  the  leading  plane.  In  multiplane  systems  in  which  the 
planes  are  placed  one  above  the  other,  each  plane  operates  in 
air  whose  motion  is  influenced  by  the  others,  and  the  ratio  of 
resistance  to  lift  is  less  than  the  ratio  which  each  would  expe- 
rience if  acting  alone.  If,  however,  the  planes  are  placed  at  a 
sufficient  distance  apart,  so  that  the  gap  between  is  roughly 
equal  to  the  chord  of  the  planes,  the  mutual  interference  pro- 
duces an  effect  comparable  with  that  due  to  a  reduction  in 
aspect  ratio  such  as  is  found  necessary  in  the  design  of  a  mono- 
plane. Using  the  same  aspect  ratio  a  given  area  is  disposed  in 
a  biplane  in  half  the  span  required  in  a  monoplane.  The  biplane 
forms  a  good  structure,  the  planes  forming  the  flanges  of  a  box 
girder.  In  the  monoplane  the  bracing  wires  make  small  angles 
with  the  planes,  with  consequent  high  tension  in  the  wires  and 
high  compression  in  the  spars  of  the  wing.  In  the  biplane  the 
wires  make  obtuser  angles  with  the  planes.  In  reviewing  the 
examples  of  the  two  types,  it  is  found  that  the  monoplanes  are 
relatively  of  heavy  wing  loading  and  low  aspect  ratio.  In  the 
triplane  the  upper  and  lower  planes  may  form  the  flanges  of  the 
girder,  or  the  structure  may  consist  of  two  girders  superposed. 
This  does  not  possess  the  same  structural  superiority  over  the 
biplane,  as  does  the  latter  over  the  monoplane.  The  triplane 
arrangement  provides  a  means  of  reducing  span  by  increasing 
height.  An  early  example  of  the  triplane  is  that  designed  and 
flown  by  A.  V.  Roe  in  1909.  A  Sopwith  triplane  was  used  by 
the  British  army  during  the  war.  The  type  may  be  suitable  to 
large  aeroplanes,  in  which  reduction  of  the  weight  of  the  structure 
and  of  bulk  is  especially  needed. 

The  great  majority  of  aeroplanes  have  been  of  the  monoplane 
and  the  biplane  types,  the  latter  predominating  since  1912. 
The  first  aeroplanes  to  fly  were  biplanes  and  by  far  the  larger 
number  of  aeroplanes  in  use  to-day  are  of  this  type.  The 
monoplane  appeared  about  the  opening  date  of  the  period  under 



FIG.  7. — Early  Wright  Aeroplane.    (Propeller  Biplane.)  (Elevators 
in  Front ;  Rudder  in  Rear.) 

discussion,  and  on  an  aeroplane  of  this  type  Bleriot  crossed  the 
Channel  in  July  igog.  It  was  more  cleanly  designed  than  the 
biplane  of  that  date  and  was  regarded  as  the  faster  type.  It 
was  largely  used  for  trick  flying,  and  figured  ever  more  widely  in 
aeronautical  exhibitions.  At  the  outset  of  the  war  it  had  still 
a  reputation  for  speed,  but  had  found  a  rival  in  the  better  de- 

FlG.  73. — Early  Farman  Aeroplane.    (Propeller  Biplane.)  (Elevator 
in  Front;  Rudder  in  Rear.) 

FIG.  7b. — Early  B16riot  Aeroplane.    (Tractor  Monoplane.)    (Eleva- 
tors and  Rudder  in  Rear.) 

signed  "  tractor  "  biplanes.  During  the  war  the  monoplane 
was  more  largely  used  by  the  French  and  the  Germans  than 
by  the  British.  The  names  most  associated  with  the  monoplane 
are  French:  Bleriot,  Morane,  Nieuport.  The  "  Fokker  "  mono- 
planes used  by  the  Germans  take  their  name  from  a  Dutch 
designer  probably  inspired  by  the  French  designs.  During  the 
years  1914-8,  the  biplane  was  in  the  ascendant,  but  the  mono- 
plane was  afterwards  revived  in  the  form  of  the  aeroplane  with 
thick  "  cantilever "  wings  without  external  bracing.  The 
monoplane  appears  to  be  a  type  convenient  in  small  sizes,  but 
unsuited  for  the  larger  aeroplanes. 

FIG.  8.— Modern  Tractor  Biplane. 

Position  of  the  Airscrew. — Airscrews  have  been  described  as 
"  tractor  "  or.  "  propeller  "  according  as  the  airscrew  shaft 
is  placed  in  tension  or  in  compression  by  the  thrust,  and  cor- 
responding aeroplanes  are  usually  called  by  the  same  names. 
The  first  biplanes,  those  of  the  Wrights  and  the  Farmans,  were 
of  the  "propeller"  type,  colloquially  "pushers";  almost  all 
monoplanes  were  "  tractors." 

In  the  tractor,  monoplane  or  biplane,  the  order  of  disposition 
of  the  component  parts  is  generally  from  front  to  rear: — air- 
screw, engine,  crew;  and  the  body  is  prolonged  to  carry  stabiliz- 
ing and  controlling  surfaces  at  the  rear.  In  the  pusher  the  order 
is  reversed  and  the  controlling  surfaces  are  carried  on  an  open 
frame  ("  outriggers  ")  in  front,  at  the  rear,  or  in  both  positions. 

On  a  "  pusher  "  the  field  of  view  forward  is  superior,  and  great 
stress  was  laid  upon  this  by  the  British  War  Office  after  the 
military  trials  in  1912.  The  necessity  of  aerial  fighting  was 
proved  in  1914,  and  the  tractor  was  found  unsuitable  owing  to 
the  obstruction  in  the  most  effective  direction  for  firing.  Pushers 
were  therefore  ordered  for  fighting,  at  first  carrying  pilot  and 
gunner,  and  later  carrying  only  one  man  with  a  machine-gun 
fixed  in  the  aeroplane.  The  situation  was  completely  altered 
by  the  device  of  firing  through  the  airscrew-  disc.  The  blades 
were  at  first  protected  by  deflector  plates,  but  shortly  after 
mechanism  was  used  to  time  the  fire  between  them,  the  inven- 
tion of  Constantinescu,  a  Rumanian.  The  aeroplane  was  directed 
bodily  at  the  target.  The  "  tractor  "  then  replaced  the  "  pusher  " 
fighting  aeroplane;  but  "  propeller  "  airscrews  continued  to  be 
used  on  seaplanes,  on  aeroplanes  for  night  duty  against  Zeppelins, 
and  on  large  twin-engine  aeroplanes. 



The  "  tractor  "  is  the  more  convenient  design,  slightly  better 
aerodynamically  and  reputed  safer  in  a  "  crash." 

FIG.  9.— Propeller  Biplane  of  1914-16. 

Weight  and  Head  Resistance. — The  aeroplane  designer  is 
continually  interested  in  the  relative  importance  of  weight  and 
head  resistance.  At  the  start  attention  was  naturally  concen- 
trated upon  the  production  of  a  light  structure.  Knowledge  of 
the  resistance  to  motion  of  bodies  of  various  shapes  was  meagre 
and  was  most  probably  gauged  in  the  mind  of  the  designer  by 
the  frontal  area  exposed,  irrespective  of  shape.  It  was  not  real- 
ized that  a  strut  of  circular  section  offers  twelve  times  the 
resistance  of  a  strut  of  the  best  "  streamline  "  or  "  fair  "  shape 
of  the  same  frontal  area.  The  light  biplane  structure  of  the 
Wrights  and  the  Farmans  contained  a  network  of  struts  and 
wires  offering  a  very  high  resistance.  To  reduce  resistance, 
exposed  parts  may  be  "  faired,"  which  involves  adding  weight; 
and  the  number  of  external  parts  may  be  reduced,  which 
again  increases  the  weight  of  the  structure.  Wrights  and  Far- 
mans  may  be  contrasted  with  the  fast  monoplanes  and  biplanes, 
the  latter  employing  only  a  single  bay  of  struts  on  either 
side,  and  finally  with  the  unbraced  monoplanes  of  Junker 
and  Fokker. 

"  Streamline  "  wires  were  first  designed  for  the  British  army 
dirigible  "Beta"  in  1912,  and  fairshaped  wires  were  in  1914 
fitted  to  aeroplanes  designed  at  the  Royal  Aircraft  Factory. 
They  have  since  become  the  most  usual  bracing  of  British  aero- 
planes. They  offer  approximately  one-eighth  of  the  resistance 
of  cable  of  the  same  tensile  strength.  Their  metallurgy  required 
careful  study,  and  hence  in  other  countries  cable  has  con- 
tinued to  be  used,  frequently  duplicated,  the  cables  lying  one 
behind  the  other  with  a  wood  "  fairing  "  between  them.  Struts 
of  streamline  shape  were  in  use  at  an  earlier  date.  The  bodies 
of  aeroplanes  have  improved  in  form,  the  crew  has  been  pro- 
tected from  wind  pressure,  and  the  spokes  of  wheels  have  been 
covered  in  with  fabric. 

The  drag  of  a  biplane  of  moderate  speed  is  made  up  roughly 
as  follows  i—- 
Main  planes 3°% 

Bracing  of  main  planes 20% 



Undercarriage 15% 

Tail  surfaces       .        .        .       .  •• 5% 

These  figures  show  the  importance  of  careful  design  of  all  parts 
Much  of  the  resistance  of  the  wing-bracing  occurs  at  the  joints 
of  wires  and  struts  to  the  planes,  and  the  resistance  of  the  body 
is  largely  due  to  the  necessity  of  cooling  the  engine,  either  by 
water  radiator  or  by  flow  of  air  over  the  cylinders. 

The  weight  of  the  complete  structure,  excluding  the  power 
unit,  fuel,  crew  and  other  load  borne,  is  about  one-third  of  the 
whole  weight  of  the  aeroplane,  but  varies  with  the  total  weight 
with  the  weight  carried  per  unit  of  area  of  lifting  surface,  anc 
with  the  strength  of  the  structure.  The  following  figures  are 
averages  for  a  number  of  British  aeroplanes: — 

Total  weight 

Area  of  lifting  surface 

Load  borne  per  unit  area 

Load  factor 

Structure  weight  of  %  of 

total  weight.      .        .        .  28  %  35  %  27  %  34  % 

2,000  Ib. 


4    I    8 

200  sq. 

10,000  Ib. 


31%  40%  29% 


The  "  load  factor  "  is  the  number  of  times  the  weight  of  the 
craft  which  the  wings  will  support;  a  measure  of  the  strength. 

Using  one  of  the  light  engines  now  available,  the  power 
unit  to  give  a  speed  of  100  m.  an  hour  will  weigh  about  one- 
quarter  of  the  total,  leaving  40  to  45  %  for  fuel,  crew  and  cargo. 

Wing  Loading  and  Horse-Power. — The  lift  of  a  wing  is  pro- 
jortional  to  its  surface,  the  atmospheric  density,  the  square  of 
:he  speed  and  the  angle  at  which  it  meets  the  air  measured 
rom  the  angle  giving  no  lift  and  up  to  an  angle  near  that 
known  as  the  "  critical  angle."  At  this  angle  the  lift  is  a  maxi- 
mum (if  the  other  factors  be  supposed  constant)  and  above  it  the 
lift  decreases.  The  wing  in  passing  through  this  angle  is  said  to 
be  "  stalled."  Stalling  occurs  when  flying  as  slowly  as  possible. 
After  stalling  it  is  no  longer  possible  to  increase  the  lift  by  de- 
pressing the  tail  of  the  aeroplane  and  it  is  necessary  to  dive  in 
order  to  recover  flying  speed.  This  has  been  a  frequent  cause 
of  accidents  when  flying  too  low  to  have  room  for  a  dive.  More- 
over, the  wings  when  stalled  have  lost  their  normal  tendency 
to  oppose  rotation  about  the  line  of  flight  and  now  tend  to 

auto-rotate "  or  act  as  a  windmill.  The  aeroplane  may 
therefore  drop  one  wing  and  pass  into  a  steep  spiral  glide  known 
as  a  "  spinning  nose-dive  "  from  which  it  may  be  brought  to 
normal  flight  by  the  same  diving  process  reducing  the  angle  of 
attack  of  the  wings.  There  is  no  danger  in  the  stall  or  the  spin 
so  long  as  there  is  space  for  the  recovery  and  knowledge  of  the 
action  required. 

100  M.P.H. 


6  10  '6   Ibs./sq.  ft. 

FIG.  10. — Curve  showing  lowest  speed  of  flight  possible  with  given 
wing-loading  and  the  usual  thin  wings. 

Wing-loading,  the  weight  borne  per  unit  area  of  sustaining 
surface,  determines  the  speed  at  which  the  wings  become 
stalled  and  therefore  the  slowest  alighting  speed.  With  constant 
loading,  as  the  speed  of  aeroplanes  increases,  wings  attack  the 
air  at  ever  finer  angles,  very  soon  passing  the  angle  of  lowest 
resistance  for  a  given  lift.  To  increase  speed  it  therefore  becomes 
desirable  to  increase  the  loading,  or  in  other  words  to  reduce  the 
area  of  the  wings.  This  reduction  has  also  the  merit  that  it 
reduces  the  bulk  of  the  craft,  the  resistance  of  external  bracing 
and  the  weight  of  the  wing  structure.  To  attain  the  greatest 
height  heavy  wing-loading  is  not  required,  and  the  best  loading 
for  a  high  ceiling  would  to-day  be  considered  a  light  loading. 
For  fighting,  power  of  rapid  manoeuvre  is  essential.  The 
aeroplane  of  light  loading  can  be  turned  in  a  smaller  circle.  The 
total  weight  is,  however,  approximately  fixed  by  military  con- 
siderations, and  light  loading  implies  large  wing  area  and  con- 
sequent greater  resistance  to  angular  acceleration,  so  that  the 
lightly  loaded  aeroplane  cannot  so  quickly  be  "  banked  "  to 
the  correct  angle  for  the  turn.  Given  the  wing  area,  the  aero- 
plane having  the  lighter  loading  is  the  more  manoeuvrable; 
given  the  weight,  the  heavier  loaded  aeroplane  is  at  least  the 
equal  of  the  other.  Aeroplanes  carry  a  larger  area  of  sustaining 
surface  than  they  require,  except  for  alighting,  and  it  is  the 



difficulty  of  bringing  the  aeroplane  to  land  at  high  speeds 
which  prevents  the  increase  of  loading  beyond  10  Ib.  to  the 
square  foot. 

In  commercial  use,  economy  dictates  an  increase  of  loading; 
safety  demands  that  the  aeroplane  may  alight  at  speeds  and  in 
a  space  impossible  with  high  loading.  Attempts  have  been 
made  to  make  the  wing  area  or  the  wing  shape  variable  in  order 
to  reduce  the  lowest  speed  of  flight,  while  retaining  the  other 
advantages  of  heavy  loading.  None  has  so  far  been  successful. 

ISO  M.P.H. 






100    h.p./IOOO  Ibs. 

FIG.  II. — Diagram  showing  speeds  attained  by  British  aeroplanes 
at  a  height  of  10,000  feet.  The  speeds  vary  between  the  upper  and 
lower  curves.  The  base  is  engine  power  at  ground  level  per  1,000 
pounds  of  total  weight.  The  dotted  lines  are  lines  of  constant  ratio 
of  tractive  force  to  weight,  marked  with  the  values  of  this  ratio. 

30,000     FEET 




10O  h.p./1.000  Ibs. 

FIG.  12.— Diagram  showing  greatest  effective  height  attainable  by 
British  military  aeroplanes.  These  vary  between  the  upper  and 
lower  curves.  The  base  is  engine  power  at  ground  level  per  1,000 
pounds  of  total  weight. 

During  the  period  1909  to  1921  the  speed  attained  by  aero- 
planes was  more  than  doubled.  The  rate  of  climb  and  the  height 
attainable  have  increased  in  a  larger  ratio.  Greater  knowledge 
and  better  design  have  improved  the  aerodynamic  efficiency  of 
the  aeroplane;  but  the  improvement  of  performance  is  in  the 
main  due  to  the  use  of  larger  engines.  In  1918  four  times  the 
power  was  being  used  that  was  used  in  1914  for  the  same 

purpose — the  reconnaissance  two-seater  aeroplane — and  the 
speed  is  more  than  half  as  great  again.  Aerodynamically  there 
is  little  difference  between  the  two  aeroplanes.  As  the  power 
of  engines  grew  their  weight  per  horse-power  was  reduced. 
To  save  two  pounds  in  every  four  on  an  engine  weighing  one- 
third  of  the  whole  aeroplane  was  important. 

The  largest  engines  developed  were  insufficient  for  the  larger 
aeroplanes,  into  which  two  engines  were  commonly  built,  and 
in  some  cases  four  or  more. 

FIG.  13. — Large  Twin-Engine  Aeroplane. 

Two  separate  power  units  have  been  regarded  as  conducive 
to  safety.  Experience  has  so  far  not  confirmed  this.  It  is  essen- 
tial that  the  power  of  one  engine  alone  should  be  sufficient  to 
fly  the  aeroplane,  and  the  "  twin-engine  "  aeroplanes  used  during 
the  war  were  not  all  provided  with  so  large  a  total  power. 
Again,  the  engines  were  carried  on  either  side  of  the  centre  and 
the  line  of  thrust  of  each  offset  by  a  considerable  amount. 
This  introduced  difficulties  of  control,  because  rudders  Vere 
unable  to  balance  the  offset  line  of  thrust  at  the  low  speed  at 
which  the  aeroplane  could  be  flown  level  on  one  engine  only, 
and  there  was  danger  in  the  event  of  sudden  failure  of  -one 
engine  near  the  ground. 

The  table  gives  some  particulars  of  a  few  typical  aeroplanes 
through  the  period  under  review.  The  figures  are  approximate : — 






Ib.  per 
sq.  ft. 
























1  68 




Roe  triplane 







Dunne  . 








Cody     . 








Roe  biplane 








The  horse-power  and  speed  given  above 

Aeroplanes  in 
British  War 


are  u 





Office  trials 






1912   . 






BE2C    . 








Bristol  Fighter    . 







SE5a    .        .'      . 








Sopwith  Camel    . 








Handley  Page 









De  Haviland  gA 








Martinsyde  F4    . 
De  Haviland 








loA   . 








Handley  Page 

V/iSoo      . 








The    Large    Aeroplane.— For    the    same    aerodynamic    per- 
formance, the  lifting-surface  of  an  aeroplane  must  be  proper- 


tional  to  the  weight.  If  aeroplanes  of  all  sizes  were  constructed 
of  the  same  materials  and  geometrically  similar  in  all  parts,  the 
weight  of  the  structure  would  increase  with  increasing  size  as 
the  cube  of  the  linear  dimensions,  that  is,  as  the  3/2  power  of 
the  total  weight.  This  does  not  in  fact  obtain,  because  geo- 
metric similarity  would  give  greater  strength  to  the  larger 
aeroplane;  also  the  design  may  be  elaborated  and  materials 
worked  to  relatively  finer  dimensions;  and  moreover,  large 
aeroplanes  are  not  designed  to  have  the  same  strength  as  smaller 
craft,  as  they  are  less  sharply  manoeuvred.  Nevertheless,  the 
weight  of  the  structure  is  to  be  expected  and  is  in  fact  found 
to  become  a  larger  proportion  of  the  total  weight  as  the  size 
increases.  It  is  therefore  disadvantageous  to  increase  size  in- 
definitely and  there  is  in  fact  a  best  size  depending  upon  the 
duty  to  be  done. 

To  carry  an  indivisible  unit  of  cargo,  such  as  a  large  bomb,  an 
aeroplane  of  at  least  a  certain  size  is  required;  hence  we  find 
size  increasing.  Sometimes  it  is  preferable  to  carry  a  total  load 
in  a  smaller  number  of  larger  aeroplanes,  because  the  weight 
of  the  crew  becomes  less  in  proportion  to  the  cargo  carried,  so 
that  every  square  foot  of  wing  and  every  unit  of  engine  power  of 
a  fleet  carries  more  useful  load.  Initial  outlay  and  fuel  consump- 
tion are  reduced  and  there  is  further  an  economy  of  pilots.  At 
some  point  the  larger  aeroplane  requires  a  larger  crew,  and  for 
war  the  larger  "  bomber  "  must  carry  a  number  of  gunners  and 
offensive  armament  for  defence  against  more  mobile  attackers. 
The  optimum  size  for  a  commercial  service  with  a  sufficient 
volume  of  traffic  is  what  would  be  termed  to-day  a  large  aero- 
plane (say  7,000  Ib.  at  least).  The  actual  size  depends  to  some 
extent  upon  the  speed  of  the  service,  which  governs  the  relative 
costs  of  fuel  and  personnel,  and  also  upon  the  distances. 

The  first  large  aeroplane  flown  was  the  Russian  Sykorsky  in 
1913.  Large  aeroplanes  were  demanded  in  1915  for  bombing 
and  were  increasingly  used  during  the  war.  The  Handley  Page 
(13,000  Ib.  gross)  was  extensively  used  by  the  British.  The 
"  Gotha  "  and  others  were  used  for  raids  on  London.  The  same 
Handley  Page  aeroplanes  and  a  subsequent  design  were  em- 
ployed on  a  passenger  service  between  London  and  Paris  through- 
out 1919  and  1920.  The  "  Vimy  "  (12,500  Ib.  gross)  crossed 
the  Atlantic,  flew  from  Cairo  to  the  Cape,  and  from  Europe 
to  Australia,  and  has  been  used  on  a  London-Paris  commercial 

Controlling  Surfaces. — Stability  in  aviation  is  discussed  in  Section 
III.  Complete  inherent  stability  is  obtainable  by  a  proper  dis- 
tribution of  weight  and  subsidiary  surfaces  and  suitable  arrangement 
of  the  main  planes.  The  planes  are  commonly  inclined  upwards 
from  root  to  tip  to  secure  a  righting  couple  if  one  wing  tip  falls  and 
the  aeroplane  begins  to  sideslip.  A  vertical  surface  at  the  rear, 
known  as  a  fin,  is  general  although  the  rudder  may  entirely  replace 
this  surface.  The  travel  of  the  "  centre  of  lift  "  of  the  wings  is  such 
as  to  produce  instability,  and  a  subsidiary  horizontal  surface  is 
required  either  in  front  or  in  the  rear.  To  secure  "  longitudinal  " 
stability,  the  centre  of  gravity  must  be  sufficiently,  forward  in  rela- 
tion to  the  main  planes,  and  the  load  on  the  subsidiary  surface  main- 
tains equilibrium.  The  aeroplane  has  three  degrees  of  angular 
freedom  and  has  almost  invariably  employed  three  means  of  con- 
trol: elevators,  to  produce  a  "  pitching  '  motion,  and  so  govern  the 
angle  of  attack  of  the  wings  and  the  speed  of  flight ;  rudders  to  pro- 
duce motion  about  the  vertical  axis ;  and  warp  or  ailerons,  to  secure 
lateral  balance  and  adjust  the  angle  of  "  bank."  The  early  Voisin 
aeroplanes  had  no  control  for  lateral  balance.  The  aeroplane  when 
turning  has  a  natural  tendency  to  bank,  which  is  accentuated  or 
reduced  by  sideslip  outwards  and  inwards  respectively  if  the  wings 
are  inclined  upwards  from  root  to  tip  or  fitted  with  a  vertical  surface 
above  the  centre  of  gravity.  The  Voisin  aeroplane  carried  curtains 
between  the  planes  to  provide  this  righting  couple  and  was  sufficiently 
controllable  for  the  requirements  of  the  pioneer  content  to  achieve 
flight.  "  Lateral  "  control  is  desirable  and  is  clearly  necessary  for 
rapid  manoeuvring.  The  Wrights  obtained  this  by  twisting  or 
"  warping  "  the  wings,  and  this  method  was  extensively  used  up  to 
the  end  of  1914.  Control  has  been  more  generally  obtained  by  means 
of  hinged  portions  of  the  wings  at  the  rear  near  the  wing  tips. 

Elevators  have  been  placed  both  in  front  and  in  the  rear:  rudders 
always  in  the  rear.  They  have  constituted  the  whole,  or  only  a  part 
of,  the  necessary  stabilizing  surfaces.  Control  with  a  single  rudder 
requires  an  effective  "  keel  "  surface,  which  is  adequately  provided 
by  the  body  of  the  aeroplane  and  the  exposed  struts  of  the  structure. 
The  tendency  of  design  towards  the  "  tractor  "  type  places  elevators 
and  rudders  most  conveniently  at  the  rear  end,  and  this  gives  a 

clear  field  of  view  forwards.  The  early  biplanes  with  an  elevator  in 
front  and  rudder  at  the  rear  disappeared  about  1914 ;  the  monoplanes 
conformed  to  the  modern  usage.  Both  elevators  and  rudders  are 
usually  hinged  portions  of  fixed  surfaces,  but  in  some  cases  the  entire 
surface  has  been  movable  and  constituted  the  elevator  or  rudder. 
The  latter  arrangement  has  not  provided  stability  if  the  controls  were 
abandoned.  Later  the  fixed  horizontal  surface  was  made  adjustable 
by  the  pilot  during  flight  and  known  as  a  "  trimming  tail  plane," 
a  device  much  used  by  the  British  from  1916  onwards.  It  enabled  the 
flier  to  vary  the  speed  of  flight  at  which  no  pressure  upon  the  con- 
trolling lever  was  required,  and  effectively  increased  the  range  of 
control  resulting  from  the  application  of  a  definite  force. 

The  arrangement  of  control  levers  or  wheels,  at  first  very  diverse, 
became  standardized  in  1915—6,  and  consists  of  a  "  rudder  bar  " 
operated  by  the  feet  and  a  hand  lever  whose  fore-and-aft  movement 
operates  the  elevators  and  whose  lateral  movement  provides  latera, 
control.  The  rudder  bar  and  the  lever  are  moved  in  the  direction 
in  which  it  is  desired  to  move  the  aeroplane.  In  larger  aeroplanes 
rotation  of  a  wheel  mounted  on  the  fore-and-aft  lever  actuates  the 
ailerons,  the  fore-and-aft  control  remaining  as  before.  The  lever 
or  wheel  is  generally  connected  to  the  control  surfaces  by  steel 
cables,  although  shafts  in  torsion  and  tension  or  compression  mem- 
bers have  also  been  used. 

Balanced  control  surfaces,  although  in  use  from  an  early  date, 
only  became  necessary  as  the  size  of  aeroplanes  increased.  A  part 
of  the  surface  to  be  balanced  is  carried  in  front  of  the  hinge  and  this 
surface  is  most  frequently  the  rear  portion  of  a  fixed  element,  the 
part  brought  forward  of  the  hinge  being  extended  beyond  the  end 
of  the  fixed  element.  This  so-called  "  horn  "  balance  proved  un- 
satisfactory. If  a  large  "  horn  "  were  used  (adequate  to  give  ease  in 
normal  flight),  there  was  overbalance  at  low  speeds,  or  when  the 
aeroplane  sideslipped,  and  the  controls  would  then  tend  to  "  take 
charge."  A  more  uniform  effort  results  if  the  balancing  projection 
is  run  the  full  span  of  the  hinge,  which  must  then  be  set  back  behind 
the  fixed  element.  The  front  edge  of  the  balanced  surface  is  sharp 
and  its  movement  takes  place  behind  the  bluff  end  of  the  fixed 
element.  Alternatively  separate  balancing  surfaces  in  advance  of 
the  hinge  have  been  rigidly  attached  to  the  moving  element  and 
placed  above  the  fixed  element. 



FIG.  14. 

FIG.  143. 

Two  Methods  of  Balancing  Ailerons. 

The  imperfection  of  balancing  obtained  has  led  to  the  develop- 
ment of  relay  motors  to  reduce  the  effort.  In  these,  power  derived 
from  the  air  by  a  small  windmill  is  brought  into  play  whenever  the 
flier  attempts  to  move  the  controls.  Relay  motors  had  been  but 
little  used  up  to  1921. 

Chassis  or  Undercarriage. — The  Wright  aeroplane  alighted 
upon  skids.  It  was  launched  by  a  catapult.  The  French  pioneers 
took  the  air  under  their  own  power,  and  the  Farman  and 
Bleriot  used  wheels.  From  1909-14  combined  wheels  and  skids 
were  used.  The  wheels  were  commonly  sprung  by  means  of 
'rubber  cord.  The  skids  might  be  brought  into  action  if  the  alight- 
ing were  imperfectly  executed,  and  were  carried  well  forward 
to  prevent  the  aeroplane  from  turning  over  forwards  when  land- 
ing. Sometimes  additional  wheels  were  fitted  in  a  forward 
position  in  place  of  the  skids  for  this  purpose.  Under  the  tail  a 
wheel  was  often  fitted,  but  a  small  skid  was  used  alternatively. 
Wing-tip  wheels  or  more  commonly  light  skids  were  used  to 
protect  the  wing  tips  from  contact  with  the  ground.  In  Bleriot's 


undercarriage  the  wheels  were  mounted  as  castors  to  facilitate 
landing  across  the  wind.  This  was  subsequently  abandoned. 

The  common  arrangement  of  undercarriage  comprises  a  pair 
of  wheels  a  little  forward  of  the  centre  of  gravity  of  the  aeroplane 
and  a  small  tail  skid.  The  wheels,  of  wire-spoke  construction 
with  pneumatic  tires,  are  carried  on  an  axle  of  steel  tube  at- 
tached to  two  V-struts  from  the  aeroplane  by  rubber  cord. 
The  tail  skid  is  also  sprung  by  means  of  rubber  and  is  mounted 
on  a  swivel.  Steering  on  the  ground  was  improved  in  1912  by 
arranging  the  tail  skid  to  be  moved  by  the  rudder  -bar.  The  use 
of  skids  and  wheels  ahead  of  the  main  wheels  was  generally 
abandoned  early  in  the  war,  except  in  the  case  of  large  aero- 

Steel  springs  have  been  used,  but  rubber  is  superior  to  steel 
because  it  stores  more  energy  for  a  given  weight.  Hysteresis  in 
rubber  is  also  much  greater  than  in  steel.  To  avoid  bouncing 
after  the  first  shock  the  energy  received  on  impact  should  be 
restored  as  little  as  possible.  This  requirement  led  to  the  design 
of  undercarriages  containing  a  combination  of  steel  spring  and 
oil  dashpot,  such  as  the  "  Oleo  "  design  fitted  to  the  Breguet 
and  to  the  Royal  Aircraft  Factory's  "  BE-2  "  in  1914.  This 
form  of  "  shock  absorber  "  was  chiefly  useful  for  night  flying. 

Methods  of  Construction. — The  first  experimenters  built  their 
aeroplanes  of  wood  and  fabric  with  metal  at  joints  and  in  the 
form  of  piano-wire  bracing.  The  aeroplane  of  to-day  uses  spruce 
for  beams  and  struts  and  steel  for  joints  and  tension  members,  the 
latter  in  the  form  of  stranded  cable,  or  "  rafwires,"  i.e.  rods 
rolled  to  a  "  streamline  "  section.  Wings  and  body  are  covered 
with  linen,  pulled  taut  by  "  dope,"  and  varnished  or  painted 
for  protection  from  sunlight  and  moisture.  Frames  composed 
entirely  of  metal  were  used  as  early  as  1911,  but  wood  remains 
in  general  use,  except  for  the  tropics.  Steel  tubes  have  been 
extensively  used  in  parts,  notably  for  the  part  of  the  body  to 
which  the  engine  is  attached,  for  struts  between  the  planes,  and 
in  the  undercarriage.  The  use  of  steel  tubes  for  the  engine- 
bearers  gave  place  to  wood  owing  to  the  greater  absorption  of 
vibration  obtained. 

The  wings  in  the  common  type  of  biplane  contain  two  wood 
spars  of  I  or  box  section  forming  the  flanges  of  a  truss  braced  by 
wood  or  steel  struts  and  cables  or  solid  wires.  To  these  spars  are 
attached  transverse  ribs  which  give  the  shape  of  the  wing  and  a 
light  wood  edge  completes  the  frame.  The  linen  covering  is  sewn 
on  to  this  with  a  seam  along  the  rear  edge;  stitched  to  every  rib 
since  1914.  The  body  is  most  often  a  frame  of  wood  compression 
members  and  wire  bracing.  Bodies  built  of  three-ply  wood,  with  or 
without  reinforcing  members,  have  also  been  used.  These  retain 
their  shape  better  and,  being  infinitely  redundant  structures,  have 
perhaps  some  advantage  against  rifle  fire;  but  the  former  have 
been  preferred  apparently  as  being  more  easily  repaired  and  in- 
spected and  allowing  of  a  more  certain  calculation  of  stresses. 

Metal  construction  advanced  further  in  Germany  than  in  other 
countries.  Junker  produced  aeroplanes  without  external  bracing, 
strength  being  obtained  by  the  use  of  thick  wings.  These  contained 
in  place  of  the  usual  two  spars  a  number  of  steel  tubes  interconnected 
by  tubes  forming  triangles.  The  wings  were  covered  with  aluminium 
sheet  corrugated  so  that  the  air  flowed  along  the  corrugations.  The 
interconnecting  tubes  and  the  corrugations  replaced  the  usual  ribs. 
Great  Britain  has  experimented  with  spars  and  ribs  of  steel  and 
duralumin,  and  secured  the  necessary  strength  without  increase  of 
weight;  but  metal  construction  is  still  in  the  experimental  stage. 
The  principal  difficulty  in  the  use  of  steel  lies  in  the  prevention  of 
local  buckling  due  to  the  thin  gauge  of  metal  required  to  secure  a 
light  structure.  Welding  is  unreliable  owing  to  the  impossibility 
of  detecting  weakness  in  the  finished  part,  and  joints  are  made  by 
rivets  or  bolts.  Bodies  have  been  made  of  duralumin  on  the  same 
lines  as  those  built  of  three-ply  wood. 

The  Strength  Required  in  the  Structure. — The  aeroplane  structure  is 
subjected  to  a  very  variable  load.  In  straight  flight  the  wings 
support  the  weight  of  the  craft.  A  sudden  gust,  or  change  in  the 
direction,  or  speed  of  the  relative  wind,  momentarily  increases  or 
decreases  the  load.  To  estimate  the  extent  of  this,  the  proportion 
which  any  possible  gust  bears  to  the  speed  of  flight  must  be  known. 
On  a  banked  turn  or  when  returning  to  level  flight  after  diving, 
the  wings  must  provide  an  accelerating  force,  depending  upon  the 
rate  of  turn  and  the  speed  of  flight.  The  pioneers  were  content  to 
fly  warily,  and  the  accelerations  necessary  when  they  turned  were 
small.  The  larger  variations  in  loads  were  due  to  gusts.  They  flew 
only  in  the  calmest  weather,  but  their  speed  was  slow.  As  soon  as  the 
aeroplane  was  used  for  trick  flying,  the  effect  of  gusts  became 
relatively  insignificant,  and  the  accelerations  due  to  manoeuvres 

became  the  necessary  basis  of  design.  In  an  aerial  combat  the  wings 
may  have  to  sustain  over  three  times  the  normal  load,  and  it  is  not 
practicable  to  design  a  fighting  aeroplane  for  the  accelerations  which 
could  be  produced  by  flattening  out  too  rapidly  from  a  steep  dive, 
in  which  a  speed  of  over  200  m.  an  hour  may  be  reached. 

The  determination  of  the  load  variation  possible  is  one  part  of  the 
problem  of  specifying  the  strength  required  of  the  wing  structure. 
We  must  also  know  how  this  load  is  distributed  over  the  surface, 
along  and  across  the  wing,  and  how  it  is  shared  by  the  different 
members  of  the  structure.  The  important  factor  is  the  variation  of 
the  "  centre  of  pressure  "  on  the  wing.  As  the  angle  between  the 
wing  and  the  direction  of  motion  decreases  the  centre  of  pressure 
moves  backward  with  increasing  rapidity.  It  may  be  noted  here 
that  in  a  nearly  vertical  dive  at  high  speed,  although  the  lift  of  the 
wings  is  small,  there  is  a  large  couple  acting  upon  them  tending  to 
twist  them  and  to  turn  the  aeroplane  over  on  its  back;  this  is 
resisted  by  the  action  of  the  tail.-  A  number  of  the  early  accidents 
occurred  in  the  course  of  a  "  vol  pique,"  or  steep  dive. 

Rough  calculations  were  probably  made  of  the  strength  of  the 
early  aeroplanes,  and  in  1911—2  those  supplied  to  the  Government 
were  tested  by  inverting  them  and  loading  the  wings  with  sand. 
Spars  of  wings  were  also  tested  separately,  but  as  a  rule  both  the 
strength  required  and  the  strength  realized  were  uncertain  quanti- 
ties. A  number  of  accidents  to  monoplanes  led  to  this  type  becoming 
suspect.  Early  in  1912  B16riot  forwarded  a  suggested  explanation  to 
the  French  War  Office,  which  resulted  in  the  suspension  for  a  few 
months  of  the  use  of  monoplanes  by  the  French  army.  Later  in  the 
year  accidents  to  monoplanes  in  England  led  to  a  suspension  of  their 
use  by  the  War  Office,  although  the  navy  continued  to  use  them. 
A  committee  was  appointed  and  reported  early  in  1913.  It  decided 
that  the  accidents  were  due  to  the  construction  of  these  monoplanes, 
but  not  to  anything  inherent  in  the  monoplane  system.  They 
recommended  that  the  wings  should  be  braced  internally  against 
drag  (a  remarkable  omission  previously),  the  main  bracing  wires 
duplicated  and  made  independent  of  the  undercarriage,  and  the 
fabric  well  fastened  to  the  ribs,  especially  on  the  upper  surface. 
Makers  were  to  supply  evidence  of  strength;  official  inspection  and 
investigation  of  accidents  were  instituted;  and  the  question  of  sta- 
bility and  the  danger  of  the  "  vol  pique  "  and  recovery  were  to  be 

Prior  to  this,  efforts  had  been  made  in  England  to  impose  a  factor 
of  strength  based  on  the  load  in  straight  level  flight  through  steady 
air.  The  same  factor  has  since  been  termed  the  "  load  factor."  In 
1914  the  British  Advisory  Committee  for  Aeronautics  issued  a  report 
on  "  factors  of  safety,"  regarding  the  load  factor  as  the  product  of 
two  factors,  one  representing  the  number  of  times  maximum  load 
might  exceed  the  normal  load,  and  the  other  a  factor  to  cover  possible 
faults  of  material  and  workmanship.  The  first  factor  is  based  on 
the  acceleration  due  to  a  banked  turn  combined  with  a  gust,  and  to 
recovery  from  a  dive.  Forty-five  degrees  was  the  steepest  angle  of 
bank  considered  advisable  and  it  is  recommended  that  to  secure 
safety  aeroplanes  should  not  be  dived  to  a  speed  exceeding  the  nor- 
mal by  more  than  20  per  cent.  The  committee  advised  that  the 
structure  should  have  a  factor  of  safety  of  at  least  2  under  the 
acceleration  so  obtained.  A  factor  of  from  6  to  8  (which  had  been 
worked  to  by  the  Royal  Aircraft  Factory  since  1912)  was  recom- 
mended, to  be  increased  to  12  if  this  should  become  possible. 
There  is  no  record  of  the  obligatory  use  of  such  factors  in  France  or 
Germany  at  this  date. 

During  the  war  the  problems  involved  were  investigated  both 
mathematically  and  by  experiment.  Loops  and  mock  fights  were 
carried  out  at  the  Royal  Aircraft  Factory  by  aeroplanes  fitted  with  an 
accelerometcr  and  with  tension  meters  on  the  wires.  The  distribu- 
tion of  pressure^  over  wings  has  been  measured  in  wind  tunnels 
(first  by  Eiffel  in  Paris)  and  on  aeroplanes  in  flight  at  Farnborough. 
It  is  now  possible  to  specify  the  strength  of  the  various  members  of 
an  aeroplane  with  sufficient  accuracy  for  any  manoeuvres  required. 
The  "  load  factor  "  demanded  has  never  risen  to  12,  but  now  ranges 
from  4  to  8,  the  lower  factor  for  the  large  aeroplane  which  is  not  so 
violently  manoeuvred.  The  adequacy  of  these  factors  has  been 
confirmed  by  experience. 

The  need  for  extreme  lightness  precludes  the  use  of  the  factors  of 
safety  currently  used  in  other  branches  of  engineering,  and  instead 
accuracy  of  stress  calculation  and  careful  inspection  and  testing  of 
materials  are  imposed.  It  became  the  practice  of  the  British  Govern- 
ment to  check  by  its  own  officials  the  strength  of  each  design  by 
detail  calculations  of  stresses  and  by  a  proof  load  on  one  aeroplane 
of  a  type.  Other  governments  followed.  Since  1918-9  Great  Britain 
requires  that  an  "  air-worthiness  certificate  "  be  obtained  before 
a  type  may  be  used  for  commercial  purposes.  Drawings  are  sub- 
mitted by  the  applicant  from  which  calculations  of  stresses  are  made 
by  the  Air  Ministry. 

The  calculation  of  stresses  proceeds  upon  the  usual  lines,  com- 
mon to  other  branches  of  engineering,  but  with  rather  greater  ac- 
curacy of  detail.  The  theorem  of  Three  Moments  is  applied  to  the 
spars,  which  require  treatment  as  beams  continuous  through  a 
number  of  supports  and  subjected  to  end  load.  Aeronautical 
practice  has  somewhat  extended  this  theorem.  A  theory  of  the 
strength  of  struts  of  tapering  section  has  been  evolved.  Knowledge 
of  the  mechanical  properties  of  timber  has  been  much  extended. 


The  Airscrew. — The  Rankine-Froude  theorems  on  propulsion 
by  the  sternward  projection  of  a  stream  of  the  surrounding  fluid  by 
the  use  of  a  screw-propeller,  or  other  means,  are  well  known.  These 
state  that  the  highest  efficiency  is  attained  by  the  projection  of  the 
greatest  amount  of  fluid  at  the  lowest  speed,  and  indicate  the  use  of 
propellers  of  the  greatest  practicable  diameter.  The  only  waste 
considered  is  the  kinetic  energy  imparted  to  the  fluid.  An  upper 
limit  of  efficiency  is  thus  determined  in  terms  of  the  diameter  and  the 
thrust  of  the  propeller  and  the  speed  of  motion.  The  design  of 
marine  screws  proceeds  mainly  upon  empirical  lines  based  upon 
experience.  The  early  airscrews  were  designed  by  a  similar  process 
of  trial  and  error. 

F.  W.  Lanchester  (Aerodynamics,  1892),  regarding  the  airscrew 
blade  as  a  twisted  aeroplane  wing  rotating  about  one  tip  as  it  ad- 
vances through  the  air,  assumed  that  the  total  reaction  may  be  ob- 
tained by  integrating  the  forces  which  would  act  upon  elements  at 
successive  radii  if  these  were  elements  of  a  complete  wing.  This 
method  of  treatment,  which  was  also  advanced  by  Drzewiecki,  has 
provided  the  basis  of  airscrew  design.  As  first  applied,  the  theory 
was  incomplete,  chiefly  because  it  ignored  the  fact  that  the  blades 
in  following  each  other  act  on  disturbed  air.  For  example,  if  the 
number  of  blades  be  increased,  the  theory  indicates  no  fall  in  the 
efficiency,  and  reactions  directly  proportional  to  the  number  of 
blades,  which  experiment  showed  to  be  untrue.  Moreover,  the  effi- 
ciency so  calculated  might  exceed  that  given  by  the  Rankine-Froude 
theorems.  It  was  therefore  sought  to  combine  the  two  aspects  of  the 
action  of  the  airscrew  in  one  theory,  and  the  further  theorem  of 
Froude  that  the  stream  has  reached  half  the  final  velocity  at  the 
propeller  disc  appeared  to  provide  a  means  of  estimating  the  degree 
of  disturbance  of  the  air  in  which  the  blade  acts.  It  is  generally 
agreed  that  the  original  theory  is  over-corrected  by  this  modification. 
The  blade  element  under  consideration  is  itself  partly  causing  the 
acceleration  of  the  stream,  and  this  acceleration  is  the  total  and  not 
merely  the  initial  disturbance  of  flow  in  the  neighbourhood  of  the 
element.  Figures  for  the  reaction  on  the  elements  were  obtained  by 
testing  a  small  wing  of  the  same  section  in  a  wind  produced  artifi- 
cially in  a  "  wind  tunnel."  This  wing  produces  a  disturbance  of 
flow  equivalent  in  an  airscrew  to  an  acceleration. 

It  was  found  in  practice  that  the  assumption  of  an  arbitrary  ac- 
celeration less  than  one-half  of  the  final  acceleration  made  it  pos- 
sible by  the  use  of  the  theory  of  Lanchester  to  predict  the  aerody- 
namic performance  of  an  airscrew  with  a  valuable  accuracy.  The  com- 
bined theory  leads  to  two  important  conclusions,  completely  verified 
by  experience.  Firstly,  the  efficiency  increases  with  increasing  ratio 
of  the  pitch  at  which  the  screw  operates  to  its  diameter  up  to  an 
optimum  value  seldom  employed  in  practice.  Secondly,  for  given 
thrust  and  speed  the  diameter  must  be  so  large  that  it  acts  upon  a 
sufficient  mass  of  air  per  unit  of  time  to  attain  a  satisfactory  effi- 
ciency. The  latter  brings  the  theory  into  conformity  with  the 
law  of  Rankine  and  Froude.  The  former  in  practice  brings  the 
airscrew  designer  into  conflict  with  the  designer  of  aeroplane  motors. 
Higher  crankshaft  speeds  are  required  to  produce  a  light-weight 
internal-combustion  engine  than  are  demanded  by  this  condition 
for  high  airscrew  efficiency.  This  has  resulted  in  a  large  number  of 
aeroplane  engines  being  arranged  to  drive  the  airscrew  through  a 
reduction  gear.  The  point  at  which  gearing  becomes  desirable  in 
practice  is  not  easily  determined.  It  depends  upon  a  number  of 
factors.  Among  these  are  a  small  loss  of  energy  in  the  gears,  added 
weight  and  cost,  various  practical  reasons  for  dispensing  with  addi- 
tional mechanism  if  this  is  not  of  sufficient  value  and  the  adverse 
effects  of  the  greater  torque  of  the  slower  running  airscrew  upon  the 
control  of  the  aeroplane,  which  must  be  offset  against  the  gain  in 
airscrew  efficiency.  In  this  question  is  also  involved  the  considera- 
tion of  the  strength  of  the  airscrew  to  resist  the  stresses  due  to  ro- 
tation. This  imposes  a  limit  upon  diameter,  decreasing  as  the  speed 
of  rotation  is  increased,  which  may  result  in  a  further  reduction  of 
efficiency  for  the  high-speed  airscrew. 

During  the  war  large  aeroplanes  were  built  for  which  single  en- 
gines of  the  required  power  were  not  available.  In  so  far  as  two  en- 
gines were  sufficient,  these  were  placed  on  either  side  of  the  main 
body  of  the  aeroplane,  each  driving  a  separate  airscrew.  It  became 
necessary  ultimately  to  install  four  engines  in  a  few  aeroplanes  and 
these  were  placed  in  pairs  driving  two  pairs  of  airscrews  in  tandem. 
The  design  of  the  rear  propeller  in  this  arrangement  involves  an 
estimate  of  the  rate  at  which  air  is  supplied  to  it  by  the  screw  in 
front.  With  the  same  limitation  of  diameter  the  efficiency  of  pro- 
pulsion attainable  is  approximately  the  same  as  if  the  two  engines 
were  coupled  and  drove  a  single  airscrew  of  the  same  diameter,  but 
is  less  than  would  be  obtained  by  the  use  of  four  separate  systems 
of  propulsion.  The  tandem  system  is  preferred  for  reasons  of  com- 
pactness and  the  difficulties  of  control  attendant  upon  the  use  of  a 
number  of  lines  of  thrust. 

The  aeroplane  propeller,  unlike  the  propeller  of  ship  or  airship, 
is  required  to  transmit  the  full  power  of  the  engine  at  different  speeds 
of  flight,  both  when  the  craft  is  flying  level  at  full  speed,  and  when 
it  is  flying  slow  in  order  to  climb.  The  airscrew  cannot  be  designed 
to  discharge  both  functions  in  the  most  efficient  manner  possible  in 
each  case.  This  was  of  little  consequence  in  the  early  days  of  flight 
when  the  range  of  flying  speed  was  small ;  but  as  the  range  was  in- 
creased, some  attention  was  paid  to  the  design  of  airscrews  of  vari- 

able pitch.  These  have  been  experimented  with,  notably  at  the 
Royal  Aircraft  Establishment,  with  some  success;  but  they  have  not 
been  used  so  far  in  service.  If  any  device  for  preventing  the  loss  of 
engine  power  with  increasing  height  by  an  initial  compression  of  the 
charge  to  ground-level  density  should  come  into  use,  the  variable 
airscrew  would  become  necessary.  Such  devices  are,  however,  still 
in  an  experimental  stage. 

The  number  of  blades  in  an  airscrew  is  commonly  two.  but  four 
blades  have  been  extensively  used.  The  two-bladed  airscrew  has  an 
advantage  in  convenience  for  storing  and  transport.  The  use  of  more 
blades  reduces  vibration  due  to  errors  in  blade  angles,  and  eliminates 
gyroscopic  vibration  when  the  aeroplane  is  turning,  and  vibration 
due  to  aerodynamic  causes  both  when  the  axis  of  rotation  is  inclined 
to  the  line  of  flight  and  when  the  aeroplane  is  turning.  Airscrews 
have  been  almost  universally  made  of  timber,  which  should  be 
continuous  through  the  boss  from  blade  tip  to  blade  tip.  This  has 
prevented  the  use  of  three  blades.  In  deciding  the  number  of  blades, 
two  or  four,  the  designer  is  largely  guided  by  the  blade  area  required, 
which  depends  upon  the  speed  of  motion  of  the  blade  and  the  power 
transmitted.  Thus  a  slow-running  airscrew  has  conveniently  four 
blades,  whereas  for  a  high-speed  screw  two  blades  are  preferred. 
A  four-bladed  high-speed  screw  might  require  such  narrow  blades 
that  in  order  to  resist  the  bending  due  to  the  thrust  they  would  be 
so  thick  as  to  reduce  the  efficiency  seriously. 

At  the  speed  of  flight  of  an  aeroplane  the  changes  of  pressure  of 
the  air  flowing  past  the  wings  amount  only  to  a  small  fraction  of 
the  atmospheric  pressure.  The  blade  tips  of  airscrews,  however, 
commonly  reach  speeds  of  800  ft.  per  second,  approaching  the  veloc- 
ity of  sound  in  air.  It  follows  that  while  the  wings  may  be  regarded 
as  operating  in  a  fluid  of  constant  density,  the  compressibility  of 
the  air  rriay  have  important  effects  in  the  case  of  the  airscrew. 
With  increase  of  blade  speed  effects  must  be  anticipated  similar  to 
the  phenomenon  of  cavitation  experienced  with  marine  screws. 
Such  effects  in  a  gas  may,  however,  occur  gradually  with  increasing 
speed.  Experiments  with  small  model  wings  in  a  wind  tunnel  in 
America  showed  a  fall  in  lift  and  increase  in  resistance  at  speeds  in 
the  neighbourhood  of  6po  ft.  per  second  at  large  angles,  and  it  is 
clear  that  the  distribution  of  low  pressure  over  the  upper  surface 
cannot  continue  indefinitely.  It  appears,  however,  that  airscrews  so 
far  designed  have  been  free  from  any  marked  effect  of  this  nature. 
The  efficiency  estimated  has  been  attained  in  practice,  although 
designers  to  a  certain  extent  miscalculated  the  power  required  to 
drive  airscrews  as  the  speed  of  the  blade  tips  was  increased.  The 
error  cannot,  however,  be  ascribed  to  the  effects  of  compressibility 
owing  to  uncertainty  as  to  many  other  factors  involved.  On  the 
whole  the  method  of  aerodynamic  analysis  led  to  sufficiently  accurate 

The  screw-propeller  as  a  mechanism  for  the  transmission  of 
power  is  convenient  and  efficient.  In  the  airscrew  narrower  blades 
can  be  used  than  in  the  marine  propeller,  and  efficiencies  as  high 
as  85  %  have  been  attained  with  airscrews  of  high  pitch  and  large 
diameter,  smaller  fast-running  airscrews  giving  efficiencies  of  75  per 


FIG.    153. — Variation    of 
Thrust  at  constant  Torque. 
FIG.    15. — Variation  of 
Thrust,     Torque     and     Effi- 
ciency of  an   Airscrew  with 
forward    speed    at    constant 
rate  of  revolution. 

Owing  to  the  light  weight  and  high  tensile  strength  of  timber  for 
its  weight,  the  designer  has  found  in  wood  his  most  convenient 
material.  African  walnut  has  proved  the  best  timber  when  the 
stresses  are  most  severe.  Honduras  mahogany  is  satisfactory  for 
most  purposes.  Spruce  and  poplar  have  also  been  used,  but  are  not 
suitable  for  higher  powers  and  speeds.  The  screw  is  constructed 
of  planks,  or  laminations,  about  an  inch  thick,  glued  together  and 
cut  to  shape.  The  grain  of  the  wood  should  be  straight  and  run  as 
far  as  possible  along  the  blade.  The  method  of  construction  secures 
a  good  approximation  to  this  requirement.  Timber  has  the  advan- 
tage of  large  hysteresis  and  consequent  power  of  damping  vibra- 
tions. The  Wright  brothers'  airscrews  were  made  of  spruce  cut 
from  a  single  piece  of  timber.  An  interesting  design  appeared  in 
1913  in  the  "  Garuda  "  airscrew,  of  laminated  wood  construction 
with  the  blades  tilted  forward  so  that  to  a  large  extent  stresses  due 
to  rotation  neutralized  those  due  to  thrust.  The  forward  tilt  was 
obtained  by  bending  the  laminations  during  manufacture,  a  rather 
questionable  practice.  This  method  of  balancing  stresses  has  not 



been  developed  beyond  carrying  the  most  forward  lamination  to  the 
tip  of  the  blade  and  succeeding  laminations  to  smaller  radii,  owing 
to  the  method  of  construction  and  the  nature  of  the  material  used. 
It  has  recently  been  stated  that  this  forward  tilt  renders  the  blade 
liable  to  twist  under  load. 

The  stresses  in  the  blades  have  been  calculated  by  crude  methods 
which  give  an  approximation  to  the  stress  along  the  grain.  Fracture 
has,  however,  almost  invariably  occurred  across  the  grain,  in  the  ear- 
lier airscrews,  by  failure  of  the  glued  joints.  Workshop  practice  has 
now  so  far  improved  that  the  strength  of  glued  joints  is  equal  to  the 
strength  of  even  hard  woods  across  the  grain.  The  evident  need  for 
knowledge  of  torsional  stress  in  an  airscrew  blade  led  to  the  practical 
solution  by  G.  I.  Taylor  and  A.  A.  Griffith  in  1916  of  the  problem 
of  torsion  of  prisms  of  any  section.  The  mathematical  equations  had 
already  been  stated  and  the  new  development  was  the  provision  of 
an  experimental  method  of  solution.  Theory  can  now  indicate  the 
shape  of  blade  required  to  avoid  twisting  under  the  loads  imposed  in 
flight.  Apart  from  the  reduction  of  stress,  this  is  of  great  value  to 
the  designer,  who  cannot  with  any  certainty  predict  the  performance 
of  an  airscrew  if  the  blades  twist  in  an  unknown  manner  in  flight. 

In  order  to  protect  the  blades  from  moisture  the  airscrew  is  var- 
nished, or  painted,  and  to  protect  against  sand  on  land  and  spray 
on  the  sea,  the  tips  have  in  some  cases  been  sheathed  in  metal,  but 
the  practice  of  covering  with  fabric  (dating  from  1912-3)  has  re-  . 
cently  found  more  favour.  Japanese  lacquer  has  also  been  used  as  a 
protective  covering. 

Several  early  airscrews  (e.g.  Breguet's)  were  entirely  of  metal, 
commonly  aluminium  blades  bolted  to  a  steel  tube,  a  method  only 
possible  with  the  low  powers  and  speeds  of  rotation  of  the  period. 
Bleriot  crossed  the  Channel  with  a  small,  high-speed,  laminated  wood 
screw.  Experiments  with  steel  construction  have  proceeded  slowly 
and  steel  may  in  time  come  into  common  use.  Failure  has  been 
largely  due  to  the  unreliable  nature  of  welding,  and  to  brittleness 
produced  in  the  process.  For  production  in  moderate  quantities, 
wood  requires  far  less  outlay.  A  modern  development  is  the  air- 
screw with  detachable  blades,  so  far  in  a  purely  experimental 
stage.  It  allows  of  adjusting  the  pitch  of  the  blades,  if  the  airscrew 
has  been  imperfectly  designed  or  the  conditions  of  operation  be 
altered,  and  of  replacement  of  a  damaged  blade  without  renewing  the 
whole.  If  the  blades  are  of  wood,  shorter  lengths  of  timber  may  be 
used,  but  it  is  doubtful  if  this  can  be  regarded  as  an  inherent  ad- 
vantage of  the  system,  because  the  difficulty  of  attaching  wood  blades 
to  a  centre  are  probably  as  great  as  the  difficulty  of  making  a  satis- 
factory joint  at  the  centre  of  an  airscrew  constructed  entirely  of 
wood.  The  airscrew  whose  pitch  is  variable  in  flight  is  a  particular 
case  of  the  detachable  blade  screw,  and  the  chief  difficulty  in  the 
design  of  such  a  screw  for  high  speeds  of  rotation  is  that  of  making 
the  joint  between  the  blades  and  the  centre. 

In  Britain  and  in  America  airscrews  have  been  tested  before  use 
in  flight  by  "  spinning  "  by  means  of  an  electric  motor.  This  test 
has  been  applied  to  new  designs,  to  airscrews  whose  strength  has 
been  suspected  by  an  inspector,  and  to  samples  taken  from  batches. 
The  practice  was  in  force  in  this  country  in  1914  and  has  been  con- 
tinued. Flight  conditions  are  not  reproduced  by  the  test,  because 
the  airscrew  is  not  advancing  through  the  air,  and  because  the  crank- 
effort  variation  and  vibration  of  the  engine  are  absent.  The  thrust 
loading  is  more  severe,  the  centrifugal  loading  less  severe.  Experi- 
ence has,  however,  given  considerable  confidence  in  the  test.  In 
France  the  only  test  applied  has  been  a  loading  of  the  blades  to 
counterfeit  the  air  forces,  without  rotation. 

BIBLIOGRAPHY. — British. — -Reports  and  Memoranda  of  the 
Advisory  Committee  for  Aeronautics  (1909-19)  and  the  Aeronau- 
tical Research  Committee  (H.  M.  Stationery  Office);  L.  Bairstow, 
Applied  Aerodynamics  (1920);  G.  P.  Thomson,  Applied  Aerodynam- 
ics (1920);  A.  I.  S.  Pippard  and  J.  L.  Pritchard,  Aeroplane  Struc- 
tures (1919);  H.  C.  Watts,  Design  of  Screw  Propellers  for  Aircraft 
(1920);  E.  C.  Vivian  and  W.  Lockwood  Marsh,  A  History  of  Aero- 
nautics; technical  periodicals: — Aeronautical  Journal;  Flight;  Aero- 
nautics; The  Aeroplane. 

American. — Reports  of  the  National  Advisory  Committee  for 
Aeronautics  (Government  Printing  Office,  Washington) ;  technical 
periodicals: — Aviation;  The  Aerial  Age. 

French. — -G.  Eiffel,  Nouyelles  recherches  sur  la  Resistance  de  I' air 
et  I' Aviation  (1919) ;  technical  periodicals: — L'Aerophile;  L' Aviation. 

German. — Technical  periodicals: — Zeitschrift fur  Flugtechnik  und 
Motorluftschifffahrt.  (R.  McK.  W.) 


Experiments  and  Calculations  on  the  Principles  of  Flight. — 
The  recent  history  of  the  development  of  aeronautics  rests 
largely  on  experiments  on  aircraft  or  models  of  aircraft  and  their 
parts.  That  branch  of  investigation  whicn  is  least  related  to 
any  other  subdivision  of  engineering  is  the  study  of  the  forces 
which  are  experienced  by  a  body  when  moving  through  the  air. 
The  air  forces  due  to  motion  are  dealt  with  under  the  general 
head  of  "  Aerodynamics."  A  knowledge  of  air  resistances  is 
a  primitive  necessity  in  connecting  the  subject  with  the  much 
older  and  well-established  subject  of  "  Dynamics." 

In  dealing  with  dynamics,  the  forces  acting  are  frequently 
given  by  a  simple  fundamental  law  such  as  the  theory  of  gravita- 
tion when  accounting  for  the  motion  of  planets  and  comets,  and 
very  many  of  the  more  complex  reactions  have  been  worked  out. 
The  corresponding  fundamental  theory  of  fluid  motion  has  been 
known  for  more  than  half  a  century,  but  application  to  the 
determination  of  air  resistances  has  proved  to  involve  mathe- 
matical problems  beyond  the  capacity  of  the  times.  Recourse 
has  therefore  been  made  to  direct  experiment ,  and  in  the  early 
stages  of  aeronautical  development  almost  every  new  idea  could 
be  tested.  The  number  of  variables  under  review  has  now  grown 
so  greatly  as  to  exclude  such  a  method  on  the  ground  of  cost,  and 
a  period  of  fundamental  experiment  is  being  entered  on.  The 
object  of  such  experiments  is  to  find  out  what  is  happening  to  the 
air  disturbed  by  the  passage  of  a  body  in  such  a  way  that  the 
results  can  be  applied,  with  a  reasonable  degree  of  approxima- 
tion, to  a  large  number  of  related  problems.  Some  success  has 
been  obtained  in  the  case  of  airscrews,  where  the  experimental 
data  are  so  used  that  it  is  unnecessary  to  test  every  new  design 
of  airscrew.  Extension  to  the  aeroplane  is  gradually  taking  place. 

For  the  same  reason — expense — experiments  on  models  have 
been  used  to  cover  the  main  field  of  inquiry,  and  the  costly  and 
frequently  dangerous  experiments  on  the  full  scale  have,  on  the 
whole,  been  directed  to  crucial  tests  of  the  validity  of  the  use  of 
models.  '  There  has,  of  course,  been  a  great  amount  of  testing 
of  aircraft  in  connexion  with  their  value  as  fighting  craft.  At 
the  present  time,  the  value  of  such  testing  as  an  aid  to  design  is 
very  limited,  detailed  analysis  being  required  to  indicate  lines  of 

It  then  happens  that  the  most  comprehensive  view  of  the 
subject  of  aeronautical  principles  is  obtained  from  those  aero- 
dynamical laboratories  which  deal  with  experiments  on  models, 
experiments  carried  out  under  almost  ideal  conditions  in  the 
artificial  air  current  of  a  wind  tunnel.  The  theory  of  the  use  of 
models1  becomes  of  great  importance  in  aeronautics  and  has 
been  studied  extensively.  When  the  maximum  possible  use  has 
been  made  of  the  theory  the  position  remains  one  for  experiment, 
and  full-scale  cooperation  is  found  to  be  essential  for  estab- 
lishing a  sound  position.  The  theory  of  models  has  great  value 
in  showing  the  correct  type  of  experiment  and  the  method  of 
comparison  with  the  full  scale.  Finally,  it  is  now  known  that 
when  certain  precautions  are  observed  in  model  tests  the  applica- 
tions to  full  scale  have  an  accuracy  sufficient  to  give  them  a  high 
value  as  an  element  in  progress.2 

A.    Air  Intake    B.   Working  Section   C.  Aerodynamic  Balance 
D.   Position  of  Airscrew     E.    Distributor 

FIG.  1 6.— Wind  Tunnel. 

Laboratory  Experiments. — (a)  The  Wind  Tunnel. — The  num- 
ber of  first-class  wind  tunnels  in  existence  in  the  world  in  July 
1921  was  probably  between  twenty  and  thirty.  Of  these,  seven 
were  at  the  National  Physical  Laboratory  at  Teddington,  three 

1  Report,  Advisory  Committee  for  Aeronautics,  1909-10,  p.  38. 

1  Report,  Scale  Effect  Sub-Committee  A.  C.  A.,  1917-8,  R  and  M, 



at  the  Royal  Aircraft  Establishment,  Farnborough,  and  a 
number  distributed  amongst  the  private  aeronautical  firms  of 
Britain.1  America  has  a  number  of  channels  of  generally  similar 
type,2  but  with  a  unique  example  in  one  instance  where  the  speed 
of  the  air  current  is  very  high.3  The  oldest  of  the  wind  tunnels 
of  importance  in  the  development  of  aviation  is  that  of  Eiffel,4 
and  from  it  in  1909-10  came  a  number  of  experiments  on  wing 
forms  at  a  time  when  flying-machines  were  becoming  realities. 
The  Eiffel  type  of  wind  tunnel  has  been  used  elsewhere  and  in 
France  a  new  installation  has  been  erected  at  St.  Cyr.s  The 
other  European  wind  tunnels  of  note  are  in  Italy  (Rome),  at 
Gottingen  University  (Germany)  and  Koutchino  (Russia). 
Owing  to  the  general  upheaval  in  Russia  the  last-named  labora- 
tory is  closed,  but  it  earned  distinction  in  the  years  of  its  activity 
particularly  in  dealing  with  interesting  experiments  on  funda- 
mental points  in  the  theory  and  practice  of  the  day. 

In  general  conception  all  wind  tunnels  agree  in  attempting 
to  obtain  a  uniformly  distributed,  non-fluctuating  air  stream; 
and  the  tendency  has  been  to  increase  the  dimensions  and  the 
velocity  attained  in  passing  from  one  installation  to  a  succeeding 
type.  Economy  of  power  for  a  given  extension  of  experimental 
range  is,  by  the  principles  of  dynamical  similarity,  more  readily 
obtained  with  large  dimensions  than  with  high  speed.  The 
best  criterion,  other  things  being  unchanged,  is  the  product  of 
diameter  and  velocity,  and  judged  on  this  standard  the  largest 
installations  of  the  various  countries  do  not  differ  materially. 

At  the  Royal  Aircraft  Establishment  (formerly  called  the 
Royal  Aircraft  Factory),  Farnborough,  a  speed  of  100  m.p.h. 
(nearly  1 50  ft.  per  sec.)  is  reached  in  an  air  stream  7  ft.  square.  At 
the  National  Physical  Laboratory  a  speed  of  1 10  ft.  can  be  pro- 
duced in  a  stream  7  ft.  deep  by  14  ft.  in  width  and  forces  on  a 
model  of  the  order  of  200  Ib.  are  there  contemplated. 

The  larger  Eiffel  tunnel  gives  an  air  speed  of  40  metres  per 
second  (130  ft.  approximately)  on  a  circular  section  about  two 
metres  in  diameter.  The  tunnel  at  McCook  field  (America) 
gives  the  very  high  speed  of  500  ft.  to  a  circular  stream  of 
air  about  3  ft.  in  diameter. 

The  experimental  section  of  an  Eiffel  type  wind  tunnel  con- 
sists of  an  air  stream  as  it  crosses  an  open  room  from  wall  to 
wall,  through  a  specially  devised  nozzle  and  collector.  The 
National  Physical  Laboratory  type  and  others  use  a  working 
section  of  the  stream  in  the  centre  of  a  chute  with  solid  walls. 
There  are  no  striking  advantages  of  either  type  so  far  as  can  be 
seen  at  the  present  time.  The  great  desiderata  are  uniformity  of 
distribution  of  velocity  across  the  stream  and  freedom  from 
large  pulsations.  Uniformity  of  distribution  is  almost  auto- 
matically secured  by  using  a  straight  air  stream.  Once  curvature 
has  been  introduced  by  the  turning  of  corners  the  difficulties  of 
producing  uniformity  are  formidable.  On  the  other  hand  the 
delivery  of  large  volumes  of  air — nearly  half  a  million  cub.  ft. 
per  minute  in  the  large  tunnels — requires  special  consideration 
if  large  eddies  in  the  room  with  consequent  pulsations  in  the 
flow  are  to  be  avoided.  There  is  an  opinion,  supported  as  yet 
only  by  crude  experiments,  that  the  N.P.L.  type  of  channel  is 
somewhat  less  fluctuating  than  the  Eiffel  type.  For  the  delicate 
adjustments  required  in  the  measurement  of  stability  coefficients 
high  value  attaches  to  the  steadiness  of  the  air  stream. 

In  dealing  with  efficient  wing  forms,  where  the  lift  may  be  more 
than  20  times  the  resistance,  it  is  important  that  the  direction  of  the 
air  stream  be  accurately  known  and  remain  fixed;  one-tenth  of  a 
degree  is  considered  to  be  the  maximum  permissible  error.  It  is 
found  by  experience  that  in  a  parallel  walled  channel  the  wind  sets 
itself  parallel  to  the  walls  with  the  accuracy  desired.  Freedom  from 
large  variations  of  velocity  across  the  section  depends  not  only  on 
the  straightness  of  the  chute  but  also  on  the  distance  over  which  the 
air  has  been  in  contact  with  solid  walls.  From  some  experiments  by 
Stanton  it  appears  that  the  final  distribution  of  velocity  in  tubes  is 
not  reached  for  some  20  to  50  diameters  behind  the  open  end.  On 
the  score  of  space  required  and  power  needed  such  proportions  are 
unrealizable  in  wind  channels  and  in  other  respects  would  be  dis- 

1  Report,  A.  C.  A.,  1912-3,  R  and  M,  68. 

2  Mass.  Inst.  of  Technology. 
»  McCook  Field. 

4  Eiffel,  La  Resistance  de  I'air  et  I' Aviation  (Dimod  &  Pinet,  1910). 
6  La  Nature,  Oct.  2  1921. 

advantageous.  Some  variation  of  velocity  distribution  from  point 
to  point  along  a  wind  channel  is  then  to  be  expected,  there  being -a 
retardation  of  flow  at  the  walls  and  an  acceleration  in  the  centre. 
This  change  of  flow  is  accompanied  by  a  fall  of  static  pressure  along 
the  working  section  of  the  channel.  For  experiments  on  wings, 
struts,  etc.,  these  departures  from  uniformity  are  unimportant  but 
in  the  case  of  long  models  of  airship  forms  there  is  introduced  a 
spurious  resistance  large  in  comparison  with  that  proper  to  the  air- 
ship model.  It  has  been  suggested,  and  experiments  are  being  car- 
ried out  to  give  effect  to  it,  that  the  objectionable  effects  of  the  wind 
channel  might  be  minimized  by  the  substitution  of  a  slightly  diverg- 
ing chute  in  the  working  section  for  the  usual  parallel  part.  It  appears 
to  be  possible  by  such  device  to  increase  substantially  the  ease  and 
accuracy  of  tests  on  airship  forms. 

The  motion  of  the  air  in  the  wind  tunnel  is  eddying  and  on  this 
account  a  difference  from  motion  through  still  air  exists.  So  far, 
however,  no  suspicions  have  been  aroused  as  to  the  inapplicability 
of  model  tests  on  this  ground.  Some  eddies  produced  in  the  working 
of  a  tunnel  are  worthy  of  mention.  If  light  sawdust  be  sprinkled  over 
the  floor  of  the  building  housing  a  wind  tunnel,  below  the  intake,  it 
will  be  noticed  that  isolated  miniature  whirlwinds  are  produced. 
Some  of  these  are  vigorous  and  the  base  will  clear  a  track  amongst 
the  sawdust  whilst  the  core  extends  upwards  to  the  tunnel  intake. 
The  spin  in  such  eddies  is  great  and  the  effect  of  the  forces  experi- 
enced by  a  body  in  the  air  flow  is  considerable.  Being  spasmodic, 
the  effect  is  easily  differentiated  from  that  of  the  mean  flow  and  an 
observer  at  an  aerodynamic  balance  is  conscious  of  a  sharp  blow  on 
his  apparatus.  To  eliminate  these  whirlwinds  sufficiently  a  honey- 
comb is  placed  across  the  intake,  the  cells  being  small  compared 
with  the  dimensions  of  the  whirlwind.  Some  10  %  to  20  %  of  the  en- 
ergy of  the  power  plant  may  be  dissipated  by  the  frictional  resist- 
ance of  the  honeycomb  and  some  appreciable  length  of  tunnel  is 
required  to  permit  of  the  levelling-up  of  the  flow  before  reaching 
the  working  section. 

The  design  of  a  wind  tunnel  will  be  seen  to  involve  much  study  if 
more  than  a  very  moderate  degree  of  refinement  of  experiment  be 
contemplated.  The  following  brief  description  of  a  tunnel  intro- 
ducing modern  knowledge  may  be  of  interest  (see  fig.  16). 

The  wind  tunnel  is  housed  in  an  unobstructed  chamber  a  little 
longer  than  itself,  a  space  of  one  and  a  half  diameters  between  the 
intake  and  wall  being  sufficient  for  the  satisfactory  admission  of  air 
from  the  chamber  to  the  tunnel.  The  cross  section  of  the  room  should 
be  25  to  30  times  that  of  the  channel,  otherwise  the  return  flow  of  air 
from  delivery  to  intake  will  produce  fluctuations  of  undesirably  large 
magnitude.  The  tunnel  proper  is  straight  and  is  placed  symmetri- 
cally in  the  building,  this  being  effective  in  securing  symmetry  of  air 
flow  in  the  working  section.  Taking  the  diameter  of  the  section — 
whether  square  or  circular — as  a  standard,  the  tunnel  would  have  an 
overall  length  of  10  to  15  diameters  made  up  of  a  parallel  working 
section  and  intake  four  or  five  diameters  long,  having  a  rounded 
entrance  and  honeycomb,  a  cone  connecting  this  working  section  to  a 
circular  race  enclosing  the  airscrew,  which  may  be  of  similar  length, 
and  a  discharge  section  to  the  end  of  the  room. 

The  airscrew  giving  steadiest  flow  is  one  of  small  pitch-diameter 
ratio  but  otherwise  similar  in  characteristics  to  those  used  in  aerial 
locomotion.  The  pitch-diameter  ratio  may  be  0-4  upwards,  the 
higher  values  giving  rather  greater  economy  of  power  and  less 
steadiness.  With  careful  design  of  airscrew  and  cone  the  divergence 
from  channel  to  airscrew  can  be  made  large  with  resulting  economy 
of  power  and  no  loss  of  steadiness. 

The  most  modern  method  of  dealing  with  the  delivery  stream  is  to 
divide  the  building  into  two  parts  by  an  openwork  brick  wall. 
Eddies  in  the  return  flow  are  thereby  broken  up  to  dimensions  which 
do  not  greatly  affect  the  steadiness  of  the  air  when  it  again  enters  the 
intake.  In  one  instance,  in  addition  to  the  partition  wall,  there  is  a 
structure  closely  surrounding  the  delivery  from  the  airscrew;  this 
delivery  is  in  the  form  of  a  jet  which  impinges  on  the  .end  wall  of  the 
building,  and  splashing  over  it,  reaches  the  corners  and  forms  rollers 
along  the  four  walls.  The  structure  over  the  jet  is  designed  to  break 
up  the  stream  more  completely  than  the  porous  wall  alone.  Instead 
of  the  free  jet  spreading  at  the  wall  it  is  distributed  through  holes  in 
the  covering  structure,  the  spacing  being  such  that  equal  volumes  of 
air  are  delivered  through  each  unit  of  area  of  the  distributor.  The 
number  of  openings  per  unit  area  is  small  near  the  wall  of  the  building 
and  increases  to  cover  the  whole  area  just  before  the  airscrew 
section.  It  is  possible  to  reduce  the  velocity  at  which  the  air  returns 
to  the  room  to  5%  of  that  in  the  jet  without  the  introduction  of 
appreciable  back  pressure  at  the  airscrew. 

Methods  of  Measurement  of  Velocity  of  Air. — Having  secured 
uniformity  of  distribution  and  a  degree  of  steadiness  sufficient 
for  the  type  of  experiment  to  be  performed,  it  is  necessary  to 
be  able  to  measure  the  air  speed.  No  simple  means  is  known  of 
obtaining  a  standard  of  reference  using  a  wind  channel  alone,  and 
only  one  measure — possibly  two — of  absolute  air  speed  appears 
to  have  been  made  under  precision  conditions.  The  particular 
measurements  made  on  a  whirling  arm  and  in  the  William 
Froude  National  Tank  at  the  National  Physical  Laboratory 



gave  a  standard  anemometer  which  is  easily  maintained  and 
reproduced  and  which  is  accepted  throughout  the  world. 

The  essential  parts  of  the  anemometer  are  an  open-ended  tube 
facing  the  air  current  and  a  parallel  walled  tube  with  its  axis  along 
the  wind,  the  walls  of  the  tube  being  perforated  by  small  holes.  The 
open-ended  tube  is  usually  referred  to  as  a  "  pitot  "  tube,  the  name 
being  that  of  one  of  the  early  users,  whilst  the  perforated  tube  is 
designed  to  give  what  is  called  "  static  pressure."  If  the  perforations 
of  the  static  pressure  tube  be  some  six  diameters  behind  the  closed 
end  it  appears  that  all  such  tubes  give  the  same  reading,  independent- 
ly of  size  from  a  fraction  of  a  millimetre  upwards,  and  that  the  pres- 
sure inside  the  tube  is  the  same  as  that  on  a  body  moving  with  the 
air  stream.  The  pressure  in  the  pitot  tube  is  higher  than  that  in  the 
static-pressure  tube  and  the  difference,  being  due  to  the  motion  of 
the  air  and  the  stoppage  of  a  central  stream  by  the  pitot  tube,  is 
usually  referred  to  as  "  dynamic  pressure  "  or  "  pitot  head."  The 
size  of  the  pitot  tube  is  unimportant  and  there  is  little  difficulty  in 
reproducing  the  standard  tubes  so  that  they  agree  with  each  other 
within  a  fraction  of  I  %.  This  represents  generally  the  order  of 
accuracy  of  aerodynamic  measurements,  but  for  certain  simple  com- 
parisons of  force  and  speed  an  accuracy  of  l/s  %  is  attainable. 

The  experiments  on  the  whirling  arm  at  the  National  Physical 
Laboratory  showed  that  the  dynamic  pressure  of  the  anemometer 
was  proportional  to  the  square  of  the  speed  through  the  air.  On 
physical  grounds  it  is  known  that  the  dynamic  pressure  is  also  pro- 
portional to  the  density  of  the  air.  So  long  as  the  compressibility  of 
the  air  does  not  enter  into  the  effects  of  motion,  the  constant  of 
proportionality  is  found  to  be  equal  to  one-half,  with  a  probable  error 
of  the  order  of  Vio  %•  The  extreme  range  of  speed  was  from  a  few 
in.  per  sec.  to  50  ft.  per  second.  On  the  principles  of  dynamical 
similarity,  to  be  explained  later,  experiments  at  a  speed  of  20  ft.  per 
sec.  in  water  can  be  used  to  give  information  as  to  what  happens  at  a 
speed  of  250  ft.  per  sec.  in  air.  Using  the  William  Froude  National 
Tank  for  the  purpose,  the  dynamic  pressure  of  the  "  pilot-static  " 
tube  anemometer  has  been  calibrated  to  within  I  %  up  to  speeds  of 
250  ft.  per  sec.  in  air. 

Over  the  whole  of  this  range  the  formula  for  dynamic  pressure 
given  by 

—  -(I) 

is  an  accurate  representation  of  observations  on  the  pitot  tube 
anemometer.  In  this  formula,  p  is  the  pressure  in  force  per  unit 
area,  p  the  mass  of  unit  volume,  v  the  velocity  of  the  air  past  the  pitot 
and  a  the  velocity  of  sound  in  undisturbed  air  at  the  place.  So  long 
as  all  the  quantities  are  measured  in  a  self-consistent  set  of  dynamical 
units  the  equation  is  satisfied.  The  second  term  in  the  bracket  will 
be  seen  to  be  small  in  comparison  with  the  first  up  to  speeds  of  200 
ft.  per  second.  The  velocity  of  sound  being  a  little  more  than  1,000 
ft.  per  second  it  will  be  seen  that  the  second  term  is  less  than  I  %  of 
the  first  within  the  range  considered.  This  I  %  is  a  measure  of  the 
effect  of  the  compressibility  of  air  and  illustrates  a  general  rule — 
that,  for  the  purposes  of  aeronautics,  air  may  be  considered  as  an 
incompressible  fluid.  The  statement  is  far  from  true  as  applied  to 
the  motion  of  a  shell  fired  at  usual  velocities  and  may  need  modifica- 
tion in  aeronautics  when  applied  to  airscrews.  In  ordinary  practice 
the  tip  speed  of  an  airscrew  is  upwards  of  600  ft.  per  sec.  and  a  few 
experimental  forms  have  been  made  to  reach  tip  speeds  of  1 ,200  ft. 
per  second.  In  the  former  case  the  effects  of  compressibility  have 
not  yet  been  disentangled  from  other  effects,  whilst  in  the  latler 
some  preliminary  observations  show  marked  changes  of  type  of  flow 
as  a  result  of  high  speed  and  the  introduction  of  modifications  due  to 
compressibility  of  the  air. 

Dynamical  Similarity. — The  understanding  of  the  laws  of 
air  motion  in  aeronautics  and  gunnery  has  been  greatly  assisted 
by  the  theory  of  dynamical  similarity.  An  early  formula  was 
given  by  Lord  Rayleigh1  and  had  a  marked  influence  on  prog- 
ress, not  only  in  Britain  but  abroad.  In  the  later  publications 
of  the  Advisory  Committee  for  Aeronautics  numerous  references 
are  made  to  aeronautical  applications  of  the  principle. 

All  the  world  is  familiar  with  the  idea  of  similarity  in  some 
form  or  other  and  there  is  little  difficulty  in  appreciating  the 
statement  that  human  beings  are  similar  to  each  other  or,  more 
accurately,  are  nearly  similar;  the  horse  would  not  be  included 
so  readily  in  the  category  of  animals  similar  to  man.  The  idea 
of  dynamic  similarity  extends  to  motions  what  is  more  usually 
applied  only  to  concrete  bodies.  Motions  may  be  exactly  similar, 
nearly  similar,  or  very  different,  and  in  the  case  of  an  invisible 
fluid  like  air  the  eye  is  no  guide  to  comparison.  It  is  true  that 
air  may  be  coloured  by  smoke  and  the  motion  followed  and  that 
some  work  has  been  carried  out  on  such  basis.  When  it  is  found, 
however,  that  the  fluid  may  be  changed  without  loss  of  essential 
characteristics  of  the  motion,  a  new  line  of  attack  is  opened  and 

1  Advisory  Committee  for  Aeronautics,  1909-10,  p.  38. 

the  study  of  the  motion  of  water  or  any  other  fluid  will  give  the 
essential  information.  A  striking  experimental  investigation  of 
the  reality  of  the  law  of  equivalence  in  certain  cases  was  made 
at  the  National  Physical  Laboratory.  The  motion  of  air  past 
a  square  plate  was  observed  and  photographed.2  Smoke  ad- 
mitted to  the  current  showed  fluid  impinging  on  the  plate  and 
spreading  in  the  water.  At  a  very  low  speed  it  was  easy  to  detect 
a  winding  of  the  air  round  two  axes  roughly  in  the  direction  of 
the  stream.  A  section  of  the  stream  across  these  axes  would 
have  shown  particles  moving  in  spirals  winding  inwards.  This 
was  a  permanent  state.  At  a  higher  speed  a  very  noticeable 
change  occurred  in  the  type  of  motion.  Instead  of  the  spirals 
retaining  a  steady  position,  the  smoke  showed  instability  had 
occurred,  and  periodically  loops  formed  across  the  two  axes, 
broke  away  and  travelled  down  stream.  It  is  known  by  the 
principles  of  dynamical  similarity  that  it  is  possible  to  produce 
similar  flow  in  water.  Exact  conditions  for  the  second  experi- 
ment follow  from  those  of  the  first.  Further  photographs3 
show  that  the  comparison  of  types  of  flow  is  exact  within 
the  limits  of  observation.  Neither  of  the  motions  described  is 
calculable  and  the  principle  of  dynamical  similarity  offers  no 
assistance  to  understanding  why  an  eddy  occurs  or  what  its 
type  will  be.  It  says,  quite  definitely,  that  if  a  given  type  of 
motion,  eddying  or  otherwise,  exists  under  certain  circum- 
stances, there  are  sometimes  a  great  number  of  other  cir- 
cumstances in  which  the  same  type  of  motion  must  occur, 
and  it  lays  down  in  precise  terms  the  other  circumstances  in 
their  relation  to  the  given  type.  The  instance  given  above  re- 
lated to  change  of  fluid;  other  changes  might  be  those  of  velocity 
or  size.  Clearly  the  change  of  size  covers  the  relation  between 
model  and  full  scale. 

The  applications  of  dynamics  to  similarity  depend  on  fundamental 
theories.  The  common  ground  exists  in  Newton's  laws  of  motion  but 
superimposed  on  this  common  ground  are  a  number  of  special  cases. 
In  investigating  the  motion  of  fluids  at  ordinary  velocities,  physi- 
cists have  identified  the  property  of  viscosity;  at  high  velocities 
compressibility  matters  and  so  on.  The  physical  properties  of  fluids 
and  the  quantities  involved  in  motion  are  expressed  in  terms  of 
numerical  factors  and  dimensions,  e.g.  10  ft.  per  sec.  means  a  velocity 
of  a  certain  magnitude,  the  numerical  factor  10  and  the  dimensions 
ft.  and  sec.  being  necessary  to  give  full  meaning  to  the  idea  of  the 
particular  velocity.  If  a  complete  dynamical  equation  be  written 
down  it  must,  if  true,  satisfy  the  condition  that  the  numerical  values 
of  the  two  sides  of  the  equation  are  equal  and  that,  independently, 
the  dimensions  are  equal.  The  latter  point  may  be  sufficient  to  give 
useful  mathematical  form  to  the  physical  ideas.  For  example,  ima- 
gine an  aeroplane  to  be  gliding  down  through  still  air  at  some  known 
speed.  The  resistance  or  drag  will  depend  on  its  shape  and  size,  its 
speed,  the  density  of  the  air  and  the  viscosity  of  the  air.  For  the 
moment  it  will  be  assumed  that  the  drag  is  dependent  only  on  the 
quantities  enumerated. 

Force  has  the  dimensions  -™-  where  M  is  the  symbol  for  mass,  L 
for  length  and  T  for  time.  Velocity,  v ,  is  represented  by  ~,  density 

by  TJ  and  viscosity  by  -—'   (See  footnote  4) 

Expressed  in  the  form  of  an  equation  the  assumptions  so  far  made 
amount  to 

R  =/(„,  l,v,*)—  —(2) 

where  R  is  the  resistance,  I  a  typical  linear  dimension  of  the  body 
and /a  functional  form  which  depends  on  the  shape  of  the  body.  It  is 
common  to  include  in /the  presentation  of  the  body  to  the  wind  as 
well  as  its  shape,  but  this  can  be  excluded  at  will  by  introducing 
angular  coordinates  into  the  arguments  of  the  function.  The  prin- 
ciple of  dynamical  similarity  states  that  /  may  only  have  such  a 
form  as  will  make  the  dimensions  of  the  two  sides  of  (2)  agree.  For 
methods  of  finding  the  most  general  expression  for/,  consistent  with 
dimensions,  reference  may  be  made  to  textbooks,  etc.6;  it  is  found 
that  (2)  cannot  have  a  more  general  form  than 


1  Advisory    Committee    for   Aeronautics,    and    Applied   Aerody- 
namics, L.  Bairstow. 

3  Ibid. 

4  The  coefficient  of  viscosity  used  in  dynamics  is  denoted  by  v  and 
referred  to  as  the  "  kinematic  coefficient  of  viscosity."      The  other 
common  coefficient  M  is  related  to  v  by  the  equation  n  =  p  y. 

6  Applied  Aerodynamics,  L.  Bairstow,  p.  380. 



No  dynamical  equation  depending  on  the  quantities  mentioned 
earlier  can  exist  which  is  not  included  in  (3).  For  the  purposes 
of  comparison  of  resistances  it  has  been  found  convenient  by  the 

aerodynamical  laboratories  to  tabulate  the  value  of  F—   for   various 

bodies  and  to  use  the  symbol  kD  for  it.  Equation  (3)  may  then  be 
written  alternatively  as 


and  in  this  form  several  points  of  importance  are  evident.  To  make 
the  case  specific,  consider  the  resistance  of  a  sphere  in  air  as  obtained 
from  a  wind-tunnel  measurement.  If  the  dimension  /  be  identified 

with  the  diameter  d  of  the  sphere  it  will  be  noted  that  -=-%  is  an 

experimentally  determinate  quantity  and  from  it  values  of  ko  are 
determined.  An  examination  of  the  dimensions  of  k0  will  indicate 
that  they  are  zero ;  the  coefficient  is  therefore  a  pure  number  and  so 
of  international  validity.  Another  method  of  statement  would 
be  to  say  that  the  numerical  value  of  k0  is  independent  of  the 
system  of  units  used  so  long  as  the  system  is  self-consistent.  Meas- 
urements of  force  may  be  made  in  dynes,  mass  in  grammes,  lengths  in 
centimetres  and  time  in  sees,  to  meet  the  standards  of  the  physicist. 
Alternatively  the  engineer  may  use  the  force  unit  of  Ib.  weight,  the 
slug  as  a  unit  of  mass,  the  foot  for  length  and  the  sec.  for  time,  or,  if 
he  prefers  it,  the  force  unit  of  poundal,  the  mass  unit  of  pound,  and 
the  foot  and  second.  In  all  cases  the  tabulated  values  of  kD  would 
be  identical.  There  are  further  advantages  of  the  system;  kD  is 
independent  of  the  air  density  and  for  most  aeronautical  purposes 
almost  independent  of  size  and  speed,  so  that  comparison  between 
model  and  full  scale  is  readily  made  by  comparison  of  the  corre- 
sponding values  of  kD.  The  extent  to  which  the  two  agree  is  a  meas- 
ure of  the  utility  of  experiments  on  models. 

Equation  (4)  also  shows  that  kD  depends  on  a  single  variable— • 

not  separately  on  v,  I  or  v.  On  theoretical  grounds  alone  therefore 
we  may  say — for  our  special  assumptions — that  kD  will  not  change 
if  the  velocity  of  the  same  body  be  doubled  in  a  fluid  having  twice 
the  viscosity.  The  kinematic  viscosity  of  air  is  12  or  13  times  that  of 
water  at  ordinary  temperatures  and  hence  the  resistance  coefficient 
will  be  the  same  if  the  velocity  of  air  be  12  or  13  times  that  of  water. 
Stanton  has  shown  that  this  is  true  for  smooth  and  rough  pipes  by 
testing  with  the  two  fluids  in  the  same  apparatus.1  The  law  was  used 
in  the  calibration  of  the  pitot-static  pressure  tube. 

—  may  be  kept  constant  in  many  other  ways;  if  air  be  the  fluid 

used  in  two  experiments,  then  v  and  /  may  vary  so  long  as  the  product 
is  constant.  A  model  aeroplane  to  one-tenth  scale  would  give  a 
resistance  coefficient  on  test  equal  to  that  on  the  aeroplane  at  one- 
tenth  the  speed.  Since  the  speeds  of  flight  reach  200  ft.  per  sec.  this 
law  is  inapplicable  to  the  complete  aeroplane,  for  compressibility 
of  the  air  would  be  very  important  in  the  model  test  at  2,000  ft.  per 
second.  In  testing  streamline  struts  or  wires,  it  is  easily  possible  to 
make  models  larger  than  the  reality  and  so  to  extend  the  equivalent 
speed  from  that  of  the  wind  tunnel  to  that  of  flight. 

It  should  be  noted,  however,  that  failure  to  satisfy  the  law  of 
corresponding  speeds,  i.e.  t)/  =  constant,  does  not  necessarily  imply 
failure  to  obtain  similarity  of  flow  between  model  and  full  scale. 
In  most  of  the  experiments  known  to  us,  resistance  varies  very 
closely  as  the  square  of  the  speed  and  the  hypothesis  that  an  exact 
law  existed  is  worth  examination. 

Since  R  varies  as  v*  it  follows  from  (4)  that  kD  is  independent  of 

v  and  further  that  fa>  must  then  be  a  constant  for  all  values  of — • 

In  such  a  case  the  law  of  corresponding  speeds  is  of  no  importance, 
for  kn  can  be  deduced  from  a  test  at  any  speed  on  any  size  of  body. 
It  needs  little  effort  to  see  that  if  R  varies  a  little  from  proportion- 
ality to  f2  the  motions  in  model  and  full  scale  will  be  nearly  similar 

and  that  the  function is  relatively  unimportant.      It  is  on  this 

variation  from  strict  theory  that  aeronautics  depends  in  many 
applications  of  model  results.  Since  there  is  no  absolute  theoretical 
sanction  except  in  the  case  of  corresponding  speeds,  the  identity  of 
the  values  of  kD  on  the  model  and  full  scale  must  be  tried  out  in  a 
sufficiently  large  number  of  typical  cases  if  reliability  is  to  be  estab- 
lished. This  has  in  effect  been  done  for  aeroplane  wings. 

It  is  exceedingly  difficult  to  determine  from  flight  experiments  the 
resistance  of  the  wings  of  an  aeroplane,  for  the  flying  apparatus  must 
be  complete  with  body,  undercarriage,  airscrew  and  engine,  all  of 
which  materially  affect  the  resistance  of  an  aeroplane.  The  com- 
parison of  the  pressures  at  chosen  points  on  an  aeroplane  wing  in 
flight  and  on  a  model  of  it  in  a  wind  tunnel  is  far  less  difficult  and 
has  been  made.2  The  theory  which  led  to  equation  (4)  leads  also  to 
the  conclusion  that  the  pressure  divided  by  air  density  and  square  of 

1  Advisory  Committee  for  Aeronautics,  1911-2,  p.  41. 

2  Report,  Scale  Effect  Sub-Committee,  A.C.A.,  1917-8,  R  and  M, 
No.  374. 

speed  is  a  function  only  of  --  Special  photographic  anemometers  3 

were  made  by  the  Royal  Aircraft  Establishment  for  use  in  flight  and 
the  pressures  over  a  section  of  the  upper  and  lower  wings  of  a  biplane 
were  measured. 

The  types  of  variation  of  pressure  on  the  full  scale  are  faithfully 
reproduced  by  the  model  and  in  three  of  the  four  comparisons  the 
actual  numerical  agreement  is  complete  within  the  accuracy  of 
measurement.  The  difference  on  the  fourth  comparison  has  not  been 
explained  and  some  doubt  exists  as  to  its  reality.  Repetition  of  the 
experiments  has  not  yet  been  made.  Generally,  however,  it  is  clear 
that  in  heavier-than-air  craft  the  use  of  models  is  amply  justified. 
For  airships  the  lack  of  full-scale  experiment  precludes  any  statement 
of  value. 

In  the  course  of  the  investigations  of  the  variations  of  &D  with 
speed  and  size  it  was  found  that  changes  of  appreciable  magnitude 
occurred  at  the  lower  speeds  of  wind  tunnels  but  that  the  values 
tended  to  a  limit.  It  is  the  value  of  ko  at  the  limit  of  capacity  of  wind 
tunnels  which  is  taken  in  default  of  correcting  factors  determined 
from  a  comparison  between  full-scale  and  model  experiments.  On 
the  score  of  cost  it  is  not  practicable  to  increase  the  size  of  wind 
channel  or  the  speed  of  the  wind  indefinitely  and  the  highest  value 
of  v  I  appears  to  be  obtained  most  economically  by  large  size  rather 
than  high  speed.  There  are  some  other  advantages  of  size;  the  com- 
pleteness of  detail  possible  increases  with  the  size  of  model  and  one 
of  the  claims  in  favour  of  the  large  7  ft.  x  14  ft.  channel  at  the  Nation- 
al Physical  Laboratory  is  that  the  model  will  be  so  large  that  an  air- 
screw can  be  fitted  to  it  and  the  combination  of  airscrew  and  aero- 
plane tested  under  conditions  very  closely  resembling  those  in  flight. 

The  Effect  of  Compressibility  on  the  Motion  of  Air.  —  The  law  of 

corresponding  speeds  expressed  by  the  relation  —  •  =  constant  is 

peculiar  to  the  assumptions  made  in  obtaining  (4)  as  to  the  experi- 
mental factors  which  have  appreciable  effects  on  resistance.  There 
is  an  indefinitely  large  number  of  laws  of  corresponding  speeds,  each 
law  being  applicable  under  limited  conditions.  The  method  of  find- 
ing the  appropriate  law  is  clear;  the  process  begins  with  a  statement 
of  the  physical  quantities  and  measurements  involved  and  concludes 
when  an  equation  of  the  correct  dimensions  has  been  found.  The 
conditions  may  be  so  complex  that  the  answer,  when  obtained,  is  of 
little  value;  in  general  the  theory  of  dynamical  similarity  is  useful 
only  when  the  number  of  important  variables  is  less  than  five. 

The  difficulty  here  indicated  can  be  seen,  if,  instead  of  limiting  the 
problem  to  a  fluid  characterized  by  density  and  viscosity  only,  an 
extra  property  defining  its  compressibility  is  included.  There  are 
various  ways  of  expressing  compressibility  and  the  most  obvious 
would  be  through  an  elasticity  modulus.  Density  is  included  already 
in  the  properties  considered,  and  the  velocity  of  sound  in  a  fluid  is 
determined  by  the  ratio  of  the  modulus  of  elasticity  to  the  density. 
It  has  then  come  to  be  usual  to  assume  that  the  velocity  of  sound  a 
is  a  convenient  variable  when  investigating  the  effects  of  compres- 
sibility of  a  fluid  on  the  resistance  to  the  motion  of  a  body  through  it. 

The  equivalent  to  equation  (2)  for  the  extended  problem  is 

R=/,  (p,  I,  v,  v,  a)  -  (5) 

and  restricting  the  form  of  /  to  that  which  satisfies  the  theory  of 

To  satisfy  the  theoretical  conditions  which  guarantee  the  con- 
stancy of  ka  it  is  necessary  to  satisfy  simultaneously  the  equations 

v  I  11 

—  =  constant,  —  =constant 

v  a 

for  such  variations  of  size,  speed  and  fluid  as  are  at  disposal.  Once 
the  fluid  is  specified,  v  and  a  are  given  and  no  law  of  corresponding 
speeds  exists.  Various  proposals  have  been  made  to  use  a  gas  such  as 
carbonic  acid  in  one  experiment  and  air  in  another,  but  little  use 
appears  to  have  been  made  of  (6)  in  the  form  given. 

The  formula  for  the  pressure  due  to  a  pitot  tube  anemometer  — 
(i)  —  is  a  particular  case  of  (6).  That  the  form  of  (i)  agrees  with  (6) 
can  be  seen  by  an  expansion  of  the  functional  operator  of  the  latter 

in  powers  of  —  ,  using  Maclaurin's  theorem.  Such  an  expansion  will 
be  useful  so  long  as  the  effect  of  compressibility  is  small  and  the 
argument  —  small.  There  is  a  further  simplification  in  the  case  of 
the  pitot  tube  since  the  resistance  does  not  depend  measurably  on 
—  .  From  experiments  on  the  issue  of  steam  from  the  nozzles  of 

turbines  and  the  measurements  of  pressure  on  a  shell  in  flight  it 
appears  that  in  many  cases 

_5_  ,  F2  (  ^\  -  (7) 

p/V  \a  J 

is  a  type  of  formula  applicable  to  the  maximum  possible  pressure  on 
a  moving  body  for  speeds  ranging  from  a  few  in.  per  sec.  to  2,000 
ft.  per  sec.  and  upwards. 

3  Report,  A.C.A.,  R  and  M,  No.  287,  p.  504,  1916-7. 


It  is  possible  that  a  correcting  factor  will  be  introduced  into  the 
design  of  airscrews  to  allow  for  compressibility  of  the  air.  In  such 
a  case,  resistance  coefficients  based  on  (7)  would  provide  the  first 
approximation  to  a  rational  formula. 

Tests  of  the  Water  Resistance  of  Flying-Boat  Hulls. — Applications 
of  dynamical  similarity  extend  over  the  whole  range  of  physics  and 
an  exhaustive  discussion  would  lead  far  away  from  aeronautics.  One 
other  illustration  is  required  to  show  the  origin  of  the  law  of  corre- 
sponding speeds  applied  in  naval  architecture  to  surface-moving 
craft.  Experimentally  it  has  been  found  that  the  resistance  of  sur- 
face craft  at  high  speeds  depends  greatly  on  the  generation  of  waves. 
If  attention  be  concentrated  on  this  new  aspect  of  resistance  it  will 
be  found — by  methods  already  indicated— to  give  the  law  of  corre- 
sponding speeds  associated  with  the  name  of  Froude. 

At  any  point  of  a  wetted  surface  the  pressure  is  proportional  to 
the  head  of  water  above  that  point  and  will  be  increased  if  a  wave 
crest  exists  in  the  neighbourhood.  The  pressure  depends  on  the  head 
and  on  the  weight  of  unit  volume  of  the  water;  alternatively  the 
weight  may  be  expressed  as  the  product  of  the  density  of  the  water 
and  the  acceleration  due  to  gravity.  Now  consider  the  problem  of 
similar  motions  between  a  ship  and  a  model  of  it.  The  scale  of  the 
model  must  apply  to  the  scale  of  the  waves  if  similarity  is  to  exist. 
It  can  be  said  therefore  that  the  resistance  depends  on  a  linear  dimen- 
sion I,  velocity  of  test  v,  density  of  water  p  and  the  acceleration  due 
to  gravity  g.  The  appropriate  formula  then  follows  and  proves  to  be 


The  law  of  corresponding  speeds  is  therefore  -j—  =  constant. 

When  dealing  with  comparisons  of  motion  on  the  earth's  surface,  g 
is  constant  and  the  law  states  that  the  speed  of  test  for  the  model 
varies  as  the  square  root  of  the  scale.  This  condition  ensures  that  the 
waves  in  model  and  full-scale  trials  shall  be  similar.  Equation  (8) 
may  apply  in  other  cases,  such  as  the  disturbed  motion  of  model  and 
actual  aeroplanes  in  free  flight,  the  governing  factor  being  the  de- 
pendence of  the  motion  on  gravitational  attraction. 

Summary  of  the  Aeronautical  Uses  of  Dynamical  Similarity. — In 
measurements  of  resistance  to  the  motion  of  a  body  through  viscous 

fluid  the  correct  law  of  corresponding  speeds  is  that  —  =  constant; 

this  is  applicable  so  long  as  the  velocity  of  motion  is  not  more  than 
about  one-quarter  that  of  sound.  At  higher  velocities,  compressibility 
of  the  fluid  modifies  the  flow,  the  changes  depending  on  a  further 

factor  —  ,  i.e.  on  the  ratio  of  the  velocity  of  the  body  through  the 

fluid  to  that  of  sound  in  the  fluid. 

If  the  wave-making  resistance  alone  be  considered  the  law  of  cor- 

responding  speeds  for  terrestrial  surface  craft  is     y  =  constant ; 

where  resistance  depends  partly  on  wave-making  and  partly  on 
viscosity  it  is  generally  assumed  that  the  two  can  be  treated  by 
special  assumptions.  A  very  accurate  method  of  treatment  of  the 
complex  problem  does  not  lead  to  practicable  formulae. 

The  Resistances  of  Bodies  of  Various  Shapes. — A  somewhat  sharp 
division  exists  between  the  resistances  of  wings  and  aerofoils  and 
those  other  bodies  with  which  aeronautics  is  concerned.  In  the  latter 
cases  the  resulting  air  force  is  either  directly  opposed  to  the  motion 
or  is  little  inclined  to  it.  In  the  case  of  wings  at  the  most  efficient 
angle  of  presentation  the  resultant  force  is  almost  normal  to  the 
direction  of  motion.  Since  there  is  always  a  real  drag  the  direction 
of  the  resultant  force  must  fall  behind  the  normal  but  the  amount 
may  be  less  than  three  degrees. 

It  has  been  found  experimentally  that  all  aeroplane  wings — 
whatever  their  variations  of  shape — have  certain  common  charac- 
teristics. The  best  ratio  of  lift  to  drag  is  obtained  only  at  a  particular 
angle  of  attack  of  the  wing  to  the  air  and  a  considerable  loss  of  effi- 
ciency is  incurred  if,  as  is  usual  in  aeroplanes,  departure  from  this 

FIG.  173. — Flow  past  wing. 
8°.  Below  critical  angle. 

angle  to  the  extent  of  5°  or  6°  be  permitted.  At  the  highest  speed 
of  flight  of  the  aeroplane  of  1921  it  is  improbable  that  the  lift  exceeds 
12  times  the  drag,  whilst  the  maximum  ratio  exceeds  twenty. 

Apart  from  efficiency  there  is  a  limit  to  the  greatest  force  which 
can  be  obtained  at  a  given  speed  by  a  wing  of  finite  area.  Omitting 
very  special  complex  wings  for  the  moment,  the  limiting  force  at  any 
given  speed  is  obtained  when  the  wing  is  inclined  at  15°  or  20°  to 
the  wind.  One  of  the  most  efficient  types  of  wing  form  for  high-speed 

FIG.  i?b. — Flow  past  wing. 
20°.  Below  critical  angle. 

flight  has  a  limiting  lift  of  about  7  Ib.  per  sq.  ft.  at  a  speed  of  50  m. 
per  hour.  Other  forms  of  fixed  section  are  known  which  give  12  Ib. 
per  sq.  ft.  at  the  same  speed.  The  general  experience  of  all  experi- 
menters with  aerofoils  has  been  that,  so  long  as  the  shape  of  the  sec- 
tion is  invariable,  high  loading  at  the  angle  of  maximum  lift  cannot 
be  obtained  at  the  same  time  as  high  efficiency  for  maximum  speed. 

Much  attention  has  been  paid  therefore  to  flexible  and  variable 
wings;  if  it  were  possible  to  vary  the  area  of  a  wing  at  will  without 
introducing  unreliable  mechanism  or  adding  greatly  to  the  weight 
of  the  wing  structure  that  solution  would  offer  the  maximum  aero- 
dynamic advantages.  It  should  be  pointed  out  here,  that  the  addi- 
tion of  weight  to  an  aeroplane  in  such  a  place  as  not  to  add  directly 
to  the  resistance  leads  to  an  immediate  and  calculable  indirect  in- 
crease of  resistance  at  a  given  angle  of  incidence;  the  amount  may  be 
estimated  as  about  one-eighth  of  the  weight  under  favourable  condi- 
tions. So  far  no  satisfactory  proposals  exist  for  the  mechanical 
variation  of  the  area  of  the  wings  of  an  aeroplane.  More  practical 
success  has  met  the  endeavours  to  vary  the  section  of  a  wing  of  given 
size  so  as  to  obtain  the  advantages  of  high  lift  and  consequent  low 
speed  for  alighting  and  high  efficiency  at  flying  speeds.  It  has  already 
been  shown  that  either  condition  may  be  obtained  by  a  wing  of  fixed 
section.  A  further  general  observation  is  that  the  high-speed  wing  is 
thin  and  flat  whilst  the  high-lift  wing  is  thick  and  greatly  curved. 
Means  of  constructing  flexible  ribs  for  wings  to  admit  of  continuous 
change  from  one  shape  to  another  have  been  developed  and  the  me- 
chanical difficulties  do  not  appear  to  be  insuperable.  A  less  obvious 
method  of  attack  has  shown  greater  promise.  Mr.  Handley  Page1 
found  by  experiments  in  a  wind  tunnel  that  the  properties  of  high 
lift  could  be  obtained  by  allowing  air  to  pass  through  the  front  part 
of  a  wing  from  the  lower  to  the  upper  side.  By  dividing  the  wing  of 
an  aeroplane  into  a  small  aerofoil  hinged  at  its  leading  edge  and  a 
large  main  wing  the  device  becomes  both  mechanically  and  aero- 
dynamically  effective. 

The  motion  of  an  aeroplane  is  now  realized  to  be  dominated  by 
other  considerations  than  those  of  lift  and  drag  and  it  may  be  that  a 
particular  high-lift  wing  would  be  useless  because  it  led  to  failure 
of  lateral  control  at  low  speeds.  This  point  is  of  growing  importance 
and  aeroplane  design  can  no  longer  ignore  the  complex  interactions 
of  aerodynamic  properties.  For  this  reason  it  may  be  anticipated  that 
the  full  advantages  from  variable  wings  will  not  be  obtained  im- 
mediately but  that  the  processes  of  evolution  will  be  followed.  Past 
history  has  been  simpler;  early  experiments  by  Langley  (1896) 
covered  the  properties  of  flat  plates  used  as  aerofoils  and  laid  the 
general  foundation  of  practical  aviation.  Lilienthal  later  showed  that 
curved  surfaces  were  more  efficient  than  flat  ones  and  attention  was 
given  to  sections  suggested  by  bird  wings,  a  subject  of  interest  still 
occupying  the  minds  of  designers.  With  little  guidance  as  to  good 
forms,  the  early  pioneers  of  night,  Wilbur  and  Orville  Wright,  Far- 
man,  Bleriot  and  others,  introduced  wing  sections  in  the  period  1906- 
10  and  on  these  Eiffel  based  his  first  series  of  experiments.2  Design 
then  began  to  be  regularized.  One  of  the  more  promising  wing  sec- 
tions examined  by  Eiffel  in  his  wind  tunnel  at  the  Champs  de  Mars, 
designated  "Bleriot  II  bis,"  was  adopted  by  the  Royal  Aircraft 
Factory  for  the  BE2A.  In  1911,  thje  National  Physical  Laboratory 
adopted  this  form  as  the  starting-point  for  systematic  variation  of 
wing  form.  In  the  series  of  experiments  which  followed,3  the  thick- 
ness of  the  wing  was  changed,  also  its  shape  on  upper  and  lower  sur- 
faces and  the  bluntness  of  the  nose,  and  in  each  case  measurements  of 
lift  and  drag  were  made.  From  this  series  it  was  possible  to  make  a 
rational  choice  of  wing  section  to  fit  the  conditions  of  the  day.  The 
absolute  maximum  of  aerodynamic  efficiency  demanded  a  wing  too 

1  Jour.  Royal  Aeronautical  Society,  1920. 

2  Resistance  de  I'atr  el  I' Aviation,  1910-1. 
8  A.C.A.,  1911-2,  pp.  73-77. 


thin  for  structural  reasons  and  the  Royal  Aircraft  in  the  early  days 
of  1913  designed  the  RAF6  wing  on  the  basis  of  these  experiments  for 
the  development  of  the  aeroplane  BE2.  At  a  later  stage,  as  engines 
of  greater  power  were  produced,  further  experiments  led  to  improve- 
ment of  wings  at  small  angles  of  incidence  and  RAF6  was  replaced 
by  RAFlS  (May  1915).  It  was  found  that  the  advantages  of  the 
latter  at  high  speeds  were  appreciable  in  spite  of  the  increase  of  wing 
area  necessary  to  maintain  a  reasonably  low  landing  speed. 

Many  attempts  have  been  made  to  introduce  new  wing  forms  and 
those  showing  value  on  preliminary  test  have  been  investigated.  It 
has  invariably  been  found  that  guesses  have  been  inferior  to  the 
results  of  systematic  investigation.  In  order  to  facilitate  comparison 
all  results  of  wing  tests  are-^in  Great  Britain — reduced  to  a  stand- 
ard form.  Different  expressions  are  common  in  France  and  America 
but  neither  of  the  latter  is  international  in  the  sense  of  being  non- 
dimensional.  In  accordance  with  principles  of  dynamical  similarity, 
the  measured  forces,  lift  and  drag,  have  been  divided  by  air  density, 
wing  area  and  sq.  of  speed  in  order  to  deduce  lift  and  drag  coeffi- 
cients. A  centre-of-pressure  coefficient  is  obtained  by  expressing  the 
position  of  the  centre  of  pressure  by  the  ratio  of  its  distance  from 
the  leading  edge  to  the  chord  of  the  wing.  The  results  are  usually 
shown  in  curves  as  well  as  tables  and,  if  uniformity  in  scale  be  adopted 
for  the  curves,  comparison  of  wings  is  greatly  facilitated,  since 
superposition  immediately  indicates  the  relative  advantages  and 

It  is  clear  to  most  workers  in  the  subject  that  the  angle  of  inci- 
dence of  a  wing  is  a  convenient  but  arbitrary  variable.  A  more  use- 
ful relation  than  lift  to  angle  of  incidence  and  drag  to  angle  of  inci- 
dence is  that  of  drag  to  lift,  and  it  is  very  common  to  find  in  the 
records  of  the  aerodynamics  laboratories  the  value  of  drag  coefficient 
plotted  on  a  base  of  lift  coefficient.  The  idea  was  in  effect  used  by 
Eiffel  in  1910  in  a  system  of  polar  diagrams.  When  comparing  wings 
for  a  given  duty  a  still  further  variation  is  sometimes  made;  the  area 
of  a  wing  depends  on  the  specified  landing  speed  and  on  the  maximum 
lift  coefficient.  Only  when  both  these  quantities  are  included  can 
the  criterion  be  of  greatest  value.  If  it  be  presumed  that  the  condi- 
tion of  prescribed  landing  speed  is  to  apply  to  an  aeroplane  with 
different  wings  it  can  be  shown  that  at  other  speeds  the  lift  coeffi- 
cients of  the  respective  wings  will  be  proportional  to  the  maximum 
lift  coefficients.  Hence  a  curve  of  drag  coefficient  on  the  ratio  of 
lift  coefficient  to  maximum  lift  coefficient  has  direct  uses. 

Further  elaborations  have  been  used,  one  of  which,  due  to  the 
Royal  Aircraft  Factory  in  191 1,1  is  equivalent  to  the  plotting  of 
horse-power  on  a  basis  of  speed.  A  new  point  is  thus  brought  into 
prominence  for  it  is  seen  that  the  choice  of  wing  form  to  meet  given 
requirements  is  affected  by  the  resistance  of  the  rest  of  the  aero- 
plane. Brief  notes  on  the  character  of  this  additional  resistance  will 
be  made  at  this  point. 

The  aeroplane  as  a  whole  is  made  up  from  various  parts:  wings  for 
support;  body  for  holding  the  engine,  pilot,  load  and  control  organs, 
and  the  undercarriage  for  leaving  the  ground  and  alighting.  The 
same  organs  are  required  by  float  seaplanes  and  amphibians  but  in 
the  boat-type  seaplanes  the  body  and  alighting  gear  are  combined 
into  one  structure.  The  wings  themselves  are  usually  supported 
by  struts  and  wiring  which  add  to  the  resistance  and  there  is  a  dis- 
position to  test  and  fit  wings  which  are  designed  to  be  strong  enough 
to  support  the  weight  of  an  aeroplane  without  external  bracing 
wires.  It  is  desirable  here  to  emphasize  the  fact  that  the  result  may 
not  be  an  effective  reduction  of  resistance  owing  to  the  less  advan- 
tageous types  of  wing  section  which  must  be  used  and  to  the  greater 
mechanical  difficulties  of  construction. 

The  resistances  of  the  body  and  undercarriage  are  easily  appre- 
ciated ;  both  vary  very  closely  as  to  the  square  root  of  the  speea  and 
are  scarcely  changed  by  alteration  of  the  angle  of  incidence  of  the 
aeroplane.  At  high  speeds  the  added  resistance  is  roughly  equal  to 
that  of  the  wings  whilst  for  the  most  efficient  flight  the  proportion  is 
more  nearly  I  to  2,  the  wings  having  the  greater  resistance.  There 
is  a  loss  due  to  the  engine  which  is  not  quite  so  evident  as  that  due 
to  the  body.  If  water-cooling  be  adopted,  the  engine  may  be  totally 
enclosed  and  so  have  no  direct  effect  on  the  air  flow,  but  in  order  to 
maintain  the  cooling,  radiators  in  the  wind  are  required.  It  does  not 
matter  whether  the  engine  be  air-cooled  or  water-cooled,  a  certain 
minimum  resistance  to  motion  must  be  incurred  to  provide  the  cool- 
ing. Experiments  have  indicated  a  relationship  between  the  heat 
dissipated  from  a  hot  surface  and  the  skin  friction  given  by  the  mo- 
tion of  a  fluid  over  that  surface,  and  the  best  known  radiator  is  the 
honeycomb  type.  Disturbance  of  the  air  by  a  cooling  surface  which 
is  such  that  the  motion  is  violently  eddying  involves  a  higher  resis- 
tance for  a  given  dissipation  of  heat. 

The  placing  of  the  radiator  in  the  wind  near  the  aeroplane  may 
have  important  secondary  effects.  The  body  is  made  to  approach  a 
streamline  form  as  closely  as  possible  in  order  to  reduce  its  resistance 
and  the  approach  to  the  best  results  is  found  to  depend  greatly  on 
the  choice  of  shape.  The  magnitude  of  the  possible  effects  of  shape 
on  resistance  is  most  clearly  shown  by  experiments  on  airship  forms. 
The  resistance  of  an  airship  envelope  is  only  from  I  %  to  2  %  of  that 
of  a  disc  which  would  cover  the  section  at  the  maximum  diameter. 
It  is  true  that  the  aeroplane  body  is  far  removed  from  this  condition 

1  See  Flight,  Jan.  13  1912,  "  An  Aeroplane  Study,"  M.  O'Gorman. 

but  it  is  still  sufficiently  fine  to  have  its  resistance  increased  by  an 
unsuitable  disposition  of  radiator.  There  is  little  systematic  knowl- 
edge as  to  the  best  arrangement,  and  the  problem  of  engine- 
cooling  and  body  form  remains  one  of  engineering  difficulty  and 

Performance  of  Aeroplanes. — Rapid  development — also  costly 
— was  facilitated  by  the  construction  and  test  of  numerous 
aeroplanes  for 'war  purposes.  Not  until  1917  did  the  measure- 
ment of  engine  power  and  aeroplane  performance  in  Britain 
reach  the  stage  of  generality  and  accuracy  necessary  for  the 
purposes  of  estimate  and  prediction.  Other  countries  entered 
the  field  at  still  later  dates  and  it  will  be  seen  that  aviation  is 
still  in  early  infancy.  Progress  is  now  less  rapid,  the  main 
aerodynamic  features  having  been  brought  to  a  state  at  which 
the  work  of  all  the  better  designers  produces  nearly  the  same 
result.  So  true  is  this  statement  tjiat  curves  can  be  drawn 
relating  engine  power  to  speed  of  flight,  rate  of  climb  and 
total  weight  curves  which  show  what  a  designer  can  attain  but 
rarely  exceed.  The  greatest  changes  in  1917-21  were  in  the 
power  plant  and  here  limits  are  becoming  clearly  discernible. 
The  changes  in  the  weight  of  the  aeroplane  structure  due  to  more 
advantageous  use  of  material  were  also  small,  and  in  all  direc- 
tions new  advance  can  only  be  won  by  assiduous  study.  The 
period  of  striking  progress  is  over  and  has  given  place  to  one  in 
which  greater  training  and  knowledge  are  required  than  in  the 
past.  This  is  particularly  true  in  matters  relating  to  the  reliabil- 
ity and  safety  of  aircraft. 

Stability. — The  idea  of  stability  as  applied  to  motion  is  very 
old  and  standard  methods  of  dealing  with  mechanical  problems 
were  gradually  developed  by  the  mathematicians  of  the  last 
century.  Laplace  applied  his  knowledge  to  an  examination  of 
the  stability  of  the  solar  system,  i.e.  he  accepted  the  theory  of 
gravitation  as  accounting  for  observations  and  made  an  exten- 
sion to  see  whether  the  motion  was  permanent  or  in  a  state  of 
change.  The  ideas  of  stability  are  quite  different  from  those  of 
performance  and  at  the  present  day  it  is  safe  to  say  are  not 
understood  by  designers  with  the  degree  of  intimacy  which  leads 
to  incorporation  in  design.  It  is  true  that  some  rough  generaliza- 
tions exist  and  are  acted  upon;  by  placing  the  centre  of  gravity 
of  an  aeroplane  very  far  forward  longitudinal  stability  is  en- 
sured whilst  a  rearward  position  tends  to  instability  and  danger. 
Similarly,  the  fin's  dihedral  angle  on  the  wing  is  known  to 
affect  lateral  stability.  Present-day  (1921)  aeroplanes  border  on 
neutral  stability  for  the  conditions  of  straight  forward  flight 
and  this  has  come  about  by  trial  and  error,  corrected  by  the 
likes  and  dislikes  of  a  pilot  during  aerial  fighting.  So  long  as  the 
pilot  be  alert  and  the  aeroplane  of  moderate  size,  say  less  than 
6,000  Ib.  weight,  it  is  possible  to  control  the  craft  in  the  air  in 
the  condition  in  which  it  leaves  the  works.  The  few  attempts  to 
make  very  large  aeroplanes,  20,000  to  50,000  Ib.  in  weight, 
have  led  to  early  disaster  owing  to  the  inability  to  approach, 
on  such  scale,  the  necessary  degree  of  refinement  of  control  and 
stability.  Alternatively  it  may  be  said  that  the  attempt  to 
develop  large  aircraft  has  overstepped  the  reasonable  limits  of 
caution  and  has  placed  on  the  pilot  a  strain  which  he  is  physically 
incapable  of  withstanding. 

Even  in  the  smaller  craft  there  are  many  which  in  normal 
flight  require  the  unremitting  attention  of  the  pilot  and  which 
if  left  to  themselves  for  a  minute  would  be  in  a  dangerous  and 
probably  uncontrollable  condition  of  flight.  This  is  not  a  neces- 
sary state  for  an  aeroplane  and  there  is  no  insuperable  difficulty, 
given  training,  in  ensuring,  without  an  appeal  to  trial  in  the  air, 
that  an  aeroplane  will  fly  itself  for  long  periods.  The  opinion 
has  been  expressed  that  aircraft  of  the  present  day  would  be  of 
commercial  value  were  the  obviously  removable  defects  dealt 
with.  Reliability  of  the  engine  installation  is  probably  the  most 
urgent  need,  but  following  that  comes  the  application  of  the 
known  theories  of  stability. 

Broadly  speaking  the  quality  called  stability  is  readily  de- 
fined. An.  aeroplane  is  taken  into  the  air  and  a  given  state  of 
motion  produced  by  the  pilot  and  maintained  for  some  time. 
This  operation  does  not  involve  stability  but  requires  adequate 
control.  When  flying  steadily  suppose  that  the  pilot  ceases 


to  operate  but  keeps  his  muscles  rigid  and  without  disturbing 
the  motion  deliberately  produces  a  condition  in  which  the 
aeroplane  has  to  control  itself  in  gusts  of  small  size.  If  the 
motion  be  stable,  no  great  changes  will  occur  as  a  result  of 
the  pilot's  relinquishing  of  control.  A  small  amount  of  pitching, 
rolling,  yawing  and  side-slipping,  etc.,  will  occur  but  on  the 
whole  the  speed  of  flight  and  the  angle  of  incidence  will  remain  at 
the  same  value  as  at  the  beginning;  the  wings  will  not  change 
their  angle  of  bank  greatly  nor  the  turning  increase  or  decrease. 

An  instability,  and  in  contradistinction  to  stability  there  are 
many  instabilities  possible,  will  magnify  the  effects  of  a  gust  with 
greater  or  less  rapidity  and  the  motion  will  depart  from  the 
initial  state  to  some  other  stable  state.  It  rarely  happens  that 
this  second  state  is  a  comfortable  one.  An  aeroplane  which  is 
unstable  in  normal  flight  •  will  usually  be  stable  upside  down 
and  may  be  so  stable  in  that  position  as  to  be  uncontrollable. 
The  time  taken  to  pass  from  one  state  to  another  is  often  only  a 
matter  of  a  few  seconds,  rarely  as  long  as  a  few  minutes. 

In  the  very  early  days  of  flying  the  problem  of  getting  into 
the  air  at  all  took  first  place  in  importance.  The  aviators  of 
1908-10  kept  a  very  close  watch  on  the  weather  and  one  of  them 
had  a  standard  test  for  satisfactory  conditions.  Standing  with 
his  feet  apart,  he  dropped  a  feather  from  the  level  of  his  shoulders 
and  if  it  fell  outside  his  feet  the  wind  was  too  great  for  flying. 
The  record  of  these  early  years  and  the  shortness  of  life  of  the 
aviators  are  sufficient  testimony  to  the  consequences  of  the 
extreme  forms  of  instability.  The  revolutionary  step  which 
made  it  possible  to  keep  the  air  for  an  hour  instead  of  a  few 
minutes  was  made  by  the  Wright  brothers  when  they  intro- 
duced wing  warping  as  a  lateral  control;  there  is  little  reason 
to  doubt  the  statement  that  flying  still  remained  an  acrobatic 
feat.  A  study  of  the  technical  papers  of  the  period  1908-14  will 
show  how  slowly  the  idea  of  banking  *  an  aeroplane  entered  into 
the  development  of  aviation.  It  is  noted  in  March  1912  as  a 
possible  cause  of  accident  that  the  pilot  "  is  reported  to  have 
endeavoured  to  rise  when  making  a  turn."  Not  until  April 
1913  do  we  find  vertical  banking  by  Chevillard  followed  by 
upside-down  flying  and  looping  by  Pegoud  in  Sept.  of  that  year. 

A  prominent  place  in  the  technical  journals  was  devoted  to 
accidents  and  a  perusal  of  these  shows  that  all  types  were  liable 
to  fail  as  late  as  1913.  A  series  of  accidents  to  monoplanes 
occurred  in  Britain  and  their  flight  was  suppressed  temporarily 
in  Sept.  1912,  whilst  a  committee  was  formed  to  investigate 
causes  and  to  suggest  lines  of  development.  The  findings  of 
this  committee2  have  had  a  marked  influence  on  British  aviation 
and  the  paragraph  relating  to  stability  is  here  quoted: — 

"  The  Committee  desire  to  urge  the  importance  of  the  general 
investigation  into  the  stability  of  aeroplanes,  whether  monoplanes 
or  biplanes.  The  experimental  data  at  present  available  are  not 
sufficient  to  allow  a  complete  theory  to  be  formulated.  It  is  under- 
stood, however,  that  the  work  of  the  Advisory  Committee  has  now 
been  carried  to  the  stage  at  which  the  problem  can  be  attacked  with 
hope  of  success,  provided  that  the  necessary  facilities — a  large  wind 
channel  in  a  sufficiently  big  enclosed  space — be  put  at  their  disposal, 
and  the  Committee  recommend  that  the  Advisory  Committee  be 
asked  to  continue  the  further  investigation  into  the  stability  of  the 
aeroplane  as  a  matter  of  great  urgency,  and  more  especially  to  exam- 
ine the  question  of  inherent  lateral  stability,  suggestions  towards  the 
solution  of  which  have  been  given  by  the  experiments  of  Lanchester 
and  the  calculations  of  Bryan." 

The  investigation  here  started  led  directly  to  the  stability 
experiments  on  REi  and  BE2,  a  combination  of  full-scale 
flights  at  the  Royal  Aircraft  Factory  and  model  and  theoretical 
preparatory  work  at  the  National  Physical  Laboratory.  Before 
dealing  with  the  results,  a  return  to  early  times  will  be  made 
to  indicate  the  position  of  the  theory  of  stability. 

Up  to  the  end  of  1909  the  chief  writers  on  the  stability  of  the 
aeroplane  were  Bryan,3  Ferber,4  '  Lanchester,5  and  Soreau.6 

1  Flight,  Feb.  17  1912. 

2  Report  of  Dptl.  Comm.  on  Accidents  to  Monoplanes,  1912  (ed. 
6506),  p.  9. 

8  Bryan  and  Williams,  "The  Longitudinal  Stability  of  Aerial 
Gliders,"  Proc.  R.  S.,  vol.  Ixxiii.,  1904,  p.  IOO. 

4  V Aviation.     6  A erodonelics,  Lanchester. 

*  Socicte  des  Ingenieurs  Civils  de  France,  and  in  a  volume:  "  Etat 
actuel  et  avenir  de  1'aviation." 

The  most  complete  method  was  that  by  Bryan.  The  papers  all 
advanced  the  study  of  the  subject  in  some  measure  but  the 
appearance  in  1911  of  Bryan's  book  Stability  in  Aviation  laid 
the  foundations  of  the  subject  as  now  known  to  us.  About  the 
same  time  other  workers  were  entering  the  field,  amongst  whom 
may  be  mentioned  Knoller,7  Bothezat 8  and  Reiszner.9  From 
that  time  the  theory  of  stability  has  been  far  ahead  of  practice. 
Developments  have  been  made  to  cover  circling  flight,  disturbed 
motion  and  the  effects  of  gusts,  but  all  are  natural  extensions  of 
the  theory  of  dynamical  stability  as  given  by  Routh  and  applied 
by  Bryan  to  the  aeroplane.  There  is  little  doubt  that  further 
extensions  will  be  made  as  required,  but  the  immediate  need  is 
the  devotion  of  existing  knowledge  to  practice  to  a  far  greater 
extent  than  has  hitherto  occurred.  As  in  other  branches  of 
research  the  World  War  has  had  an  adverse  effect  in  curtailing 
opportunities  for  reasoned  progress. 

In  March  1913  a  report  *°was  issued  showing  the  possible  applica- 
tions of  the  theory  of  stability  in  numerical  detail.  The  mathema- 
tical analysis  cannot  be  useful  unless  a  number  of  quantities,  known 
as  resistance  derivatives,  can  be  obtained  from  experiment.  The  re- 
port in  question  represents  the  first  systematic  attempt  to  apply 
experimental  research  to  the  evaluation  of  the  quantities  required 
for  application  of  the  theory.  A  discussion  is  given  of  the  meaning 
and  origin,  from  the  physical  side,  of  the  resistance  derivatives  and 
rough  estimates  were  made  as  to  the  ranges  of  the  quantities  for 
then  existing  aeroplanes.  For  one  condition  of  flight  more  accurate 
data  were  obtained  and  a  table  of  some  18  derivatives  deduced  cover- 
ing the  longitudinal  and  lateral  stabilities  of  an  aeroplane  in  normal 
flight.  There  are  a  number  of  approximations  which  assist  in  the 
understanding  of  the  relation  between  cause  and  effect  which  were  of 
importance  in  the  infancy  of  the  subject. 

By  such  a  preliminary  examination  on  the  model  scale,  the 
phenomena  to  be  looked  for  on  the  full  scale  were  clearly  defined. 
The  now  well-known  "  phugoid  "  oscillation  was  then  unobserved 
and  only  indicated  by  calculations:  It  is  indeed  possible  that  up  to 
that  date  longitudinal  stability  did  not  exist  apart  from  the  very 
special  design  of  Dunne.  The  mathematical  theory  indicated  quite 
clearly  that  special  shapes  were  unnecessary  and  that  aeroplanes 
of  more  usual  form  could  be  made  stable  by  attention  to  the  dis- 
position of  weights  and  the  arrangements  of  the  aerofoil  surfaces. 
In  particular,  the  importance  of  a  dihedral  angle  on  the  wings  and 
an  adequate  fin  and  rudder  were  shown  in  relation  to  lateral  stability. 

In  the  course  of  the  12  months  which  followed  great  progress  was 
made;  in  a  series  of  papers  "  from  the  National  Physical  Laboratory, 
the  effect  of  varying  essential  quantities,  such  as  the  centre  of  gravity 
of  the  aeroplane,  the  amount  of  area  of  the  tail  plane,  the  extent  of 
the  dihedral  angle,  rudder  and  fin  area,  etc.,  was  examined  in  detail. 
It  was  shown  that  partial  experiments  on  lateral  stability  would  fail 
since  there  is  a  relation  between  the  dihedral  angle  on  the  wings  and 
the  appropriate  fin  and  rudder  area. 

Further,  the  exact  method  of  inherent  adjustment  of  an  aeroplane 
to  gusts  was  shown  and  the  details  of  flight  of  a  longitudinally  stable 
aeroplane  in  a  natural  wind  obtained.  This  was  done  not  only  for 
uncontrolled  but  for  controlled  flight.  By  the  summer  of  1914  the 
investigation  of  the  effect  of  natural  properties  of  an  aeroplane  on 
mechanical  devices  for  controlling  it  were  being  envisaged,  but  the 
outbreak  of  the  war  broke  the  continuity  and  the  subject  still  remains 
at  that  point  of  theoretical  development. 

In  the  meantime  full-scale  experiments  were  being  made  at  the 
Royal  Aircraft  Factory.12  A  few  extracts  from  these  reports  are  of 
historical  value  and  are  here  reproduced: — 

"  Although  completely  controllable  under  all  circumstances  by 
means  of  the  elevator,  it  has  been  found  that  the  BE2A  aeroplane, 
fitted  with  the  old  tail  plane  (TP  l)  was  not  stable  with  the  elevator 
free  or  even  locked.  .  .  .  Two  methods  of  experimenting  have  been 
adopted: — (a)  Variation  of  the  section  and  plane  form  of  tail,  (b) 
Variation  of  the  position  of  the  centre  of  gravity  of  the  aeroplane 
relative  to  the  position  of  the  wings." 

"  Experiment  (i)  with  tail  (TPl).  Area  of  tail  61  sq.  feet.  Centre 
of  gravity  at  0-38  of  the  mean  chord  behind  the  leading  edge.  At  a 
height  of  about  2,000  ft.  the  elevator  control  lever  was  held  in  a 
fixed  position.  After  a  short  time,  a  steady  dive  developed,  which  was 
allowed  to  continue  so  long  as  it  was  considered  safe  by  the  flier,  in 
this  instance  during  a  flight  of  about  500  yards.  There  was  no  ten- 
dency for  the  path  to  revert  to  the  horizontal.  ...  It  was  found 
that  there  was  just  as  much  tendency  for  a  steady  rearing  to  be 
developed  as  a  dive.  ..." 

7  "Cber  Langstabilitat  der  Drachenflugzeuge,"  Ztschr.  fur  Flug- 
technik  und  Motorluftschifffahrt,  July  and  Aug.  1911. 

8  £tude  de  la  Stabilite  de  I'aeroplane  (Dimod  &  Pinet.  191 1). 

9  Ztschr.  fiir  Flugtechnik  und  Motorluftschifffahrt,  Feb.  10  1912. 

10  R  and  M,  No.  77,  Advisory  Committee  Tor  Aeronautics,  1912-3. 

11  Reports,    Advisory     Committee    for    Aeronautics,   1913-4,  pp. 

12  Reports,  Advisory  Committeefor  Aeronautics, 1913-4,  pp.  385-394. 



"  Experiment  (2).  Another  tail  was  tried  (TP2)  ...  A  long 
glide  was  also  made  with  the  elevator  locked.  During  these  flights 
a  marked  improvement  in  the  behaviour  of  the  machine  was  obtained, 
damped  phugoids  being  described.  ...  It  may  certainly  be  said, 
however,  that  with  TPa  and  the  other  conditions  of  this  experiment, 
BE2  was  proved  to  be  capable  of  flying  indefinitely  with  the  elevator 
locked  in  winds  with  gusts  up  to  30  m.  per  hour." 

"  Experiment  (3).  The  same  tail  plane  was  fitted  and  the  condi- 
tions were  approximately  the  same  except  that  the  centre  of  gravity 
was  considerably  further  back.  .  .  .  This  very  backward  position 
of  the  centre  of  gravity,  of  course,  made  the  aeroplane  quite  unstable, 
and  increasing  dives  or  rearings  were  performed  almost  as  soon  as 
the  elevator  was  locked.  ..." 

"  Experiment  (4).  The  centre  of  gravity  was  brought  forward  and 
a  considerable  improvement  was  obtained.  It  was  now  found  that 
even  with  the  elevator  free,  damped  phugoids  were  obtained.  In  the 
absence  of  gusts  at  the  time,  these  phugoids  were  started  by  move- 
ments of  the  elevator  control  lever.  When  the  machine  had  been 
forced  to  assume  a  sharp  dive,  the  control  lever  was  totally  released 
and  it  was  found  that  after  two  or  three  complete  oscillations  the 
amplitude  became  too  small  to  be  noticed.  .  .  .  The  period  of 
oscillations  was  found  to  be  about  20  seconds." 

"  Apart  from  the  practical  utility  of  these  experiments  in  develop- 
ing the  particular  aeroplane  in  question  their  wider  significance  un- 
derlies the  fact  that  they  agree  with  and  confirm  the  model  experi- 
ments on  the  full  scale  both  as  regards  the  characteristics  of  the  tail 
planes  and  the  interference  of  the  main  planes  with  them;  and  the 
two  sets  of  experiments  give  data  from  which  a  tail  can  be  designed 
for  any  aeroplane  to  give  any  degree  of  longitudinal  stability  required." 

It  appears  from  recent  investigation  of  accidents  that  the  type  of 
instability  described  above  is  not  avoided  in  all  modern  aircraft.  The 
effect  of  the  instability  is  serious  and  epidemic  failures  to  control  have 
been  traced  to  this  cause  alone.1  Some  photographic  records  of 
longitudinal  motion  taken  at  a  much  later  period  will  be  found  as  re- 
productions in  the  Wilbur  Wright  lecture2  for  1919.  The  actual  time 
required  for  the  testing  of  longitudinal  stability  is  now  so  short  that 
the  production  of  records  has  been  made  an  addition  to  the  older 
established  performance  trials.  Progress  has  been  steady  but  rather 
slow  and  the  influence  of  the  tests  is  not  yet  evident  in  new  design. 

In  the  case  of  lateral  stability  the  records  of  the  early  experiments 
at  the  Royal  Aircraft  Factory  are  of  equal  or  greater  interest  with 
those  on  longitudinal  motion: — 

"  RE  I  rolling  stability  experiments,  by  Mr.  Bush.  .  .  .  The 
wing  flap  controls  were  entirely  abandoned  and  the  aeroplane  was 
flown  75  m.  with  two  turns  without  their  use.  The  rudder  was  used 
for  steering  or  was  kept  straight  to  avoid  complicating  the  investi- 

"  The  evolutions  of  the  aeroplane  bore  out  the  theoretical  expec- 
tations. Disturbance  by  a  gust  was  followed  by  side-slip  towards  the 
low  side,  which  brought  the  dihedral  angle  into  effect,  righting  the 
machine.  In  both  the  above  experiments  the  recovery  from  a  roll 
seemed  rather  slow,  and  it  was  decided  to  double  the  amount  by 
which  the  wings  were  bent  up." 

"  The  results  of  the  above  experiments  were  sufficiently  satisfac- 
tory to  warrant  the  abandonment  of  the  warp  and  the  use  of  wings 
with  flaps  for  RE5  and  other  aeroplanes  in  course  of  design." 

Rotative  Stability. — The  rotative  stability  with  the  rudder  in  a 
fixed  position  was  next  examined.  Up  to  this  point  the  aeroplane  had 
been  usually  steered  on  a  straight  course,  which  made  recovery 
quicker.  When  the  rudder  is  fixed,  however,  disturbance  of  level  is 
followed  by  a  turn  towards  the  low  side  as  well  as  a  side-slip.  If 
the  directional  stability  is  too  great,  the  increased  speed  of  the  outer 
wing  will  counteract  the  restoring  effect  of  the  side-slip,  and  the 
aeroplane  will  continue  to  turn  with  increasing  bank  and  angular 
velocity.  The  manoeuvre  if  not  controlled  ends  in  a  spiral  dive." 

"  Dec.  8  1913. — In  this  experiment,  the  rudder  was  adjusted  for 
straight  flight  and  then  held  fast  by  the  feet,  friction  of  the  heels 
against  the  floor  making  absence  of  movement  certain.  When  all  was 
ready  the  aeroplane  was  disturbed  by  the  wing  flaps,  which  were  then 
returned  to  their  normal  position.  The  experiment  is  rather  delicate, 
as  any  want  of  symmetry  will  cause  the  aeroplane  to  be  stable  when 
rolled  in  one  direction  and  unstable  in  the  other.  It  appeared,  how- 
ever, that  the  aeroplane  was  just  stable,  righting  herself  slowly." 

Complete  stability  test. — The  aeroplane  was  flown  from  Long 
Valley,  Aldershot,  to  Froyle  near  Alton,  and  also  from  Froyle  to 
Fleet,  distances  of  6  J  and  8m.,  without  the  use  of  wing  flaps  or  eleva- 
tor. The  wing  flaps  were  left  free  as  usual  and  the  elevator  was  locked. 
The  flying  was  very  comfortable,  and  the  pilot  considered  that  re- 
connaissance under  these  conditions  would  be  considerably  easier  for 
a  pilot  alone." 

For  normal  flight  the  description  of  lateral  stability  given  in 
these  abstracts  still  represents  the  position.  The  experiment  is 
still  delicate  and  it  may  be  doubted  whether  any  aeroplane  has 
an  appreciable  degree  of  lateral  stability.  The  early  work  on 
stability  cleared  the  way  to  a  large  extent;  the  temptation  to 

'Accidents  Investigation.  Advisory  Committee  for  Aeronautics, 
Jan.  1919.  R  and  M  No.  617,  also  R  and  M  No.  629,  Dec.  1918. 

2  Supplement  to  Aeronautical  Jour.,  July  1919. 

complex  design  for  safety  was  removed  and  dangerous  instability 
rarely  exists  so  long  as  a  pilot  is  alert.  The  introduction  of 
aerobatics  and  the  training  of  pilots  to  loop,  spin,  roll,  etc.,  at 
the  same  time  as  it  inspired  confidence  in  the  ability  to  control  an 
aeroplane  also  led  to  conditions  far  removed  from  those  of  normal 
straight  flight.  It  was  then  found  that  the  stability  of  aircraft 
under  extreme  conditions  has  great  importance,  particularly 
when  the  angle  of  maximum  lift  has  been  reached  or  exceeded. 

A  very  large  proportion  of  accidents  arises  from  engine  failure 
whilst  near  the  ground.  In  holding  up  the  nose  of  the  aeroplane 
whilst  attempting  to  turn  back  into  an  aerodrome,  the  pilot 
not  infrequently  stalls  the  craft  and  violent  lateral  instability 
results.  Recovery  from  the  effects  of  this  instability  is  rare  and 
much  study  has  been  made  of  the  phenomenon. 

There  is  now  little  doubt  as  to  the  cause  of  this  instability 
but  the  methods  of  removing  it  are  far  less  clear.  The  same 
cause  which  produces  instability  removes  the  effectiveness  of 
the  controls;  it  is  probable  that  high -lift  wings  have  charac- 
teristics antagonistic  to  those  of  stability  and  further  investiga- 
tion of  the  subject  is  required  before  satisfactory  design  for 
speeds  less  than  that  of  stalling  can  be  reached. 

More  recent  papers  on  various  aspects  of  stability  will  be 
found  in  the  reports  of  the  societies  and  bodies3  dealing  with 
aeronautics;  there  are  no  striking  developments  but  much  solid 
work  has  been  done  by  a  few  workers  in  the  subject.  There  are 
difficulties  in  the  nature  of  variation  of  nomenclature  which 
make  the  comparison  of  work  laborious  and  in  an  attempt  to 
deal  with  this  aspect  of  the  problem  of  stability  the  Royal 
Aeronautical  Society,  acting  as  a  sub-committee  of  the  British 
Engineering  Standards  Association,  has  drawn  up  and  recom- 
mended the  use  of  a  particular  set  of  symbols  and  axes  of  refer- 
ence. Still  in  its  infancy  as  regards  application,  the  subject  merits 
greater  attention.  It  is  scarcely  likely  that  the  degree  of  stabil- 
ity— still  undefined — thought  suitable  for  military  use  will 
be  that  correct  for  civil  uses.  Extreme  manoeuvrability  is  con- 
sidered to  be  essential  in  the  first  and  safety  in  the  second. 
Whilst  not  wholly  incompatible  it  is  clear  that  a  degree  of  stabil- 
ity can  be  introduced  without  discomfort  in  a  straight  and  un- 
eventful flying  which  is  disliked  for  the  purposes  of  aerial 
fighting.  (L.  Bw.) 


The  aircraft  pioneers,  being  their  own  designers,  builders 
and  financiers,  used  the  simplest  design,  manufacture  and 
assembly,  and  the  cheaper  materials. 

Between  1912  and  1914  came  a  striving  for  efficiency;  fixed 
charges  were  relatively  high,  and  research  costs  were  extremely 
great  for  the  small  output  of  the  day;  this  conduced  to  the 
quest  for  the  best  materials  and  made  costly  machining  to  reduce 
weight  and  establish  types  permissible.  In  the  World  War  the 
aerodynamic  advances  made  in  this  way  were  used,  but  as  bulk 
production  set  in  before  schemes  and  tools  for  bulk  production 
existed,  aeroplanes  had  to  be  made  regardless  of  cost  until  the 
tools  were  evolved. 

Standardization  of  materials,  of  sizes  and  of  parts  and  com- 
ponents, notably  bolts,  nuts,  bracing  connexions,  piping  con- 
nexions, etc.,  common  to  most  types  of  aircraft,  had  previously 
to  1914  been  started,  but  was  extended  in  1915  to  cover  tubes, 
bracings,  methods  of  jointing,  length  of  bracings,  wheels  and 
axles,  airscrew  bosses,  etc.  Also  some  of  the  larger  components, 
wings,  elevators,  rudders,  and  ailerons,  which  could  be  utilized 
on  more  than  one  type,  were  standardized.  Master  and  work- 
shop gauges  were  made  and  distributed  to  ensure  interchange- 
ability.  Continuous  records  of  tests  led  to  the  selection  of  the 
most  suitable  materials,  and  to  standard  specifications.  These 
have  been  continuously  evolved  up  to  the  present  day,  and  their 
dissemination  has  spread  far  and  wide  much  acquired  knowledge. 

3  Reports  of  the  Advisory  Committee  for  Aeronautics  to  date, 
Jour,  of  the  Royal  Aeronautical  Society. 

Reports  of  the  National  Advisory  Committee  for  Aeronautics, 
United  States  of  America. 

"  Applied  Aerodynamics,"  L.  Bairstow. 

"  Aeronautics:  A  Class  Text,"  E.  B.  Wilson. 

"  Aeronautics  in  Theory  and  Experiment,"  Cowley  and  Levy. 



The  earliest  steps  in  England,  or  indeed  anywhere,  to  unify 
such  standards  were  taken  by  the  Royal  Aircraft  Factory  at 
Farnborough  in  1913.  They  were  extended  and  improved 
as  experience  developed  under  the  Aircraft  Inspection  Depart- 
ment (A.I.D.)  in  England  (towards  the  end  of  1915),  and  later 
under  the  British  Engineering  Standards  Association,  which  in 
1921  was  instrumental  in  founding  in  Paris  the  "  Comite  Inter- 
national pour  1'Unification  Aeronautique  "  to  internationalize 
the  same  work. 

Components. — Fuselages,  wings,  undercarriages,  tail  planes  and 
controlling  surfaces,  prior  to  1914  were  not,  save  in  one  or  two  cases, 
designed  as  self-contained  units,  i.e.  their  manufacture  was  usually 
completed  during  erection  into  the  aeroplane.  This  involved  hand- 
fitting,  trial  and  error  adjustment,  constant  inspection  and  slow 
production,  while  spares  were  not  interchangeable. 

By  1915  each  component  became  a  unit  in  itself,  made  to  limits, 
corresponding  with  the  connexion  points,  and  interchangeability  was 
safeguarded  by  the  use  of  jigs  and  fixtures.  By  1919  even  compo- 
nents were  subdivided  into  standardized  parts,  and  the  assembly  of 
components  into  a  complete  aeroplane  could  be  effected  after  deliv- 
ery to  the  field.  The  jigs  and  fixtures  were  usually  confined  to  the 
location  of  junction  fittings  on  which  the  structure  was  erected. 
These  replaced  the  fixtures  of  1915,  which  held  all  members  of  the 
component  in  position  during  construction,  but  proved  not  to  be 
satisfactory,  owing  to  the  distortion  of  the  finished  piece  on  re- 
moval from  the  fixture. 

Girder  types  of  construction,  such  as  fuselages,  wings,  etc.,  were 
latterly  constructed  to  jigs  rather  than  on  fixtures,  in  order  that 
their  truth  of  erection  might  be  more  permanent.  Monocoque  con- 
structions, however,  were  always  built  on  cradles  or  moulds,  which 
definitely  determined  their  final  shape;  the  individual  members, 
being  free  from  initial  load,  were  free  from  distortion  on  removal 
from  the  mould. 

The  development  of  portable  gauges  (gauge  points  mounted  on 
tensioned  wires)  occurred  in  1916. 

In  1917  component  junctions  were  designed  so  that  all  positioning 
was  determined  by  one  joint,  clearance  in  one  direction  being  allowed 
on  the  remaining  joints;  the  gauging  of  components  was  simplified 
thereby,  and  many  of  the  more  costly  gauges  could  thus  be  super- 
seded by  simpler  ones  used  in  conjunction  with  a  measuring  operation. 
Woodwork. — Wood  is  eminently  suitable  for  light  construction 
and  for  obtaining  a  rapid  output  by  machining.  The  mechanical 
properties  and  suitability  of  various  timbers  were  little  known  in 
1913.  Bamboo,  the  lightest  timber,  was  found  unsuitable  in  about 
191 1 ;  it  lacks  uniformity  in  size,  and  is  difficult  to  connect  at  the  end 
of  members.  Ash  (Fraxinus  excelsior)  and  hickory  (Carya  alba, 
Hichora  ovatd)  were  early  used,  but  hickory  is  scarce,  and  variable 
in  its  mechanical  properties,  and  ash  is  heavy  as  well.  Ash  is  re- 
stricted to  use  where  high  flexibility  and  shock-resisting  are  essential. 
Silver  spruce  (Picea  Sitchenis,  Carr.)  was  introduced  in  1913  for 
spars,  struts,  longerons  and  other  members,  being  uniform,  light  and 
suitable  for  machining  for  weight  reduction. 

Between  1913  and  1915  accurate  information  of  the  strength  and 
elasticity  of  this  timber  was  acquired.  Methods  of  converting  the 
timber  for  the  various  uses  were  determined  in  order  to  eliminate  de- 
fects peculiar  to  coniferous  timbers,  such  as  spiral  grain, cross  and  diag- 
onal grain,  dote  or  rot,  gum  pockets,  alternating  hard  and  soft  grains, 
low  density,  wide-ringed  timber  and  brittle  or  lifeless  timber  (brash). 
The  great  demand  in  1916  in  England  led  to  the  importation  of 
unseasoned  timber,  needing  to  be  conditioned  for  use.  The  French 
and  Americans  had  already  experience  of  this.  Kilns  were  erected  in 
England  (on  the  Sturtevent  system  of  drying).  Humidities,  tem- 
peratures and  time  periods  of  drying  were  determined.  Control  of 
the  moisture-content  of  timber  was  found  to  be  essential. 

The  larger  aeroplanes  in  1916  and  1917,  and  the  demand  in  excess 
of  supply  Tor  best  of  spruce  of  long  lengths,  led  to  spars  being  made  of 
short  lengths  joined  together,  the  joints  being  situated  at  points  of 
low  stress.  A  study  of  various  joints  in  1918  led  to  the  adoption 

FIG.  1 8. 

of  the  plain  vertical  scarf  joint  with  an  inclination  of  I  in  9,  reinforced 
by  bolts  through  the  splice,  and  bound  with  fabric  (see  fig.  18). 
Shorter  timbers  glued  together  as  laminations  then  became  permis- 
sible for  all  spars,  and  defects  could  thus  either  be  cut  out  or  re- 
inforced. Joints  in  these  laminations,  after  being  admitted  for  a 
period,  were  ruled  out  in  1919. 

To  supplement  the  supplies  of  silver  spruce  in  1917  the  following 

timbers  were  tried  in  1918,  the  peculiarities  of  each  being  allowed  for: 

Quebec  Spruce  (Picea  alba  and  Picea  nigra,  Link  ) 

White  Sea  White  Deal  (Picea  excelsa,  Link.). 

White  Sea  Red  Sea  Yellow  Deal  (Pinus  sylvestris,  Link.). 

West  Virginia  Spruce  (Picea  rubeus,  Sargent). 

North  Carolina  Spruce  (when  this  is  the  same  as  West  Virginia 
Spruce,  but  grown  in  North  Carolina). 

Louisiana  Red  Cypress  (Bald.). 

Port  Orford  Cedar  (Chamaecyparis  Lawsoniana,  Murr.). 

New  Zealand  Kauri  (Agathis  [Dammara]  auslralis). 

Canadian  White  Pine  (Pinus  Strobus,  Link.). 

Oregon  Pine  (Psettdotsuga  Douglasii,  Carr.). 

Cypress,  which  is  very  variable,  liable  to  brittleness  and  unsuitable 
for  glueing,  was  barred  in  1918.  Oregon  pine,  which  is  liable  to  frac- 
ture under  shock,  and  may  split  when  cut  into  small  dimensions 
must  be  restricted  to  struts  and  used  in  the  solid.  Small  knots  in  the 
deals  can  be  allowed  in  laminations  if  the  knots  l>e  distributed  to 
obtain  uniformity  of  the  member.  Laminated  struts  were  used  in 
1919,  with  fabric  binding  to  safeguard  against  the  opening  out  of 
joints.  Early  in  1918  box  sections,  which  have  all  the  advantages  of 
laminating,  were  used,  and  their  use  continues. 

About  1915-6  the  glues  used  in  the  above  processes  were  classified 
into  three  grades:  (i)  the  best  for  airscrews;  (2)  for  less  highly 
stressed  joints;  (3)  for  unimportant  details.  Glue  shops  were  main- 
tained at  a  constant  70°  Fahrenheit.  Micro-investigation  of  glued 
joints  proved  the  value  of  carefully  preparing  the  timber  and  glue; 
timber  was  aged  to  prevent  warping,  by  storing  in  the  7O°-F.  rooms 
for  long  periods  before  glueing.  Roughing  of  the  surfaces  to  be  glued 
was  adopted  to  secure  keying. 

In  1915-6  it  was  found  that  if  an  entire  series  of  laminations  were 
glued  in  one  operation  before  clamping  the  first  joint  would  become 
chilled  before  the  clamping  occurred.  Later,  by  using  trained  crews 
and  special  appliances  for  quick  glueing  and  clamping,  the  en  bloc 
process  of  glueing  with  the  more  rapid  output  became  possible  and 
satisfactory.  Where  heated-glue  rooms  could  not  be  used,  "  liquid  " 
glue  or  jelly  glues  (containing  an  ingredient  which  delays  the  setting 
poin^of  the  glue,  thus  allowing  of  ordinary  temperatures — 55°  F. 
to  60°  F. — with  ample  time  for  assembly  of  parts)  were  adopted. 

Metal  Fittings. — In  1910  fittings  for  the  structures,  attachment  of 
bracings,  etc.,  were  made  of  mild  steel,  a  metal  selected,  no  doubt 
because  it  could  be  worked  cold.  This  was  often  used  in  double 
thickness  to  ensure  against  flaws.  Oxy-acetylene  welding  was  often 
used  in  joints,  even  in  some  that  were  subject  to  stress.  Tubes  and 
plates  were  welded  together  to  make  sockets,  and  bent  to  shape  with- 
out being  subsequently  normalized.  Failures  at  welds  led  to  the 
substitution  in  1915  of  mild-steel  drop  forgings.  These  were  ma- 
chined all  over  to  save  weight  and  to  get  the  size  accurate  to  toler- 
ances too  small  for  the  stamping  industry  at  that  time. 

The  correct  temperature  for  forging  and  subsequent  heat  treat- 
ment of  the  forging  in  high  tensile  steel  was  not  currently  known. 
The  facilities  were  lacking,  and  the  control  of  the  temperatures 
needed  was  left  too  much  to  the  estimate  of  the  skilled  operative. 
Stampings  brittle  and  unreliable  for  use,  as  well  as  difficult  to  ma- 
chine, were  made.  In  1915-6  the  impact  test,  long  known  but  little 
used,  was  supported  by  the  War  Engineering  Committee  of  the 
Royal  Society,  and  was  found  valuable  for  ensuring  that  the  material 
so  tested  would  bear  prolonged  shock  stress. 

By  1917  the  call  for  speedy  output  led  to  a  reversion  from  forgings 
to  sheet-metal  sockets  and  fittings,  using  a  low  carbon  sheet-steel  of 
26  tons'  ultimate  tensile  strength.  The  pressings  were  shaped  in  jigs 
which  ensured  an  adequate  radius  at  the  bend,  and  they  were  nor- 
malized to  remove  strains  due  to  bending  or  punching.  Where  com- 
plicated fittings  were  built  up  of  simpler  pressings  these  were 
riveted  and  soldered  together  to  avoid  welding.  Dip-brazing  of 
such  constructions  came  in  in  1918,  with  the  advantage  that  the 
temperatures  could  be  better  controlled  than  when  brazed  with  a 
slow-pine.  Such  pressings  are  interchangeable  and  need  less  gaug- 
ing and  inspection.  Turnbuckles,  universal  joints,  shackles,  etc., 
litherto  machined  from  the  bar,  were  re-designed  for  quicker  manu- 
'acture  from  sheet  metal. 

Bracings. — In  1910-1  8o-ton  steel  "  piano  wire  "  was  much  used 
ror  bracing  the  structure,  but  the  fastenings  for  this  had  only  some 
60%  of  the  strength  of  the  wire;  the  loops  stretched,  and  the  struc- 
ture was  soon  distorted.  Flexible  cables  spliced  on  to  wiring  plates 
and  adjusted  by  turnbuckles  were  then  used  with  greater  safety,  but 
these  also  stretched  and  increased  the  air  resistance,  to  reduce  which 
wooden  fairings  were  applied  to  the  cables.  Solid  wires  swaged  to 
streamline  form,  and  left  thick  at  the  ends  for  screwing,  were  made 
as  early  as  1911,  but  they  were  difficult  to  manufacture.  In  1913  this 
:air  section  was  abandoned  for  the  elliptical,  to  allow  of  rolling  instead 
of  swaging  the  rods,  while  a  special  steel  and  heat  treatment  evolved 
by  the  Royal  Aircraft  Factory  overcame  the  difficulties.  These 
wires  were  not  generally  adopted  till,  in  1915,  standardized  aeroplanes 
ed  to  a  demand  which  warranted  bulk  production. 

Wires  of  streamline  section  were  swaged,  not  rolled,  because  these 
asymmetrical  sections  tend  to  curve  over  sideways  as  they  pass  out 
'rom  the  rolls.  The  elliptical-section  wires  were  called  "  Rafwires," 
o  distinguish  them  when  they  were  standardized.  The  screwing  of 
he  end  of  these  wires  was  carried  on  after  heat  treatment  (at  550° 
"".).  Subsequently  the  wires  were  tempered  at  a  lower  temperature 



(450° C.),  and  later  the  tempering  was  abandoned.  Round  swaged 
tie-rods  were  made  from  the  same  steel  as  the  streamline  wires 
drawn  to  an  ultimate  strength  of  80  tons  per  sq.  in.  without  any  sub- 
sequent heat  treatment.  The  adoption  of  tie-rods  and  streamline 
wires  for  bracing  extended  the  period  for  which  the  aeroplane  retained 
its  truth,  while  it  was  improved  both  in  speed  and  climb  by  the 
fair  wires. 

Flexible  cables  used  for  controls  consisted  generally  of  seven 
strands,  each  of  19  wires  of  go-ton  tensile.  To  increase  the  war  out- 

Eut  a  single  lay  cable  of  larger  strands  was  used.   This  cable  could  not 
e  spliced,  and  joints  were  made  by  turning  the  ends,  wrapping  with 
wire,  and  soldering — a  process  that  requires  much  care. 

In  a  few  cases  in  1919  the  structures  were  built  on  the  strut-tie 
principle  without  wire  bracing;  this  gave  quick  erection  and  main- 
tained very  well  the  truth  of  structure. 

Dope. — The  fabric  stretched  over  the  wings  becomes  slack  after 
exposure  to  alternations  of  humidity.  Prior  to  1909  rubber  cotton 
fabric  was  tried,  and  alternatively  the  plain  cotton  was  tautened  by  • 
painting  with  flour  paste.  In  1909  thin  sheets  of  cellulose  acetate 
were  applied  over  the  cotton,  and  later  the  substance  was  dissolved 
in  acetone  and  applied  with  a  brush,  camphor  being  used  to  keep  the 
coat  pliable ;  however,  the  camphor  evaporated,  and  thereupon  the 
dope  cracked  on  exposure.  The  search  for  a  suitable  softener  that 
did  not  evaporate  from  the  dope  was  prosecuted.  Tetrachlorethane 
was  tried  with  success,  but  it  proved  dangerous  to  the  operatives 
applying  it  in  enclosed  places.  Moreover,  sunlight  decomposed 
tetrachlorethane;  to  yield  hydrochloric  acid,  which  eventually  at- 
tacked the  fabric. 

In  1916  benzyl-alcohol  was  tried  with  success.  When  the  evil 
effect  of  light  on  linen  and  dope  was  discovered  in  England  a  pig- 
ment varnish  was  introduced  by  the  Royal  Aircraft  Factory  ( 
which  protected  the  fabric  and  dope  from  light  and  increased  the  life 
of  both.  In  1916  a  nitrocellulose  dope  was  introduced,  to  economize 
in  the  acetic-acid  radicals  which  were  in  demand  elsewhere  for  ex- 
plosives. From  1916  onwards  the  acetate  and  nitro  dopes  were  used; 
to  them  benzyl-alcohol  was  added  to  render  the  film  plastic,  and 
triphenyl-phosphate  to  render  the  film  waterproof  and  fireproof. 
After  removing  all  saponifiable  grease  from  the  fabric  the  dope  was 
applied  by  hand  in  three  to  five  coats,  till  1918,  when  spraying  was 
introduced  for  the  coats  other  than  the  first,  which  needed  to  be  well 
brushed  in.  Constant  temperature  and  low  humidity  are  required  in 
dope-rooms  to  avoid  the  deposit  of  water  due  to  evaporation  of  the 

Rubber  Hose.— Rubber  tube  introduced  in  pipe  lines  to  give  flexi- 
bility is  deteriorated  by  petrol  and  oil.  In  1916  some  resistance  to 
petrol  was  introduced  by  using  pure  para  heavily  loaded  with  mineral 
matter  and  rather  over-vulcanized.  This  withstood  boiling  petrol  for 
one  hour,  and  immersion  for  23  hours,  but  its  life  in  use  is  very  short 
and  it  frequently  required  renewal  after  four  months. 

Engine  Testing.— The  airscrew,  the  flat  plate  air  brake,  the  electric 
dynamo  and  the  water  dynamometer  of  Heenan  and  Froude  were 
used  for  testing  aero  engines. 

Later  the  Escargot  reaction  torque  brake  was  evolved,  correspond- 
ing in  principle  to  the  Heenan  and  Froude  water  brake  in  that  an  air 
fan  brake  is  rotated  inside  a  closely  fitted  case,  into  which  the  air  is 
drawn  through  central  ports  and  expelled  centrifugally  through 
tangential  outlets  at  top  and  bottom;  the  engine,  mounted  on  a 

FIG.  19. 

built-up  stand  pivoted  about  the  propeller  shaft  axis,  is  held  and  the 
torque  measured  with  a  graduated  bar  and  counterpoise. 

To  vary  the  power  absorbed  at  a  given  speed,  the  Fell  type  of 
Escargot  (see  figs.  19  and  iga),  introducing  Butterfly  valves  in  the 
tangential  outlets,  was  developed  late  in  1917.  Restriction  of  the  air 
outlet  from  the  Escargot  perforce  reduces  the  work  to  be  done  by  the 
fan  on  the  air,  which  tends  to  rotate  with  the  fan  and  so  increase  the 
speed  of  the  engine  to  a  corresponding  degree.  A  power  curve  range 
is  thus  obtained  comparable  with  that  given  by  the  Heenan  and 
Froude  brake.  The  Escargot  method  provides  a  ready  means  of 
cooling  air-cooled  engines  by  taking  special  ducts  from  the  outlets 
to  the  engine  cylinders,  whereas  the  Heenan  and  Froude  brake  re- 
quires a  separate  cooling-fan  and  driving-motor. 

In  determining  the  useful  H.P.  of  rotary  engines,  "  windage  loss," 
or  the  power  absorbed  by  the  engine  itself,  had  first  to  be  determined 
for  each  type,  and  then  deducted  from  the  total  nominal  power, 
calculated  on  the  weight  bar  reading.  Originally  the  bench  tests 
comprised  an  endurance  test  of  four  hours,  followed  by  complete 
dismantlement  and  examination  for  defective  parts,  excessive 
wear,  reassembly,  and  final  one-hour  test,  the  engine  being  run 
throughout  at  normal  speed  and  at  full  throttle,  petrol  and  oil  con- 
sumptions being  recorded  in  both  tests.  Subsequently  all-round 
experience  and  increased  reliability  of  materials  and  their  treatment 
permitted  of  a  reduction  of  this  endurance  test,  first  to  three  hours, 
and  then  to  two  hours,  with  a  final  half-hour  test.  The  engine  through- 
out, save  for  the  last  five  minutes,  was  throttled  down  to  90  %  and 
sometimes  even  to  80  %  of  full  power  at  normal  speed,  to  prevent  the 
overheating  of  and  detonation  in  the  relatively  high  compression 
engines.  Such  engines  were  designed  to  give  full  power  at  5,000  ft. 
height  rather  than  at  ground  level. 

Standardization  of  the  actual  flow  measurement  of  carburetter 
jets  in  place  of  orifice-diameter  calibration  made  it  possible  to  tune 
up  engines  for  bench  tests  on  a  few  minutes'  running  only.  Also 
standard  jets  suitable  for  flight  purposes  were  substituted  for  bench- 
test  jets  before  delivery,  so  that  the  time  of  tuning-up  on  installation 
of  the  engine  into  the  aircraft  was  diminished.  In  1916  a  petrol- 
flow  meter,  whereby  the  actual  flow  into  each  carburetter  is  indicated, 
facilitated  the  determination  of  petrol  consumptions. 

Crank- shafts. — The  aero-engine  materials  were  covered  by  definite 
specifications  originally  issued  by  the  Royal  Aircraft  Factory.  The 
chemical  composition  was  closely  defined,  heat  treatment  provided 
for,  and  an  Izod  Impact  Test  added  to  the  usual  tensile  test,  to  give 
some  indication  as  to  the  shock-resisting  power  of  the  material. 
The  Izod  Impact  Test,  though  it  does  not  reproduce  the  alternating 
and  fatiguing  stresses  of  actual  running,  has  proved  to  be  indispen- 
sable in  detecting  steel  which  has  been  improperly  heat-treated. 
"  Temper  brittleness  "  induced  in  alloy  steels  by  slow  cooling  from 
the  tempering  temperature,  even  after  correct  initial  heat  treatment, 
is  detected  by  the  2-3  ft.  Ib.  obtained  as  compared  with  the  25-30 
ft.  Ib.  with  the  identical  steel  if  properly  heat-treated  and  quenched 
after  tempering.  This  brittleness,  which  obviously  unfits  steel  for 
crank-shaft  use,  cannot  be  detected  otherwise  than  by  the  impact 
test,  since  the  usual  tensile  results  and  micro-structure  examination 
in  no  way  differentiate  between  the  sound  and  temper-brittle  condi- 

Early  in  1915  the  British  Aeronautical  Inspection  directorate  sug- 
gested the  following  nickel  chromium  steel  for  crank-shafts,  connect- 


ing  rods,  etc.,  with  good  results: — Carbon  35%;  Nickel  3-5%; 
Chromium  o-6-l  %. 

Difficulties  attended  the  manufacture  of  crank-shafts  for  12-cyl- 
inder  engines  which,  in  order  to  reduce  the  overall  length,  employed 
roller  main  bearings.  At  first  such  crank-shafts  were  produced  from 
billets  twisted  through  120°  at  the  main  journal,  which  provided 
only  3  in.  length  in  which  to  effect  the  twist,  necessitating  so  high 
a  twisting  temperature  that  no  subsequent  heat  treatment  could 
restore  the  structure  to  a  uniform  and  satisfactory  condition.  The 
use  of  a  billet  of  double  width  involving  a  twist  of  only  60°  was  then 
tried,  with  improved  but  not  entirely  satisfactory  results.  Finally 
such  crank-:;hafts  were  produced  from  a  billet  first  pressed  or  crinkled 
to  a  general  crank-shaft  form  to  provide  a  continuous  grain  flow 
throughout  journals,  webs  and  pins,  and  finished  finally  by  drop 
stamping  and  twisting,  where  necessary,  the  main  journal  through 
60  degrees. 

The  elimination  of  all  sharp  corners,  as  in  keyways  and  the  under- 
cutting of  webs  in  grinding  journals  and  pins,  was  found  to  be  of  the 
utmost  importance  to  prevent  fatigue  failure. 

Rough  machining  before  heat  treatment  was  also  required,  es- 
pecially in  the  rotary  single-throw  crank  with  large  variations  in  mass 
of  section,  to  secure  uniformity  of  condition. 

Cylinders. — In  1914  air-cooled  cylinders  were  of  mild  steel  for 
rotary  and  cast  iron  for  stationary  engines.  The  steel  cylinders  were 
machined  from  the  solid  billet;  by  1916  forged  blanks  were  used. 

By  1915-6  cast-iron  cylinders  were  cast  from  metal  patterns  and 
machine-moulded,  and  a  close  limitation  of  chemical  composition 
adopted  to  secure  clean  casting  of  the  thin  sections,  and  to  overcome 
distortion  and  cracking  in  running.  To  eliminate  casting  stresses 
cylinders  were  normalized  after  casting,  and  set  aside  for  some  weeks 
to  "  age  "  before  machining. 

For  water-cooled  engines  having  separate  cylinders  cast  iron  (with 
a  sheet-steel  jacket  pressed  to  shape,  and  welded  on,  or  a  copper 
jacket  electrically  deposited)  was  used.  To  allow  the  jackets  to 
expand,  crinkles,  both  circumferential  and  round  the  exhaust  valve 
seatings,  and  sparking-plug  bosses  were  introduced,  as  the  local 
expansion  of  the  jacket  differs  from  that  of  the  cylinder  when 

Later,  mild-steel  cylinders  turned  from  forged  blanks  were  used  m 
lieu  of  cast  iron.  Valve  pockets,  sparking-plug  bosses,  and  thin 
sheet  jackets  were  then  welded  on  as  first  tried  by  Vickers  in  1909. 

Aero-engine  cylinders  are  also  cast  together  in  one  block  for  the 
sake  of  the  rigidity  of  the  cylinders  one  to  another.  At  first,  following 
motor-car  practice,  cast  iron  was  used  for  this.  Towards  the  end  of 
1916,  however,  aluminium,  with  its  low  weight  and  high  heat  con- 

FIG.  20. 

ductivity,  took  its  place.  The  first  prominent  "  Mono  block  "  (see 
fig.  20)  comprised  a  mild-steel  cylinder  liner  complete  with  head  and 
valve  seats,  screwed  into  an  aluminium  block  which  took  four 
cylinders,  and  constituted  a  complete  enclosed  water-jacket.  The 
liners  were  not  in  contact  with  the  cooling  water,  and  with  bigger 
cylinders  overheating  and  loss  of  contact  between  the  liner  and  the 
surrounding  aluminium  jacket  occurred  particularly  in  the  flat  head. 
A  natural  development,  therefore,  was  to  remove  the  top  of  the  liner, 
leave  it  open,  and  let  the  aluminium  itself  form  the  combustion  head 
of  each  cylinder.  Two  difficulties  then  had  to  be  overcome : — (i)  The 
provision  of  a  gas-tight  joint  between  the  top  of  the  liner  and  the 
jacket  and  head;  (2)  the  insertion  of  rings  in  the  head  to  form  valve 
seatings.  The  first  was  overcome  by  screwing  the  liner  hard  up 
against  the  shoulder  in  the  head,  and  the  second  (which  was  achieved 
without  distortion  or  burning  of  the  seatings)  by  casting-in  or  ex- 
panding-in  steel  or  hard  bronze  rings.  To  improve  further  the  cool- 
ing of  the  cylinders,  the  lower  portion  of  the  aluminium  jacket  in 
contact  with  the  liners  was  omitted,  the  liner  being  held  only  by  a 
screw  thread  of  some  l-in.  depth  at  the  top  and  a  rubber  joint  and 
ordinary  lock  nut  ring  at  the  bottom. 

The  form  of  aluminium  cylinder  head  and  jacket  casting  is 
complicated,  and  experiments,  both  as  regards  method  of  casting 
and  choice  of  aluminium  alloy,  led  to  the  selection  of  a  mixture  of 

14-5%  zinc,  2'5%  to  3-0%  copper,  alloy  with  virgin 
i-    The  pouring  temperature  is  66o°C.    The  percentage  of 

12-5%. to     _    . 

aluminium  The  pouring  temperature  is  66o°C.  The  percentage  of 
scrap  is  high,  say,  10%  to  15%  in  the  simplest  forms  of  block,  and  up 
to  30%  or  40%  for  more  complicated  designs.  To  overcome  the 
porosity  of  castings,  stove  enamelling  of  the  interior  of  the  blocks  or 
the  application  of  water-glass  under  pressure  is  used. 

The  Royal  Aircraft  Factory  experiments  in  1915  led  the  way  in  air- 
cooled  stationary  cylinder  engines  in  the  use  of  aluminium  heads 
gilled  for  cooling,  using  a  steel  liner  and  inserted  valve  seatings.  For 
rotary-engine  cylinders  in  one  instance  a  thin  steel  liner  was  shrunk 
into  a  finned  aluminium  shell  which  formed  a  jacket,  the  head  of 
steel  being  secured  to  the  liner  with  a  plain  metal-to-metal  joint  by 
bolts  from  the  head  to  the  crank-case,  thus  securing  the  cylinder  as  a 

Cylinders  of  all  types  before  erection  on  engines  are  tested  inter- 
nally to  450-500  Ib.  hydraulic  pressure,  and  for  the  jackets  to  30-40 

Connecting  Rods. — Connecting  rods,  as  regards  material,  followed 
crank-shaft  practice  in  the  standardization  of  plain  nickel  chrome 
steel,  heat-treated  to  give  50-60  tons'  tensile  strength. 

The  6-cylinder  and  early  8-  and  12-cylinder  types  conformed 
to  motor-car  practice  in  the  use  of  solid  H  "  section  shanks  and 
white-metal  big-ends,  without  a  bronze  bush,  the  cap  being  held 
usually  by  four  bolts  or  studs.  To  reduce  th'e  crank-shaft  length  of 
certain  "  V  "  type  engines  the  connecting-rods  on  one  side  of  the 
engine  were  provided  with  lugs  to  carry  a  wrist-pin,  this  wrist-pin,  on 
one  side  of,  and  parallel  to,  the  big-end  bearing,  carrying  the  auxil- 
iary connecting-rod.  Alternatively  to  the  same  end  a  pair  of  rods 
superposed.  In  one  case,  a  hollow  circular  sectioned  shank  carried 
an  integral  big-end,  white-metalled  internally  and  externally,  the 
second  rod,  being  fork-ended,  oscillating  on  the  sleeve  formed  by  the 
first  rod.  The  comparatively  thin  and  flexible  section  of  the  inner 
rod  sleeve,  however,  enhanced  the  difficulty  of  white-metalling  and 
led  to  cracking  in  running. 

A  further  development  therefore  (of  square  hollow  sectioned 
shank)  provided  a  bronze  shell  rigidly  gripped  by  the  forked  ends  of 
the  outer  rod,  while  the  inner  rod  oscillates  on  the  middle  portion  of 
the  shell,  which  is  white-metalled  internally  to  provide  the  main  big- 
end  bearing,  as  shown  in  fig.  21. 

FIG.  21. 

Connecting-rods  of  rotary  and  radial  engines  consist  usually  of  one 
master  rod,  ball  or  rollcr-bearinged,  with  the  big-end  enlarged  to 
form  circular  lugs  to  secure  wrist-pins  carrying  the  plain  or  auxiliary 
type  of  rod  of  the  remaining  cylinders.  One  exception  provided  a  big- 
end  consisting  of  a  separate  lead  bronze  shell  (in  two  halves  bolted 
together)  mounted  on  ball  bearings  and  provided  on  the  inside  with 
white-metalled  concentric  grooves  in  which  oscillate  the  concen- 
trically formed  heels  of  the  connecting  rods. 

Initially,  the  ordinary  small-end  bronze  bush  system  with  gudgeon 
pins  fixed  in  the  piston  was  used.  Later,  variations  with  loose  bushes 
and  loose  gudgeon  pins  were  developed,  the  pins_in  the  latter  being 
secured  endwise  in  the  piston  by  wire  circlips  let  into  grooves  on  the 
outside  edges  of  the  piston  bosses. 

Rough  machining  before  heat  treatment  is  necessary  on  the  rotary 
type  master-rod  stamping  which  has  a  large  big-end  mass  and  a 
comparatively  small  stem  section,  to  secure  uniform  structure  and 
freedom  from  quenching  cracks.  The  elimination  of  all  sharp  corners 
and  abrupt  changes  of  section  is  essential. 

Main  Bearings. — Ball,  roller  and  white-metal  bearings  are  to  be 
found  in  various  types.  The  two  former  permit  of  high  loading  and 
reduce  the  length  of  the  engine  (bearing  loads  approximating  to  100  % 
over  normal  practice  being  found  to  give  a  total  life  commensurate 
with  the  rest  of  the  engine  under  service  conditions).  White-metal 
main  bearings,  usually  bronze  shelled,  are  secured  either  by  separate 
loose  caps  bolted  on  or  studded  to  the  top  half  crank-case ;  or,  as  in 
usual  German  practice,  by  the  bottom  half  crank-case  itself,  which 
carries  the  lower  halves  of  the  whole  of  the  crank-shaft  bearings ;  this 
adds  to  the  rigidity  and  general  strength  of  the  engine,  but  increases 
the  difficulty  of  production  and  fitting. 

Valves. — Valve  breakage,  originally  a  trouble,  was  almost  eliminated 
by  the  standardization  of  valve  steels  and  by  stamping  the  valves 



so  that  the  grain  flow  in  the  valve  head  swept  continuously  and  uni- 
formly from  the  rim  into  the  throat  and  stem,  thus  providing  strength 
to  resist  sheer  at  all  points  of  the  head.  The  original  practice,  before 
bulk  production  warranted  the  use  of  stampings,  had  been  to  turn 
valves  from  the  solid  bar,  a  procedure  which  gave  in  the  head  a  grain 
flow  parallel  to  the  stem. 

For  exhaust  valves  a  steel  having  14%  tungsten  and  3-5% 
chromium  is  necessary  in  certain  of  the  "  hotter  "  stationary-type 
engines.  For  the  cooler-running  engines  a  high-chromium  stainless 
steel  gives  satisfaction.  Either  of  such  steels  would  be  satisfactory 
for  inlet  valves,  but,  for  economy  of  such  high-grade  materials,  a 
plain  nickel  steel  is  used  with  great  success.  (R.  K.  B.-W.) 


Historical  Resume.— For  many  years  mechanical  flight  was 
delayed  for  want  of  a  light  engine,  and  indeed  from  the  first 
flight  to  the  present  day  (1921)  the  aeroplane  was  ahead  of  its 
prime  mover.  Flight  should  have  been  possible  in  1901  when 
Manley,  in  the  United  States,  built  for  S.  P.  Langley  a  five- 
cylinder  radial  petrol  engine  developing  52  H.P.  and  weighing 
only  2-9  Ib.  per  H.P.  By  bad  fortune  this  engine  was,  however, 
never  used  in  flight  until  1914,  when  it  was  mounted  in  the 
Langley  aeroplane  for  which  it  was  intended. 

For  their  first  flights  in  1903,  the  brothers  Wright  built  a 
four-cylinder  car-type  engine  of  12  H.P.  weighing  12-7  Ib.  per 
H.P.  By  1905  it  was  improved  to  19  H.P.,  with  a  weight  of 
9-5  Ib.  per  H.P.  and,  as  redesigned  in  1908,  gave  35  H.P.  and 
weighed  5-5  Ib.  per  H.P. 

The  aero  engine  proper  dates  from  about  1909,  and  the 
progress  made  is  traceable  reliably  by  the  results  of  competitive 
tests  held  from  time  to  time.  Such  tests  were  carried  out  in 
France,  1909-11-13,  in  cooperation  with  La  Ligue  Nationale 
Aerienne  and  the  Auto  Club  de  France;  in  England  in  1909-12- 
14;  in  Italy  in  1913,  and  in  Germany  in  1912-4. 

A  certain  section  in  England  centred  its  hopes  erroneously 
on  the  use  of  very  small  engines.  A.  V.  Roe  made  the  wonderful 
achievement  of  flying  an  aeroplane  with  only  9-10  H.P.  in  1909. 
The  Alexander  prize  of  1911  at  first  stipulated  for  engines  of 
only  25  H.P.  This  was  increased  by  the  Advisory  Committee 
at  the  request  of  the  supt.  of  the  Army  Aircraft  Factory  to  admit 
"  40  to  75  H.P."  and  was  won  by  24  hours'  continuous  running 
by  a  50-60  H.P.  Green  sent  in  on  Sept.  n  1911.  This  engine 
weighed  296  Ib.  complete,  and  developed  an  average  of  53-5 
H.P.  The  British  Government  competition  of  1914,  although 
won  by  a  no  H.P.  Green  engine,  was  chiefly  useful  in  showing 
the  merits  of  the  100  H.P.  Gnome  and  the  90  H.P.  RAF. 
Both  of  these  did  yeoman  service  in  the  war,  but  soon  proved  to 
be  too  small. 

In  Germany,  the  development  of  the  airship  led  to  the  earlier 
study  of  larger  aero  engines,  although  the  German  competition 
of  1914  was  won  by  a  100  H.P.  Benz,  weighing  4-2  Ib.  per  H.P. 
The  importance  of  the  aeroplane  in  war  service  gave  an  immense 
impetus  to  engine  development  along  two  main  lines:  (a)  An 
extensive  development  of  high  tensile  steels  and  aluminium 
alloys,  and  a  more  scientific  use  of  the  materials,  led  to  a  diminu- 
tion of  the  weight;  (b)  attention  to  detailed  design,  guided  by 
scientific  investigation,  greatly  increased  the  mean  effective 
pressure  developed  in  the  cylinders  and  the  thermal  efficiency. 
The  speed  of  rotation  was  also  increased  so  that  output  was 
augmented,  while  at  the  same  time  fuel  consumption  was 

Modern  aero  engines  may  be  divided  into  two  classes: — (a) 
Engines  which  are  developments  of  the  motor-car  type,  i.e. 
all  the  water-cooled  vertical,  Vee,  and  broad-arrow  engines; 
(b)  types  designed  specially  for  aerial  flight,  i.e.  the  radial  rotary 
engines  and  the  air-cooled  Vee  engines. 

The  rotary  air-cooled  type,  which  was  one  of  the  earliest  of 
these,  was  almost  entirely  due  to  the  French;  e.g.  the  Gnome, 
Le  Rhone  and  Clerget  engines.  In  this  type  minimum  weight 
was  the  objective.  The  arrangement  of  the  engine,  with  its 
cylinders  radiating  star  fashion  in  one  plane  and  operating  on  a 
single  crank,  afforded  a  crank -shaft  and  crank-case  of  minimum 
dimensions  and  accordingly  gave  a  motor  of  extremely  light 
weight.  To  increase  the  cooling  by  air  draught,  and  save  the 
weight  of  a  fly-wheel,  the  cylinders  were  made  to  rotate  round 

the  crank-shaft,  which  was  fixed.  Weight  was  economized  by 
making  the  cylinders  of  steel,  with  very  thin  walls,  and  the 
difficulties  due  to  distortion  of  such  thin  cylinders  with  heat 
were  ingeniously  met  by  using  a  brass  obturator  ring,  as  sub- 
stitute for  the  cast-iron  piston  rings  which  are  universal  in  other 

In  1909  a  number  of  rotary  engines  of  powers  ranging  from 
30  to  too  H.P.  were  available.  Of  these  the  100  H.P.  Gnome 
was  the  most  powerful.  In  1913  a  i4-cylinder  Gnome  of  160 
H.P.  was  launched,  and  on  a  British  army  aeroplane  achieved 
the  fastest  flight  up  to  that  time,  namely  130  m.  per  hour. 
At  the  outbreak  of  war  in  1914,  the  100  H.P.  Monosoupape 
Gnome,  and  at  a  slightly  later  stage  the  no  H.P.  Clerget  and 
the  100  H.P.  Le  Rhone  came  into  current  use,  and  the  160 
H.P.  Gnome  was,  unfortunately  from  the  war  fighter's  point 
of  view,  discarded  on  the  score  of  complication.  In  France  in 
1917  a  higher-powered  Monosoupape  developing  150  H.P.  was 
put  into  commission,  while  in  Great  Britain  the  BRi  and  the 
BR2  rotaries,  developing  respectively  150  and  220  H.P.,  were 
produced.  Including  the  propeller  boss  the  later  Mono-Gnome 
weighed  2-03  Ib.  per  H.P.  and  the  BR2  2-21  Ib.  per  H.P. 

In  1914,  and  indeed  at  a  later  stage,  none  of  the  rotary  en- 
gines were  quite  satisfactory;  the  type  suffers  from  certain 
inherent  disadvantages.  It  is  liable  to  the  distortion  and  over- 
heating of  its  cylinders;  the  earlier  examples  required  special 
precautions  against  catching  fire;  its  petrol  and  oil  consumptions 
are  high ;  and  it  requires  frequent  dismantling  and  overhauling. 

In  spite  of  this  the  best  of  these  rotaries  formed  the  basis 
on  which  European  air  experience  was  founded,  and  as  recently 
as  1912  the  best  aero  engines  (from  the  point  of  view,  be  it  under- 
stood, of  the  aeroplane's  performance,  which  is  dominantly  a 
matter  of  weight)  were  probably  the  Gnome  rotaries  weighing 
from  3-0  to  3-5  Ib.  per  H.P.  At  this  time  long-distance  flights 
were  exceptional  and  therefore  their  large  fuel  and  oil  con- 
sumption was  not  so  serious.  Throughout  the  war,  and  espe- 
cially in  its  earlier  stages,  they  gave  their  best  service  in  ma- 
chines of  the  single-seater  high-speed  class,  in  competition  with 
the  heavier  water-cooled  vertical  engines  on  which  the  German 
air  service  relied  almost  entirely. 

When  the  distance  of  flight  was  extended,  the  water-cooled 
car-type  engine  came  to  the  front  partly  because  the  smaller 
weight  of  fuel  to  be  carried  compensated  for  the  greater  weight 
of  the  engine  itself,  and  partly  because  it  was  at  that  time  more 
reliable.  The  following  table  shows  the  total  weights  of  engine, 
fuel  and  oil,  for  flights  of  different  duration,  in  the  case  of  a  typ- 
ical air-cooled  rotary  engine  weighing  2-25  Ib.  per  H.P.  and 
consuming  i-io  Ib.  of  fuel  and  oil  per  H.P.  hour,  and  of  a  water- 
cooled  engine  weighing  4-0  Ib.  per  H.P.  and  having  a  total 
consumption  of  0-55  Ib.  per  H.P.  hour. 

Weight  of  engine,  petrol,  oil  (Ib.  per  hr.). 

Duration    of    flight 
(hrs.)      .        .        . 
Rotary  air-cooled 
engines  . 
Water-cooled  engines 













For  longer  flights  than  35  hours  the  water-cooled  engine  is  here 
shown  to  involve  a  smaller  gross  weight. 

It  was  largely  emulation  of  the  rotary  which  forced  the  pace 
of  the  progress  on  the  car-type  engine.  This  led  to  the  replace- 
ment of  cast  iron  by  sheet  metal  for  water-jackets;  to  the  use  of 
thin  steel  instead  of  cast  iron  for  cylinder  barrels  and  of  alu- 
minium for  cylinder-head  castings;  and  to  the  use  of  two,  and  in 
some  cases  three,  rows  of  cylinders  operating  on  a  single  crank- 
shaft arid  mounted  on  a  common  crank -case.  The  use  of  steel 
or  aluminium  alloy  instead  of  cast  iron  for  the  pistons  had 
been  initiated  in  experiments  for  motor-cars.  In  some  few 
cases  air-cooling  was  adopted,  e.g.  in  France  the  70  H.P.  eight- 
cylinder  Vee  Renault  of  1912,  and  notably  in  England  the 
90  H.P.  eight-cylinder  Vee  RAF  of  1913-4,  and  the  140 
H.P.  twelve-cylinder  Vee  RAF4a,  all  of  which  had  cast-iron 
L-headed  cylinders.  The  last-named  engine  weighed  4-0  Ib.  per 
H.P.  and  gave  excellent  service  during  the  war. 


Still  the  car  engine  of  given  cylinder  capacity  remained 
appreciably  heavier  than  the  contemporary  rotary,  until  care- 
ful studies  in  1916-17-18  were  made  to  increase  the  output 
per  unit  of  cylinder  volume,  and  the  thermal  efficiency. 

The  volumetric  efficiency  was  increased  by  improving  the 
design  of  the  inlet  pipes,  valves,  and  valve  gearing,  and  the 
combustion  space  of  the  cylinder.  The  thermal  efficiency  and 
the  mean  effective  pressure  were  increased  by  augmenting  the 
compression.  Since  high  compression  is  only  practicable  with  a 
compact  and  symmetrical  combustion  chamber  the  L-headed 
cylinder  was  replaced  by  the  overhead  valve-cylinder.  More- 
over, since  high  compression  necessitates  good  cooling  of  the 
cylinder,  the  water-cooled  engine  gained  a  distinct  relative  ad- 
vantage over  the  earlier  air-cooled  engines  which  were,  in  general, 
inadequately  cooled.  As  a  result  of  these  steps  in  the  detail 
design,  the  brake  mean  effective  pressure  was  raised  from 
the  75  to  95  Ib.  usual  on  cars,  to  as  high  as  130  Ib.  per  sq.  in.  in 
the  best  modern  aero  engines,  while  at  the  same  time  the  petrol 
consumption  was  reduced  to  approximately  0-45  Ib.  per  B.H.P. 
hour,  a  value  some  40%  better  than  that  of  the  average  car 

In  many  cases  the  output  was  also  improved  by  increasing 
the  speed  of  the  engine.  The  speed  of  the  rotary  engine  was 
limited  to  about  1,200  revolutions  per  minute,  by  the  stresses  due 
to  centrifugal  force.  In  the  fixed  cylinder  engine,  however,  much 
higher  rotational  speeds  could  be  adopted  by  attention  to  the 
balance  of  the  moving  parts,  and  to  the  design  of  the  bearings. 
These  speeds  now  range  from  1,400  to  2,100  revolutions  per 
minute,  reduction  gears  being  used  for  the  airscrew  drive  in 
the  case  of  the  larger  and  less  rapidly  flying  aeroplanes. 

The  resultant  weight  economy  was  considerable.  Thus  the 
300  H.P.  Hispano-Suiza  water-cooled  Vee,  rotating  at  2,000 
r.p.m.,  weighed  only  1-80  Ib.  per  H.P.  and  the  450  H.P.  Napier 
"  Lion  "  of  1921  only  1-89  Ib.  per  H.P.  In  each  case  these 
weights  include  that  of  the  propeller  boss,  but  not  that  of  the 
radiator  and  its  water,  which  would  add  approximately  0-55  Ib. 
per  H.P. 

These  advances  in  the  car  type  of  aero  engine  were  accom- 
panied by  improvements  in  the  specialized  type.  In  1912  the 
radial  engine  with  fixed  cylinders  was  represented  by  a  few 
examples  of  which  the  9-cylinder,  water-cooled  "  Salmson  " 
developing  no  H.P.,  the  6-cylinder,  water-cooled  "  Laviator  " 

up  to  6  in.  and  up  to  50  B.H.P.  per  cylinder,  give  an  output  and 
fuel-consumption  of  similar  order  to  those  from  the  best  water- 
cooled  cylinders. 

No  air-cooled  engine  with  these  large  cylinders  reached  the 
stage  of  production  in  quantity  during  the  war.  A  number  of 
British  radial  engines  were,  however,  developed  in  1918,  and  of 
these  the  "  A. B.C.  Dragonfly,"  having  nine  steel  cylinders, 
giving  300  H.P.  and  weighing  2-22  Ib.  per  H.P.,  and  the  450 
H.P.  "  Cosmos  Jupiter,"  having  nine  steel  cylinders  with 
an  aluminium  patch  containing  the  inlet  and  exhaust  ports 
bolted  to  each  head,  and  weighing  1-42  Ib.  per  H.P.,  are  worthy 
of  mention. 

As  compared  with  these  it  will  be  recalled  that  the  150  Mono- 
Gnome  of  the  same  date  weighed  2-03  Ib.  per  H.P. 

A  i2-cylinder  Vee  experimental  engine  with  aluminium  cylin- 
ders was  built  at  the  Royal  Aircraft  Factory  in  1916-7  and  gave 
excellent  results  in  flight  and  on  the  test  bed.  This  developed 
210  H.P.  and  weighed  3-0  Ib.  per  H.P. 

Prior  to  1914  the  American  aero  engine  was  mostly  of  the 
car  type,  and  was  outdistanced  during  the  first  two  years  of  the 
war  by  the  more  intensive  development  in  those  countries  active- 
ly engaged.  At  that  time  the  160  H.P.  Curtiss  was  probably 
the  most  outstanding  engine  in  America,  and  when  the  United 
States  declared  war  in  1917  her  need  for  high-powered  aero 
engines  became  acute.  In  May  1917  it  was  decided,  in  confer- 
ence with  the  Allied  Mission  in  the  United  States,  to  design 
and  build  the  Liberty  engine,  of  which  an  8-cylinder  model 
was  completed  for  test  on  July  3  1917.  This  was  not  put  into 
production,  as  advices  from  France  indicated  that  demands  for 
increased  power  would  render  it  obsolete  before  it  could  be 
produced  in  quantity.  Efforts  were  then  concentrated  on  a  12- 
cylinder  model,  the  first  of  which  passed  its  so-hour  test  on  Aug. 
25  1917.  This  engine  is  a  water-cooled  Vee,  originally  developing 
400  H.P.  and  weighing  2-0  Ib.  per  H.P.  More  recent  improve- 
ments have  increased  the  output  to  510  H.P.  and  reduced  the 
dry  weight  per  H.P.  to  1-75  Ib.  or  about  2-3  Ib.  with  cooling 
water  and  radiator. 

The  progress  in  the  average  aero  engine  in  service  between 
1910  and  1918,  in  power,  weight,  and  efficiency,  is  shown  in  the 
following  table.  The  main  details  are  abstracted  from  the 
report  of  the  American  National  Advisory  Committee  for 
Aeronautics  in  1918: — 





per  H.P. 

Average  petrol 
(Ib.  per  B.H.P.) 


rage  i 

n  sen 

/ice  . 

















developing  80  H.P.,  and  the  6  and  10  cylinder,  air-cooled 
"  Anzani  "  developing  60  and  100  H.P.  are  among  the  most 
noteworthy.  The  Salmson  was  developed  at  a  later  stage  as  a 
i4-cylinder,  two-row  engine  of  200  H.P.  and  the  Anzani  as  a  20- 
cylinder,  four-row  engine  of  200  H.P.  These  engines  were 
French,  but  since  1914  British  designers  have  greatly  advanced 
the  science  of  the  air-cooled  engine. 

The  fixed  radial  engine  has  a  number  of  features  of  superiority 
over  the  rotary.  It  enables  a  normal  type  of  carburetter  and 
of  piston  to  be  used;  it  eliminates  the  large  windage  losses; 
while  since  the  cylinders  are  not  exposed  to  centrifugal  stresses 
aluminium  alloys  can  be  used.  This  light  and  highly  conducting 
metal  has  greatly  helped  air-cooling.  Owing  to  the  greater  ease 
of  installation  of  the  air-cooled  engine  in  an  aeroplane,  the 
absence  of  a  fragile  radiator  liable  to  freeze  on  descent  from  great 
heights,  as  well  as  to  its  adaptability  to  work  in  the  tropics, 
much  attention  was  paid  during  the  war  to  the  design  of  air- 
cooled  cylinders.  A  composite  construction  using  aluminium 
alloy  for  cylinder  heads  was  evolved  at  the  Royal  Aircraft 
Factory,  Farnborough,  between  1915  and  1921,  with  the  result 
that  air-cooled  cylinders  became  available  which,  for  diameters 

Since  the  water-cooled  engines  cannot  function  without 
radiator  and  water,  an  addition  of  0-55  Ib.  per  H.P.  has  been 
made  in  their  case  to  render  Table  A  comparative.  The  weights 
after  deduction  of  0-55  Ib.  are  actual  measurements,  and  include 
those  of  the  propeller  boss  and  of  the  gear,  if  any.  In  cases 
where  the  respective  makers  produce  a  series  of  engines  of 
different  powers,  only  representative  examples  have  been  quoted. 

During  the  latter  part  of  the  war,  the  demand  for  engines 
of  large  H.P.  for  bombing  aeroplanes  and  dirigibles  led  to 
the  production  of  many  experimental  engines,  which  were 
available  by  1921,  e.g.  the  800-900  H.P.  Sunbeam  Coatalen, 
the  850  H.P.  Fiat,  the  1,000  H.P.  Lorraine  Dietrich,  and  the 
1,000  H.P.  Napier  "  Cub." 

Types  of  Engines. — Of  the  total  heat  from  the  fuel,  25  %  to  35  % 
passes  through  the  walls  and  piston  and  must  be  dissipated  by  water- 
cooling  or  direct  air-cooling  if  the  normal  operation  of  the  engine  is  to 
be  maintained. 

Water  or  air-cooling  have  their  respective  advantages  and  dis- 

For  the  water-cooled  engine  is  claimed: — 

(l)  A  lower  cylinder-wall  temperature;  a  reduced  tendency  to 
the  burning  of  exhaust  valves  ana  pistons;  and  more  effective  lubri- 



TABLE  A. — Details  of  the  Principal  Engines  Available  in  1918  for  Service. 







Wt.  per 

Great  Britain 


6  cyl.  W.C. 






6     '    W.C  






12     '     Vee  W.C  





Rolls  Royce  Eagle 

12     '    Vee  W.C.  . 





Falcon      .        .        . 

12         Vee  W.C  





"      Napier  Lion    . 

12     '    broad-arrow 





Sunbeam  Arab      .... 

8     '    Vee  W.C  





Maori    .... 

12    "    Vee  W.C  





Siddeley  Puma      .        .        .        . 

6    "    W.C. 






6    "    W.C  






12    "    VeeA.C  

1  60 




B.R.I.    .        .        .     '  . 

9    "     Rotary  A.C.      . 





A.B.C.  Dragonfly 

9    '      Rotary  A.C.      . 
9    '      Radial  A.C. 





Cosmos  Mercury 

14    "     Radial  A.C. 





France  . 

Hispano  Suiza       .... 

8  cyl.  Vee  W.C  





"            11 

8    "    Vee  W.C  






12    "    Vee  W.C  





Lorraine  Dietrich 

8    "    Vee  W.C  





Canton  Unne        .... 

9    "     Radial  W.C.     . 






10    '     Radial  A.C.      .        . 





Le  Rhone       

9    '      Rotary  A.C. 






9    '      Rotary      .... 





Mono-Gnome        .... 

9    '      Rotary      . 





it           " 

9    '      Rotary       .... 





Italy      . 


6  cyl.  Vertical  W.C.   . 






12    "     Vee  W.C  





Isotta  Fraschini    .... 

6    "    Vertical  W.C.   . 


574    . 



14                              11 

6    "    Vertical  W.C.   . 






12    "    Vee  W.C  






6    "    Vertical  W.C.   . 






12    '      Radial  A.C. 






Austro  Daimler     .... 

6  cyl.  Vertical  W.C.   . 






6    "    Vertical  W.C.   . 






6    "    Vertical  W.C.   . 






6    "    Vertical  W.C.  . 



6    "    Vertical  W.C.  . 






6    "    Vertical  W.C.   . 






6    "    Vertical  W.C.   . 





(2)  A  greater  uniformity  of  temperature  throughout  the  cylinder, 
and  therefore  less  tendency  to  distortion. 

(3)  Generally,  greater  reliability  and  higher  efficiency. 

These  advantages  could  justly  be  claimed  over  the  earlier  types 
of  air-cooled  engines ;  to-day  they  are  less  clear.  Thus  the  first  claim 
is  only  justified  where  great  attention  is  paid  to  the  design  and 
arrangement  of  the  jackets  and  circulating  systems.  Measurements 
confirm  claim  (2),  but  also  show  that  the  lack  of  uniformity  is  not 
necessarily  a  serious  matter,  while  troubles  from  overheated  exhaust 
valves  have  recently  been  more  prevalent  on  water-cooled  than  on 
the  modern  air-cooled  type. 

For  the  air-cooled  engine  is  claimed : — 

(1)  Smaller  weight  per  H.P.  of  the  complete  power  unit. 

(2)  No  danger  of  water  freezing  on  gliding  from  great  heights,  or 
when  standing. 

(3)  Reduced  vulnerability  in  war  service  and  easier  installation. 

(4)  Special  adaptability  for  use  under  widely  differing  atmospheric 
temperatures,  and  for  the  tropics. 

(5)  Better  adaptability  for  application  of  some  supercharging 
device  to  give  constant  power  at  heights. 

Claim  (l)  is  a  matter  of  demonstration,  the  usual  weight  allow- 
ance for  water-cooling  being  0-6  Ib.  per  H.P.  while  the  very  best  is 
0-4  Ib.  per  H.P.  Claim  (2)  is  admissible  to  the  extent  that  if  freezing 
be  prevented  by  the  use  of  some  other  liquid,  such  as  a  mixture  of 
alcohol  and  water,  the  alcohol  evaporates  unless  the  temperature  of 
the  fluid  is  kept  below  about  70°  C.  which  increases  the  radiator  size. 

There  is  undoubtedly  a  future  for  the  air-cooled  engine  of  the 
fixed-cylinder  type  up  to  a  certain  size  of  cylinder.  What  this  limit 
of  size  may  be  is  not  known  at  present.  Cylinders  of  8-in.  bore  by 
lo-in.  stroke  developing  over  too  H.P.  have  been  made  and  proved 
to  be  possible,  and  investigations  on  cylinders  up  to  10  in.  in  diameter 
are  in  progress.  Twelve  6-inch  cylinders  would  give  600  H.P.,  a 
useful  size  at  present,  and  an  800  or  900  B.H.P.  air-cooled  engine  is 
certainly  feasible. 

Design  of  Air-Cooled  Cylinders. — The  useof  aluminium  alloyforthe 
cylinder  heads  has  largely  conduced  to  these  results.  In  a  normal 
design  the  middle  portion  of  the  head  is  the  hottest  point  because 
the  flow  of  cooling  air  and  the  placing  of  fins  at  this  point  is  impeded 
by  the  inlet  and  the  exhaust  valve  ports  and  valve  gear.  Most  of  the 
heat  has  to  be  conducted  outwards  till  dissipated  from  the  periphery 
of  the  combustion  head,  and  the  aluminium  alloy  effects  this  well, 
both  because  its  conductivity  is  3-5  times  greater  than  the  steel,  and 

because  being  0-4  of  the  density  of  steel  it  may  be  used  in  ample 

Such  a  cylinder  must  be  of  composite  construction,  since  the  valve 
seats  and  the  working  surface  of  the  cylinder  barrel  must  be  of  some 
harder  material  than  aluminium.  The  valve  seats  may  consist  of 
rings  of  steel  or  of  bronze,  and  these  may  be  either  cast  or  expanded 
into  position.  Tests  appear  to  favour  a  steel  barrel  with  integral 
cooling  fins,  screwed  into  an  aluminium  head  for  diameters  as  large 
as  eight  inches. 

Arrangement  of  Cylinders. — Aero  engines  may  be  subdivided 
according  to  the  arrangement  of  their  cylinders,  into  the  following 
types: — 

(1)  Single  line  engines  suitable  for  water-cooling. 

(2)  Vee  engines  suitable  for  water-  or  air-cooling. 

(3)  Broad  arrow  engines  suitable  for  water-cooling. 

(4)  Radial  engines — fixed  cylinders ;  air-cooling. 

(5)  Rotary  engines  suitable  for  air-cooling. 

The  general  arrangement  of  these  types  is  shown  in  fig.  22. 

The  straight  line  engine  (a),  with  six  or  eight  cylinders  in  line, 
offers  a  low  hea,d  resistance  and  is  accessible.  On  the  other  hand  its 
fore-and-aft  length  is  large.  The  crank-shaft  and  crank-case  are 
long,  and  hence  the  type  is  heavy. 

In  the  Vee  type  engine  (6)  two  lines  of  cylinders  are  used  inclined 
to  each  other  to  form  a  Vee  in  elevation,  and  the  corresponding  port 
and  starboard  cylinders  operate  a  common  crank-pin.  Weight  is 
saved  on  crank-shaft,  case,  and  valve  gear. 

In  the  Broad  Arrow  (c)  three  lines  of  cylinders  are  used  as  above 
with  further  weight  saving. 

In  the  Radial  engine  (d)  economy  of  crank-shaft  and  case  is  carried 
to  its  logical  conclusion.  The  cylinders  are  mounted  in  one  plane  at 
equal  angular  intervals  around  the  crank-shaft.  All  the  connecting 
rods  operate  on  a  single  crank-pin.  The  small  fore-and-aft  length  of 
the  engine  helps  the  aeroplane  designer  but  its  considerable  diameter 
may  hamper  him. 

To  obtain  explosion  impulses  at  equal  intervals  throughout  each 
revolution  an  odd  number  of  cylinders  must  be  used,  the  usual 
number  being  seven  or  nine.  Where  a  larger  power  is  required  two 
rows  of  cylinders  may  be  used,  operating  a  two-throw  crank-shaft. 
The  radial  cylinders  may  be  stationary  or  rotating.  In  the  latter 
case  the  airscrew  is  mounted  on  a  continuation  of  the  rotating  crank- 
case.  The  rotating  cylinder  engine  is  quite  unsuited  for  water- 
cooling.  Although  the  radial  engine  with  fixed  cylinders  is  not  well 


FIG.  22. 

adapted  for  water-cooling,  engines  of  this  type  have  been  built  and 
operated  successfully.  Among  these  is  the  recent  300  H.P.  9- 
cylinder  Fiat,  weighing  1-7  Ib.  per  H.P.  The  difficulty  of  arranging 
the  water  circulation  so  as  to  avoid  all  danger  of  air  locks  in  the 
inverted  cylinders  is,  however,  appreciable,  and  the  head  resistance 
of  the  completed  engine  is  large.  For  these  reasons  there  is  not 
likely  to  be  any  great  future  for  the  water-cooled  radial  engine  on 
aeroplanes  of  present  types. 

Installations  of  Air-Cooled  Engines. — Some  form  of  cowling  is 
needed  to  distribute  the  air  evenly  over  the  various  cylinders,  and  the 
success  of  a  Vee  engine  depends  largely  on  the  cowling,  whereas  even 
air-cooling  is  more  easily  obtained  on  a  "  radial." 

With  rotary  engines  the  cooling  is  not  as  good  as  might  be  expected 
from  the  high  peripheral  velocity,  and  the  windage  losses,  even  with 
a  cowling,  amount  to  some  10%  of  the  total  power  developed. 

In  these  engines  the  air-petrol  mixture  is  led  through  the  hollow 
crank-shaft  to  the  crank-case.  In  the  original  Gnome  engine  auto- 
matic inlet  valves  fixed  in  the  piston  heads  and  opened  by  the 
suction  on  the  inlet  stroke  admitted  the  charge.  These  valves  were 
light,  often  broke,  and  were  inaccessible. 

In  the  Monosoupape  Gnome  the  valve  in  the  piston  is  eliminated 
and  a  mechanically  operated  valve  in  the  cylinder  head  is  used.  This 
serves  as  an  exhaust  valve,  but,  instead  of  closing  at  the  end  of  the 
exhaust  stroke,  it  remains  open  for  a  part  of  the  inlet  stroke  and  then 
admits  air  to  the  cylinder.  When  it  closes,  the  further  motion  of  the 
piston  produces  a  partial  vacuum  in  the  cylinder,  until,  near  the  end 
of  its  stroke,  the  piston  uncovers  a  ring  of  openings  in  the  cylinder 
walls  communicating  with  the  crank-case.  The  fuel  jet  is  adjusted 
to  give  a  mixture  too  rich  to  be  explosive,  and  this  mixture  enters  into 
the  cylinders  and  mixes  with  the  air  admitted  through  the  inlet 
valve  to  form  an  explosive  charge. 

Other  modern  rotary  engines  have  mechanically  operated  inlet 
and  exhaust  vajves,  with  which  efficient  valve  timing  becomes 
possible.  The  mixture  in  the  crank-case  then  passes  into  a  circular 
box  fixed  to  the  rear  of  the  crank-case  and  rotating  with  it,  whence 
it  is  led  by  inlet  pipes  to  the  cylinders  in  the  ordinary  way. 

These  methods  of  mixture  supply,  though  crude,  gave  the  rotary 
engine  the  advantage  of  having  a  fuel  supply  adjustable  by  hand  to 
suit  the  air  density  when  flight  at  great  heights  first  became  impor- 
tant. On  the  other  hand,  the  non-rotary  engines,  fitted  with  normal 
carburetters,  received  a  mixture  too  rich  for  efficient  operation  at 
considerable  heights.  To  obviate  this,  automatic  carburetter  con- 
trols had  to  be  devised,  but  pending  this  the  rotary  engine  had  a 
distinct  advantage  for  high  Hying. 

The  lubrication  of  the  rotary  engine  is  peculiar  to  the  type.  All 
oil  in  the  crank-case  is  thrown  centrifugally  into  the  cylinders,  and 
once  there  cannot  be  drained  out,  cooled,  and  circulated  again  as  in 
fixed-cylinder  engines,  but  must  be  discharged  through  the  exhaust 
valves.  Consequently  the  oil  consumption  is  high.  Moreover  the 
lubricating  oil  must  be  insoluble  in  petrol,  so  that  castor  oil  is 

The  power  of  the  rotary  engine  falls  off  more  rapidly  with  height 
than  that  of  the  fixed-cylinder  engine  if  the  latter  has  a  suitably 
controlled  carburetter,  and  at  a  height  of  15,000  ft.  the  difference  in 
horse-power  is  about  10  per  cent. 

The  Differential  Engine. — For  large  powers,  each  of  the  two  types 
of  radial  engine  has  its  own  peculiar  limitations.  In  the  fixed  radial 
the  fly-wheel  effect  is  small,  while  it  becomes  difficult  to  design  an 
engine  exceeding  about  400  H.P.  on  a  single  crank  because  of  the 
excessive  load  on  the  big-end  of  the  connecting-rod.  In  the  rotary 
radial  this  difficulty  is  less,  but  windage  losses,  centrifugal  stresses, 
gyroscopic  effects  and  valve-gear  difficulties  are  encountered. 

The  "differential"  engine  has  been  proposed  to  combine  some  of 
the  advantages  of  each  type.  Here  the  cylinder  ring  rotates  in  one 
direction  and  the  crank-shaft  in  the  opposite  direction  at  the  same 
speed.  In  this  way  the  big-end  loading  may  be  kept  within  reasonable 
limits;  the  gyroscopic  effect  is  negligible ;  centrifugal  forces  and  wind- 
age losses  are  comparatively  small ;  and  the  speed  of  rotation  is  low 
enough  to  permit  an  efficient  airscrew  to  be  fitted. 

If  the  big-end  loading  be  taken  as  the  criterion,  the  power  of  the 
differential  engine  is  about  30%  greater  than  that  of  the  fixed  radial 
engine,  or,  deducting  the  windage  loss,  about  26  per  cent.  Whether 
this  advantage  outweighs  the  complication  in  design,  remains  to 
be  proved. 

Cycles  of  Operation. — All  aero  engines  are  of  the  single-acting  type 
in  which  driving  impulses  are  received  on  one  side  only  of  the  piston, 
and  in  the  majority  of  engines  the  four-stroke  cycle  is  adopted.  The 
two-stroke  cycle  has  not  hitherto  been  adapted  successfully  to  the 
aero  engine,  owing  to  its  comparative  inefficiency  in  a  high-speed 
engine  which  requires  to  operate  over  a  wide  range  of  speeds. 

A  six-stroke  cycle  is  in  the  experimental  stage.  It  consists  of  the 
four-stroke  cycle  with  the  addition  of  a  suction  and  compression 
stroke.  The  first  suction  stroke  draws  in  a  charge  which  is  com- 
pressed into  an  auxiliary  reservoir  on  the  succeeding  stroke.  The 
next  stroke  is  also  a  suction  stroke  which  draws  in  another  fresh 
charge.  At  the  end  of  this  stroke  a  valve  opens  and  admits  to  the 
cylinder  the  charge  compressed  during  the  preceding  stroke,  and 
during  the  succeeding  stroke  both  charges  are  compressed  into  the 
clearance  space  and  fired.  In  this  way  a  charge  of  double  weight  is 
obtained  and  the  mean  effective  pressure  during  the  expansion  stroke 
is  twice  as  great  as  in  the  four-stroke  cycle.  The  mean  effective 
pressure  over  the  whole  six  strokes  of  the  cycle  is  thus  33  %  greater 
than  the  mean  effective  pressure  over  the  whole  four  strokes  of  the 
ordinary  cycle.  Since  the  explosion  pressures  are  approximately 
twice  as  great  as  in  the  four-stroke  cycle  the  cylinder  construction  is 

For  evenness  of  turning  moment,  the  two-stroke  is  better  than  the 
four-stroke,  and  this  than  the  six-stroke  cycle. 

In  each  of  these  cycles  the  mixture  is  drawn  into  the  cylinder, 
compressed,  burnt  at  constant  volume,  and  expanded  to  the  same 
volume  as  before  compression.  The  theoretical  efficiency  of  this  cycle 

is  given   by  the  expression  I  —  (  —  Jy~l  where  r  is  the  ratio  of  the 

volumes  before  and  after  compression  and  y  is  the  ratio  of  the  specific 
heats  of  the  working  fluid  at  constant  pressure  and  constant  volume. 
This  is  known  as  the  air  standard  efficiency.  It  assumes  that  the 
specific  heat  is  constant  at  all  temperatures,  and  that  there  is  no  loss 
of  heat  to  the  walls  of  the  cylinder,  in  which  case  the  value  of  y  is 

Taking  into  account  the  variation  of  specific  heat  with  tempera- 
ture, the  appropriate  value  of  y  in  this  expression  becomes  1-295 
and  except  for  losses  of  heat  to  the  cylinder  walls  and  piston,  the 
efficiency  of  an  aero  engine  should  attain  the  values  corresponding  to 
its  compression  ratio,  which  are:— 

Compression  ratio 




















These  figures  indicate  the  importance  of  a  high  compression  ratio. 
This  is  particularly  important  in  the  case  of  an  aero  engine,  since  the 
drop  in  power  with  height  diminishes  as  the  compression  ratio  is 

A  limit  is,  however,  set  to  the  compression  ratio  in  practice  by  the 
tendency  of  a  petrol-air  mixture  to  detonate  when  compressed  to  a 
high  pressure  and  temperature.  Such  a  mixture  has  a  "  spontaneous 
ignition  "  temperature  corresponding  to  any  definite  pressure,  at 
which  it  will  detonate,  and  should  this  combination  of  temperature 
and  pressure  be  attained  in  operation  it  is  apt  to  cause  overheating  of 
:he  sparking  plugs  and  to  lead  to  general  overheating  of  the  cylinder 
and  ultimately  to  pre-ignition. 

The  tendency  to  detonation  depends  largely  on  the  design  of  the 
combustion  chamber.  It  is  less  where  this  is  compact  and  symmetri- 
cal than  where  it  contains  pockets  as  in  a  cylinder  of  the  L-headed 
:ype.  It  also  depends  appreciably  on  the  position  of  the  sparking 
Dlugs,  and  on  the  composition  of  the  fuel.  The  addition  of  benzol  or 
Denzene  to  petrol  enables  a  higher  compression  ratio  to  be  used,  but 
owing  to  the  comparatively  high  freezing-point  of  benzol,  not  more 
:han  about  25  %  can  be  used  in  admixture  with  petrol,  for  use  at 
reat  heights. 

By  attention  to  design  it  is  now  found  possible  to  use  c6mpression 
ratios  as  high  as  5-5  when  using  petrol  as  a  fuel,  and  as  high  as  6-5 
when  using  petrol-benzol  mixture.  With  such  compression  ratios, 


fuel  consumptions  in  the  neighbourhood  of  0-45  Ib.  per  B.H.P.  hour 
may  be  attained. 

Supercharging  for  High  Flying. — Since  the  power  is  proportional 
to  the  weight  of  petrol-air  mixture  taken  in  per  cycle,  and  since  this 
weight  depends  on  the  density  of  the  surrounding  atmosphere,  the 
power  falls  off  with  the  height  reached.  Tests  show  that  in  the  aver- 
age engine  the  power  is  sensibly  proportional  to  the  atmospheric 
pressure.  The  law  of  variation  with  atmospheric  density  varies 
slightly  with  the  type  of  engine,  but  may  be  taken  approximately 

B.H.P.  is  proportional  to  p"  where  P  is  the  density,  and  n  varies 
from  i-l  to  1-3.  increasing  slightly  with  the  height.  At  different 
heights  the  power  developed  by  a  2OO-H  P.  engine  at  a  constant  engine 
speed  is  thus  approximately  as  follows : — 

Height,  feet 









Density  . 








B.H.P.    .      . 







B.H.P.   as    %  of 
ground  B.H.P. 








Since  the  resistance  to  the  motion  of  an  aeroplane  diminishes  directly 
as  the  air  density,  other  things  being  unchanged,  the  level  speed 
should  only  diminish  slightly  with  an  increase  in  height.  This 
diminution  in  speed  is,  however,  rendered  more  pronounced  by  the 
fact  that  the  angle  of  incidence  of  the  planes  requires  to  be  increased 
in  order  that  they  may  support  the  same  weight  in  air  of  reduced 
density,  and  this  increases  the  head  resistance. 

The  climbing  speed  of  the  aeroplane  is  reduced  in  a  much  greater 
degree,  since  the  energy  to  be  expanded  in  lifting  the  dead  weight  of 
the  machine  through  a  given  height  is  independent  of  the  density 
and  remains  constant  at  all  heights;  and  at  some  definite  height, 
depending  on  the  design  of  the  aeroplane  and  the  power  of  the 
engine,  the  latter  is  only  sufficient  to  overcome  the  head  resistance 
when  flying  level  at  the  minimum  safe  speed  of  the  aeroplane  with 
the  increased  angle  of  incidence  of  the  planes,  without  leaving  any 
surplus  lifting  capacity.  This  height  is  termed  the  "  ceiling  "  of  the 

Any  device  which  would  enable  the  power  of  the  engine  to  be  main- 
tained at  height  would  not  only  increase  the  level  speed,  but  more 
especially  the  rate  of  climb  and  the  height  of  the  "  ceiling." 

Three  such  devices  have  shown  promise.  In  the  first  the  engine  is 
fitted  with  differential  pistons.  Air  is  drawn  into  the  space  between 
these  on  the  outward  stroke  of  the  engine,  compressed  on  the  return 
stroke,  passed  through  a  cooler,  and  forced  into  the  cylinder  through 
a  series  of  ports  uncovered  by  the  piston  slightly  before  the  end  of 
the  suction  stroke.  By  this  method  the  weight  of  mixture  in  the 
cylinder  is  increased.  The  degree  of  "  supercharging  "  may  be 
adjusted  by  a  regulating  valve  so  as  to  keep  the  power  constant 
over  a  range  of  heights  up  to  about  10,000  feet.  This  scheme  has 
not  as  yet  been  very  successful  owing  mainly  to  mechanical  defects. 

In  the  second  system  a  centrifugal  blower  is  geared  to  the  engine. 
The  discharge  from  this  is  passed  through  the  carburetter  on  its  way 
to  the  cylinders  which  are  thus  fed  with  mixture  under  an  increased 
pressure.  The  system  is,  of  course,  an  added  complication  and 
involves  the  maintenance  of  very  high-speed  gears  and  bearings.  As 
the  induction  system  is  under  pressure,  any  leaky  joints  will  derange 
the  operation  of  the  engine,  and  lastly,  since  the  speed  of  the  blower  is 
constant  at  constant  engine  speeds,  the  amount  of  supercharging 
falls  off  with  height,  while,  near  the  ground,  air  must  be  blown  to 
waste  through  a  bypass  valve. 

In  the  third  system  the  engine  exhaust  is  discharged  through  a 
single-wheel  high-speed  impulse  turbine  of  the  Rateau  type.  This 
turbine  is  direct  coupled  to  a  centrifugal  blower  feeding  the  car- 
buretter, and  delivers  sufficient  air  to  the  engine  to  maintain  its 
power  at  all  heights  up  to  about  15,000  feet.  This  method  is  partially 
automatic  in  that  if  the  pressure  in  the  induction  pipe  is  maintainec 
constant,  the  pressure  of  the  exhaust  gases  will  be  constant,  anc 
since  the  pressure  on  the  exhaust  side  of  the  turbine  diminishes  with 
height,  the  pressure  available  for  driving  the  turbine  increases  with 
height  to  an  extent  which  compensates  for  the  increased  demand  for 
power  by  the  blower.  A  valve  for  bypassing  the  whole  or  part  of  the 
exhaust  gas  directly  into  the  atmosphere  is  provided  to  enable  the 
output  from  the  blower  to  be  regulated. 

Here  also  the  induction  system  is  under  pressure.  The  weight 
complete  for  a  2OO-H.P.  installation  can  be  cut  down  to  about  60  Ib 
and  at  15,000  ft.  the  gain  in  power  is  about  80  H.  P.  for  an  expenditure 
of  only  0-75  Ib.  per  H.P.  thus  gained. 

The  increased  complexity  of  the  installation,  the  work  thrown  on 
the  pilot,  and  the  risk  of  breakdown  will  all  retard  the  introduction 
of  such  schemes.  Moreover,  the  additional  weight  may  alternatively 
be  devoted  to  increasing  the  size  of  the  cylinders,  leaving  the  crank- 
case  and  crank-shaft,  etc.,  sensibly  unaltered.  Such  a  "  light  " 
engine  would  not  withstand  being  opened  out  fully  near  the  ground, 
and  special  precautions  would  require  to  be  taken  to  prevent  this 
happening.  At  height,  however,  it  could  be  fully  opened  up,  and  the 
increased  power  corresponding  to  its  increased  cylinder  diameter 
taken  advantage  of.  Such  a  unit  has  the  advantage  of  simplicity. 
Many  of  the  latest  and  most  powerful  engines  are  really  in  a  modified 

degree  "  light  "  engines,  in  that  they  cannot  be  run  for  more  than  a 
very  few  minutes  "  all  out  "  near  the  ground. 

Other  methods  of  reducing  the  drop  in  power  with  height  are 
possible.  One  such  method  is  to  design  the  engine  with  a  compression 
ratio  too  high  to  permit  of  ground  operation,  and  to  reduce  this 
near  the  ground  by  a  cam  giving  a  late  closing  to  the  inlet  valve. 
As  the  height  is  increased  the  inlet  valve  would  be  closed  earlier  in 
the  stroke  until,  at  some  predetermined  height,  normal  timing  would 
be  attained.  A  second  method  which  has  been  suggested  consists  in 
admitting  a  proportion  of  cooled  exhaust  gas  to  the  cylinder  with  the 
working  mixture.  This  reduces  the  tendency  to  detonation  and 
enables  a  higher  compression  ratio  to  be  adopted  than  would  other- 
wise be  possible.  As  the  height  increases  the  proportion  of  exhaust 
gas  would  be  reduced,  until,  at  the  predetermined  height,  the  engine 
would  be  working  on  a  normal  mixture. 

Engine  Starters. — The  operation  of  starting  an  aeroplane  engine 
by  swinging  the  airscrew  by  hand  has  always  been  dangerous,  and 
to  remove  the  necessity  for  this,  several  types  of  self-starter  have 
been  devised.  An  electric  motor  geared  to  the  crank-shaft  through  a 
clutch  achieves  this,  but  the  number  of  starts  possible  with  one 
charge  is  limited  by  the  accumulator,  and  the  weight  and  bulk  of  the 
installation  restrict  its  sphere  of  usefulness.  A  compressed-air 
starter  is  lighter.  Here  a  high-pressure  cylinder  supplies  air  to  the 
correct  cylinders  by  means  of  a  distributor  operated  from  the  crank- 
shaft of  the  engine. 

The  most  usual  starting  system  consists  of  a  supplementary 
magneto  placed  in  the  cockpit  and  rotated  by  hand  by  the  pilot 
when  the  crank-shaft  has  been  brought  into  the  correct  position. 
For  success  one  or  more  of  the  cylinders  must  contain  an  explosive 
charge  and  therefore  the  crank-shaft  is  rotated  slowly  by  hand, 
drawing  a  charge  of  petrol  vapour  from  the  carburetter  as  in  normal 
operation.  The  plan  is,  however,  unsatisfactory  in  cold  weather,  and 
starting  is  facilitated  by  admitting  coal  gas  or  hydrogen  into  the 
induction  pipe  from  a  small  container,  while  the  crank-shaft  is  being 

One  modern  device,  still  (1921)  in  the  experimental  stage,  consists 
of  a  small  two-stroke  single-cylinder  engine  which  is  started  by  hand 
and  drives  a  compressor  which  draws  an  explosive  mixture  from  its 
induction  pipe  and  forces  this  through  a  distributor  into  the  appro- 
priate cylinders  of  the  main  engine.  This  charge  is  then  fired  in  the 
usual  way. 

Future  Development  of  the  Aero  Engine. — The  development  of  the 
aero  engine  must  increase  its  reliability,  its  useful  life,  its  efficiency 
and  its  output  in  horse-power  per  unit  weight,  especially  at  height. 
Experience  gained  in  the  operation  of  existing  types,  by  a  process  of 
survival  of  the  fittest,  slowly  leads  to  the  elimination  of  those  details 
in  design  which  are  in  the  main  responsible  for  breakdowns.  The 
reduction  of  bearing  loads  and  the  improvement  in  bearings,  in- 
creased perfection  in  balancing,  better  design  of  valve  springs  and  of 
valve  gears,  of  pistons  and  piston  rings  and  of  lubrication  systems, 
will  all  add  to  the  useful  life,  while  improvements  in  carburation,  in 
cooling  and  lubrication,  induction  systems,  and  in  sparking  plugs, 
will  lead  to  increased  reliability  of  operation.  Efficiency  will  be 
enhanced  mainly  by  such  modifications  in  cylinder  design  or  by  the 
use  of  such  fuels  as  will  admit  of  higher  compression  pressures. 

It  seemed  possible  in  192 1  that  the  Diesel  cycle  might  be  developed 
for  aero-engine  work,  and  the  Junker  engine  of  this  type  was  said  to 
have  attained  a  fairly  advanced  stage  of  development  in  Germany. 
In  view  of  the  heavy  cylinders  required  a  sufficiently  light  Diesel 
engine,  however,  appears  to  be  very  difficult  of  attainment.  Failing 
this,  the  direct  injection  of  fuel  into  the  cylinder  during  the  suction 
stroke,  using  moderate  compression  ratios,  may  have  possibilities. 
This  is  a  modification  of  the  method  used  in  the  early  Antoinette 
engine,  where  fuel  was  injected  by  a  pump  into  the  inlet  pipe  of  each 
cylinder.  The  method  has  the  advantage  of  eliminating  the  car- 
buretter and  induction  system  and,  in  theory,  of  enabling  a  uniform 
mixture  to  be  given  to  all  the  cylinders.  Promising  experiments  on 
single-cylinder  engines  were  in  progress  in  1921. 

Outside  existing  designs  in  1921  there  appeared  to  be  scope  for 
an  engine  working  on  the  two-stroke  cycle,  and  for  a  double-acting- 
line  engine  with  cylinders  in  tandem.  It  is  true  that  attention  had 
already  been  paid  to  both  these  types  without,  as  yet,  successful 
results.  Still,  many  of  the  initial  difficulties  had  been  surmounted, 
and  there  was  every  reason  to  hope  that  a  successful  design  would 
ultimately  be  evolved.  Such  an  engine  would  have  excellent  pros- 
pects of  fulfilling  the  ideal  conception  of  I  Ib.  per  B.H.P.  which  is 
at  present  the  dream  of  the  aero-engine  designer.  In  view  of  the 
immense  progress  in  the  design  of  aero  engines  during  1911-21,  it 
seemed  probable  that  the  aero  engines  of  the  future  might  well  show 
as  much  improvement  as  those  of  1921  did  as  compared  with  the 
machinery  to  which  the  early  fliers  entrusted  their  lives. 

(A.  H.  Gi.) 


Historical. — Navigation  is  the  art  of  selecting  the  course 
which  a  craft  should  take  in  order  to  proceed  from  any  one 
position  on  the  waters  to  any  other.  For  guidance  in  the  building- 
up  of  air  navigation  centuries  of  experience  of  the  sister  art  ot 


sea  navigation  may  be  drawn  on,  and  much  of  this  experience  is 
capable  of  direct  application  to  the  air.  The  earlier  forms  of 
marine  navigation  were  of  a  rudimentary  type  and  would  now 
be  included  in  the  general  term  "  pilotage."  Whenever  they 
could  manage  to  do  so  the  primitive  sea  voyagers  were  careful 
to  keep  in  sight  of  the  coastline,  so  that  even  a  rough  map 
sufficed  to  enable  the  position  of  the  ship  to  be  noted.  The 
great  voyagers  of  the  middle  ages  were  bolder  and  depended 
no  longer  on  mere  pilotage  methods;  then  it  was  that  scientific 
navigation  had  its  birth.  The  compass  came  into  use  in  Europe 
about  the  i4th  century,  and  by  its  means,  combined  with  a 
rough  measurement  of  the  speed  of  the  craft  through  the  sea, 
it  was  possible  to  keep  a  reckoning  on  the  chart — called  a 
"  dead  reckoning,"  or  briefly  D.R. — of  the  position  from  day 
to  day.  This  allowed  nothing  for  drift  due  to  tides  or  currents 
or  leeway,  but  since  in  the  early  voyages  these  were  quite  un- 
known in  amount  no  allowances  could  be  made.  Experience 
showed  that  the  D.R.  position  thus  obtained  was  often  con- 
siderably in  error,  and  some  check  upon  it  became  very  neces- 
sary. For  this  the  simple  cross-staff  and  the  astrolabe  were  em- 
ployed. With  these  instruments  a  rough  measurement  of  the 
altitude  of  the  sun  at  midday,  or  of  the  pole  star  at  night,  enabled 
the  latitude  to  be  determined  to  perhaps  half  a  degree,  or  30 
nautical  miles.  But  a  simple  latitude  observation  like  this  did 
not  suffice  to  ascertain  the  ship's  position,  since  it  merely  gave 
the  information  that  it  must  lie  somewhere  on  an  east-west 
line  drawn  so  many  degrees  N.  or  S.  of  the  equator.  If  the 
course  were  N.  or  S.,  this  measurement  gave  the  run,  but  no 
check  on  the  estimated  course;  whilst  if  the  course  were  E.  or 
W.,  the  latitude  measurement  gave  no  information  as  to  the  run. 
Later  on,  when  better  instruments  were  available — the  introduc- 
tion of  the  Hadley  sextant  in  1731  marked  a  very  real  advance — 
methods  were  adopted  to  enable  longitude  as  well  as  latitude  to 
be  measured,  but  the  necessary  calculation  of  lunar  distances 
was  troublesome,  and  it  was  not  until  the  perfection  of  the 
marine  chronometer  in  the  latter  half  of  the  i8th  century  that  it 
became  open  to  the  average  sea  navigator  to  work  out  his  longi- 
tude as  well  as  his  latitude,  and  so  obtain  a  check  on  both  run 
and  course. 

Experience  with  air  navigation  has  followed  a  generally  sim- 
ilar path;  compressed  of  course  into  a  very  few  years.  When 
air  craft  were  first  navigated  they  followed  pilotage  methods 
only;  the  earth  was  continuously,  or  almost  continuously,  in 
sight,  and  the  position  from  time  to  time  was  ascertained  by  the 
recognition  of  landmarks,  or,  where  these  were  scarce,  by  a 
system  of  dead  reckoning  based  on  the  compass  course  and  the 
speed  through  the  air.  Here,  however,  arises  the  great  difference 
between  sea  and  air  conditions.  Currents  in  the  sea  rarely  exceed 
a  few  knots,  but  in  the  air  are  quite  commonly  of  20  knots, 
velocity,  and  may  be  even  four  or  five  times  as  much ;  moreover, 
whilst  the  former  may  be  charted  the  latter  cannot.  This  would 
tend  to  make  air  navigation  the  more  difficult,  but  its  effect  is 
mitigated  by  the  fact  that  the  air  ocean  has  the  great  merit — 
for  this  purpose — of  being  transparent  (except  for  occasional 
cloud  sheets)  and  of  enabling  the  direction  and  course  of  air 
currents  to  be  measured  by  watching  the  apparent  motion  of 
objects  on  the  earth's  surface.  A  wind  of  50  knots  opposing 
an  aircraft  having  a  speed  through  the  air  of  100  knots  will  re- 
duce its  speed  over  ground  by  one-half,  while  if  favouring  it 
will  cause  the  ground  speed  to  exceed  the  air  speed  by  50%: 
neither,  however,  will  cause  any  apparent  sideways  drift  of  the 
craft.  If,  in  either  of  these  cases,  the  speed  over  the  ground  be 
measured  in  some  convenient  way,  it  is  possible  to  determine 
both  the  velocity  and  direction  of  the  air  current,  i.e.  the  wind. 
A  similar  but  slightly  more  troublesome  measurement  gives 
the  wind  velocity,  and  direction,  when  the  flight  is  oblique  to 
the  wind.  This  ability  is  not  shared  by  the  sea  navigator,  who 
cannot  see  the  bottom  of  the  ocean  on  which  he  sails,  and  has 
instead  to  assume  the  accuracy  of  the  information  given  on  his 
charts  and  in  his  sailing  directions. 

The  fact  that  an  aircraft,  when  flying  with  the  wind,  may  have 
a  ground  speed  of  as  much  as  1 50  to  200  knots,  makes  it  essential 

to  determine  the  position  with  rapidity.  An  observation  which 
took  10  minutes  to  reduce  would  afford  information  of  a  position 
some  30  nautical  m.  to  the  rear.  Hence  speedy  methods  are 
essential;  and  fortunately — owing  to  the  absence  of  aerial  rocks 
and  shoals,  and  the  extensive  field  of  view — much  less  accuracy 
of  position-finding  is  required  in  the  air  than  at  sea.  An  accuracy 
of  determination  of  10  m.  suffices  for  almost  all  air  purposes; 
whereas  the  sea  navigator  aims  hopefully  at  "an  accuracy 
within  a  mile  or  less. 

Dead  Reckoning. — Hakluyt,  recording  in  1580  "  instructions  and 
notes  very  necessary  and  needful  to  be  observed,"  points  out  that 
"  in  keeping  your  dead  reckoning,  it  is  necessary  that  you  doe  note 
at  the  ende  of  every  foure  glasses  what  way  the  shippe  hath  made 
(by  your  best  proofes,  to  be  used)  and  how  her  way  hath  beene 
through  the  water,  considering  withall  for  the  sagge  of  the  sea,  to 
leewards,  according  as  you  shall  finde  it  growe.  Doe  you  diligently 
observe  the  latitude  as  often,  and  in  as  many  places  as  you  may 
possible;  and  also  the  variation  of  the  compasse.  .  .  ."  These 
instructions,  so  necessary  and  needful  to  be  observed  at  sea,  are  for 
air  navigation  not  less  so.  But  in  the  latter  case  special  difficulties 
arise.  The  course  over  the  ground  is  determined  by  the  apparent 
motion  of  objects  on  the  earth  relative  to  the  fore-and-aft  line  of  the 
craft ;  but  owing  to  the  rolling,  yawing  and  pitching  of  the  latter,  and 
of  all  instruments  carried  upon  it,  such  measurements  are  far  from 
simple.  However  straight  the  pilot  may  try  to  fly  he  will  yaw 
slightly  from  side  to  side,  and  this  will  cause  the  flight  path  to  be 
more  or  less  sinusoidal,  with  an  accompanying  lateral  acceleration 
tending  to  cause  the  machine  itself,  and  all  instruments  fastened  to 
it,  to  roll  periodically  to  port  or  starboard.  This  will  cause  any 
objects  below  the  craft  to  appear  to  follow  an  oscillatory  path  instead 
of  a  straight  line,  and  so  make  the  determination  of  the  angle  of 
drift  much  more  difficult.  Nor  is  it  possible  to  surmount  this 
obstacle  by  making  the  observing  apparatus  pendulous  in  the  hope 
that  it  will  remain  vertical.  The  lateral  acceleration  due  to  the 
slightly  curved  path  will  cause  the  centre  of  gravity  of  the  pendulous 
mass  to  seek  a  position  such  that  the  moments  about  the  point  of 
support  of  the  weight  will  balance;  in  other  words,  the  instrument 
tends  to  set  itself  not  to  the  true  vertical  but  to  the  "  apparent 
vertical  "  given  by  the  resultant  of  the  gravitational  and  the  lateral 
acceleration.  If  the  pendulous  instrument  has  a  substantial  amount 
of  inertia,  it  will  not  have  time  to  pick  up  this  direction  before  the 
aircraft  will  have  entered  on  a  fresh  part  of  its  sinusoidal  path  corre- 
sponding to  a  fresh  position  of  the  apparent  vertical.  The  instrument 
therefore  continually  hunts  the  apparent  vertical,  but  is  always  in 
arrear  to  the  one  side  or  the  other.  It  may  appear  that  by  making 
the  inertia  sufficiently  great  the  motion  of  the  instrument  would  be 
so  slow  and  so  slight  as  to  be  negligible,  but  calculation  shows  that 
unless  gyrostatic  forces,  with  their  attendant  complication,  are 
brought  into  play  it  is  not  possible,  within  the  necessary  limits  of 
dimensions  of  the  craft,  to  achieve  this.  These  ever-present  oscilla- 
tions are  of  great  importance  in  the  study  of  aircraft  instruments. 
Not  only  is  the  apparatus  for  measuring  the  angle  of  drift  of  the 
ground  affected  by  them,  but  equally  any  apparatus  for  getting  a 
reading  of  the  ground  speed,  and,  by  no  means  least,  the  magnetic 
compass  itself.  Compasses  fitted  to  ships  usually  have  a  period  of 
oscillation  much  longer  than  the  period  of  roll  of  the  ship,  hence  the 
compass  has  not  time  to  be  very  much  disturbed  by  such  movements. 
In  aeroplanes,  however,  the  period  of  roll  is  longer  and  the  early  types 
of  aircraft  compass  by  an  unlucky  coincidence  had  just  about  the 
same  period,  hence  resonance  was  a  frequent  occurrence,  and  wild 
oscillations  of  the  compass  needle  were  all  too  frequently  reported. 
Later  on  the  cause  of  the  phenomenon  was  recognized  and  a  remedy 
was  found. 

That  a  magnetic  compass  points  magnetic  N.  instead  of  true  N. 
gives  rise  to  the  correction  called  "  variation,"  and  this  applies 
equally  to  sea  and  air  craft.  Variation  charts  are  equally  available 
and  no  difficulty  is  presented.  With  the  correction  known  as 
"  deviation  "  due  to  the  magnetism  residing  in  the  structure  of  the 
craft  itself,  air  conditions  are  simpler  than  those  at  sea,  in  that  the 
masses  of  magnetic  material  near  the  compass  position  are  much 
less  in  amount;  but  on  the  other  hand  the  value  of  the  deviation  on 
each  point  of  the  compass  is  rather  more  troublesome  to  determine 
and  much  more  likely  to  vary  with  the  life  history-  of  the  craft  itself. 

The  measurement  of  the  speed  through  the  air  fortunately  pre- 
sents none  of  these  difficulties  since  the  forces  produced  by  the 
relative  air  stream  are  dependent  only  on  velocity  and  air  density, 
and  the  latter  being  known  for  any  given  altitude  of  flight  it  is 
possible  to  obtain  a  measure  of  velocity  through  the  air  free  from  any 

Except  for  flying-boats  engaged  on  anti-submarine  patrol  scarcely 
any  aircraft  prior  to  the  end  of  the  World  War  had  need  to  employ 
navigational  methods  of  flight:  ordinary  pilotage  sufficed  for  their 
journeys.  The  work  of  the  flying-boat  patrols,  however,  required 
meticulous  care  in  navigation  since  their  duties  carried  them  far 
out  of  sight  of  land  and  it  was  imperative  that  they  should  make  a 
landfall  before  the  petrol  supply  ran  out.  The  method  employed  was 
dead-reckoning  navigation  carried  out  with  that  care  which  the  risk 



of  failure  made  necessary  for  all  employed  on  this  arduous  service. 
That  so  few  flying-boats  were  lost  on  such  patrols  says  much  for  the 
care  with  which  the  instruments  were  attended  to  and  the  skill  with 
which  their  indications  were  heeded.  An  error  of  only  two  degrees  in 
the  course  made  good  would  throw  out  the  position  by  over  3  m. 
in  each  too  flown:  the  consequences  on  a  misty  day  for  an  aircraft 
trying  to  make,  say,  the  Scilly  Is.  base  can  be  imagined.  There  were 
then  no  facilities  for  astronomical  navigation,  and  dead  reckoning 
had  to  be  relied  upon. 

Not  only  had  the  flying-boats  on  war  service  to  be  navigated  but 
the  pilot  and  observer  had  also  to  "  navigate  "  a  bomb  to  its  desired 
target.  Since  a  bomb,  or  any  other  heavy  body,  maintains  the  course 
and  speed  of  its  carrier  aircraft  substantially  unaltered  during  its 
fall  to  sea  level,  the  sighting  problem  is  the  same  as  the  dead-reckon- 
ing navigation  problem:  in  fact,  one  observing  instrument  can 
serve  both  purposes.  The  horizontal  motion  of  the  bomb  is  com- 
pounded of  the  wind  velocity  and  the  air  speed  of  the  craft.  The 
distance  it  will  travel  horizontally  will  be  the  product  of  the  resultant 
of  these  two  velocities  and  the  time  taken  to  fall  from  the  height  at 
which  the  aircraft  is  operating.  This  then  must  be  the  horizontal 
distance  of  the  craft  from  its  target  at  the  moment  of  release  and  the 
line  of  attack  must  of  course  be  that  of  the  course  being  made  good. 
The  angle  ahead  of  the  vertical  which  the  target  subtends  at  the 
moment  of  release  is  called  the  sighting  angle,  and  obviously  it  will 
vary  with  the  direction  in  which  the  target  is  attacked  unless  the 
wind  velocity  happens  to  be  zero.  This  requires  that  the  instru- 
ment should  be  set  for  height,  air  speed,  wind  velocity  and  wind 
direction,  and  further  that  it  should  make  automatic  provision  for 
the  right  combination  of  these  elements  for  any  direction  of  attack. 

FIG.  23 — Course-Setting  Sight 

The  best  known  instrument  for  doing  this  is  the  course-setting 
sight  shown  in  the  illustration  (fig.  23),  and  much  used  on  flying- 
boats;  in  its  navigational  use  it  enables  the  velocity  and  direction  of 
the  wind  to  be  measured  whilst  in  flight,  and  it  indicates  the  course 
to  be  steered  for  any  given  track,  and  the  time  taken  in  flying  any 
desired  distance  in  that  direction.  Towards  the  end  of  the  war  the 
French  made  some  use  of  navigational  bomb  sights,  and  the  United 
States  Government  had  a  large  number  constructed,  but  so  far  as  is 
known  no  such  efforts  were  made  elsewhere. 

For  D.R.  navigation  on  land  aircraft  use  is  often  made  of  an 
instrument  called  an  aero  bearing  plate.  This  was  an  adaptation  of 
a  marine  bearing  plate,  or  pelorus,  having  a  transparent  centre  to 
admit  of  vertical  observations  of  the  ground,  and  having  one  or  more 
longitudinal  rods  or  wires  which  could  be  aligned  parallel  to  the 
apparent  earth  flow  so  as  to  enable  the  drift  angle  to  be  read  off.  A 
graduated  height  bar  also  permitted  the  ground  speed  to  be  measured 
by  noting  the  time  taken  for  an  object  on  the  earth  to  pass  through 
the  vertical  angle  corresponding  to  a  distance  of  flight  of  half  a  mile, 
or  other  convenient  distance. 

New  Navigational  Instruments. — One  of  the  first  instruments 
known  to  have  been  used  for  the  determination  of  latitude  in  mari- 
time navigation  was  the  astrolabe.  This  device  consisted  of  a 
pendulous  disc  graduated  round  its  circumference  in  degrees  and 
carrying  at  its  centre  a  rod  fitted  with  back  and  fore  sights  the 
inclination  of  which  to  the  horizontal  could  be  read  off  on  the  degree 
scale.  A  sight  on  a  star  would  therefore  give  a  measurement  of  its 
altitude.  The  use  of  a  pendulum  or  "  plumb  bob  "  is,  of  course,  a 
familiar  way  of  obtaining  a  vertical  line,  but  it  suffers  from  the 
disadvantage  that  it  no  longer  indicates  truly  if  its  point  of  attach- 
ment is  not  kept  still.  On  board  ship  the  point  of  support  is  neces- 
sarily in  general  motion  and  in  consequence  the  pendulum  con- 
tinually oscillates:  its  average  position  still  gives  the  vertical,  but  it 
is  a  tedious  business  to  find  what  the  average  position  really  is. 
Seamen  turned,  therefore,  to  the  visible  horizon  as  a  more  satis- 
factory datum  from  which  to  measure  the  altitude  of  heavenly 

bodies;  the  early  cross-staffs  were  inaccurate,  but  a  nearly  perfect 
form  of  instrument  for  this  purpose  was  discovered  in  the  Hadley 
sextant  of  1731.  It  depended  on  the  very  important  fact  that  if  a 
beam  of  light  be  reflected  from  two  plane  mirrors  in  sequence,  the 
total  angle  through  which  the  beam  is  turned  depends  only  upon 
the  angle  between  the  two  mirrors  and  not  on  the  angle  between 
the  rays  of  light  and  the  mirrors  themselves.  Thus,  if  the  two  mirrors 
are  fixed  at  an  angle  of  40°  to  one  another,  the  angle  through  which 
the  ray  of  light  will  be  turned  after  the  double  reflexion  will  be 
exactly  80°;  if  this  reflecting  system  be  now  used  to  view  a  star 
having  an  angular  elevation  above  the  visible  horizon  of  80°  then 
the  star  will  appear  to  be  "  brought  down  "  to  the  horizon  and  its 
apparent  position  will  not  be  affected,  however  much  the  frame 
carrying  the  two  mirrors  may  be  rocked  in  a  vertical  plane.  It  will 
easily  be  seen  that  for  use  on  a  rolling  platform,  such  as  the  deck  of  a 
ship,  this  is  a  most  valuable  property.  The  seaman  will  see  the 
horizon  rising  and  falling  relative  to  the  ship,  but  the  image  of  the 
star  will  rise  and  fall  with  it.  If  the  two  images  only  came  into 
coincidence  when  the  deck  was  level,  the  instrument  would  be 
useless.  It  is  the  fact  that  star  image  and  horizon  appear  to  move 
together  when  the  ship  rolls  or  pitches  which  makes  the  sextant  the 
valuable  instrument  it  is.  Inasmuch  as  the  pitching  and  rolling  of  an 
aircraft  is  sometimes  just  as  bad  as  the  pitching  and  rolling  of  a 
seacraft,  it  might  be  thought  that  the  Hadley  sextant  would  equally 
be  of  use  in  the  air.  Indeed,  the  instrument  is  equally  available,  but 
the  horizon  is  not.  At  10,000  ft.  height  the  horizon  is  about  90  m. 
away,  and  unless  the  day  is  exceptionally  clear  there  will  be  sufficient 
mist  to  prevent  so  distant  a  horizon  being  visible  as  a  clear  line.  If 
the  horizon  has  therefore  to  be  abandoned  as  a  datum  line,  it  be- 
comes necessary  to  fall  back  once  more  on  the  method  of  the  mediae- 
val astrolabe  and  to  employ  plumb-bob  methods  of  obtaining  the 
vertical.  This,  of  course,  has  the  great  disadvantage  that  it  is  only 
the  average  of  a  number  of  such  observations  that  can  give  the  true 

There  is,  however,  a  half-way  house,  though  not  a  good  one. 
Although  the  true  horizon  may  be  invisible  there  will  often  be  false 
horizons  given  by  the  upper  surface  of  cloud  layers  or  banks  of  mist. 
These  false  horizons  are  not  so  far  below  the  level  of  the  aircraft  as 
is  the  sea,  hence  their  distance  is  much  less  and  the  line  of  separation 
between  cloud  level  and  sky  is  often  sufficiently  sharp  to  be  of  use. 
The  great  drawback  is,  however,  the  absence  of  definite  knowledge 
of  the  height  of  such  cloud  levels,  and  therefore  of  their  value  as 
datum  lines  for  sextant  observations.  A  wrong  guess  at  the  height 
may  give  a  totally  false  value  to  the  sun's  altitude,  and  therefore  to 
the  position  line  deduced  from  it.  Attempts  have  been  made  to 
avoid  such  errors  by  assuming  that  the  false  horizon  on  the  port  side 
is  of  the  same  altitude  as  that  to  starboard,  and  then,  by  taking  a 
point  half-way  in  between  as  the  zenith,  to  make  all  measurements 
from  that  as  datum.  This  is  correct  just  as  often  as  the  two  horizons 
do  happen  to  be  of  the  same  height ;  but  it  does  not  appear  that  this 
is  always  the  case,  nor  in  fact  is  a  second  horizon  always  visible,  and 
at  night  time  neither  the  one  nor  the  other.  Moreover,  such  level 
cloud  or  mist  layers  can  only  be  expected  when  the  temperature  lapse 
rate  is  small  and  the  air  is  very  stable.  On  very  many  occasions  these 
conditions  do  not  hold,  the  air  is  frequently  "  bumpy,"  and  the 
cloud  masses  heaped  and  tumbled.  Speaking  generally,  the  condi- 
tions in  which  large  flat  cloud  sheets  extend  are  conditions  favourable 
to  navigational  measurements,  and  they  are  also  the  conditions  in 
which  accurate  knowledge  of  position  is  most  essential.  Such 
conditions  arise  when  the  temperature  falls  but  slowly  with  altitude. 
When  this  lapse  rate  (as  it  is  called)  is  much  lower  than  the  10°  C.  per 
km.  which  marks  the  condition  of  instability,  there  is  little  atmos- 
pheric turbulence,  and  the  aircraft  is  comparatively  steady;  even 
a  plumb-bob  instrument  is  then  a  convenient  method  of  making 
measurements.  A  spirit  level  is  of  course  a  form  of  plumb-bob,  in 
that  the  bubble  is  a  kind  of  inverted  "  bob,"  which  tries  to  get  as 
high  up  as  possible  instead  of  as  low  down.  Such  levels  have  long 
been  used  in  inclinometers  for  surveying,  witness  the  well-known 
"  Abney  level."  They  suffer,  however,  from  the  disadvantage  that 
when  the  instrument  rocks,  the  image  and  bubble  move  in  opposite 
directions.  No  such  device  could  be  a  success  in  the  air,  and  it  is 
necessary  to  incorporate  the  double  reflexion  method — or  its  equiva- 
lent— of  the  Hadley  sextant.  This  has  been  done  by  the  staff  of  the 
Royal  Aircraft  Establishment,  Farnborough,  in  England,  and  by 
Prof.  Wilson  in  America. 

The  principle  of  action  of  the  R.A.E.  instrument  is  shown  in  fig.  24. 
la  this  instrument — known  as  the  R.A.E.  bubble  sextant — the 
vertical  is  given  by  the  position  of  the  bubble  in  a  spherical  level, 
capable  of  being  illuminated  at  will  by  a  little  electric  lamp.  The 
eye  may  take  up  either  position  (i)  or  position  (2).  The  former  is 
best  for  star  or  planet  observations,  and  the  latter  for  those  on  the 
sun,  though  theoretically  there  is  no  reason  why  either  position 
should  not  be  used  for  all  observations.  It  is  a  matter  of  convenience 
which  is  used ;  a  star  is  more  easily  identified  and  held  in  view  by  the 
method  of  direct  vision,  whilst  for  observations  of  the  sun  there  is 
no  risk  of  confounding  it  with  any  other  heavenly  body,  and  it  is 
much  more  comfortable  to  the  eve  to  look  downwards  and  so  avoid 
the  glare  of  the  sky  in  the  neighbourhood  of  the  sun.  The  lens  is 
chosen  to  have  a  focal  length  equal  to  its  optical  distance  from  the 
bubble,  and  since  the  curvature  of  the  upper  surface  of  the  latter  is 




Position  2 

Plain  Glass  Plate, 
capable  ot  being 
rotated  through  a 
measured  angle 



i.  '  A  > .' "v   y 

FIG.  24. 

carefully  chosen  to  be  equal  also  to  this  distance,  the  bubble  will 
remain  in  focus  and  will  appear  to  move  with  the  sun  or  star  if  the 
instrument  should  rock  in  the  hand. 

Gyrostatic  Horizons. — When  sextant  observations  are  made  at  a 
ground  station  it  is  best  to  employ  an  artificial  horizon,  usually  in 
the  form  of  a  bath  of  mercury.  The  sextant  is  then  used  to  measure 
the  angle  between  the  heavenly  body  itself  and  its  image  seen  in  the 
reflecting  surface  of  the  mercury;  half  this  angle  is  the  angle  of 
elevation  of  the  body  above  the  horizontal.  Such  a  method  is 
inapplicable  to  an  aircraft  for  two  reasons:  first,  that  the  vibration 
would  cover  the  mercury  surface  with  ripples  and  cause  it  to  reflect 
a  shimmer  instead  of  a  definite  image ;  and  secondly,  that  the  accelera- 
tion forces  would  act  on  the  mercury  and  cause  its  surface  to  tilt  in 
one  direction  or  another.  For  this  reason  use  has  sometimes  been 
made  of  a  little  gyrostat  spinning  on  a  pivot  and  carrying  a  small 
circular  mirror  fixed  at  right  angles  to  the  axis  of  rotation.  If  this 
gyrostat  accurately  kept  its  axis  vertical  the  little  mirror  would  form 
a  convenient  substitute  for  the  mercury  bath.  But  it  also  is  subject 
to  the  disturbing  effect  of  acceleration  forces,  and  is  thereby  deflected 
more  or  less  from  the  desired  position.  Its  behaviour  in  this  respect 
is,  however,  much  in  advance  of  that  of  a  simple  pendulum  or  bubble; 
although  since  it  is  a  rotating  body  it  has  the  double  disadvantage  of 
requiring  power  to  drive  it,  and  of  being  adversely  affected  in  its 
performance  by  the  inevitable  wear  of  its  pivot.  It  is  still  uncertain 
whether  a  sextant  using  a  bubble  or  a  little  gyrostat  will  in  the  long 
run  prove  the  more  suitable  for  air  purposes.  Gyrostatic  means  of 
measurement  are,  however,  of  much  importance  for  air  navigation, 
and  the  first  application  on  a  wide  scale  is  that  of  the  gyrostatic 
"  turning  indicator."  In  this  device  a  gyrostat  is  spun  in  bearings 
so  that  its  axis  lies  normally  in  a  horizontal  plane.  If  then  the  frame- 
work containing  the  bearings  is  turned  about  a  vertical  axis — due  to 
the  aircraft  carrying  it  turning  to  port  or  starboard — the  gyrostat 
will  tend  to  turn  itself  about  an  axis  perpendicular  alike  to  that  about 
which  the  forced  turn  occurs,  and  that  about  which  the  gyrostat  is 
itself  rotating.  This  effect  is  called  "  precession  "  and  the  couple 
brought  into  play  is  called  the  "  precessional  couple";  this  couple 
is  caused  either  to  compress  or  to  wind  up  a  spring  and  in  so  doing 
to  move  a  pointer,  the  indications  of  which  give  a  measure  of  the 
degree  of  rapidity  of  the  turn,  and  whether  the  direction  is  to  port  or 
starboard.  Such  turning  indicators  are  invaluable  when  flying  in 
cloud,  mist  or  fog.  Without  them  a  pilot  tends  to  lose  all  sense  of 
direction,  and  the  indications  of  the  compass,  which  might  be 
thought  a  sufficient  safeguard  against  such  uncertainty,  are  in  some 
cases  so  affected  by  the  large  and  sudden  acceleration  forces  brought 
into  play  as  to  be  quite  misleading  in  their  indications.  The  reason 
for  this  will  be  dealt  with  at  greater  length  in  what  follows.  The 
gyro  turning  indicator  was  first  employed  for  measuring  the  rate  of 
roll  of  ships  (apparatus  for  this  purpose  was  made  both  by  J.  B. 
Henderson  and  H.  E.  Wimperis  prior  to  the  World  War)  and  its  use 
on  aircraft  came  in  the  later  stages  of  the  war.  In  the  meantime  an 
aircraft  turning  indicator  due  to  H.  Darwin  had  been  employed; 
this  depended  on  the  static  air  pressure  at  the  two  wing  tips  being 
communicated  to  a  differential  manometer  (air-speed  indicator  type) 
and  a  reading  being  given  whenever  the  aircraft  turned,  since  in  so 
doing  it  introduced  centrifugal  forces  which  disturbed  the  balance 
of  the  two  pressures  and  so  gave  a  plus  or  minus  deflection  of  the 
manometer  needle.  The  instrument  works  well,  but  needs  more 
attention  than  the  gyro  device. 

Gyrostats  are  also  used  in  aircraft  as  azimuth  indicators  for 
experimental  or  test  purposes;  they  may  some  day  be  used  as  part  of 
a  gyrostatic  compass,  but  the  necessary  weight  limit  will  make  their 
introduction  for  this  purpose  a  matter  of  some  difficulty. 

Magnetic  Compass. — The  design  of  the  magnetic  compass  as 
applied  to  aircraft  has  in  late  years  undergone  a  marked  improve- 
ment. Quite  early  tests  showed  that  the  compass  should  be  a  liquid 
one,  and  that — to  avoid  the  effect  of  engine  vibrations — the  pivot 
should  be  above  the  cup.  But  most  of  the  early  compasses  had 

periodic  times  of  oscillation  about  equal  to  those  of  the  airplanes  on 
which  they  were  carried,  and  resonance  in  vibration  took  place,  so 
that  when  the  airplane  rolled  even  a  little,  the  compasses  oscillated 
through  considerable  angles.  Moreover,  such  short  compasses  gave 
false  readings  of  a  turn  when  flying  on  any  course  between  N.E. 
and  N.W.  The  simplest  explanation  of  this  phenomenon  (first 
given  by  Keith  Lucas  at  the  Royal  Aircraft  Factory  in  1915)  is  that 
since  in  these  latitudes  the  north-seeking  end  of  a  balanced  magnetic 
needle  tends  to  dip  downwards  it  is  customary  to  add  a  weight  to 
the  south  end  in  order  to  keep  the  compass  card  horizontal.  When 
an  airplane  flying  N.  begins  to  turn  to  starboard  this  little  weight  is 
acted  upon  by  a  centrifugal  force  acting  from  E.  to  W.  and  hence 
tends  to  turn  the  compass  card  also  to  starboard.  An  ideal  compass 
would  remain  pointing  exactly  N.,  and  the  turn  of  the  aircraft  to 
starboard  would  be  noticed  by  the  apparent  motion  of  the  lubber 
mark  from  N.  towards  E.  around  the  compass  card ;  but  if  the  card 
is  also  rotating  in  the  same  direction,  and  at  perhaps  a  greater  angular 
speed  than  the  airplane,  the  lubber  mark  may  appear  to  move 
towards  the  W.,  giving  the  false  impression  of  a  turn  to  port.  Hence 
a  flier  unable  to  see  the  ground  may  infer  quite  wrongly  that  he  is 
turning  to  port  when  he  is  really  turning  to  starboard.  In  order,  as 
he  thinks  to  correct  his  turn,  he  tends  still  more  to  starboard  whereas 
he  really  should  have  turned  to  port.  The  compass  therefore  fails  to 
keep  him  on  a  straight  course.  Many  of  the  earlier  types  of  compass 
had  this  defect,  but  by  making  the  compass  period  very  much  longer 
(as  suggested  by  Keith  Lucas),  or  by  making  the  damping  friction 
very  much  greater  (as  suggested  later  by  Campbell  &  Bennett),  the 
northerly  turning  error  was  either  eliminated  or  greatly  reduced. 
There  is,  however,  a  practical  limit  to  the  length  of  the  periodic  time, 
since  if  this  be  too  great  it  becomes  difficult  to  use  the  compass  for 
ordinary  navigation :  it  is  too  sluggish  in  giving  its  indications.  This 
limit  also  concerns  the  highly  damped — or  aperiodic — compass,  but 
not  in  the  same  degree.  It  is  easier  to  construct  a  good  compass  by 
making  the  degree  of  damping  approach  the  aperiodic  than  in  any 
other  way.  Theory  indicates  that  the  performance  of  compasses  is 
governed  more  by  the  product  of  undamped  periodic  time  and  the 
damping  coefficient  than  by  any  other  equally  simple  factor.  In  the 
early  types  of  compass  both  elements  entering  into  the  product  were 
too  low;  this  was  remedied  by  Keith  Lucas  in  the  one  direction  and 
by  Campbell  &  Bennett  in  the  other.  Actually  it  is  best  to  use  both 
means  subject  always  to  the  limit  of  not  making  the  compass  too 
slow  in  its  movements. 

Air  Speed  and  Height_  Measurements. — The  measurements  of  air 
speed  and  height  are  linked  together,  since  both  depend  on  the 
temperature,  pressure  and  density  of  the  air.  The  usual  form  of  air- 
speed indicator,  first  made  by  M.  O'Gorman  in  1911,  makes  use  of  the 
difference  in  the  air  pressure  in  two  tubes,  one  of  which  has  an  open 
end  facing  the  direction  of  motion,  and  the  other  a  closed  end,  but 
with  a  hole  in  the  side.  In  the  latter  the  static  pressure  is  read,  and 
in  the  former  the  larger  pressure  due  to  the  addition  to  the  static  of 
the  kinetic  effect  of  the  air  speed.  A  simple  instance  of  a  similar 
effect  is  seen  when  a  plank  is  dipped  vertically  into  a  flowing  stream; 
the  surface  facing  up-stream  will  be  wetted  higher  up  than  the  one 
facing  down-stream.  The  difference  in  height  is  a  measure  of  the 
velocity — or  rather  of  the  square  of  the  velocity — of  the  stream.  In 
the  case  of  a  compressible  fluid  like  air  it  also  depends  on  its  density. 
In  fact,  the  reading  of  the  air-speed  indicator  is  proportional  to  the 
product  of  the  density  of  the  air,  by  the  square  of  the  velocity 
through  the  air.  Since  such  instruments  are  always  calibrated  so  as 
to  read  correctly  at  sea  level,  it  follows  that  the  "  indicated  "  air 
speed  will  always  be  less  than  the  true  air  speed  at  altitude.  Thus 
an  aeroplane  travelling  at  140  m.  an  hour  at  a  height  of,  say,  21,000 
ft.  will  only  be  credited  with  100  m.p.h.  on  the  air-speed  indicator. 
Such  indicators  are  therefore  sometimes  provided  with  circular  cal- 
culators around  their  circumferences  to  enable  the  true  air  speed  to 
be  read  for  navigational  purposes.  For  aerodynamic  purposes  such 
corrections  are  quite  unnecessary  since  the  forces  due  to  air  pressure 
acting  on  the  wings,  the  fins,  the  tail  and  all  other  surfaces  will  also 
be  proportional  to  the  product  of  air  density  by  the  square  of  the 
speed,  and  an  instrument  like  the  air-speed  indicator  which  gives  a 
reading  proportional  to  this  product  is,  for  this  purpose,  ideal  and 
needs  no  correction.  So  that,  although  for  purely  navigational 
requirements  it  might  be  thought  advisable  to  introduce  a  type  of 
air-speed  indicator  giving  true  air  speed,  such  action  would  be 
disadvantageous  from  the  purely  flying  point  of  view.  Hence  it  is 
best  to  retain  the  present  instrument  and  to  add  for  navigational 
purposes  a  circular  calculator  to  effect  the  conversion.  The  case  of 
the  aneroid  is  not  entirely  parallel,  but  it  also  needs  a  supplementary 
device  if  the  true  height  is  to  be  read.  Almost  all  altimeters  in  use 
are  based  on  the  pre-flight  aneroid  in  which  the  trade  convention 
was  to  assume  everywhere  an  atmospheric  temperature  of  10°  C. 
Although  this  is  not  widely  out  for  the  average  surface  temperature 
it  is  manifestly  most  incorrect  at  a  height,  since  on  the  average  the 
temperature  falls  by  about  6°  C.  for  every  km.  (3,281  ft.)  of  ascent. 
Thus  at  7  km.  (23,000  ft.)  the  mean  temperature  of  the  atmosphere 
would  be  about  21°  below  the  assumed  steady  level  of  IO°C.;  a 
difference  of  about  7  %,  leading  to  an  over-estimate  of  height  by  the 
same  amount.  This  is  corrected  by  reading  the  temperature  at 
height  on  a  strut  thermometer  and  using  a  circular  calculator  (the 
A.M.L.  height  computer) — as  in  the  case  of  the  air-speed  indicator — 



to  give  the  true  result.   For  surveying  work  an  accurate  measure  of 
the  height  is  of  special  importance. 

Reduction  of  A  stronomical  Observations. — The  traditional  method  of 
maritime  navigation  is  to  employ  logarithmic  tables  for  the  solution 
of  the  spherical  triangle.  The  problem  is:  given  the  declination  of 
the  heavenly  body,  the  latitude  of  the  assumed  position  and  the  hour 
angle  at  the  moment  of  observation,  to  determine  the  corresponding 
altitude  of  the  heavenly  body.  The  difference  between  the  altitude 

To  make  this  calculation  by  means  of  logarithmic  tables  is  simple 
enough  on  board  an  airship,  but  is  not  easily  performed  in  an  aero- 
plane. Nor  is  the  degree  of  accuracy  to  which  the  existing  tables  are 
worked  out  necessary  for  air  navigation.  A  method,  which  was 
tried  in  a  Handley  Page  machine,  was  to  use  the  rectangular  nomo- 
gram  devised  by  d'Ocagne,  but  it  was  found  that  within  the  limits  of 
space  available  it  was  not  possible  to  draw  the  diagram  to  a  suffi- 
ciently large  scale  to  ensure  the  final  answer  being  accurate  withfn 
the  necessary  one  or  two  minutes  of  arc.  (It  is  true  that  the  deter- 
mination of  position  to  within  10  m.  easily  suffices,  but  there  is  not 
infrequently  an  error  of  this  amount  in  the  sextant  observations 
themselves;  and  to  these  unavoidable  errors  of  observation  it  is  not- 
desired  to  add  any  larger  error  due  to  the  process  of  reduction  of 
more  than  one  or  two  miles.)  Trial  was  next  made  of  the  ingenious 
method  suggested  by  Veater  of  employing  a  Mercator  projection  of 
the  sphere  and  using  certain  curves  drawn  thereon  to  solve  the 
spherical  triangle  by  the  equivalent  of  a  rotation  of  the  sphere.  This 
method  gave,  in  small  compass,  a  means  of  attaining  the  accuracy 
desired ;  but  it  was  difficult  to  use  the  curves  without  eye  strain,  and 
the  method  eventually  gave  place  to  the  cylindrical  slide  rule  devised 
by  L.  C.  Bygrave.  The  whole  procedure  is  by  this  last  means  made 
both  simple  and  accurate.  The  advantage  of  the  spiral  scale  of  cylin- 
drical rules  is  that  an  immense  length  of  scale  is  compactly  housed  ;  an 
accuracy  on  this  rule  of  one  or  two  minutes  of  arc  is  easily  attained. 

Directional  Wireless. — During  recent  years  wireless  telegraphy  has 
been  made  use  of  for  the  determination  of  the  position  of  both  sea- 
craft  and  aircraft.  The  invention  followed  from  the  discovery  of  a 
method  by  which  the  direction  from  which  wireless  waves  were 
arriving  could  be  accurately  measured.  An  analogy  would  be 
afforded  were  it  possible  to  determine,  from  the  receipt  of  ripples  at 
the  margin  of  a  pond,  the  direction  of  the  spot  at  which  a  stone  had 
fallen  into  the  water.  It  was  found  that  if  a  rectangular  coil  hap- 
pened to  be  placed  so  as  to  face  the  direction  from  which  the  wireless 
waves  were  travelling,  no  current  would  flow  in  the  coil,  whilst  if  the 
latter  were  placed  "  edge  on,"  it  was  possible  to  detect  an  oscillating 
current  in  the  coil.  In  intermediate  positions,  intermediate  results 
were  obtained.  Once,  therefore,  a  search  coil  of  this  kind  is  mounted 
on  a  vertical  axis  it  can  be  turned  until  the  current  is  either  a  maxi- 
mum or  a  minimum,  and  by  these  means  the  direction  of  the  sending 
station  be  determined.  It  is  true  that  a  station  N.E.,  say,  could  not 
be  distinguished  from  one  to  the  S.W.,  but  other  considerations 
usually  enable  a  right  choice  to  be  made  from  these  two  alternatives. 
In  practice  various  electrical  improvements  have  been  made  on  this 
simple  circuit  but  the  principle  is  the  same;  and  it  is  the  results 
obtained  by  such  means  which  are  of  importance  to  the  navigator. 
The  navigator  will  of  course  require  of  the  wireless  officer  that  W/T 
bearings  so  given  shall  be  "  true,"  and  that  corrections  due  to  any 
possible  bending  of  the  waves  shall  have  been  allowed  for. 

There  are  two  methods  by  which  "  directional  wireless  "  (as  it  is 
termed)  can  be  employed.  The  first  and  simplest  is  by  having  suit- 
able search  coils  mounted  in  wireless  beacons  ashore.  Two  or  more 
of  such  beacons  take  note  of  the  direction  of  the  calling  aircraft,  and 
communicate  with  each  other  so  that  one  of  them  can  plot  on  a  map 
the  several  bearings  which,  by  their  common  point  of  intersection, 
determine  the  position.  This  is  then  communicated  to  the  aircraft. 
This  plan  has  the  double  disadvantage  that  the  aircraft  is  forced  to 
disclose  its  position,  and  that  the  number  of  messages  sent  out  "  into 
the  air  "  is  thereby  increased.  The  alternative  is  to  mount  the 
search  coil  on  the  aircraft,  and  for  the  latter  to  determine  the  bear- 
ings of  two  or  more  sending  stations,  and  to  do  its  own  position- 
plotting  on  the  chart.  The  latter  alternative  is  usually  preferred, 
but  it  suffers  from  the  difficulty  that  the  bearing  of  the  wave  is  not 
infrequently  altered  immediately  prior  to  receipt  by  the  influence  of 
the  many  flying,  and  other,  wires  forming  part  of  the  structure  of 
the  aircraft.  These  are  called  quadrantal  errors,  and  they  correspond 
to  the  errors  which  would  be  obtained  in  magnetic  compasses  if  devia- 
tion were  not  allowed  for.  A  difficulty  common  to  both  methods  lies 
in  the  bending  of  the  ray's  direction  when  crossing  a  coast  line,  or  the 
boundary  of  day  and  night — such  effects  need  to  be  allowed  for.  The 
plotting  of  wireless  bearings,  whether  in  the  aircraft  or  ashore, 
requires  care.  If,  as  is  usual,  a  Mercator  chart  is  employed,  it  has  to 
be  borne  in  mind  that  straight  lines  on  such  charts  are  not  great 
circles,  and  since  the  waves  travel  along  the  latter  (except  for  the 
disturbances  above  mentioned)  it  is  necessary  to  draw  the  path  of  the 
waves  by  means  of  a  certain  curve,  the  bending  of  which  will  depend 
on  its  distance  from  the  equator.  Approximate  methods  of  doing 
this  are  in  use,  but  the  best  method  (following  Veater)  is  to  make  use 
of  the  Littrow  projection  of  the  sphere  (more  familiarly  known  as 
the  "  Weir  diagram  "). 

Much  work  has  still  to«be  done  before  it  can  be  determined  how 
accurately  the  position  of  an  aircraft  can  be  found  by  means  of 
directional  wireless.  But  it  has  a  great  use  apart  from  position  find- 
ing, since  it  enables  a  straying  aircraft  to  fly  back  to  its  parent  ship 
by  flying  "  home  "  along  the  wave  path.  Its  path  may  not  be  a 
straight  line,  and  it  may  take  some  time  to  make  the  flight,  but  if 
persisted  in  it  is  bound  to  bring  the  craft  home  sooner  or  later. 

World  Flights. — The  famous  world  flights  of  1919  and  1920 
were  the  transatlantic  crossings  by  the  American  flying-boat 
NC4,  by  the  Vickers-Vimy  aeroplane,  and  the  rigid  airship  R34 
(not  forgetting  the  gallant  attempt  of  the  Sopwith  aeroplane) ; 
the  flight  to  Australia  by  a  Vickers-Vimy  aeroplane,  and  the 
several  attempts  to  fly  an  aeroplane  down  the  length  of  Africa. 

In  the  case  of  the  Australia  flight  the  coast  line  was  usually 
followed  and  methods  of  air  pilotage,  as  distinct  from  air  naviga- 
tion, sufficed.  The  African  flights  were  in  part  over  uncharted 
territory,  and  pilotage  alone  did  not  suffice;  both  there  and,  of 
course,  in  the  transatlantic  flights  the  course  was  steered  by 
navigational  methods.  In  the  case  of  the  R34  the  operations 
were  carried  out  by  officers  accustomed  to  the  navigation  of 
naval  ships,  and  in  so  roomy  a  craft  the  work  was  much  more 
easily  arranged  than  in  the  more  compact  aeroplanes  and  flying- 
boats.  Comm.  Mackenzie  Grieve,  the  navigator  of  the  Sopwith, 
stated  that  even  in  his  tiny  aeroplane  he  navigated  by  celestial 
observations  and  found  that  his  position,  as  given  by  his  ob- 
servations of  the  stars,  when  picked  up  after  the  forced  landing 
in  the  sea  was  "  practically  correct." 

The  instruments  available  in  1921  for  navigation  were  much 
more  satisfactory  than  those  in  use  prior  to  1920.  In  future 
world  flights  the  determination  of  position,  course  and  speed 
will  not  only  be  simpler  and  more  speedy,  but  will  also  be  very 
much  more  accurate  than  anything  hitherto  known  in  the  history 
of  air  navigation. 

BIBLIOGRAPHY. — S.  F.  Card,  Navigation  Notes  and  Examples  (igif), 
and  Air  Navigation  Notes  and  Examples^  (1919);  J.  E.  Dumbleton, 
Aerial  Navigation  (1920);  H.  E.  Wimperis,  Primer  of  Air  Navigation 
(1920) ;  Hawker  and  Grieve,  Our  Atlantic  Attempt  (1920). 

(H.  E.  Wi.) 


The  pre-war  legislation  of  individual  States  generally  pre- 
sumed sovereignty  of  the  air,  but  the  doctrine  was  not  finally 
accepted  until  the  World  War.  Thus  in  1911,  at  the  Madrid 
session  of  the  Institute  of  International  Law,  a  resolution  was 
passed  that  "  International  aerial  circulation  is  free,  subject 
to  the  right  of  States  to  take  certain  steps,  which  shall  be  fixed, 
to  ensure  their  security  and  that  of  the  persons  and  property  of 
their  inhabitants."  This  principle  was  modified  in  the  Report 
of  the  Committee  on  Aviation  of  the  International  Law  Asso- 
ciation in  1913:— 

"  It  appears  to  the  Committee  impossible  to  contend  that  accord- 
ing to  existing  International  law  the  air  space  is  free,  nor  do  they 
think  that  States  would  be  willing  to  accept  or  to  act  on  that  view 
of  the  law.  But  they  are  of  the  opinion  that,  subject  to  such  safe- 
guards as  subjacent  States  may  think  it  right  to  impose,  aerial 
navigation  should  be  permitted  as  a  matter  of  comity.' 

Though  in  some  quarters  the  assertion  of  state  sovereignty 
only  up  to  some  prescribed  height  was  advocated,  individual 
States,  and  among  them  Great  Britain,  asserted,  mainly  for 
military  reasons,  their  right  to  close  their  atmosphere  ab- 
solutely (usque  ad  coelum)  to  the  aircraft  of  other  States.  It  was 
the  conflict  of  opinion  between  the  British  and  German  delegates, 
as  to  the  right  of  each  State  to  the  exercise  of  control  and  juris- 
diction in  the  air  space  over  its  territories,  that  prevented  the 
completion  of  an  International  Convention  by  the  conference 
held  in  Paris  in  1910.  By  the  first  British  Aerial  Navigation 
Act  (1911)  power  was  taken  to  prohibit  the  navigation  of  air- 
craft over  prescribed  areas.  In  the  Act  of  1913  this  power  was 
extended  for  the  purposes  of  the  defence  or  safety  of  the  realm 
to  the  whole  or  any  part  of  the  coastline  of  the  United  Kingdom 
and  territorial  waters,  while  the  Statutory  Rules  and  Orders  of 
that  year  limited  the  landing  areas  for  aircraft  coming  from  any 
place  outside  the  United  Kingdom  to  a  comparatively  few  strips 
of  coastline,  and  forbade  foreign  naval  or  military  aircraft  to 
pass  over  or  land  within  any  part  of  the  United  Kingdom  except 



with  express  permission.  By  a  French  decree  of  1913  the  cir- 
culation in  France  of  foreign  military  aircraft  was  forbidden, 
and  the  draft  Franco-German  Agreement  of  1913  practically 
admitted  the  principle  of  the  sovereignty  of  the  air  by  allowing 
each  country  the  right  of  making  such  regulations  as  it  pleased 
for  flights  above  its  own  territory. 

From  the  beginning,  therefore,  air  sovereignty  and  air  legis- 
lation were  influenced  by  a  predominantly  military  conception 
of  aviation,  and,  on  the  outbreak  of  war,  the  doctrine  of  the 
freedom  of  the  air  was  doomed.  In  the  words  of  the  Civil  Aerial 
Transport  Committee  in  1918:  "  Since  the  outbreak  of  the  war 
sovereignty  over  the  air  has  been  generally  claimed  and,  except 
by  Germany,  recognized."  During  the  war  neutral  countries 
consistently  regarded  the  passage  of  belligerent  aircraft  over 
their  territory  as  an  unneutral  act. 

Pre-war  legislation  was  in  spirit  and  effect  distinctly  national,  and 
in  Great  Britain  regulations  affecting  the  entry  of  foreign  aircraft 
from  abroad  were  stringent.  In  the  case  of  airships  a  clearance  from 
a  British  consular  officer  was  required,  and  in  the  case  of  aeroplanes 
notice  had  to  be  sent  to  the  Home  Office  giving  the  proposed  place 
of  landing,  time  of  arrival,  and  nationality.  Aircraft  were  forbidden 
to  carry  mails  or  goods  chargeable  upon  importation,  and  before 
departure  were  obliged  to  report  to  an  officer  at  one  of  the  pre- 
scribed landing-places.  Otherwise,  with  the  exception  of  an  Order 
prohibiting  the  navigation  of  aeroplanes  within  four  m.  of  Charing 
Cross  and  of  a  number  of  small  areas  over  which  flying  was  prohibited 
on  military  grounds,  there  was  no  State  regulation  of  flying,  and 
certification  and  other  safety  measures  were  carried  out  by  the  Royal 
Aero  Club,  which  represents  Britain  on  the  Federation  Aeronautique 

A  similar  state  of  things  existed  in  France  until  the  passage  of  the 
Aerial  Navigation  Act  of  1913,  which  was  to  a  considerable  extent 
based  on  the  draft  Convention  of  1910,  and  made  the  owner  of  an 
aircraft  responsible  for  damage  to  property,  provided  for  the  regis- 
tration, marking  and  inspection  of  aircraft,  pilots'  certificates  and 
log  books,  and  prohibited  the  transport  of  foreign  merchandise  or  of 
national  merchandise  unaccompanied  by  papers  testifying  to  its 
French  origin. 

The  only  serious  attempt  to  place  aviation  on  an  international 
civil  basis,  by  the  adoption  of  a  code  of  regulations  common 
to  all  countries,  was  the  draft  Convention  of  1910,  which  dealt 
with  the  nationality  and  registration  of  aircraft,  certificates 
and  licences,  the  admission  of  aerial  navigation  over  the  territory 
of  foreign  States,  customs  and  transportation,  and  rules  of  the 
air.  The  international  aspect  of  aviation  did  not,  however, 
completely  die  with  the  failure  of  the  Convention  to  materialize. 
The  Institute  of  International  Law,  in  its  session  of  1911,  adopted 
rules  distinguishing  aircraft  as  public  and  private,  confining  an 
aircraft  to  one  nationality,  i.e.  that  of  the  country  in  which  it 
was  registered,  and  imposing  identification  marks.  Another 
step  in  international  air  traffic  was  the  Franco-German  Agree- 
ment of  1913  permitting  the  entry  of  civil  aircraft  into  each 
country  subject  to  the  conditions  that  machines  were  provided 
with  navigation  licences  and  distinctive  identification  marks, 
that  the  fliers  were  provided  with  proficiency  and  nationality 
certificates,  and  that  the  requirements  of  international  law 
and  the  customs  and  air  regulations  of  each  country  were 

In  England  in  1913  the  Convention  of  1910  was  reconsidered 
by  a  sub-committee  of  the  Committee  of  Imperial  Defence;  and 
when  the  advance  in  flying  during  the  war  indicated  the  great 
potentialities  of  aircraft  for  civil  transport,  a  Civil  Aerial  Trans- 
port Committee  under  the  chairmanship  of  Lord  Northcliffe 
was  appointed  by  the  Air  Board  in  1917  to  consider  the  whole 
subject,  both  from  its  international  and  national  aspects.  It 
was  not,  however,  until  after  the  Armistice  that  the  first  steps 
were  taken  by  a  departmental  committee  of  the  Air  Ministry 
to  frame  regulations  for  civil  flying  in  Great  Britain.  Shortly 
after,  the  drafting  of  a  Convention  governing  international  civil 
flying  was  included  in  the  work  of  the  Peace  Delegates  at  Paris — 
the  coordination  of  the  British  proposals  therewith  being  under- 
taken by  Sir  Frederick  Sykes,  and  took  shape  as  the  Interna- 
tional Air  Convention,  which  was  signed  by  the  majority  of  the 
Allied  and  Associated  Powers  on  Oct.  13  1919,  though  up  to 
Aug.  1921  ratification  was  not  yet  complete. 

The  objects  aimed  at  by  the  Convention  are  the  encourage- 

ment of  the  peaceful  intercourse  of  nations  by  means  of  air  inter- 
communication, and  the  establishment  of  a  broad  basis  upon 
which  a  uniform  procedure  for  the  control  of  air  traffic  can  be 
drawn  up  by  the  contracting  States. 

The  parties  to  the  Convention  recognize  the  exclusive  sover- 
eignty of  every  Power  over  the  air  space  above  its  own  territory  and 
territorial  waters  and  those  of  its  colonies,  and  while  each  contract- 
ing State  allows  freedom  of  innocent  passage  above  its  territory, 
except  over  certain  areas  prohibited  for  military  reasons,  to  the  air- 
craft of  other  contracting  States,  it  may  not,  except  by  a  special 
temporary  authorization,  permit  the  flight  above  its  territory  of 
aircraft  belonging  to  non-contracting  States  (Article  5). 

Every  aircraft  of  a  contracting  State  has  the  right  to  cross  the  air 
space  of  another  State  without  landing,  subject  to  following  the  route 
fixed  by  the  State,  but  if  it  passes  from  one  State  into  another  it  must 
land,  if  required  to  do  so  by  the  regulations,  at  an  appointed  aero- 
drome. Every  State  has  the  right  to  establish  reservations  and 
restrictions  in  favour  of  its  national  aircraft  in  connexion  with  the 
carriage  of  persons  and  goods  for  hire  between  two  points  in  its 
territory  but  is  liable  to  reciprocity  on  the  part  of  other  States.  Any 
aerodrome  in  a  contracting  State  open,  on  payment  of  charges,  to 
public  use  by  its  national  aircraft,  is  likewise  open  to  the  aircraft  of 
all  the  other  contracting  States. 

Aircraft  engaged  in  international  navigation  must  be  provided  by 
the  State  whose  nationality  it  possesses  with  certificates  of  registra- 
tion and  airworthiness,  certificates  of  competency  and  licences  for  the 
crew,  which  must  be  recognized  as  valid  by  the  other  States,  a  list  of 
passengers,  and,  if  freight  is  carried,  bills  of  lading,  log  books  and  a 
special  licence  for  any  wireless  equipment  carried. 

The  Convention  forbids  the  carriage  by  aircraft,  engaged  in  inter- 
national navigation,  of  explosives,  arms  and  munitions  of  war.  All 
private  aircraft,  i.e.  aircraft  which  are  not  used  for  military  pur- 
poses, or  employed  exclusively  in  State  service,  are  subject  to  the 
provisions  of  the  Convention. 

A  series  of  annexes  to  the  Convention  give  detailed  regulations 
with  regard  to  the  marking  of  aircraft  (Annex  A),  certificates  of  air- 
worthiness (Annex  B),  log  books  (Annex  C),  lights  and  signals  and 
rules  of  the  air  (Annex  D),  pilots'  and  navigators'  certificates 
(Annex  E),  maps  and  ground  markings  (Annex  F),  the  collection 
and  dissemination  of  meteorological  information  (Annex  G)  and 
customs  (Annex  H). 

The  Convention  provides  for  the  establishment  of  a  permanent 
International  Commission  of  Air  Navigation,  affiliated  to  the  League 
of  Nations,  consisting  of  two  representatives  of  the  United  States. 
France,  Italy  and  Japan,  one  representative  of  Great  Britain  and 
each  of  the  British  Dominions  and  India,  which  are  deemed  States 
for  the  purposes  of  the  Convention,  and  one  representative  of  each 
of  the  other  contracting  States,  for  carrying  out  the  terms  of  the 
Convention  and  the  interchange  of  information. 

Disagreements  among  States  as  to  the  interpretation  of  the  Con- 
vention and  technical  regulations  are  to  be  settled  respectively  by 
the  Permanent  Court  of  International  Justice  and  a  majority  of 
votes  of  the  Commission.  A  State  which  took  part  in  the  war  of 
1914-9  but  which  is  not  a  signatory  of  the  Convention  may  only 
adhere  to  it  if  a  member  of  the  League  of  Nations,  or,  until  Jan.  I 
1923,  if  its  adhesion  is  approved  by  the  Allied  and  Associated 
Powers,  or  after  that  date  if  it  is  agreed  to  by  at  least  three-fourths  of 
the  signatory  States. 

States  which  remained  neutral  during  the  war  have  not  availed 
themselves  of  the  Article  permitting  their  adhesion  to  the  Conven- 
tion, mainly  owing  to  the  restriction  placed  by  Article  5  on  their 
intercourse  by  air  with  late  enemy  States.  To  overcome  this  diffi- 
culty, a  Protocol  was  subsequently  added  to  the  Convention 
permitting  certain  derogations  to  Article  5  and  authorizing  the 
contracting  States  profiting  thereby  to  allow,  for  a  limited  period 
of  time,  the  aircraft  of  one  or  more  named  non-contracting  States  to 
fly  over  its  territory. 

The  above  Convention  of  1919,  the  charter  of  international 
flying,  may  be  regarded  as  prescribing  the  minimum  control 
required  from  contracting  States.  There  is  no  reason  why  States 
should  not  make  their  regulations  more  stringent  for  their  own 
aircraft  in  the  interests  of  safety  and  efficiency.  The  harmoniza- 
tion of  the  regulations  enforced  by  the  contracting  States  will 
undoubtedly  form  an  important  part  of  the  functions  of  the  Inter- 
national Commission  of  Air  Navigation. 

During  1919-20  a  large  number  of  countries,  including,  among 
others,  Great  Britain,  France,  Belgium,  Spain,  the  Scandinavian 
kingdoms,  Holland,  Italy,  Switzerland  and  Germany,  passed  regula- 
tions more  or  less  in  accordance  with  the  requirements  of  the  Con- 
vention, though  in  most  cases  frequent  additional  Acts  or  Decrees, 
embodying  modifications  in  the  original  regulations,  have  been 
found  necessary  to  secure  stricter  conformity  with  the  Convention. 
Thus  the  British  Aerial  Navigation  Act  of  1919,  and  the  Regulations 
issued  by  its  authority  which  were  influenced  by,  but  actually  pre- 
ceded, the  signature  of  the  Convention  were  only  temporary,  and 
were  superseded  by  the  Air  Navigation  Act  of  1920. 



The  Act  of  1920  asserts  absolute  sovereignty  over  all  parts  of  His 
Majesty's  dominions  and  adjacent  waters,  provides  for  the  applica- 
tion of  the  Convention  by  Order  in  Council  to  internal  flying,  the 
regulation  of  civil  Hying  and  the  supplementing  of  the  Convention, 
as  necessary,  by  general  safety  regulations.  It  authorizes  any  steps 
to  be  taken  for  preventing  aircraft  from  flying  over  prohibited  areas 
or  entering  the  British  Isles  in  contravention  of  the  law,  and  permits 
the  extension  of  the  provisions  of  the  Act  to  British  Possessions  other 
than  the  Dominions  and  India.  The  Act  also  provides  for  the  pro- 
hibition of  all  Hying,  and  the  taking  over  of  aircraft,  etc.,  in  time  of 
emergency;  the  establishment  and  maintenance  of  aerodromes  by 
the  Air  Council  or  local  authorities;  purchase  of  land;  compulsory 
investigation  of  accidents;  and  penalties  for  dangerous  flying.  No 
action  lies  in  respect  of  trespass  or  nuisance  by  reason  of  the  flight 
of  aircraft  over  any  property  at  a  reasonable  height  above  the 
ground,  or  the  ordinary  incidents  of  such  flight,  so  long  as  the  pro- 
visions of  the  Act  and  Orders  made  thereunder  are  complied  with, 
but  where  damage  is  caused  by  aircraft,  damages  may  be  recovered 
from  the  owners  of  the  aircraft.  The  law  relating  to  wreck  and 
salvage  at  sea  applies  to  aircraft  in  the  same  way  as  to  vessels. 

Administration.  —  The  methods  of  administration  adopted  in 
Great  Britain  in  conformity  with  the  Air  Navigation  Acts  were 
probably,  in  1921,  in  advance  of  those  in  other  countries,  but 
they  might  be  regarded  as  typical  of  what  would  be  required, 
at  least  in  the  near  future,  before  aircraft  could  be  operated 
by  companies  or  private  individuals  in  accordance  with  the  terms 
of  the  International  Air  Convention.  Their  essential  points  are 
given  below. 

(i)  Registration  of  Aircraft.  —  Every  aircraft  must  possess  a  certifi- 
cate of  registration,  which  lapses  on  change  of  ownership. 

(ii)  Licensing  of  Personnel.  —  For  a  private  pilot's  licence  the  Royal 
Aero  Club  certificate  is  accepted  as  a  certificate  of  competency,  the 
Club  having  agreed  to  bring  their  tests  for  this  certificate  into  line 
with  those  laid  down  in  the  International  Air  Convention.  A  person 
qualified  as  an  R.A.F.  pilot  is  entitled  to  a  private  pilot's  licence. 
For  a  licence  to  fly  a  passenger  or  goods  aircraft  for  hire  or  reward 
an  applicant  must  undergo  a  medical  examination,  pass  certain 
practical  flying  tests  and  a  technical  examination,  submit  proof  of 
reasonable  flying  experience  within  the  previous  six  months  on  the 
class  of  machine  for  which  a  licence  is  required,  and  pass  an  exam- 
ination in  navigation  and  elementary  meteorology.  In  the  case  of 
applicants  who  are  qualified  as  R.A.F.  pilots  the  tests  are  limited  to 
an  examination  in  navigation  and  meteorology.  Licences  are  issued 
for  six  months.  There  are  five  grades  of  licences  for  navigators. 
Aerial  navigators,  fourth-class,  are  licensed  only  to  navigate  civil 
aircraft  over  land  by  day,  those  qualified  for  the  third-class  certificate 
are  licensed  to  navigate  only  over  land  by  day  or  night,  whjlst  those 
attaining  the  higher  classes  are  licensed  to  navigate  over  both  land 
and  sea  by  day  or  night.  Licences  for  ground  engineers,  usually 
valid  for  twelve  months,  are  granted  for  the  inspection  and  main- 
tenance or  overhaul  of  aircraft  or  engines. 

(iii)  Airworthiness.  —  In  order  that  an  aircraft  may  receive  a 
certificate  of  airworthiness,  its  design,  including  the  design  of  its 
components,  must  be  approved  as  satisfying  the  requirements  of 
safety  in  regard  to  both  strength  and  stability;  it  must  be  con- 
structed of  approved  materials  and  by  workmanship  of  approved 
quality,  and  its  engine  must  be  approved. 

In  order  that  such  certificate  may  be  valid  on  any  particular 
occasion  the  aircraft  must  be  examined  before  flight  and  be  periodi- 
cally overhauled  by  a  competent  person  duly  licensed;  it  must  be  so 
loaded  that  its  total  weight  does  not  exceed  a  given  maximum,  and 
its  centre  of  gravity  must  be  situated  within  certain  given  limits. 
If  the  application  for  a  certificate  is  in  respect  of  a  "  type  "  aircraft, 
inspection  is  carried  out  by  representatives  of  the  Aeronautical 
Inspection  Directorate,  and,  in  addition,  such  drawings  and  par- 
ticulars are  required  to  be  furnished  to  the  Director  of  Research,  as 
will  enable  him  to  approve  the  design.  In  the  case  of  "  subsequent  " 
aircraft  constructed  by  a  firm  whose  inspection  is  approved,  sole 
responsibility  lies  with  the  Aeronautical  Research  Directorate,  the 
constructor  insuring  that  the  conditions  governing  the  inspection  of 
"  type  "  aircraft  are  applied  to  "  subsequent  "  aircraft.  A  certificate 
of  airworthiness  is  not  valid  unless  the  aircraft  concerned  is  regu- 
larly inspected  by  a  licensed  ground'  engineer  employed  by  the 
owner  of  the  machine. 

(iv)  Aerodrome  Licences.  —  The  regulations  for  aerodrome  licences 
are  framed  to  insure  that  only  those  aerodromes  which  are  safe  for 
passenger  work  receive  licences. 

The  dimensions  laid  down  as  a  preliminary  guide  for  the  classifica- 
tion of  aerodromes  are  as  follows:  — 
800  yd.  run  in  any  direction, 

with  good  approaches,  etc.    Suitable  for  any  type  of  aircraft. 

Suitable  for  all  but  the  larger  types 
of  aircraft,  i.e.  not  suitable  for 
H.P.V.  1,500. 

.  .  Suitable  as  permanent  aerodrome  for 
aircraft  of  Avro  5O4.K  or  similar 

600  yd 

300  yd.  by  400  yd. 

300  yd.  run  in  any  direction     .   Temporary     aerodrome     for     Avro 

5O4K  and  similar  types. 

Any  aircraft  may  use  a  licensed  aerodrome  of  the  appropriate 
class,  subject  to  the  payment  of  the  landing  and  housing  fees 
approved  at  the  time  of  the  issue  of  the  licence. 


(i)  Air  Ports,  (a)  Aerodromes. — The  early  aerodromes  were 
usually  any  large,  level  grass  fields,  and  the  first  real  aerodromes 
were  established  in  France,  England,  Germany  and  America. 
Their  early  equipment  consisted  only  of  rough  sheds  for  aero- 
planes, and  fliers  carried  out  at  the  local  smithy  or  garage  such 
repairs  as  could  not  be  done  on  the  spot  or  in  their  own  homes. 
Repair  shops  were  only  available  at  a  very  few  of  the  military 
flying  grounds.  As  aeroplanes  became  more  numerous,  work- 
shops equipped  with  power-driven  machinery  were  established 
at  large  aerodromes  such  as  Farnborough  and  Hendon,  and  the 
occupations  of  "  aeroplane  mechanic  "  and  "  aeroplane  rigger  " 
were  defined.  With  the  increase  of  flying,  certain  rules  were 
laid  down  for  the  control  of  aerodromes;  aeroplanes  were  not 
allowed  to  be  moved  about  the  aerodrome  without  ascertaining 
that  they  were  clear  of  other  craft  alighting,  and  when  in  the 
air  in  the  vicinity  of  aerodromes,  were  obliged  to  conform  to 
circuit  rules,  i.e.  machines  were  made  to  circle  round  an  aero- 
drome in  one  direction,  which  was  indicated  by  a  coloured  flag 
hoisted  in  a  prominent  position;  and  some  form  of  indicator, 
such  as  a  smudge  fire,  was  used  to  afford  pilots  a  guide  to  the 
direction  of  the  surface  wind. 

From  these  simple  rules,  the  complex  system  of  aerodrome 
control  which  developed  during  the  World  War  was  built 
up.  While  the  original  principles  of  aerodrome  management 
remained  the  same  as  in  1914,  new  inventions  produced  much 
greater  efficiency.  With  the  advent  of  night  flying  new  methods 
of  visual  signalling  were  adopted  (see  below) ;  the  bucket  flares, 
used  at  the  beginning  of  the  war  to  indicate  wind  direction,  were 
replaced  by  electric  lights  or  the  "  Money  "  flare;  and  a  stand- 
ardized system  was  introduced  to  permit  of  machines  leaving 
and  arriving  at  an  aerodrome  in  quick  succession  both  by  day 
and  night. 

The  results  of  the  experience  'accumulated  during  the  war  in 
the  control  of  aerodromes  were  embodied  after  the  war  in  Annex 
D  of  the  International  Air  Convention. 

According  to  the  regulations  laid  down  therein,  every  aerodrome 
consists  of  three  zones  looking  up-wind:  a  right-hand  or  taking-off 
zone,  a  left-hand  or  landing  zone  and  a  neutral  zone.  At  night  the 
taking-off  and  landing  zones  are  marked  by  white  lights  placed  in 
the  position  of  an  "  L,"  as  shown  in  fig.  25. 


FIG.  25. 

An  aeroplane  must  land  as  near  as  possible  to  the  neutral  zone, 
but  on  the  left  of  any  aeroplanes  which  have  already  landed,  and 
immediately  taxi  into  the  neutral  zone.  No  aeroplane  may  com- 
mence to  take  off  until  the  preceding  aeroplane  is  clear  of  the  aero- 
drome. A  flag  is  hoisted  in  a  prominent  position  to  indicate  whether 
an  aircraft  which  finds  it  necessary  to  do  so  should  make  a  left- 
handed  (red  flag)  or  right-handed  (white  flag)  circuit.  Aeroplanes 
must  comply  with  this  rule  within  500-1,000  metres  of  the  nearest 
point  of  the  aerodrome  unless  flying  at  a  height  above  2,000  metres. 
The  direction  of  the  wind  must  be  clearly  indicated,  and  aeroplanes 
must  take  off  or  alight  up-wind,  those  flying  at  a  greater  height 
being  responsible  for  avoiding  those  at  a  lower.  Aeroplanes  in  dis- 



tress  are  given  free  way  in  attempting  to  land.  At  night  suitable 
markings  are  required  on  all  fixed  obstacles  dangerous  to  flying 
within  a  zone  of  500  metres  of  an  aerodrome. 

The  London  terminal  aerodrome  at  Croydon,  Sur.,  may  be 
taken  as  typical  of  a  modern  air-port  for  commercial  traffic. 
It  consists  of  a  level  grass  field  900  yd.  long  by  800  yd.  wide, 
and  is  equipped  with  a  continental  arrival  and  departure  station, 
a  customs  office,  repair  shops  and  stores,  aeroplane  hangars 
and  the  private  offices  of  companies  engaged  in  air  and  road 
transport.  An  indicator,  consisting  of  a  conical  linen  bag,  painted 
in  conspicuous  colours  and  attached  to  a  mast,  shows  the  direc- 
tion of  the  wind  by  day;  and  the  movements  of  machines  are 
directed  from  a  control  tower.  Along  the  south  side  of  the 
aerodrome  the  name  Croydon  is  let  into  the  turf  in  chalk  letters 
of  30  ft.,  legible  from  a  height  of  10,000  feet.  For  the  assistance 
of  night  flying  an  aerial  lighthouse  shows  the  position  of  the 
aerodrome,  while  a  searchlight  distinguishes  the  aerodrome  from 
its  surroundings  and  illuminates  the  path  of  the  machines. 
Electric  lights  are  sunk  into  the  ground  to  indicate  the  direction 
of  the  wind  for  landing.  A  wireless  transmitting  and  receiving 
station  is  installed  capable  of  telegraphic  communication  with 
ground  stations  within  400  miles  and  aircraft  within  200  miles, 
and  of  telephonic  communication  within  200  and  100  miles 

(b)  Coastal  Stations. — A  sheltered  stretch  of  water,  usually  an 
inland  lake,  was  selected  by  the  pioneers  of  hydro-aviation,  a 
sloping  beach,  a  rough  shed  and  one  or  two  small  boats  being 
the  only  other  requirements.    The  equipment  of  the  English 
station  at  Lake  Windermere,  the  scene  in  1911  of  the  first  take- 
off and  landing  on  water  by  a  British  aeroplane,  was  almost 
negligible,  and  it  was  not  until  1913  that  the  first  organized 
seaplane  stations  came  into  existence.  The  management  of  these 
stations  is  very  similar  to  that  of  an  aerodrome,  with  the  excep- 
tion of  slipways  up  and  down  which  aircraft  are  moved  on  leav- 
ing and  entering  the  water,  mechanical  power  for  hauling  heavy 
machines,  and  wheeled  trucks  to  move  them  about  on  shore. 
At  most  of  the  early  stations,  however,  man-power  was  sufficient 
to  move  machines,  which  were  small  and  light,  up  and  down  the 
sloping  beaches,  while  the  pilot  was  carried  to  and  from  his  sea- 
plane while  it  was  still  afloat. 

The  first  British  flying-boat  was  produced  in  1912,  but  it  was 
not  until  1915  that  the  larger  boats  were  sufficiently  developed 
to  enable  them  to  stay  out  on  the  water  for  days  at  a  time. 
This  development  caused  a  corresponding  expansion  in  the 
organization  of  seaplane  bases.  Launches  and  rowing-boats, 
used  previously  to  assist  machines  in  difficulties,  became  ferry- 
boats for  taking  fuel,  stores,  and  personnel  to  and  from  the 
large  flying-boats  which  were  moored  out  to  buoys  in  sheltered 
waters  adjacent  to  the  coastal  stations.  The  organization  and 
management  of  these  depots,  until  the  formation  of  the  Royal 
Air  Force  in  1918,  was  modelled  on  that  of  H.M.  ships. 

Calshot,  Hants.,  was  in  1921  the  most  up-to-date  coastal  station 
in  Great  Britain ;  the  sheltered  area  of  Southampton  Water  provides 
ample  sea  room  for  craft  getting  off  and  alighting,  while  the  narrow 
promontory  on  which  Calshot  Castle  stands,  almost  surrounded  by 
water,  allows  of  numerous  slipways  for  the  handling  of  machines  in 
and  out  of  the  sea  at  most  states  of  the  tide.  Repair  shops,  sheds 
and  living-quarters  occupy  a  large  area  ashore;  boat  seaplanes, 
which  are  gradually  replacing  float  seaplanes  for  all  but  special 
purposes,  are  moored  out  in  a  backwater;  launches  and  rowing-boats 
are  moored  alongside  a  small  pier,  and  trucks  of  special  construction 
are  held  in  readiness  on  the  beach  to  move  craft  about  on,  when  they 
have  been  hauled  up  the  slipways  by  electric  power  capstans. 

(c)  River  Stations. — The  value  of  river  stations  lies  in  the  fact 
that  they  can  be  located  in  the  centre  of  many  large  cities,  and 
passengers  by  air  can  thus  save  the  time,  now  lost,  in  reaching 
aerodromes  necessarily  situated  on  the  outskirts.   River  stations 
were  still  in  1921  in  an  experimental  stage,  but  stations  on  the 
Thames,  the  Seine  and  the  Spree  will  probably  be  developed  to 
serve   the   three   capitals — London,   Paris  and   Berlin — which 
are  already  important  airline  termini. 

(d)  Airship  Harbours. — In  the  early  days  of  airships  any 
convenient  open  space,  such  as  a  parade  ground  or  moorland, 
was  utilized,  but  as  their  size  increased  stations  were  selected 
so  as  to  afford  shelter  from  the  wind,  accessibility  by  air  and 

road,  suitable  accommodation  for  personnel,  and  privacy.  In 
1909  the  Royal  Aircraft  Factory,  then  called  the  Balloon 
Factory,  -Farnborough,  was  used  for  the  first  airship  flights  in 
England,  and  in  1912-3  it  was  provided  with  an  elementary 
mooring  mast.  This  station  was  abandoned  in  1915.  After  the 
outbreak  of  the  World  War  large  airship  harbours  and  construc- 
tion stations  were  erected  in  many  parts  of  the  United  Kingdom, 
thus  following  on  the  far  greater  development  in  Germany. 

The  first  sheds  for  the  housing  of  airships  were  comparatively 
small  and  constructed  of  various  materials,  such  as  canvas,  wood 
or  corrugated  iron.  As  the  development  of  the  airship  progressed 
these  were  superseded  by  sheds  about  750  ft.  long,  built  of  cor- 
rugated iron  on  iron  girders,  and  capable  of  accommodating 
two  large  rigid  airships  and  several  smaller  non-rigid  types.  The 
annexes  of  the  sheds  contained  all  the  requisite  workshops  for 
engineering,  carpenter  and  fabric  work  as  well  as  stores  for 
general  equipment  and  laboratories  for  research. 

The  development  of  the  airship,  however,  was  so  rapid  that 
it  was  not  possible  to  keep  pace  with  the  construction  of  airship 
stations,  which  entailed  considerable  labour  and  expense.  For 
this  reason  other  schemes  for  housing  had  to  be  devised. 

The  first  method  for  small  airships  was  a  reversion  to  the  early 
one  of  "  housing  "  them  under  natural  shelter,  but  it  had  the 
disadvantage  that  the  airship  fabric  rapidly  deteriorated  by 
constant  exposure. 

Owing,  however,  to  the  length  of  rigid  airships  it  was  im- 
possible to  dock  them  in  this  manner.  Experiments  were  accord- 
ingly made  for  mooring  them  in  the  open  by  the  three-wire 
system  (see  AIRSHIPS,  Section  9).  This  was  superseded  by 
reversion  to  the  mooring  mast,  which  proved  so  successful  that 
a  large  mast  was  erected  at  Pulham,  where  the  first  attempt 
was  made  in  England  to  organize  an  airship  harbour  for  com- 
mercial traffic,  and  the  largest  airships  have  been  moored  to  it 
for  long  periods  and  in  high  winds.  The  adoption  of  the  mooring 
mast  has  enabled  the  sheds  to  be  mainly  used  for  the  housing 
of  airships  for  the  purpose  of  overhaul  and  repair,  and  has  re- 
duced the  personnel  required  for  handling  airships  on  the  ground 
from  an  average  of  about  200-350'  to  an  average  of  eight  men. 

Airship  harbours  have  facilities  for  gassing  airships  with 
hydrogen,  either  from  steel  bottles  or  by  manufacture  on  the 
spot  by  the  water-gas  process. 

(ii)  Signals. — The  methods  for  effecting  communication  with 
aircraft  are  ground  signals,  such  as  flags,  pennants  and  ground 
strips;  smoke  signals-,  rockets,  flares,  flash  lamps  and  search- 
lights; and  wireless  telegraphy  (latterly  also  wireless  telephony). 

Visual  signals  for  indicating  wind  direction  and  landing- 
grounds  date  from  the  birth  of  flying,  while  flash  lamps,  flares 
and  rockets  have  long  been  used  at  night,  or  in  fog.  Ground  strips 
of  cloth  or  canvas,  which  are  generally  white  on  one  side  and 
black  on  the  other  so  as  to  show  up  against,  dark  and  light  back- 
grounds respectively,  were  placed  in  varying  positions,  according 
to  a  pre-arranged  code.  The  flash  lamp  using  Morse  code  was 
a  little  used  prior  to  the  World  War,  whilst  the  flier  dropped 
written  messages  in  a  weighted  bag  attached  to  coloured 
streamers  or  a  white  parachute;  early  in  the  war  the  signalling- 
lamp  (involving  a  knowledge  of  Morse  by  both  operators)  was 

Annex  D  of  the  International  Convention  prescribes  that  an  air- 
craft in  the  air,  or  stationary  upon  land  or  water,  but  not  anchored, 
shall  carry  forward  and  at  the  rear  a  white  light,  on  the  right  side  a 
green  light,  and  on  the  left  a  red  light.  These  lights,  which  are 
visible  at  varying  dihedral  angles  and  distances,  are  fixed  so  that 
only  one  can  be  seen  at  a  time.  On  airships  all  lights  are  doubled.  An 
aircraft  when  on  the  surface  of  the  water,  and  not  under  control,  dis- 
plays two  red  lights  visible  all  round  the  horizon.  When  moored,  but 
not  near  the  ground,  the  airship,  the  mooring-cable  and  the  object 
to  which  it  is  moored  are  marked  by  lights  or  streamers. 

An  aircraft  wishing  to  land  at  night  on  an  aerodrome  fires  a  green 
Very's  light  or  flashes  a  green  lamp,  and  makes  by  international 
Morse  code  the  letter  group  forming  its  call  sign,  permission  being 
given  by  the  repetition  of  the  same  call  sign  from  the  ground  fol- 
lowed by  a  green  light.  It  is  forbidden  to  land  by  the  firing  of  a  red 
light  or  the  display  of  a  red  flare.  If  it  is  compelled  to  land,  a  red  light 
is  fired  from  the  aircraft  and  a  series  of  short  flashes  made  by  the 
navigation  lights.  When  an  aircraft  is  in  distress  it  gives  one  or 
more  of  the  following  signals:  the  international  SOS,  the  inter- 



national  code  flag  signal  of  distress,  a  square  flag  having  either  above 
it  or  below  it  a  ball ;  a  continuous  sounding  with  any  sound  appa- 
ratus; or  a  succession  of  white  Very's  lights.  The  following  signals 
are  used  to  require  an  aircraft  to  land :  by  day,  three  discharges,  at 
intervals  of  10  seconds,  of  a  projectile  showing  on  bursting  black  or 
yellow  smoke;  by  night,  a  similar  projectile  showing  on  bursting 
red  stars  or  lights.  In  fog  and  bad  visibility,  sound  signals  may  be  used. 

From  the  date  of  the  formation  of  the  British  Royal  Flying  Corps 
in  May  1912  the  importance  of  wireless  telegraphy  in  connexion  with 
aircraft  was  fully  recognized,  both  in  the  naval  and  military  wings; 
and  at  a  very  early  period  of  the  World  War  its  superiority  over 
other  methods  of  signalling  from  the  air  was  clearly  demonstrated. 
Standard  patterns  of  instrument  for  naval  and  military  work  were 
gradually  evolved ;  how  reliable  even  these  early  types  were  may  be 
seen  from  the  fact  that  a  few  of  them  are  actually  still  in  use  to-day 
in  a  practically  identical  form.  The  demand  for  the  control  of 
artillery  fire  by  aircraft  became  steadily  greater  until,  at  the  Armis- 
tice, on  the  British  section  of  the  western  front  alone  there  were  over 
600  aeroplanes  and  approximately  1,000  ground  stations  in  use.  AH 
these  machines  were  employing  a  spark  system,  and  with  the 
advent  of  the  long-distance  reconnaissance  and  bombing  squadrons 
with  their  higher-powered  sets  the  need  became  apparent  for 
improvements  allowing  of  less  interference  and,  if  possible,  a  larger 
number  of  machines  working  within  the  same  limits  of  wave  length-. 

The  introduction  in  the  early  part  of  1917  of  the  oscillation- 
valve  continuous-wave  transmitter — an  extremely  light  and 
efficient  instrument  with  a  range  of  100  m.  from  air  to  ground  — 
overcame  these  difficulties  and  opened  up  a  new  vista  with  immense 
possibilities.  Reception  of  ground-station  signals  by  aircraft, 
although  actually  accomplished  by  the  military  wing  at  Farnborough 
as  far  back  as  1913,  became  a  reliably  consistent  proposition.  Air- 
craft, whose  duties  carried  them  over  considerable  distances,  were 
enabled  to  maintain  a  constant  communication  with  their  base,  and, 
what  was  perhaps  more  important,  the  introduction  of  the  con- 
tinuous-wave set  opened  up  the  possibilities  of  the  design  of  an 
efficient  pattern  of  wireless  telephone  capable  of  withstanding  the 
most  rigorous  usage. 

Although  hostilities  terminated  before  the  full  benefits  of  these 
latter  developments  had  become  appreciable,  the  progress  which  has 
since  resulted,  both  in  service  and  civil  aviation,  is  considerable. 
Airways  have  rapidly  sprung  into  being,  and  the  necessity  for 
rapid  signalling  along  the  route,  reporting  arrivals,  departures  and 
delays  of  machines  and  of  communicating  with  the  aircraft  them- 
selves, has  been  responsible  for  the  growth  in  England  of  the  seven 
ground  stations  now  existing,  and,  abroad,  of  the  stations  of  the 
continental  airports.  The  Air  convention  provides  that  every  air- 
craft used  in  public  transport  and  capable  of  carrying  ten  or  more 
persons  shall  be  equipped  with  sending  and  receiving  wireless 
apparatus,  and  to-day  most  of  the  passenger-carrying  aeroplanes  of 
the  London-Paris  and  other  continental  routes  are  equipped  for  the 
transmission  and  reception  of  wireless  telephony,  and  are  thus 
enabled  to  keep  in  touch  with  the  ground  throughout  their  flight. 
On  several  occasions  during  the  year  1921  telephone  conversation 
was  carried  out  direct  between  a  passenger  flying  between  London 
and  the  Continent  and  a  friend  in  his  own  home  or  office  in  London; 
the  line  telephone  being  used  as  far  as  the  aerodrome  station  at 
Croydon,  and  thence  being  relayed  by  wireless  telephone  to  the 

Another  important  war  development,  now  becoming  more  and 
more  extensively  used,  which  was  the  outcome  of  the  determination 
of  the  direction  of  passage  of  electro-magnetic  waves,  is  the  system 
of  navigation  by  "  direction  finding,"  or  "  radiogoniometry."  By 
this  system  two  or  more  ground  stations  can  detect  the  position  of  ah 
aircraft  using  wireless  telegraphy  or  telephony,  and  can  pass  that 
information  direct  to  it  within  a  few  seconds. 

The  converse — an  aircraft  taking  the  bearing  by  W/T  of  two  or 
more  W/T  stations  on  the  ground  can  plot  her  own  position,  and  thus 
enable  the  navigator  to  settle  his  position  without  asking  for  any 
information  from  the  ground  stations.  This  method  is  still  in  its 
infancy,  but  will  undoubtedly  prove  of  value  to  aerial  navigation. 

(iii)  Weather  Information. — The  value  of  the  collection  and 
distribution  of  meteorological  information  for  the  assistance  of 
aeronautics  was  early  recognized,  notably  in  Germany.  In 
England  in  1909  the  Meteorological  Office  was  represented  on 
the  Advisory  Committee  for  Aeronautics;  in  1010  a  meteoro- 
logical station  was  started  at  the  Royal  Aircraft  Factory,  and 
in  1912  at  the  Central  Flying  School  at  Upavon;  both  of  these 
eventually  prepared  daily  weather  charts,  and  were  the  pre- 
cursors of  the  present  local  distributive  stations.  During  the 
war  meteorological  services  developed  under  the  War  Office  and 
the  Admiralty,  a  portion  of  the  service  under  the  Admiralty 
being  transferred  in  1918  to  the  Air  Ministry.  In  1919-20  all 
branches  of  the  Meteorological  Service  were  coordinated  and 
attached  to  the  Air  Ministry. 

The  information  required  for  air  traffic  to-day  consists  of  existing 
weather  conditions  on  any  route,  or  landing-ground  forecasts  and 

warnings.  General  information  as  to  weather  conditions  is  provided 
by  the  Daily  Weather  Service  of  the  Meteorological  Office,  which 
receives  information  by  wireless  telegraph  or  telephone  four  times 
daily  from  a  network  of  observing-stations  throughout  the  British  Isles. 
The  reports  obtained  from  these  are  issued  collectively  in  the  form 
of  synoptic  messages  four  times  daily,  and  are  available  to  anyone 
within  wireless  range  either  in  the  British  Isles  or  European  countries, 
while  the  latter  distribute^their  local  information  in  a  similar  manner. 
According  to  the  code  drawn  up  by  the  International  Commission 
for  Weather  Telegraphy  the  information  transmitted  to  the  Central 
Office  in  these  reports  consists  of  surface  conditions,  atmospheric 
pressure,  wind,  general  state  of  the  weather,  temperature,  visibility, 
humidity,  cloud,  rainfall,  upper-air  conditions,  etc.,  the  observations 
relating  to  each  element  being  very  detailed.  In  addition  to  the 
above,  reports  and  forecasts  usually  covering  a  period  of  24  hours  are 
issued  four  times  daily  to  each  of  four  Aviation  Weather  Groups  into 
which  the  British  Isles  are  divided.  Warnings  are  issued  from  the 
Central  Office  to  all  flying-centres  when  gales  are  threatened. 

Local  distributive  centres  are  fully  equipped  meteorological 
stations  established  at  certain  important  flying-centres,  especially 
terminals,  and  will  eventually  number  about  twenty.  Their  duties 
include  local  observation  and  the  issue  of  special  information  to  the 
Aviation  Services  within  their  area.  The  establishment  of  a  regular 
air  service  such  as  that  between  London  and  Paris  entails  a  distribu- 
tive station  at  each  terminus,  subsidiary  observing-stations  along  the 
route,  and  the  hourly  distribution  of  information.  While  in  the  air 
the  flier  can  obtain  information  as  to  the  weather  in  front  of  him  by 
wireless  telephony  or  from  ground  signals.  (V.  B.-J.) 


Early  Attempts  at  Flying  from  the  Water. — Among  the  earliest 
aircraft  designed  to  fly  from,  and  alight  on,  the  water  were  a 
French  craft  by  M.  Fabre  (1910),  the  Parseval  monoplane  con- 
structed in  Germany  in  1911,  and  the  Grabadini  monoplane 
tested  at  Monaco  in  1911.  Their  difficulties  were  considerable 
and  their  successes  slight,  but  by  the  end  of  1911  floats  were  sub- 
stituted for  wheels  on  aeroplanes  that  were  already  proved  to  fly; 
thus  in  Oct.  of  that  year  Glenn  Curtiss,  in  America,  flew  from 
the  water  on  a  craft  adapted  from  the  Curtiss  aeroplane  which 
won  the  Gordon  Bennett  Trophy  at  Reims  two  years  before. 
Its  performance  as  a  hydro-aeroplane  suffered  from  the  extra 
weight  and  resistance  of  the  floats.  In  England  the  first  flight 
from  the  water  was  by  Comm.  Swarm,  R.N.,  and  S.  V.  Sippe  on  an 
Avro  biplane  with  35-H.P.  Green  engine  at  Barrowin  Nov.  1911. 

Henri  Fabre's  "  Canard,"  an  original  "pusher  "  monoplane 
with  a  5O-H.P.  Gnome  engine,  made  several  straight  flights  at 
Monaco  in  April  1912,  and  Voisin,  Caudron  and  R.  E.  Pelterie 
thereafter  successfully  equipped  their  standard  aeroplanes  with 
Fabre  floats.  This  float  was  a  fairshape,  rectilinear  in  plan,  and 
made  of  a  wooden  framework  covered  with  proofed  canvas. 
This  type  was  displaced  later  by  pontoon-shaped  floats  covered 
with  3-ply  wood  or  mahogany  planking. 

In  1912  Colliex,  on  a  Voisin  "  Canard  "  equipped  as  an  "  am- 
phibian "  with  both  wheels  and  floats,  left  the  land  at  Issy-les- 
Moulineaux,  and  alighted  on  the  Seine  at  Auteuil.  Donnet  and 
Leveque  in  France  in  1912  built  and  flew  the  first  boat  seaplane, 
a  two-seater  pusher  having  a  central  hull  with  the  engine  above 
the  boat,  sufficiently  high  under  the  plane  for  the  airscrew  to 
clear  the  hull.  The  tips  of  the  lower  plane  carried  small  floats 
to  balance  the  craft  on  the  water,  and  wheels  were  later  fitted 
to  the  hull.  The  high  centre  of  thrust  relative  to  its  centre  of 
gravity,  which  signalized  this  craft,  had  been  demonstrated  in 
1909  by  Bleriot  on  an  aeroplane.  The  design  of  this  boat  generT 
ally  made  it  the  forerunner  of  the  seaplane  of  1921.  In  1912  the 
Royal  Aircraft  Factory  equipped  an  F.E.  biplane  pusher  with 
floats,  and  later  a  tractor  biplane  was  made  there  and  flown  from 
Frensham  Lake  to  Southampton  Water. 

At  the  end  of  1913,  Short  made  a  loo-H.P.  Gnome  tractor 
biplane  waterborne  on  a  single  central  float  and  small  wing  tip- 
floats.  On  the  next  seaplane,  however,  two  floats  were  used  in 
place  of  the  central  float.  These  craft  and  their  successors  proved 
fairly  seaworthy,  and  were  useful  on  naval  manoeuvres.  About 
this  time  the  experience  of  the  shocks  met  with,  when  flying 
from  broken  water,  led  to  the  use  of  rubber  shock  absorbers,  be- 
tween the  floats  and  the  supporting  struts. 

In  America,  following  the  lead  of  Glenn  Curtiss,  several  aeror 
planes  were  fitted  with  pontoons.  Towards  the  end  of  1912 
Curtiss  replaced  the  single  central  pontoon  by  a  boat-shaped 


hull,  which  carried  the  tail  members.  To  protect  the  crew,  a  wood 
and  canvas  superstructure  had  been  built  on  the  fore-part  of  the 
original  pontoon,  making  its  appearance  very  similar  to  that 
of  the  later  Curtiss  flying-boats.  With  experience  this  pontoon 
was  extended  further  aft  to  carry  the  tail  members,  and  so  this 
flying-boat  appears  to  have  been  progressively  evolved. 

In  April  1913  a  prize  of  £10,000  was  offered  by  the  Daily  Mail 
for  crossing  the  Atlantic  in  72  hours,  and  Rodman  Wanamaker 
had  a  two-engined  (2x90  H.P.)  Curtiss  flying-boat,  called  the 
"America,"  made  for  this.  Loaded  to  the  necessary  5,000  Ib. 
gross,  it  could  not  leave  the  water.  With  a  third  engine  it  could 
do  so,  but  the  air  endurance  was  thus  reduced,  and  in  July  1914 
the  flight  was  abandoned. 

War  Period. — Up  to  July  1914  seaplane  design  was  thus  very 
backward,  and  its  war  usefulness  to  a  fleet  was  but  little  indicated. 
The  non-existence  of  any  particular  line  of  advance  that  could 
be  systematically  developed  had  adversely  influenced  its  evolu- 
tion. In  England  in  1914  seaplanes  were  used  in  coast-defence 
work,  and  one  seaplane  carrier  was  in  commission.  By  Aug. 
the  carrying  of  aircraft  on  board  ship  had  been  facilitated  by  the 
introduction  of  folding  wings,  and  their  offensive  value  enhanced 
by  the  successful  launching  of  a  locomotive  torpedo  from  the  air. 
This  led  to  the  conversion  of  small  passenger  vessels  into  seaplane 
carriers,  and  soon  the  merits  and  limitations  of  the  float  type 
of  seaplane  were  ascertained.  As  no  launching-  or  landing-deck 
was  available,  the  seaplane  had  to  be  operated  from  the  sea, 
and  this  could  be  undertaken  only  in  very  favourable  weather. 
An  increase  of  air  endurance  and  useful  load  was  achieved,  but 
at  the  expense  of  some  of  the  seaworthy  qualities.  With  a  crew 
of  two,  wireless,  and  about  60  Ib.  of  bombs,  an  endurance  of  two 
to  three  hours  at  70  knots  was  possible. 

By  1915  an  improvement  of  the  same  type  (known  as  the 
"Short  184"),  which  survived  throughout  the  war,  could  carry 
a  heavier  load  for  about  five  hours.  They  were  intended  mainly 
for  duties  with  carrying  ships,  originally  proposed  for  service 
with  the  fleet,  and  with  the  light  cruiser  and  destroyer  squadrons. 
As,  however,  these  "  float  seaplanes  "  lacked  sea-going  qualities, 
and  their  carrier  ships  were  vulnerable,  many  of  the  operations 
intended  for  them  were  abandoned.  They  were  utilized  in  the 
Gallipoli  campaign. 

Air-cooled  rotary  engines,  used  on  the  seaplanes  of  1914  be- 
cause they  gave  the  lightest  weight  for  power  where  weight  was  a 
cardinal  consideration,  soon  proved  unsuitable  at  sea,  and  were 
replaced  by  water-cooled  engines.  "  Float  seaplanes  "  were  also 
employed  with  the  Grand  Fleet  during  the  first  two  years  of  the 
war  for  observation  with  the. fleet  at  sea,  and  patrol,  but  they 
were  handicapped  because  their  sea-going  qualities  were  not 
.  adequate  for  the  bad  weather  prevalent  in  the  Ngrth  Sea.  At 
this  time  only  one  ship  was  provided  with  a  forecastle  deck  large 
enough  to  enable  a  seaplane  to  be  launched  therefrom  on  a  light 
subsidiary  carriage,  thus  avoiding  the  necessity  for  stopping  the 
ship  with  the  attendant  risk  from  submarines,  when  getting  a 
seaplane  into  the  air. 

In  the  absence  of  seaplanes  with  good  sea-going  qualities, 
ordinary  aeroplanes  were  carried  in  fighting-ships  with  a  launch- 
ing-platform.  Latterly  carrier  ships  have  been  evolved  with  an 
alighting-deck  as  well.  This  led  to  the  small  seaplane  not  being 
pressed  forward  in  the  way  the  small  aeroplane  was  by  the  stimu- 
lus of  the  war. 

The  "  Boat  Seaplane." — In  1914  there  was  in  the  British  serv- 
ice a  small  Sopwith  boat  seaplane  fitted  with  wheels  (winner  of 
the  Mortimer  Singer  trophy),  and  also  two  small  French  and 
American  machines.  They  could  not  carry  any  appreciable  load 
nor  could  their  wings  be  folded  for  operation  from  carrier  ships; 
accordingly  they  were  not  then  developed.  'In  July  1914  Lieut. 
Porte,  who  was  engaged  upon  the  twin-engined  boat  seaplane, 
the  "  America,"  previously  mentioned,  was  instrumental  in 
developing  the  modern  "  boat  seaplane."  In  1915  several 
"  Americas  "  with  their  two  go-H.P.  engines  were  delivered  at 
Felixstowe.  Their  performance  was  poor  on  account  of  their 
lack  of  horse-power  for  their  weight;  and  they  were  too  small — 
36  ft.  hull— to  give  good  sea -going  qualities. 

The  much  larger  "  Porte  "  boats  with  their  three  engines  of 
275  H.P.  and  air  endurance  of  8  hours,  a  total  weight  of  about 
8  tons,  and  a  hull  60  ft.  long,  were  laid  down.  The  increase  of 
dimensions  carried  with  it  a  great  improvement  in  sea-going 
qualities,  but  the  air  performance  was  but  little  better,  and  the 
type  was  not  further  developed.  One  H.P.  for  20  Ib.  was  in- 
sufficient power,  and  bigger  engines  for  the  weight  had  to  be  used. 

The  Curtiss  "  H8,"  built  in  America,  was  better  in  this  respect. 
Only  one  of  these  was  made,  but  knowledge  obtained  in  England 
during  its  construction  was  embodied  in  its  successor,  the  "  Hi  2." 
Many  Hi27s,  with  340-H.P.  Rolls-Royce  engines,  were  used  with 
success  against  submarines.  The  Hi2's  weighed  5  tons,  carried 
5  persons  and  500  Ib.  of  bombs  at  80  knots  for  6  hours,  and  were 
armed  with  three  or  four  machine-guns.  They  had  i  H.P.  for 
every  16  Ib.  and  when  first  used  had  a  higher  performance  than 
any  other  sea-going  aircraft  over  the  North  Sea.  They  showed 
that  hydroplaning  efficiency,  previously  regarded  as  cardinal, 
could  be  sacrificed  for  sea-worthiness,  provided  sufficient  engine- 
power  were  available. 

All  the  earlier  types,  including  the  H8  and  the  Hi2's,  were 
practically  flat-bottomed,  and  pounded  heavily  in  disturbed 
water;  the  higher  power  available  in  the  latter  type  enabled  these 
seaplanes  to  take  off  rapidly  and  the  improvement  of  providing 
them  with  a  pronounced  V-section  bottom  was  adopted  first 
on  a  small  "  America,  "  and  then  on  the  H8  with  the  two  Eagle 

This  combination  of  Felixstowe  hull,  H8  wings  with  Rolls- 
Royce  engines  known  as  the  F2  was  the  forerunner  of  all  the 
many  boat  seaplanes  of  the  latter  part  of  the  war.  These  craft, 
one  of  which  is  illustrated  (see  Plate  II.),  corresponded  in  size, 
weight  and  power  to  the  Hi2  type,  but  on  account  of  their  V- 
section  hulls,  were  capable  of  alighting  in,  and  taking  off  from, 
disturbed  water  with  less  risk  of  damage  to  the  hulls.  Their 
effectiveness  against  submarines  led  the  Germans  to  evolve  high- 
performance  two-seater  fighter  seaplanes  of  the  float  type. 
Among  the  most  effective  of  these  were  the  Brandenburg  mono- 
plane seaplanes.  These  remarkable  craft  became  useful  as  a 
menace  to  the  heavier  "  boat  seaplanes,"  and  as  they  were  carry- 
ing only  a  light  machine-gun  load  and  comparatively  little  fuel 
they  out-manoeuvred  them. 

It  has  been  seen  that  the  small  seaplane  that  might  have  count- 
ered these  was  undeveloped  in  England.  The  defensive  arma- 
ment of  the  large  seaplanes  was  increased,  though  such  additional 
load  adversely  affected  their  performance  and  sea-going  qualities. 
Small  two-seater  seaplanes  to  escort  the  larger  ones  were  con- 
structed, but  as  these  were  not  delivered  until  after  the  cessation 
of  hostilities,  the  technical  advantages  to  be  derived  from  this  new 
field  of  study  were  only  partly  reaped.  Summarizing  the  above 
we  see  that  the  smaller  boat  seaplane  originated  in  France,  the 
large  one  in  the  United  States  of  America,  the  very  large  one  in 
England.  Many  seaplanes  were  brought  to  England  from  Amer- 
ica were  improved  by  experience  obtained  in  Britain,  and  sub- 
sequently the  types  designed  at  Felixstowe  and  built  in  England 
were  reproduced  in  America  in  quantities. 

The  construction  of  the  American  "  NC  "  type,  and  its  cross- 
ing of  the  Atlantic,  was  a  wonderful  achievement.  The  fact 
that  from  lack  of  fuel  "  NC3  "  alighted  in  mid-Atlantic,  and 
arrived  at  Ponta  Delgada  after  travelling  180  sea  miles  on  the 
water  in  54  hours  with  bad  weather,  pays  a  high  tribute  to  the 
design  and  is  a  sign  of  the  future  value  of  the  seaplane  in  com- 
mercial transport. 

In  France  the  war  incentive  to  seaplane  progress  was  lacking. 
France  has  mainly  used  the  small  boat  seaplane  for  coast  defence, 
and  patrol  for  submarines.  Up  to  the  end  of  1918  sufficiently 
high-powered  engines  were  lacking  for  sea-going  craft;  the 
Hispano-Suiza  200-H.P.  being  in  most  general  use. 

In  July  1914  the  Germans  had  few  seaplanes  in  service,  and 
of  these  one  had  been  imported  from  England.  They  were  nearly 
all  of  the  two-float  type,  and  suffered  from  the  defects  of  that 
type  previously  mentioned.  Their  activities  were  mainly  de- 
fensive, and  did  not  require  either  long  endurance  or  good  sea- 
worthiness. Torpedo-carrying  seaplanes  were  made  use  of  in 


1916  from  the  Belgian  coast  in  attacks  on  merchant  shipping 
but  these  were  not  required  to  cover  great  distances,  and  were  not 
remarkable.  Isolated  small  boat  seaplanes  have  been  constructed 
in  Germany,  but  not  in  quantity. 

The  Germans  (no  doubt  in  consequence  of  their  greater  study 
of  airships)  continuously  kept  a  heavier,  and  more  reliable,  engine 
than  the  Allies,  but  by  1917  the  Allies  had  produced  higher- 
powered  units,  and  it  is  probable  that  these  two  facts  are  mainly 
responsible  for  the  German  retention  of  the  smaller  "  float  sea- 
plane." Moreover,  their  engine  failures  at  sea  were  few,  and 
there  was  not,  therefore,  so  much  pressure  for  their  seaplanes  to 
withstand  open  sea  conditions. 

The  Brandenburg  seaplanes  of  1917-8  had  rather  heavy  engines 
of  180  to  200  H.P.,  yet  they  had  very  high  performance.  Their 
success  in  fighting  was  due  to  the  unusual  monoplane  wing 
arrangement  which  gave  a  clear  field  of  fire  in  all  directions  above 
the  horizontal  plane,  and  to  their  clean  general  design  without 
any  external  wire  bracing.  They  employed  the  more  recent  type 
of  twin  floats. 

Before  the  period  of  limitation  of  aircraft  construction  set  by 
the  Allied  Commission  of  Aeronautical  Control,  the  Germans  had 
been  developing  the  giant  aeroplane  in  several  experimental 
forms,  differing  mainly  in  the  arrangement  of  multiple-engine 
units.  These  ranged  in  total  weight  roughly  from  9  to  12  tons, 
and  in  the  case  of  the  larger  types  difficulty  was  experienced  in 
providing  sufficient  area  of  contact  between  the  wheels  and 
ground.  This  difficulty  did  not  exist  in  the  giant  seaplanes,  a 
few  examples  of  which  had  been  built  by  the  Zeppelin  works  on 
Lake  Constance.  Their  aerodynamic  design  was  not  good,  and 
the  type  was  not  perpetuated  in  its  original  great  size  on  account, 
probably,  of  difficulties  of  control.  The  Staakener  Giant  was 
another  example;  this  had  two  long  floats  made  entirely  of 
duralumin.  These  giant  seaplanes  would  no  doubt  have  devel- 
oped but  for  the  prohibition,  and  an  interesting  comparison  of 
advantages  would  have  been  obtainable  between  the  giant  sea- 
plane, and  the  giant  aeroplane. 

Characteristics  of  Seaplanes. — The  boat  seaplane,  a  craft  suitable 
for  less-sheltered  waters  than  the  early  float-equipped  aeroplane, 
or  hydro-aeroplane  as  it  was  called,  must,  to  be  of  real  value  in  naval 
operations,  be  fully  sea-worthy,  and  such  progress  as  had  been  made 
had  not  yet  proved  by  1921  whether  this  was  completely  obtainable. 
But  there  were  then : — (i)  the  smaller  craft  to  operate  from  sheltered 
waters,  rivers  and  lakes,  and  (2)  the  boat  seaplane  to  operate  over- 
sea. The  first  includes  all  types  of  small  dimensions  of  less  than,  say, 
4  tons,  and  all  existing  "float"  types  in  1921  fell  into  this  category. 

To  the  considerations  of  design,  stability  and  control  applying 
to  aeroplanes  must  be  added  the  design  and  distribution  of  the  float 
system,  so  that  the  forces  due  to  water  shall  not  affect  adversely  the 
stability  and  control.  These  water  forces  are  controlled  by  means  of 
the  aerodynamic  elements,  which  are  ineffective  except  at  the  higher 
hydroplaning  speeds.  Hence  the  float  system  must  be  such  that  any 
instability  that  occurs  between  the  air-borne  and  water-borne  con- 
ditions shall  take  place  at  speeds  high  enough  for  the  air  controls  to 
be  dominant. 

Wheeled  seaplanes,  for  land  and  sea  alighting,  had  been  built  by 
1921  as  experiments,  but  their  development  had  only  just  begun. 
Their  wheel  system,  springing,  ground  clearance  and  like  factors 
are  those  of  the  aeroplane.  These  amphibians  are  handicapped  by 
the  weight  of  the  float  system,  but  show  promise  of  very  useful  speed 
and  climb. 

Most  large  centres  of  population  possess  areas  of  smooth  water, 
rivers,  lakes  or  harbour,  affording  an  alighting  area  comparable  with 
the  average  aerodrome,  and  if  the  proposed  route  provides  large 
water  areas  for  any  forced  alighting,  this  fact  can  be  taken  advantage 
of  by  carrying  a  heavier  load  per  sq.  ft.  of  wing  area  with  a  corre- 
sponding gain  of  speed,  reduction  of  structure-weight  and  increase 
of  efficiency. 

The  desiderata  for  seaplanes  for  the  open  sea  are  less  well  known, 
and  more  difficult  of  attainment.  They  must  for  sea-worthiness 
be  large.  They  had  reached  15  tons  by  1921  and  were  still  far  below 
the  dimensions  of  the  small  coasting  vessel ;  with  the  existing  construc- 
tional materials  science  places  a  very  early  and  definite  limit  to  the 
increase  of  size  possible.  In  order  to  enable  even  a  15-ton  seaplane 
to  carry  a  reasonable  weight  of  fuel,  crew  and  equipment,  the  load 
factor  is  in  some  cases  reduced  to  three  and  a  half.  The  increase  of 
wing-loading,  though  it  entails  a  higher  stalling  speed,  and  the  adop- 
tion of  a  wing-section  of  high  lift,  may  yet  improve  matters. 

For  commercial  purposes,  a  high  top  speed  is  not  so  essential  as 
for  war,  and  model  tests  indicated  in  1921  that  the  overall  efficiency 
of  a  seaplane  with  high-lift  wings  may  compare  with  craft  with  the 
usual  flatter  wing.  The  reduced  area  of  wings  so  obtained  has  kept 

down  the  structure  weight.  For  war  the  wing  whose  camber  is  vari- 
able to  give  high  speed  with  good  lift  at  low  speed  may  be  perfected 

Three  arrangements  of  "float  seaplanes"  are  possible;  in  all,  the 
engine,  crew  and  loads  are  carried  in  one  or  more  fuselages  well  above 
the  floats  in  such  a  way  as  to  bring  the  centre  of  gravity  and  thrust 
axis  into  approximate  alignment : — • 

(a)  Two  main  floats  which  together  support  the  whole  weight 
and  provide  lateral  and  longitudinal  support. 

(i)  Two  main  floats  together  with  one  or  more  tail  floats,  the  for- 
mer supporting  nearly  the  whole  weight,  but  being  dependent  on  the 
latter  for  longitudinal  support. 

(c)  One  central  main  float  supporting  the  whole  weight  and  pro- 
viding longitudinal  support,  two  comparatively  small  wing  floats 
providing  lateral  support. 

Systems  (a)  and  (b)  provide  positive  metacentric  height  both  longi- 
tudinal and  transverse,  while  system  (c)  is  always  dependent  on  the 
wing  floats  for  lateral  support;  for  small  angles  of  roll  this  is  lack- 
ing, as  it  is  necessary  to  carry  the  wing  floats  clear  of  the  water  when 
the  seaplane  is  on  an  even  keel. 

Systems  (a)  and  (b)  are  most  usually  employed  because  they  avoid 
this  defect.  A  main  advantage  of  the  system  (c)  is  that  the  float  im- 
pedes the  view  much  less. 

Arrangement  (a)  is  better  than  (b),  as  the  tail  float  of  (c)  is  easily 
damaged,  and  thereupon  longitudinal  support  being  lost,  the  sea- 
plane turns  over  on  its  back. 

Float  seaplanes  have  the  following  merits  over  the  boat  type : — 

(1)  They  can  be  handled  on  slipways  with  the  most  primitive  ar- 
rangements, and  can  be  beached  safely  on  any  smooth  foreshore. 

(2)  The  aerodynamic  elements  give  the  normal  balance,  stability 
and  control. 

(3)  They  may  be  convertible  into  aeroplanes,  or  vice  versa. 

(4)  The  floats  are  simple  in  design,  and  can  be  subdivided  into 
watertight  compartments. 

(5)  The  static  transverse  stability  of  systems  (a)  and  (b)  enable  the 
wings  to  be  folded  afloat,  for  hoisting  the  craft  from  the  water  to  a 
ship  or  a  quay. 

(6)  For  war,  good  arcs  of  fire  are  obtainable  over  the  rear  hemi- 

The  following  are  the  disadvantages : — 

(1)  The  floats  are  uneconomical  of  structure- weight. 

(2)  The  aerodynamic  drag  is  comparatively  high. 

(3)  Arrangements  (a)  and  (b)  cannot  be  used  for  larger  craft  than 
3  tons  as  heavy  racking  stresses  are  set  up  in  the  structure  connect- 
ing the  two  floats  when  on  disturbed  water. 

In  the  "  boat  seaplane  "  the  displacement  of  the  craft  is  borne  by 
the  central  hull.  Longitudinal  stability  on  the  water,  both  static 
and  dynamic,  is  supplied  by  the  length  of  the  hull,  and  the  distri- 
bution of  its  planing  surfaces.  Wing-tip  floats  are  necessary  for 
lateral  support. 

The  advantages  of  the  type  are  as  follows: — 

(1)  An  excellent  crew  position  for   flying  and   observation,  e.g. 
in  anti-submarine  operations. 

(2)  Comfort :  the  crew  can  move  about,  the  pilot  be  relieved,  etc. 

(3)  Economy  of  structure-weight. 

(4)  Compact  design — low  air  drag. 

(5)  Absence  of  racking  forces,  and  large  size  possible.     This  last 
advantage  is  the  most  important,  and  the  limit  of  size  of  aircraft, 
as  already  discussed  in  the  section  on  "aeroplane  design,"  applies 
here  save  as  regards  the  hull.    Experience  shows  that  the  hull  weights 
do  not  increase  even  in  the  same  proportion  as  the  total  displace- 
ment, a  slight  reduction  in  the  ratio  of  the  hull  weight  to  total  weight 
having  been  obtained,  and  if  this  continues  further,  it  is  clear  that  a 
reduction  in  hull  weight  can  be  set  off  against  an  increase  in  wing 
weight,  resulting  possibly  in  the  most  economical  scale  being  greater 
than  anything  yet  constructed. 

The  disadvantages  are : — 

(1)  The  wings  cannot  be  folded  afloat. 

(2)  Cannot  be  beached  except  in  very  soft  mud,  and  requires 
elaborate  apparatus  to  move  it  to  a  shed  on  shore. 

(3)  In  war  it  is  difficult  to  defend  from  attack  astern. 

(4)  The  large  distance  between  the  centre  of  gravity  and  the 
thrust  axis,  and  the  low  position  of  the  centre  of  gravity  in  relation 
to  the  centre  of  lift.    The  former  produces  a  variable  pitching  mo- 
ment, the  latter  influences  adversely  the  lateral  control. 

Elements  of  Design  Peculiar  to  Seaplanes. — Many  of  the  desiderata 
in  a  seaplane  design  are  antagonistic  to  each  other. 

Flight  can  be  achieved  with  I  H.P.  for  each  25  Ib.  to  be  flown,  but 
jood  speeds  and  climbing  need  I  H.P.  for  each  8  or  10  Ib.;  therefore, 
structure-weight  must  be  economized. 

No  wings  can  stand  a  blow  from  any  large  volume  of  water.  The 
wings  must  clear  the  waves  and  any  but  light  spray.  Regarded  as 
an  aircraft  the  centre  of  gravity  of  the  whole  and  the  centre  of  pres- 
sure of  the  wings  should  De  nearly  coincident,  and  for  this  the  centre 
of  gravity  should  be  high  above  the  water.  As  a  watercraft,  how- 
ever, a  relatively  low  position  of  the  centre  of  gravity  is  needed  in 
relation  to  the  waterplane.  The  compromise  necessary  puts  the 
centre  of  gravity  so  that  the  metacentric  height  (apart  from  the  wing- 
ip  floats)  is  negative. 


The  position  of  the  airscrew  dominates  the  design.  Air  inflow  near 
the  blade-tips  sucks  spray  off  the  sea,  and  picks  up  spray  thrown  by 
the  hull,  with  damage  to  the  blades.  This  is  prevented  either  by 
putting  it  high  up  or  over  some  part  of  the  seaplane,  e.g.  the  lower 
wing  or  hull.  This  places  the  thrust  axis  well  above  the  centre  of 
gravity,  and  the  smaller  the  seaplane,  the  more  this  effect  is  notable. 
The  high  thrust  axis  produces  a  downward  pitch  varying  from 
zero  in  gliding  flight  to  a  maximum  at  full  power.  In  the  earlier 
boat  seaplane  this  was  uncorrected,  and,  in  order  to  get  balance  in 
normal  flight,  the  craft  was  very  "tail  heavy"  when  gliding. 

This  effect  has  been  diminished  by  placing  the  tail  plane  in  the 
slipstream,  by  setting  it  at  a  negative  angle  to  the  chord  of  the  main 
planes,  and  by  distributing  the  weights  so  as  to  bring  the  centre  of 
gravity  particularly  far  forward.  The  thrust-couple  thus  opposed 
by  the  tail-couple  can  be  nearly  balanced  out.  As  the  main  reactions 
on  the  tail  are  downwards,  the  tail  plane  is  sometimes  set  with  the 
camber  downwards. 

Unusually  large  airscrews  and  geared-down  engines  are  used  for 
efficiency  at  low  speeds,  i.e.  at  about  4/10  of  the  stalling  speed, 
because  the  water  resistances  are  greatest  at  this  speed. 

The  hull  must  provide  longitudinal  stability,  both  at  rest  and  in 
motion  on  the  water.  To  ride  in  a  seaway  and  not  bury  its  nose  when 
accelerating,  a  long  forebody  is  used.  The  section  of  this  part  should 
be  veed  at  the  keel,  and  well  flared  at  the  chines,  respectively  to 
reduce  shocks  from  on-coming  waves,  and  to  keep  the  divergent  wave 
formation  low  and  clear  of  the  wings  and  airscrews.  For  the  same 
reasons  the  keel  and  chine  lines  have  a  gradual  rise  forward  with 
overhang  forward  of  the  fore-end  of  the  water-line. 

At  least  a  300  %  reserve  of  buoyancy  is  given  to  boat  seaplanes  to 
provide  adequate  freeboard  at  sea.  With  watertight  floats  120% 
reserve  is  adequate. 

Above  4/10  of  the  minimum  flying  speed,  called  the  "hump" 
speed,  the  water  resistance  due  to  wave-making  begins  to  fall.  Above 
the  hump  speed  the  water  resistances  are  probably  due  as  much 
to  skin  friction  of  the  planing  surfaces  as  to  wave  or  eddy  making, 
and  by  disposing  steps  in  the  planing  bottom,  the  wetted  surface, 
and  consequently  the  resistance  is  reduced.  From  the  hump 
speed  onwards  these  hydroplane  resistances  decrease,  the  weight  is 
transferred  more  and  more  to  the  wings  until  the  seaplane  leaves  the 

The  larger  the  planing  surface  (i.e.  the  wider  the  beam)  the  sooner 
the  hull  rises,  and  the  earlier  the  hump  occurs,  but  this  increases  the 
resistance  at  lower  speeds,  and  makes  the  hull  heavy  for  its  strength. 

Models  tried  in  the  Froude  National  Tank  at  Teddington  (Eng- 
land) show  that  but  a  slight  reduction  of  max.  E.H.P.  at  or  about 
the  hump  speed  is  obtained  when  the  beam  exceeds  about  \  the 
length  of  forebody.  Where  a  high  power  is  available  on  other  ac- 
counts, the  beam  may  be  still  further  reduced.  A  narrow  hull  with 
spray-deflecting  sections,  and  without  flat  surfaces,  or  main  "  step," 
though  desirable,  was  found  not  to  give  the  necessary  lowering  of 
resistance  beyond  the  hump  speed.  The  resistance  increased  as  the 
displacement  diminished  with  speed. 

The  main  "  step  "  under  the  centre  of  gravity  was  proved  necessary, 
but  the  area  of  the  planing  surface  forward  of  less  importance.  The 
boundaries  of  the  planing  surfaces  must  have  sharp  edges  to  make 
the  water  break  clear  away  from  them ;  water  clings  to  rounded  sur- 
faces even  of  small  radius,  and  these  would  cause  unnecessary  resis- 
tance. The  angle  between  the  hull  surface  at  the  chines  and  steps 
should  not  exceed  90°  for  the  same  reason. 

In  a  seaplane  hull  we  require  static  stability  at  rest  on  the  water, 
and  dynamic  stability  in  motion  at  the  higher  speeds.  Longitudinal 
stability  of  the  whole  at  rest  is  obtained  by  the  length  of  the  water- 
plane  area  and  presents  no  difficulties. 

The  tendency  of  all  craft  to  trim  by  the  bow  at  low  speeds  is  ag- 
gravated in  the  seaplane  by  the  high  thrust  axis.  The  heaviest 
waves  are  formed  while  this  tendency  to  dive  is  still  present,  and  it 
is  at  these  speeds  (in  the  region  of  \  to  J  of  the  minimum  flying 
speed)  that  clean  running  in  disturbed  water  is  most  difficult  to  attain. 

The  modern  hull  possesses  large  restoring  moments  at  small  nega- 
tive angles  of  trim,  but  if  the  forward  trim  exceeds  about  3°,  the 
moments  will  have  become  negative,  and  an  attempt  to  alight  at  such 
an  angle  will  break  up  the  hull. 

Lateral  stability  at  rest  (though  sought  in  early  boat  seaplanes  by 
providing  sufficient  beam  to  give  a  small  positive  metacentric  height) 
is  destroyed  by  the  lightest  side  wind,  and  therefore  wing-tip  floats 
are  a  necessity.  The  transverse  metacentric  height  is  always  nega- 
tive to-day,  and  wing-tip  floats  are  relied  on. 

Stability  in  the  hydroplaning  condition  becomes  increasingly  im- 
portant with  size.  Beyond  the  hump  speed  the  hydrodynamic 
reactions,  the  air  reactions  and,  to  a  diminishing  extent,  the  buoyancy 
combine  to  support  the  hull,  and  to  determine  the  stability  of  the 
whole.  Just  above  the  hump. speed  hydroplaning  reactions  are  great, 
while  the  air-forces  are  small;  so  are  the  moments  due  to  the  air- 
controls.  Here  the  planing  surfaces  and  steps  must  afford  stability. 
When  the  speed  increases  the  water-forces  become  less,  and  the  air- 
forces  greater,  till,  on  approaching  the  minimum  flying  speed,  any 
instability  that  may  occur  can  be  counterbalanced  by  the  air-con- 
trols. In  the  larger  seaplanes,  however,  the  water  moments  may  be 
large  even  at  high  speeds,  and  their  hulls  must,  therefore,  be  stable 
over  the  whole  range  of  water  speeds. 

The  stability  depends  on  the  relative  size  and  positions  of  the 
steps  and  planing  surfaces,  on  the  angles  of  the  planing  surfaces  to 
the  mean  water-line  to  each  other,  and  to  the  chords  of  the  aerofoil 
surfaces ;  and  on  the  position  of  the  centre  of  gravity  in  relation  to 
these  and  to  the  height  of  the  thrust  axis. 

The  problem  is  one  of  great  complexity,  and  partly  on  account  of 
its  recent  origin  is  as  yet  unsolved. 

During  the  war,  model  work  was  called  for  on  individual  designs 
and  delayed  the  general  investigation,  but  clues  have  been  found. 
Usually  the  smaller  hulls  are  proved  more  apt  to  develop  instability 
both  in  the  tank  tests  and  on  the  full  scale.  The  minimum  flying 
speed  being  much  the  same  on  large  and  small  seaplanes,  the  wave 
lengths  at  any  given  speed  are  much  the  same.  A  hull  of  45  ft.  gave 
best  results  with  the  main  step  slightly  forward  of  the  C.G.  and  the 
rear  step,  very  small  relatively,  18  ft.  aft  of  it.  Here  instability  was 
delayed  until  the  air-controls  were  effective,  and  when  tried  in  the 
full  scale,  no  instability  was  apparent,  probably  on  account  of  the 
damping  action  of  the  air-surfaces,  since  the  seaplane  took  the  air 
without  operation  of  the  controls  by  the  flier. 

A  somewhat  similar  model  of  a  much  larger  seaplane  with  steps 
32  ft.  apart  was  stable  throughout  the  speed  range. 

In  the  small  types  the  hull  length  restricts  the  distance  apart  of 
the  steps.  The  two  steps  may  be  compared  to  the  wings  and  tail 
surfaces  of  an  aeroplane ;  the  main  step  nearly  under  the  C.G.  does 
the  lifting  of  the  boat  on  to  the  surface,  while  the  rear  step  provides 
the  pitching  moments  for  equilibrium,  and  is  most  effective  for  this 
purpose  when  far  aft  and  of  small  dimensions.  Tank  experiments 
on  models  show  that  not  more  than  about  l/io  of  the  total  resistance 
is  due  to  the  rear  step  and  after  body.  The  two  steps  must  also  be 
arranged  in  such  a  way  that  the  intermediate  hull-sections  and  that 
part  of  the  hull  carrying  the  tail  surfaces,  aft  of  the  rear  step,  are 
clear  of  the  two  depressions  formed  in  the  water  by  the  passage  of 
the  steps.  The  object  is  to  reduce  the  wetted  surface,  aft  of  the  main 
step,  to  the  minimum  necessary  (at  the  rear  step  itself)  to  give 
stable  conditions.  This  best  arrangement  can  only  be  obtained,  at 
present,  by  individual  model  experiments.  The  full  scale  has  cor- 
roborated the  restjlts,  and  accordingly  the  resistance,  running  angles, 
pitching  moments  required  for  equilibrium  and  general  characteris- 
tics of  running  can  be  obtained  in  the  Froude  tank,  where  waves 
can  also  be  reproduced  artificially.  Tests  show  that  complete 
stability  on  the  model  is  obtained  under  more  difficult  conditions 
than  in  the  full  scale,  hence  the  seaplane  corresponding  to  a  stable 
model  may  be  fully  relied  upon. 

Between  Air  and  Water. — The  water  reactions  on  a  badly  designed 
hull  may  continue  to  be  considerable  up  to  the  moment  of  quitting 
•the  water;  then,  their  sudden  disappearance  may  produce  moments 
dangerous  at  a  time  when  their  correction  by  air-controls  requires 
big  movements.  Such  a  seaplane  at  a  high  speed  on  water,  and  kept 
at  the  angle  for  maximum  lift  of  the  wings  by  means  of  the  air- 
controls,  is  subject  to  a  moment  in  pitch  due  to  the  water  reaction 
on  the  steps.  This  is  balanced  by  a  moment  due  to  the  elevator  until 
it  leaves  the  water,  when  all  the  water  forces  are  lost.  If  the  elevator 
moment,  which  had  been  applied  by  the  flier  were  positive  (i.e. 
increasing  the  angle  of  attack),  the  seaplane  would  stall.  These 
moments  should  either  not  exist  or  be  negligible.  If  they  do  exist 
they  are  less  dangerous  if  operative  in  the  inverse  sense  to  those  in 
the  example.  Their  existence  can  only  be  ascertained,  and  as  a  rule 
eventually  elinHnated,  by  experiment.  From  such  experiments  a 
canon  for  design  will  be  evolved. 

To  keep  hull  weight  low  there  are  special  methods  of  construc- 
tion. The  timbers  used  in  boat-building  practice  have  so  far  been 
found  best.  In  the  present  sizes  steel  is  out  of  the  question.  Alumin- 
ium alloys  have  been  used  in  Germany  with  success  for  float  con- 
struction, but  it  is  doubtful  whether  duralumin  or  any  other  alumin- 
ium alloy  is  superior  to  mahogany  for  the  hull  skin  as  regards 
strength,  hysteresis  or  durability.  In  any  case  of  timbers,  mahogany 
is  the  best  for  this  purpose. 

Unsuccessful  attempts  have  been  made  to  depart  from  the  time- 
worn  principles  and  practice  of  light  boat  building.  A  planked  skin 
through-fastened  on  to  timbers  and  stringers  in  the  usual  manner  is 
essential  for  watertightness  and  durability. 

Design  is  addressed  to  keeping  down  the  weight  of  the  skin,  and 
its  supporting  structure.  Seaplane  hulls  have  been  built  having  a 
bare  weight  from  20  %  to  9 1  %  of  the  total  weight.  The  latter  figure 
was  got  on  a  boat  displacing  about  15  tons. 

The  two  principal  methods  of  construction  are:  the  rigid  and  the 
flexible.  For  most  hulls  the  skin  is  supported  by  a  rigid  structure 
which  permits  of  easy  subdivision  by  transverse  bulkheads  like  the 
ordinary  steel  steamship  except  that  timber  is  employed.  The  main 
objection  to  this  method  is  its  low  specific  strength.  The  rigid 
structure  produces  strong  local  points  in  the  skin  with  intermediate 
areas  poorly  supported,  resulting  in  sudden  changes  of  cross  section 
and  localized  deflections  under  load.  Such  a  hull  to  have  sufficient 
strength  for  taking  off  in  disturbed  water  weighs  15  %  of  its  displace- 
ment at  least. 

The  flexible  method  as  developed  by  Linton  Hope  has  its  trans- 
verse sections  approximately  circular  throughout  the  whole  length, 
while  the  planing  surfaces  are  built  on  outside  the  main  hull,  produc- 
ing what  is  virtually  a  double  bottom.  The  structure  is  tubular,  its 
whole  strength  being  concentrated  in  the  skin  and  its  local  support- 



ing  members.  Two  or'more  thicknesses  of  mahogany-planking  are 
through-fastened  to  transverse  timbers  of  small  section  closely  spaced ; 
these  are  connected  longitudinally  by  a  large  number  of  stringers  of 
rectangular  section  lying  in  a  radial  plane,  edge  on  to  the  timbers; 
the  stringers  are  in  turn  supported  on  their  inner  edges  by  elm  hoops 
•of  comparatively  heavy  section  widely  spaced.  The  small  section 
timbers  are  placed  so  closely  that  no  fastenings  need  be  passed 
through  the  skin  anywhere  between  timbers.  This  type  is  water- 
tight, durable  and  light.  The  average  hull  weighs  not  more  than 
II  %  to  12  %  of  its  displacement. 

The  flexibility  absorbs  the  shocks  of  alighting  and  taking  off,  and 
precludes  heavy  local  pressures.  Care  is  taken  to  distribute  the  air 
loads,  which  are  generally  concentrated  along  two  lines  transversely 
to  the  axis  of  the  hull,  over  a  sufficient  area  of  the  skin,  and  all 
internal  installation  is  arranged  to  allow  for  comparatively  large 
relative  movements  of  components.  Transverse  subdivision  is  prac- 
tically impossible,  but  the  provision  of  a  subdivided  double  bottom 
is  easy  and  effective. 

Seaplane  in  Operation. — The  preparations  made  for  housing  and 
upkeep  of  seaplanes  were  unfortunately  dominated  by  the  require- 
ments of  the  early  types.  The  seaplane  station  was  modelled  on 
aerodrome  lines,  with  the  addition  of  a  slipway  to  the  water.  The 
flat  floats  of  the  float  seaplanes  were  placed  on  trolleys,  and  thence 
by  slipways  to  the  water.  The  delicate  V-section  hull  of  the  heavy 
boat  seaplane  is  ill-suited  for  such  handling.  The  draught  of  the 
modern  boat  (with  a  trolley  under  it)  exceeds  what  can  be  negotiated 
by  men  in  waders.  If  such  boats  are  to  be  brought  ashore  at  all  new 
devices  are  required  for  doing  so.  Experience  shows  that  boats  of 
only  5  or  6  tons  are  damaged  in  such  handling,  though  they  draw 
little  more  than  2  ft.  of  water.  To  limit  the  bringing  ashore  to  slack 
water  periods  in  good  weather,  would  be  intolerable  for  commercial 
work.  Better  water-side  facilities,  such  as  covered  sheds  with  direct 
access  to  the  water  for  the  construction,  erection  and  repair  of 
modern  seaplanes  are  needed.  These  should  allow  of  admitting  water 
to  part  of  the  shed  to  reduce  the  out-of- water  handling  to  a  minimum. 
As  a  large  expanse  of  sheltered  water  is  necessary,  and  the  rise  and 
fall  of  the  tide  is  important,  floating  sheds  may  be  needed. 

Closed  sheds  are  not  essential  for  operating  seaplanes.  The  larger 
the  seaplane  the  more  can  it  resist  exposure  for  long  periods,  and  the 
practice  of  mooring  out  will  become  an  economical  necessity,  but  the 
seaplane  must  be  designed  with  this  in  view,  and  proper  auxiliary 
services  for  heating,  fuelling  and  repairs  provided.  In  high  winds 
seaplanes  moored  out  have  risen  off  the  water  at  their  moorings  and 
destroyed  themselves,  but  this  is  avoidable  by  destroying  the  air-flow 
over  the  lower  planes  by  attaching  light  boarding  along  the  leading 
edges  at  a  large  negative  angle  to  the  chord.  As  the  seaplane  for  com- 
merce has  been  but  little  studied,  marked  developments  may  be 
expected  in  this  direction ;  sea-worthiness  is  still  the  main  problem 
for  warcraft  and  increase  of  size  the  most  direct  solution. 

In  transport  work,  sea-worthiness  is  an  insurance  against  engine 
failure ;  remove  this  risk  and  operation  would  take  place  from  shel- 
tered water  only,  design  would  be  freer,  size  would  be  dictated  by 
load,  capacity  and  economy.  The  need  to  counter  the  winds  rather 
than  competition  against  the  slow  surface  ship  would  dictate  the  air 
speed  of  such  craft. 

For  operation  from  smooth  waters  structure-weight  and  hull 
weight  can  be  reduced  and  wing  load  increased,  while  high-lift  wing 
sections  also  offer  much  promise. 

It  is  remarkable  that  though  the  viewpoint  for  seaplanes  is  so 
different  from  that  for  aeroplanes,  the  reliable  engine  unit  is  equally 
found  to  be  the  prime  desideratum  for  present  progress.  (A.  J.  M.) 


Airships  are  divided  into  three  main  types: — (i)  The  rigid,  which 
has  a  hull  structure  of  rigid  members  covered  by  an  outer  fabric 
fairing,  and  containing  a  number  of  separate  gas  cells.  (2)  The 
semi-rigid,  in  which  the  whole  or  part  of  the  bending  and  longi- 
tudinal compression  induced  in  the  ship  by  the  rigging  wires  is 
taken  by  a  rigid  keel.  The  envelope  from  which  this  keel  is  car- 
ried is  kept  distended  by  the  pressure  of  the  gas,  but  is  mainly 
subject  to  vertical  loads.  (3)  The  non-rigid,  in  which  the  envelope 
maintains  its  shape  solely  on  account  of  an  internal  pressure 
which  must  exceed  the  outside  pressure. 

Small  airships  up  to,  say,  300  ft.  long  are  necessarily  non-rigid, 
as  there  is  not  sufficient  lift  to  justify  a  rigid  framework.  The 
largest  airships  have  a  rigid  hull  structure  because  the  pressures 
involved  in  an  envelope  of  large  diameter  necessitate  very  heavy 
fabric  and  make  a  system  of  compartments  essential.  Between 
the  two,  the  semi-rigid  seeks  to  reduce  the  fabric  tensions  by  the 
use  of  a  rigid  keel  girder,  but  it  is  doubtful  whether  this  justifies 
the  keel,  except  as  a  convenient  means  of  carrying  the  loads 
from  the  envelope. 

A  rigid  airship  has  a  hull  structure  of  light  aluminium  girders, 
arranged  with  some  25  longitudinals  connecting  some  17  main 
transverse  polygonal  rings.  At  each  main  ring  a  bulkhead  is 
formed  of  the  load  wires  which  suspend  the  weight  of  the  keel 
from  the  upper  part  of  the  framework  and  the  radial  and  chord 
wires  which  retain  the  shape  of  cross  section  of  the  ship.  A  spe- 
cially strong  keel  of  triangular  section  and  some  8  ft.  high  runs 
nearly  the  whole  length  of  the  ship  and  carries  the  petrol  tanks, 
water-ballast  bags  and  other  weights,  being  itself  supported 
at  the  main  transverse  rings.  The  30-metre  spaces  between 
the  bulkheads  are  each  fitted  with  a  single  gasbag  of  gas-tight 
fabric.  The  degree  of  fullness  of  these  bags  varies  from  the 
maximum  to  sometimes  less  than  50%  full,  when  the  upper  parts 
of  the  space  alone  will  be  occupied  by  the  bag,  whose  lower  part  is 
collapsed  and  empty.  A  cover  of  fabric  is  stretched  over  the 
outside  of  the  whole  frame,  so  as  to  present  a  smooth  surface  and 
protect  the  gasbags  from  weather  and  light.  Separate  engine 
cars  are  attached  below  the  hull  at  points  along  its  length. 

Performance  Table  of  Seaplanes,  1914-20. 

Float  Seaplanes. 




Load  In- 
cluding Crew 


Speed  in  m.p.h. 
at  Sea  Level 






M.  Farman       .... 
Sopwith-Schneider  . 


1  60 









•  i,  600 


Short  184  









Sopwith-Schneider  . 









Fairey  Type  III. 
Short  184.     Improved 
Short  320.          .... 












Fairey  Type  III.  c. 
Westland  Single-Seater  . 
Hanriot  Single-Seater 





















Fairey  Type  III. 








*  Total  weight  carried  for  performance  shown. 



Performance  Table  of  Seaplanes,  1914-20. 

Boat  Seaplanes. 




Load  In- 
cluding Crew 


Speed  in  m.p.h. 
at  Sea  Level 





Curtiss  America       . 

1  80 









Norman  Thompson 

1  20 








Large  America.  H  12 
Porte  Boat        .... 

i,  080 











A.D.  Boat 


i,  066 








F5  (Light  Load)       .        .        . 
Phoenix  PS  (Light  Load) 















7,  1  60 



Felixstowe  Fury 
F.B.A.        .               ... 
Nieuport  Macchi 
Cornier  G.S.I.  (Zeppelin) 

i,  800 
i,  600 
















Vickers  Viking  Mk.  III. 








*  Total  weight  carried  for  performance  shown. 

The  early  development  of  rigid  airships  was  carried  out  by 
Count  Zeppelin  in  Germany,  and  represents  an  extraordinary 
record  of  perseverance.  This  development  was  only  rendered 
possible  by  political  influence  and  by  the  repeated  financial 
assistance  available.  The  Schiitte-Lanz  airships  were  of  wooden 
construction  and  developed  more  slowly.  They  appear,  however, 
to  have  embodied  considerably  more  original  and  perhaps  cou- 
rageous developments  than  did  the  Zeppelins,  which  were  de- 
veloped more  as  gradual  minor  improvements  on  the  original 

British  Rigid  Airship  No.  i  was  started  in  1909.  During  the 
construction  great  consideration  was  given  to  the  various  auxiliary 
gear  required  by  the  ship  and  to  the  problems  included  in  the 
handling  and  mooring  as  well  as  the  actual  flying  of  the  ship. 
The  thoroughness  and  accuracy  with  which  this  auxiliary  work 
was  developed  is  most  remarkable  in  the  light  of  later  experience. 
Before  the  first  flight  was  made  the  ship  was  moored  by  the  bow 
to  a  mast  with  her  cars  resting  on  the  water.  The  ship  was  broken 
amidships  in  Sept.  1911  as  the  result  of  a  mistake  in  handling 
while  she  was  being  returned  to  her  shed  after  one  of  the  trials 
of  handling  before  flight.  Comparison  of  the  details  and  esti- 
mated performance  of  this  ship  with  the  contemporary  Zeppelins 
shows  that  she  was  a  remarkably  good  first  design  and  that  had 
it  not  been  decided  to  abandon  rigid-airship  construction  the 
British  development  of  these  ships  would  almost  certainly  have 
become  at  least  equal  to  that  of  Germany. 

British  Rigid  Airship  Rg,  by  Vickers,  stopped  at  the  beginning 
of  the  World  War,  was  restarted  in  July  1915  and  made  her 
first  flight  in  Nov.  1916.  She  made  a  rather  remarkable  passage 
to  Howden  through  a  snowstorm  over  the  Pennine  range.  Being 
somewhat  inadequate  in  buoyancy,  she  was  used  for  instruction 
and  ultimately  for  mooring  experiments. 

She  was  followed  by  four  ships  of  R23  class,  built  by  Vickers, 
Beardmore  and  Armstrong,  and  again  by  R27  and  Rag,  which 
were  remarkable  for  the  absence  of  the  keel  which  had  existed 
in  all  previous  rigid  airships  and  had  been  looked  upon  as  con- 
stituting the  real  strength  of  the  ship  to  resist  bending  and  shear- 
ing forces.  This  keel  subsequently  reappeared  in  German  Zep- 
pelins and  in  the  ships  built  in  England,  but  then  merely  as  a 
means  of  distributing  to  the  main  frames  the  weights  of  petrol 
tanks,  etc.,  arranged  along  it. 

Two  wooden  ships,  RJI  and  R32,  were  built  by  Short  to  a  design 
closely  similar  to  that  of  the  Schiitte-Lanz  type.  They  were 
considerably  faster  than  contemporary  ships. 

Rigid-airship  construction  in  Germany  had  advanced  con- 
tinuously and  was,  therefore,  greatly  ahead  of  French  and  British. 
A  combination  of  the  talent  and  experience  of  the  Zeppelin  and 
Schiitte-Lanz  firms  early  in  1916  resulted  in  the  design  of  L3o, 
giving  a  speed  and  performance  far  ahead  of  any  earlier  ships. 
L$3  of  this  class  was  brought  down  in  Sept.  1916  in  such  a  com- 
paratively undamaged  condition  that  it  was  possible  from  her  to 
prepare  a  design  in  England  to  which  R33  and  R34  were  built. 
These  ships  were  not,  however,  completed  till  late  in  1918. 

The  German  L65  class  marked  a  further  advance  in  speed  and 
performance,  while  the  L?o  class,  of  which  the  first  ship,  L7o,  was 
destroyed  on  the  first  flight  to  England  with  some  of  the  chief 
constructional  experts  on  board,  marked  still  further  progress  in 
performance  and  in  the  simplification  of  the  machinery  installa- 
tion, in  the  adoption  of  fins  of  triangular  cross  section.  1,72, 
which  was  not  actually  completed  until  after  the  Armistice,  had 
again  a  slightly  higher  performance. 

After  the  Armistice  Germany  built  a  much  smaller  airship, 
the  "  Bodensee,"  for  commercial  purposes,  and  with  her  carried 
out  a  remarkable  series  of  passenger  flights.  The  ship  was  then 
enlarged  and  a  sister  ship,  "  Nordstern,"  also  constructed. 

Subsequent  to  the  R33  class  the  British  R36  and  R37  were 
constructed  to  a  generally  similar  design,  of  somewhat  greater 
capacity  and  much  improved  detail.  R8o,  designed  and  con- 
structed by  Vickers,  embodied  several  entirely  new  features,  but 
her  size  was  so  restricted  by  the  dimensions  of  the  construction 
shed  that  her  performance  was  seriously  handicapped.  R38 
made  radical  changes  in  features  of  design,  and  a  clear  and  def- 
inite departure  from  German  methods.  The  United  States  had 
contracted  for  its  purchase.  It  was  to  be  used,  as  it  was  gener- 
ally understood,  for  an  experimental  service  from  New  York  to 
San  Francisco  and  for  that  purpose  masts  and  intermediate 
stations  were  being  prepared.  R38,  while  on  the  final  test  flight 
before  delivery  on  August  24  1921,  caught  fire  and  fell  owing 
to  structural  weakness,  and  many  lives  were  lost. 

Non-Rigid  Airships. — In  1913  the  chief  general  classes  of  non- 
rigid  airships  were: — (i)  Those  with  a  plain  circular  envelope 
from  which  the  car,  etc.,  was  suspended  from  special  fittings  on 



the  envelope,  and  of  which  the  British  military  airships  are 
typical.  (2)  The  Parseval  type,  in  which  the  circular  envelope  is 
reinforced  against  bending  under  the  rigging  tension  by  Parseval 
trajectory  bands  passing  over  the  envelope  and  secured  to  a 
girdle  to  which  the  car  is  rigged.  (3)  The  Torres  type,  made  by 
the  Astra  firm  of  Paris,  trilobe  in  section,  with  riggings  led  inside 
the  envelope  and  divided  into  fans  secured  to  points  along  the 
two  top  ridges. 

The  two  latter  systems  are  intended  to  decrease  the  distance 
between  the  envelope  and  the  car  without  producing  excessive 
tendency  to  bend  in  a  large  ship. 

At  the  beginning  of  the  war  the  French  had  several  non-rigid 
ships  of  various  types  which  carried  out  bombing  operations, 
but  no  important  new  ships  were  built.  Germany  had  a  few 
Parseval  airships,  which  did  a  little  work  on  the  Russian  front, 
but  there  was  no  important  development  of  small  ships.  England 
had  three  small  non-rigids,  also  one  Parseval  and  one  Astra. 
It  became  necessary,  however,  at  the  beginning  of  1915  to  develop 
the  very  small  non-rigid  airship  as  rapidly  as  possible  as  an  anti- 
submarine protection.  Extreme  simplicity  was  essential  in  order 
to  allow  of  rapid  production  by  firms  having  no  previous  expe- 
rience. For  the  first  30  ships  aeroplane  bodies  were  used  as  cars, 
but  later  special  cars  far  more  suitable  for  patrol  work  were 
adopted.  Engines  of  about  90  H.P.  were  used  and  a  crew  of  three 
carried.  Some  150  ships  of  the  S.S.  classes  were  built,  but  at  the 
end  of  the  war  it  had  been  decided  to  adopt  a  slightly  larger  ship 
with  twin  engines  and  a  crew  of  five  as  being  more  suitable  for 
the  longer  patrols  which  became  necessary.  Later  in  1915  a 
larger  type — -the  Coastal  class — having  greater  speed  and  taking 
a  crew  of  five,  was  built.  For  these  the  Astra  system  of  rigging 
was  adopted  in  order  to  reduce  to  a  minimum  the  necessary 
height  of  the  sheds.  Thirty-five  of  these  ships  and  ten  of  an 
improved  (C*)  class  were  built  during  the  war.  These  ships  later 
carried  a  crew  of  five  and  had  an  endurance  of  1 2  hours  at  a  full 
speed  of  51  knots.  In  1916  the  first  ship  of  the  North  Sea  type 
was  flown.  This  class  was  intended  to  work  with  the  fleet  and 
had  an  endurance  of  some  24  hours  at  50  knots.  Sixteen  of  these 
ships  were  built. 

The  characteristic  of  these  ships,  more  particularly  the  N.S. 
class,  was  that  the  petrol  tanks  and  all  other  weights  possible 
were  carried  direct  on  the  envelope.  In  the  N.S.  class  the  car 
was  separate  from  the  power  unit  and  the  weight  distributed 
over  the  length  of  the  ship.  This  gave  important  advantages 
over  all  earlier  non-rigids  where  the  loads  had  been  concentrated 
in  the  car.  The  S.S.,  Coastal  and  N.S.  classes  were  all  designed 
and  built  at  the  R.N.  Airship  Station,  Kingsnorth.  They  con- 
stitute a  very  interesting  development  from  the  small  supply  of 
ships  and  experience  available  at  the  beginning  of  the  war. 

A  considerable  number  of  British  non-rigid  airships  were  built 
and  supplied  to  the  French,  Italian,  Russian  and  American  serv- 
ices, and  one  Italian  semi-rigid  was  supplied  to  England  for 
experiment.  A  large  Astra  ship  of  some  800,000  cub.  ft.  capacity 
was  built  in  France  with  two  large  cars.  It  is  understood 
that  lack  of  longitudinal  rigidity  of  the  envelope  gave  trouble. 

The  Italian  airship  design  has  favoured  the  semi-rigid  type 
of  construction,  their  most  successful  type  being  one  in  which 
the  keel  girder  was  not  in  itself  rigid  but  "  vertebrate,"  consisting 
of  a  number  of  pin-jointed  frames  capable  of  taking  the  longitu- 
dinal thrust  induced  by  the  car  riggings,  so  long  as  the  envelope 
held  the  keel  in  line.  This  system  did  not  greatly  reduce  the 
height  of  the  ship,  as  the  points  of  attachment  of  the  riggings 
were  necessarily  at  the  bottom  of  the  envelope  instead  of  near 
the  level  of  its  centre  line.  It  did,  however,  enable  a  much  lower 
envelope  pressure  to  be  used  than  in  the  non-rigids  of  the  same 
size.  This  enabled  a  very  light  envelope  fabric  to  be  used  and 
also  a  system  of  automatic  pressure  regulation  by  air  taken  at  the 
nose  of  the  airship.  These'  ships  were  designed  for  bombing 
raids  at  great  heights  across  the  Adriatic  Sea.  The  excellent 
weather  conditions  rendered  their  comparatively  slow  speed 
quite  satisfactory. 

Germany  built  a  few  large  semi-rigids  of  the  M  type  and  the 
Parseval  type.  The  two  largest,  PL26  and  27,  were  of  some 

1,120,000  cub.  ft.  capacity.  They  embodied  many  interesting 
features,  including  spherical  partitions  which  divided  the  envelope 
into  sections  so  that  the  accumulation  of  pressure  at  the  upper 
end  of  the  ship  when  pitched  was  avoided.  As  far  as  is  known, 
no  very  thorough  trial  of  these  scrips  was  made,  but  as  far  as  the 
experiment  was  carried  it  appears  to  have  been  satisfactory. 
The  type  was  not,  however,  proceeded  with  on  account  of  the 
decision  to  concentrate  on  the  rigid  type. 

Italy,  after  the  Armistice,  built  a  large  semi-rigid  "  Roma," 
intended  for  transatlantic  service. 

An  interesting  aircraft  which  was  developed  experimentally 
as  a  counter  to  the  Zeppelin  raids  was  the  "  airship-plane  " 
devised  by  Wing  Comm.  Usborne.  A  complete  aeroplane  was 
rigged  under  the  envelope  of  an  S.S.  airship  in  such  a  way  that, 
after  patrolling  at  a  great  height,  the  envelope  could  be  released 
and  the  aeroplane  left  free  to  deliver  its  attack.  After  several 
preliminary  flights  the  first  attempt  to  slip  the  envelope  in 
flight  failed  on  account,  probably,  of  temporary  loss  of  pressure 
in  the  envelope.  The  machine  was  partly  released  prematurely, 
and  was  damaged  as  it  fell  away;  Wing  Comm.  Usborne  and 
Wing  Comm.  Ireland  were  both  killed.  The  former  particularly 
was  a  most  serious  loss,  as  he  had  up  to  that  time  been  mainly 
responsible  for  the  exceptionally  rapid  airship  development. 

Kite  Balloons. — The  Drachen  kite  balloon,  in  the  form  origi- 
nally used  by  Maj.  von  Parseval  and  Capt.  von  Sigsfeld  in  1896, 
was  used  by  the  Germans  immediately  on  the  declaration  of  war 
for  observation  of  artillery  fire.  Its  value  became  at  once  ap- 
parent, and  it  was  immediately  copied  by  the  Allies,  very  large 
numbers  being  made.  The  stability  was,  however,  so  poor  that 
this  type  could  only  be  used  in  fair  weather,  and  accurate  ob- 
servation was  often  difficult.  Capt.  Caquot  of  the  French  army 
designed  an  improved  arrangement  of  stabilizers.  Three  fins, 
one  at  the  bottom  of  the  tail  and  two  120°  from  it,  were  in  the 
summer  of  1916  ultimately  adopted  instead  of  the  single  fin  of 
the  Drachen  and  the  string  of  parachutes  which  were  necessary 
with  it.  Considerably  improved  stability  was  obtained,  ana 
there  was  an  important  increase  of  the  dynamic  lift  which  gave 
increased  height.  This  type  was  generally  adopted  by  the  Allies 
for  military  use  and  worked  well  up  to  6,000  feet.  The  same  type 
of  balloon  was  used  by  the  navy,  but  was  replaced  by  a  similar 
one  designed  to  resist  higher  wind  speeds  and  capable  of  only 
2,000  feet.  This  was  used  extensively  by  the  fleet  for  gunnery 
observation  and  as  a  look-out  for  submarines.  The  balloon,  being 
in  continuous  telephone  communication  with  the  captain  of  the 
ship,  could  transmit  information  more  completely  and  rapidly 
than  other  aircraft.  The  balloons  were  also  used  in  the  ships 
protecting  convoys,  although  it  was  sometimes  contended  that 
they  acted  as  buoys  to  show  the  position  of  the  convoy  to  a  sub- 
marine which  could  thereby  keep  in  touch  at  a  safe  distance 
during  the  day  and  deliver  its  attack  at  night.  These  naval 
balloons  were  capable  of  very  high  wind  speeds,  in  one  instance 
80  knots  being  recorded. 

An  Italian  A.P.  type  of  balloon  having  a  considerably  smaller 
length  to  diameter  ratio  was  adopted  to  give  very  great  static 
lift  in  calm  air.  These  were  used  for  the  apron  defence  against 
aeroplane  attack.  A  line  of  balloons  lifted  to  a  height  of  some 
15,000  ft.  a  horizontal  cable  from  which  hung  thin  vertical  wires 
arranged  to  foul  the  wings  of  the  hostile  aircraft. 

Airship  Operations. — During  the  early  days  of  the  war  French 
airships  were  employed  for  bombing  behind  the  German  line, 
but  the  damage  to  the  ships,  usually  through  gas  leakage  caused 
by  shell  and  bullets,  was  so  great  that  only  a  limited  amount  of 
work  was  done. 

The  Italian  airships  designed  specially  for  bombing  raids  at 
very  high  altitude  across  the  Adriatic  obtained  considerable 
protection  from  their  height,  and  more  useful  results  appear  to 
have  been  achieved. 

The  Zeppelin  raids  over  England  were  an  interesting  achieve- 
ment from  the  airship  point  of  view.  So  much  of  the  effect 
of  these  raids  was  indirect,  in  the  delays  to  munition  work  during 
raid  nights,  large  amount  of  personnel  and  material  retained  for 
defence,  and  also  iji  the  psychological  effect  produced,  that  it  is 


impossible  to  assess  the  full  value  of  this  work  as  a  warlike 

A  less  well-known  Zeppelin  activity  was  the  patrol  of  the  North 
Sea  in  conjunction  with  the  navy.  These  patrols  were  of  extra- 
ordinary extent  and  thoroughness,  and  must  have  proved  a  most 
valuable  assistance  to  the  naval  authorities.  The  value  of  a 
similarly  thorough  patrol  to  the  British  would  probably  have 
been  even  greater.  British  airship  activity  was  confined  almost 
entirely  to  anti-submarine  work  carried  out  by  non-rigid  ships 
partly  as  patrols  over  definite  areas  and  partly  as  protection 
to  convoys.  As  a  prevention  to  submarine  activity  these  small 
ships  were  extremely  effective,  although  the  number  of  sub- 
marines actually  destroyed  through  their  direct  agency  was 

small.  The  use  of  a  hydrophone  from  an  airship  while  in  flight 
was  being  successfully  developed  at  the  time  of  the  Armistice, 
and  promised  greatly  to  increase  the  effectiveness  of  their  work. 
The  function  of  these  ships  was  to  detect  and  keep  touch  with 
the  submarine  until  the  surface  craft  arrived  with  better  locating 
gear  and  a  much  more  ample  supply  of  explosive  with  which  to 
carry  out  the  actual  destruction.  The  large  ships  did  a  certain 
amount  of  scouting  work  for  the  fleet,  but  this  operation  was 
really  only  in  course  of  development  at  the  time  of  the  Armistice. 
The  number  of  hours  flown  on  patrols  was  over  87,000  and  the 
distance  covered  well  over  two  million  miles. 

One  remarkable  operation  by  the  Zeppelin  Ls7  was  her  flight 
to  East  Africa  for  the  relief  of  the  German  force  there.   She  left 


















cub.  ft. 












Germany:  — 
Zeppelin  L4    .... 
Lio  .... 

L2O   .... 

L30  .... 
L58  .      .      .      . 
L72  .      .      .      . 
"  Bodensee"  (modified) 
Lioo  (design)    . 
Schiitte-Lanz  SL3 
SL6      .      . 
SL8     .      . 
SL20   .      . 
Britain:  — 




















i  -200 





















60-  1 


















1  80 















1  80 


1  06 











R32  (Schiitte-Lanz  type) 

R8o                 .... 


R38  (design)  .... 



























1  6O 









1  20 





MSI                 .... 

Forlanini  5      .... 
Forlanini  6      .... 

Germany:  — 
M.  IV.  E  

Britain:  — 


















46  , 







































20-1  ^ 















1  80 







































North  Sea       .... 
Germany:  — 


France:  — 
Astra  19    
Tunisie            .... 

Zodiac  Vedette     .      .      . 
America:  — 

C                      .... 


NOTE. — The  trials  made  with  the  earlier  ships  were  less  complete  and  less  accurate  than  those  made  later.  The  performance  was  in 
many  instances  calculated  and  recorded  on  a  basis  very  different  from  the  present  standard.  The  figures  given  in  the  table  are,  however, 
the  best  that  can  be  derived  from  the  sources  available. 

The  endurance  depends  upon  the  weight  available  for  petrol  when  a  deduction  from  the  useful  lift  has  been  made  for  crew,  armament, 
stores,  etc.  This  deduction  necessarily  varies  with  different  types  of  ship,  and  the  basis  on  which  it  is  made  is  usually  not  stated  in  the 
records  that  have  been  preserved.  The  endurance  should  not,  therefore,  be  regarded  as  a  reliable  basis  of  comparison.  The  figures  given, 
are  those  for  the  best  ship  of  each  class. 










Jamboli  (Bulgaria)  at  4:30  A.M.  on  Nov.  21  1917  with  over  ten 
tons  of  machine-guns,  ammunition  and  medical  stores.  She  had 
passed  Khartum  when  she  was  recalled  and  landed  again  at 
Jamboli  at  5:30  A.M.  Nov.  25,  having  covered  3,000  m.  in  97 
hr.  with  her  full  load  of  stores. 

The  Atlantic  flight  of  R34  was  slightly  better  in  point  of  time. 
Leaving  East  Fortune,  near  Edinburgh,  at  1:42  A.M.  July  2  1919, 
she  reached  New  York  at  1:54  P.M.  on  July  6  after  108  hr. 
12  min.  in  the  air.  The  return  journey  to  Pulham  in  Norfolk 
occupied  only  75  hours. 

The  longest  flight  by  an  N.S.  airship  was  101  hours.  The 
record  for  an  S.S.  ship  was  51  hr.,  equally  remarkable  when  it  is 
realized  that  the  crew  of  three  were  continuously  on  duty. 

As  indicating  the  regularity  of  the  patrols,  it  is  interesting 
that  in  1918  from  Jan.  to  Nov.  there  were  only  eight  days  on 
which  there  was  no  airship  patrol.  As  showing  the  life  of  a  ship, 
that  of  Coastal  No.  9  at  her  patrol  station  in  Cornwall  may  be 
quoted.  She  was  inflated  on  July  i  1916,  and  deflated  on  Sept.  14 
1918.  During  this  805  days  she  flew  2,500  hr.,  or  an  average 
of  3  hr.  6  min.  per  day,  over  the  whole  period.  The  deduction 
to  be  drawn  from  the  airship  operations  carried  out  appears  to 
be  that  for  future  warlike  operations  their  duties  will  be  limited 
to  those  areas  where  intense  hostile  anti-aircraft  fire  or  hostile 
aeroplanes  are  unlikely  to  be  met.  With  this  reservation  their 
uses  are  likely  to  be  the  same  as  in  the  past  war,  with  a  very 
important  extension  to  work  over  undeveloped  country,  the 
airships  acting  as  patrols  and  for  the  transport  of  stores.  The 
use  of  a  large  airship  as  a  carrier  from  which  fighting  or  bombing 
aeroplanes  could  be  released,  and  to  which  they  could  return, 
was  considered.  An  aeroplane  was  on  two  occasions  dropped 
from  a  rigid  airship  with  no  inconvenience  or  danger  to  the  pilot. 
Arrangements  for  the  complementary  process  of  hooking  on 
again  were  not  completed  at  the  time  of  the  Armistice. 

For  passenger  and  goods  transport  over  distances  longer  than 
the  aeroplane  can  profitably  cover  at  one  stage  the  airship  has 
important  advantages.  By  eliminating  the  time  spent  at  inter- 
mediate stops  and  by  flying  day  and  night  with  the  passengers 
in  reasonable  comfort,  the  effective  speed  over  a  long  journey  is 
probably  greater  than  that  of  the  aeroplane.  To  this  must  be 
added  the  ability  to  make  long  ocean  passages  in  safety  and  so  to 
select  a  course  as  to  take  advantage  of  trade  winds  or  local 
meteorological  conditions. 

German  commercial  airship  activity  was  already  in  1921  very 
completely  planned  and  was  only  suspended  by  the  restrictions 
of  the  Peace  Treaty.  The  "  Bodensee  "  had  already  carried  out 
a  remarkable  series  of  flights  between  Berlin  and  Friedrichshafen, 
making  100  flights  in  97  days  and  carrying  in  all  2,300  passengers. 
The  ship  has  now  been  enlarged  and  a  sister  ship  built  in  order 
to  extend  the  flights  to  Scandinavia.  Larger  ships  and  an  ex- 
tension of  the  service  to  London  and  other  capitals  were  con- 
templated, and  a  service  of  ships  of  considerably  larger  size  from 
Cadiz  to  N.  and  S.  America  was  planned. 

Mooring  and  Handling. — The  earliest  activity  of  airships  had  been 
limited  rather  by  the  ability. to  handle  them  on  the  ground  than  by 
their  ability  to  meet  weather  conditions  in  flight.  British  Rigid  Air- 
ship No.  I  was  moored  by  the  bow  to  a  mast  and  sheltered  by  a  screen 
on  Cavendish  Dock,  Barrow,  before  the  ship  was  flown.  This  trial 
was  successful,  the  ship  remaining  safe  during  winds  with  gusts 
up  to  48  m.  an  hour.  In  the  course  of  these  trials  the  screen  was 

The  Royal  Aircraft  Factory  in  1912  devised  and  used  continuously 
for  many  months  a  new  form  of  mooring  mast  to  which  a  non-rigid 
airship  was  attached  while  floating  in  the  air.  To  prevent  the  ship 
overriding  the  mast  in  gusty  weather  and  to  facilitate  approach, 
the  mast  carried  at  its  head  a  swinging  cone  duly  counterpoised, 
into  which  the  nose  of  the  airship  was  drawn  by  a  rope  running  down 
the  inside  of  the  mast.  The  cone  was  free  to  rotate  about  the  axis 
of  the  mast  as  well  as  to  rock  vertically  on  a  universal  joint  and  the 
mast  functioned  satisfactorily,  save  that  side  gusts  caused  the  cone 
to  rub  the  bows  of  the  ship  with  a  tendency  to  bend  it.  These  mast 
moorings  were  the  precursors  of  one  of  the  great  developments  in 
airship  use,  but  till  they  were  adopted  generally  the  airship  had  to 
fie  housed  in  a  shed,  and  hence  the  activity  of  the  ship  was  limited 
to  those  occasions  when  it  was  possible  to  take  her  out  in  winds  of  less 
than  10  or  15  m.  an  hour  with  a  reasonable  chance  of  rehousing 
her  under  equally  good  conditions. 

Under  war  conditions  this  restriction  was  serious,  and  the  method 

of  the  mooring  mast  was  again  examined.  A  non-rigid  envelope 
rigged  with  a  dummy  car  was  secured  to  the  head  of  a  mast  at  Kings- 
north,  first  with  a  cone  but  later  with  the  cone  removed.  The  ship 
was  reinforced  to  take  the  pull  of  the  mast,  by  fitting  inside  her  bow 
a  spar,  the  after-end  of  which  was  supported  by  a  cone  of  cords  led 
slightly  forward  and  secured  round  a  circle  on  the  inside  of  the  en- 
velope. The  tension  in  the  fabric  of  the  envelope  and  in  these  cords 
held  the  spar  rigidly,  and  supplied  the  reinforcement  which  was 
necessary  for  stiffening  the  bow  of  the  envelope  while  in  flight  and 
also  for  mooring. 

A  further  set  of  experiments  was  carried  out  at  Barrow  with  a  ship 
secured  to  a  short  stump  mast,  attached  to  her  mooring  point  and 
stepped  on  a  lighter.  The  point  of  attachment  was  not  on  the  axis. 
Indeed,  it  was  so  low  on  the  envelope  that  side  gusts  produced  se- 
rious rolling.  Accordingly  a  form  was  devised  in  which  a  somewhat 
taller  mast  was  fitted  with  a  horseshoe  head,  so  that  fittings  carried 
at  the  top  of  its  arms  could  be  attached  to  suitably  reinforced  points 
aft  of  the  nose  of  the  envelope.  This  gave  support  against  rolling, 
but  the  point  of  attachment  was  some  distance  aft  on  the  ship,  and 
consequently  the  steadiness  was  not  quite  so  good  as  when  the  en- 
velope was  attached  by  its  extreme  bow  point. 

Definitely  comparative  tests  between  mooring  at  the  nose,  using 
the  spar  inside  the  bow  of  the  envelope  and  using  the  horseshoe  mast 
were  carried  out  at  Pulham.  After  considerable  time  the  internal 
spar  of  the  former  broke,  for  a  reason  that  was  not  explained,  and  the 
horseshoe  mast  was  preferred.  As,  however,  other  means  were  found 
for  mooring  the  small  ships  at  advanced  patrol  stations,  the  horse- 
shoe was  little  employed. 

Mast  mooring  was,  however,  realized  to  be  important  for  rigid 
airships,  and  prolonged  trials  with  R24  secured  to  the  head  of  a  mast 
at  Pulham  were  instituted  in  July  1919  with  success.  The  ship 
later  remained  continuously  at  the  mast  for  70  days  and  experienced 
winds  up  to  35  with  gusts  of  43  m.  per  hour.  Difficulty  was  experi- 
enced in  taking  the  ship  to  the  mast  in  any  but  light  winds. 

Experiments  were  continued  with  R33  on  Feb.  2  1921,  and  up  to 
the  beginning  of  June  1921  the  ship  had  worked  entirely  from  the 
mast.  On  a  few  occasions  she  had  been  into  the  shed,  but  never  for 
more  than  five  days.  During  April  and  May  1921  she  averaged 
between  four  and  five  flights  per  week.  In  this  case  the  mast  is 
provided  at  its  upper  end  with  a  single  arm,  pivoted  at  its  middle 
point.  Down  the  centre  of  this  arm  passes  the  wire  rope,  which  is 
attached  to  that  dropped  by  the  ship  and  by  which  she  is  hauled  in. 
This  arm,  therefore,  comes  in  contact  with  the  bow  of  the  ship  before 
that  has  actually  reached  the  head  of  the  rigid  mast,  and  gives  im- 
proved safety  as  the  ship  approaches  the  masthead.  Difficulty  was 
experienced  with  the  control  of  the  winch  which  hauls  in  the  ship's 
wire.  In  the  experiments  with  R24  a  kite-balloon  winch  was  em- 
ployed and  abandoned  owing  to  its  irregular  action  and  control. 
For  the  experiments  with  R33  a  steam  ploughing  engine  was  used 
temporarily  and  found  to  be  satisfactory. 

The  process  of  landing  to  the  mast  consists  in  the  airship  dropping 
to  the  ground  a  rope  some  1,000  ft.  in  length,  which  is  then  secured 
to  the  rope  led  from  the  winch  up  the  centre  of  the  mast  and  down 
to  the  ground.  The  winch  hauls  in  these  ropes  and  draws  the  ship  to 
the  masthead.  There  is  no  difficulty  until  the  ship  comes  within  some 
200  ft.  of  the  masthead,  but  as  this  distance  decreases  there  is  a 
tendency  of  the  ship  to  swing  both  sideways  and  fore  and  aft,  under 
the  influence  of  gusts  of  wind.  This  difficulty  is  less  serious  when  the 
ship  is  trimmed  somewhat  down  by  the  stern,  so  that  the  wind  force 
on  the  bow  is  approximately  in  the  same  direction  as  the  tension  in 
the  wire.  If  this  arrangement  is  not  made,  the  variation  in  the  wind 
force  causes  swinging  of  the  bow  of  the  ship,  and  a  tendency  to  over- 
ride and  strike  the  head  of  the  mast. 

Even  with  the  stern  of  the  ship  trimmed  considerably  down,  there 
was  still,  owing  to  disturbed  conditions,  a  distinct  tendency  to  swing- 
ing, and  it  was  often  desirable  to  employ  side-guys  led  from  the  bow 
of  the  ship  to  fixed  points  on  the  ground,  in  order  to  guide  the  bow  to 
the  masthead.  With  these  arrangements,  it  was  possible  to  secure  a 
6o-ton  ship  to  the  head  of  the  mast  in  winds  of  30  m.  an  hour,  with 
not  more  than  eight  men  in  addition  to  those  actually  in  the  ship. 

During  the  time  that  R33  was  secured  to  the  Pulham  mast,  an 
engine  was  hoisted  out  and  replaced  by  a  spare,  and  a  gasbag  was 
deflated  and  replaced  by  a  spare. 

Three-Wire  System  of  Mooring. — As  an  alternative  to  the  system 
of  mooring  an  airship  to  a  mast,  and  as  a  more  temporary  arrange- 
ment, the  "three-wire  system"  was  developed  from  one  in  which  the 
ship  was  secured  by  her  mooring-point  to  the  head  of  a  pyramid 
formed  of  three  cables,  the  lower  ends  of  which  were  secured  to  the 
points  of  an  equilateral  triangle  of  some  800  ft.  side. 

The  height  of  the  apex  was  arranged  to  be  between  100  and  200  ft. 
in  order  that  the  downward  component  of  the  wires  when  resisting 
the  wind  force  should  not  be  excessive.  A  considerable  weight  of 
wire  was,  however,  necessarily  supported  by  the  ship,  and  a  large 
amount  of  static  lift  was  therefore  necessary.  This  system  gave 
considerable  success  during  1918,  but  was  found  defective  in  gusty 
winds  owing  to  the  liability  of  one  wire  going  slack  under  the  influ- 
ence of  side  gusts.  A  wind  along  the  axis  of  the  ship  produces  a 
certain  amount  of  dynamic  lift  which  balances  the  downward  com- 
ponent due  to  the  tension  in  the  wire.  The  force  caused  by  a  side- 
ways gust  produces  no  corresponding  increase  of  dynamic  lift,  and 


there  is,  therefore,  a  tendency  for  the  lee  wire  to  go  slack.  When  the 
gust  ceases  and  this  wire  draws  taut,  a  serious  impulse  is  brought  on 
the  bow  of  the  ship. 

It  was  also  found  that  the  wires  of  this  system  were  so  nearly 
horizontal  that  they  fouled  the  car  of  R33- 

To  overcome  these  difficulties,  a  running  system  was  devised. 
Various  alternative  forms  were  tried  giving  varying  degrees  of 
rigidity  of  support.  The  final  system  which  has  been  found  most 
satisfactory  is  that  shown  in  fig.  26.  This  has  the  additional  advan- 

Gl.  G2.  G3.   Denotes  swivelling   Pulley  attached  to  Ground  Bollards 
S.  Denotes  Mooring  Point.  A.  B.C.  Denotes  Rings. 

FIG.  26. 

tage  that  only  the  comparatively  short  wires,  SA,  SB,  and  SC,  are 
carried  in  the  ship,  the  remainder  of  the  wires  lying  on  the  ground  and 
being  picked  up  when  the  ship  lands.  Complete  experiments  with 
this  system  have  not  been  carried  out,  but  it  is  considered  that  a 
ship  could  withstand  any  ordinary  wind  forces  when  secured  in  this 
way.  She  would  be  much  more  difficult  to  secure  in  this  way  than 
to  a  mast,  and  could  not  be  easily  supplied  with  water  ballast,  fuel 
or  additional  gas. 

In  order  to  meet  the  greatly  increased  requirements  for  small  air- 
ships for  anti-submarine  patrol  during  the  war,  a  system  of  mooring- 
out  grounds  was  developed.  These  mooring-out  stations  were  formed 
by  making  clearings  in  suitable  woods  and  cutting  a  comparatively 
narrow  avenue  through  the  wood  to  the  clearing.  Small  airships 
were  secured  in  these  clearings,  and  re-fuelled  and  repaired  in  exactly 
the  same  way  as  in  proper  sheds.  The  protection  was  so  good  that 
ships  have  been  totally  undamaged  even  though  winds  of  60  m.  an 
hour  were  blowing  over  the  top  of  the  wood  at  the  time. 

Airship  Sheds. — The  construction  of  airship  sheds  has  been  an 
important  item  in  the  expense  of  airship  work.  The  cost  of  the  shed 
increases  very  rapidly  with  height  and  with  the  span,  both  of  which 
must  be  considerable  with  any  but  the  very  small  ships.  Apart  from 
the  cost  of  the  shed,  there  is  considerable  difficulty  in  taking  a  ship 
into  the  shed  in  any  but  very  calm  weather.  When  a  wind  is  blow- 
ing across  the  mouth  of  the  shed,  the  airship  has  to  be  hauled  broad- 
side on  to  the  wind  in  order  to  pass  in  through  the  door,  and  this 
represents  a  very  difficult  operation  when  the  wind  is  of  considerable 
strength  or  of  a  gusty  nature.  In  order  to  afford  protection  during 
this  operation,  all  early  airship  sheds  were  provided  with  wind- 
screens running  from  the  corners  of  the  shed  outwards  parallel  to 
the  axis.  These  screens  were  of  a  height  nearly  equal  to  that  of  the 
shed,  and  afforded  considerable  protection  against  the  horizon- 
tal force  of  the  wind.  They,  however,  caused  a  serious  eddy  to  be 
formed,  which  produced  a  vertical  disturbance  on  the  ship  nearly 
as  difficult  to  overcome  as  the  horizontal  force  which  would  have 
existed  had  there  been  no  wind-screens  present.  Experiments  were 
carried  out  with  the  wind-screens  formed  of  expanded  metal,  and 
with  screens  of  corrugated  iron  in  which  30  %  of  the  sheeting  had  been 
omitted.  These  screens,  although  they  reduced  the  horizontal  wind 
to  a  smaller  extent  than  the  solid  screens,  avoided  the  serious  vertical 
air  disturbance  and  were,  for  that  reason,  considerably  preferable. 

Experience  in  Germany  had,  however,  shown  that  a  system  of 
rails  provided  with  easily  running  trolleys  was  the  most  satisfactory 
system  of  supporting  the  ship  against  sideways  forces.  These  rails 
ran  out  from  the  corners  of  the  shed  parallel  to  the  axis,  and  the 
side-guys  of  the  ship  were  attached  to  trolleys  running  on  these 
rails.  The  support  of  the  ship  obtained  in  this  way  is  so  good  that 
wind-screens  are  rendered  unnecessary,  and  the  vertical  air  disturb- 
ance connected  with  them  is  thereby  avoided.  Even  with  this  sys- 
tem of  handling  rails,  the  housing  of  an  airship  presents  considerable 
difficulties.  A  landing  party  of  several  hundred  men  is  required  to 
receive  a  6o-ton  airship  on  the  landing  ground,  to  carry  her  to  the 
end  of  the  handling  rails  and  to  haul  her  round  parallel  to  the  rails. 
The  air  in  the  neighbourhood  of  the  shed  is  necessarily  so  disturbed 
that  considerably  greater  difficulty  is  experienced  near  the  shed  than 
when  on  the  open  landing  ground  or  in  the  neighbourhood  of  a  moor- 
ing mast.  The  difficulties  connected  with  airship  sheds  are,  there- 
fore, considered  to  be  so  great  that  the  shed  must  only  be  regarded 
as  the  dock,  the  mooring  mast  being  regarded  as  the  normal  method 
of  securing  an  airship  between  flights. 

When  secured  to  the  mast  the  airship  can  be  supplied  with  gas, 
water  ballast  and  fuel.  The  passengers  can  be  passed  up  the  mast 
by  a  lift  and  can  walk  through  the  bow  of  the  ship  down  to  the  cabin. 
The  airship  appears  to  behave  satisfactorily  in  any  wind.  The  most 

difficult  conditions  to  meet  are  those  in  which  there  is  no  wind  but 
rapid  changes  of  temperature  which  affect  the  lift  of  the  ship. 
Tiiis  necessitates  rapid  adjustment  of  the  ballast  in  the  ship  by 
taking  in  or  discharging  water.  As  long  as  there  is  a  considerable 
wind  the  trim  can  be  regulated  by  the  elevators,  as  in  flight. 

Attempts  have  been  made  to  anchor  a  ship  to  the  ground  by  a 
single  wire.  This  operation  would  have  considerable  advantages 
for  a  ship  which  became  broken  down  and  required  to  avoid  drifting 
with  the  wind.  At  sea  a  drogue  can  be  lowered  into  the  water,  and 
the  ship  will  ride  to  it  satisfactorily  provided  she  is  correctly  trimmed 
some  five  degrees  up  by  the  bow  in  order  to  derive  the  necessary 
dynamic  lift.  It  is,  however,  necessary  to  steer  the  ship  continuously 
while  secured  in  this  way,  exactly  as  though  in  flight.  Anchoring 
to  the  ground  is  a  considerably  more  difficult  problem.  A  grapnel 
cannot  obtain  a  sufficiently  firm  hold  to  resist  the  impulsive  upward 
pull  in  the  airship  trail  rope.  Experiments  were  carried  out  with  a 
form  of  dropping  grapnel  consisting  of  a  large,  suitably  shaped  weight 
dropped  from  a  height  of  some  200  feet.  This  grapnel  obtained  a 
satisfactory  hold  either  on  very  hard  ground  or  on  soft  ground 
where  the  penetration  was  very  deep.  The  hold  was,  however,  quite 
unyielding,  and  the  shock  produced  on  the  ship  when  thus  checked 
was  far  too  serious.  Various  forms  of  friction  device  to  allow  a  grad- 
ual check  to  be  brought  on  the  ship  were  tried,  but  were  never  found 
sufficiently  satisfactory  for  adoption. 

Towing. — The  earliest  test  in  connexion  with  airship  towing  is 
perhaps  the  most  interesting  one.  Naval  Airship  No.  2  broke  down 
about  40  m.  from  Farnborough,  and  in  order  to  save  the  loss  of  gas 
and  the  probable  damage  to  the  ship  that  would  have  attended  her 
deflation,  she  was  towed  home  by  another  airship, ' '  Eta, "  of  a  slightly 
greater  size.  The  operation  presented  no  difficulty  whatever.  "  Eta  " 
landed  alongside  the  damaged  ship;  a  wire  some  600  ft.  in  length 
was  laid  out  between  the  two  ships;  both  ships  were  made  light 
and  allowed  to  rise  into  the  air.  The  towing  ship  then  went  ahead 
slowly  and  towed  the  disabled  one  back  to  Farnborough. 

Occasion  for  repeating  this  towing  operation  has  not  since  pre- 
sented itself,  but  the  complete  success  which  attended  the  first 
attempt  indicates  that  there  is  no  serious  difficulty  in  connexion 
with  it.  It  is  probable  that  for  certain  special  purposes,  where  large 
weights  have  to  be  carried  and  where  speed  is  not  of  great  importance, 
the  towing  of  one  or  more  "  air  barges  "  by  an  airship  presents  very 
interesting  possibilities. 

Naval  Towing. — Various  trials  were  made  to  determine  the  possi- 
bility of  towing  an  airship  to  the  scene  of  operations  so  that  she 
should  arrive  there  with  her  full  supply  of  petrol  still  available. 

In  May  1916  a  Coastal  airship  was,  after  a  few  preliminary  tests 
with  a  motor  launch,  towed  by  a  light  cruiser  steaming  at  26  knots 
up,  down  and  across  a  wind  of  some  15  knots.  In  a  further  trial 
the  airship  was  hauled  down  to  the  deck  of  the  cruiser  and  the  crew 
changed  and  gas  and  fuel  supplied.  The  same  operation  was  carried 
out  at  a  height  of  150  ft.  to  provide  for  occasions  when  the  sea  was 
too  bad  to  allow  the  airship  to  be  brought  close  down.  These  trials 
were  entirely  satisfactory. 

In  Aug.  1918  a  ship  of  the  S.S.  class  carried  out  extended  trials  in 
tow  of  a  submarine.  These  caused  no  difficulty  except  that  it  was 
desired  to  make  the  ship  capable  of  being  towed  without  a  crew. 
Arrangements  for  the  automatic  maintenance  of  pressure  and  the 
greater  degree  of  stability  required  caused  the  extension  to  this  much 
more  difficult  operation  to  be  abandoned. 

In  Nov.  1918  the  towing  of  an  S.S.  ship  by  a  destroyer  was  again 
actively  being  developed  with  a  view  to  replacing  kite-balloons  by 
airships  for  convoy  work.  In  Aug.  1919  N.S-7  carried  out  a  long  tow- 
ing operation  with  the  fleet.  She  was  in  tow  continuously  for  some 
40  hrs.,  and  was  gassed  and  refuelled  in  a  wind  of  30  knots. 

The  conclusion  to  be  drawn  from  these  tests  is  that  an  airship 
can  be  towed  without  difficulty  provided  she  is  steered  and  handled  as 
in  flight.  The  towing  is  little  relief  to  the  crew,  but  the  expenditure 
of  fuel  is  avoided.  The  crew  can  be  changed  and  fuel  and  gas  can  be 
supplied  in  reasonably  fair  weather. 

Airship  Fabrics. — The  outer  cover  of  a  rigid  airship  has  to  form 
a  smooth  fairing  over  the  hull  structure  and  gasbags.  Unless  it 
remains  taut  under  all  conditions  the  passage  of  air  over  it  and 
more  particularly  the  disturbed  air  in  the  vicinity  of  the  airscrews 
gives  rise  to  flapping,  which  not  only  increases  the  ship's  resistance 
but  may  cause  the  cover  to  chafe  and  ultimately  be  torn.  The  taut- 
ness  is  produced  and  maintained  by  a  dope,  applied  to  the  fabric 
partly  before  and  partly  after  the  sheets  of  fabric  are  laced  to  the 
hull  framework.  The  dope  is  generally  similar  to  that  used  on  aero- 
plane wings,  but  the  unsupported  expanses  of  fabric  are  so  large — 
usually  3  metres  by  5  metres — that  the  prevention  of  flapping  is  a  much 
more  difficult  problem ;  indeed,  these  surfaces  are  so  large  that  the 
maintenance  of  a  correct  difference  of  pressure  between  the  inside 
and  the  outside  of  the  ship  is  more  effective  than  exactly  correct 
tautness.  The  weight  of  the  outer  cover  is  such  a  large  proportion 
of  the  total  of  the  ship  that  very  great  care  must  be  taken  to  apply 
only  the  minimum  of  dope  necessary. 

The  outer  surface  must  be  made  reflecting  in  order  to  reduce  as 
far  as  possible  the  amount  of  radiant  heat  absorbed  and  transmitted 
to  the  gas  in  the  cells  and  the  air  inside  the  hull. 

The  pigment  or  dye  employed  in  the  dope  must  be  such  that  the 
part  of  the  light  which  most  rapidly  deteriorates  the  cellulose  of  the 



gas  cells  is  eliminated  as  far  as  possible.  A  certain  amount  of  light 
is  necessary  in  the  keel,  and  this  usually  enters  through  the  bottom 
two  strakes  of  outer  cover  on  which  a  transparent  dope  is  used.  The 
surface  of  the  dope  should  be  water-repellent  in  order  to  reduce  the 
weight  of  water  taken  up  in  a  rainstorm. 

The  fabric  usually  employed  for  the  outer  cover  is  linen  weighing 
about  90  grms.  sq.  metre,  although  cotton,  mercerised  as  thread  before 
weaving,  appears  to  have  some  advantages  owing  to  its  great  uni- 
formity of  contraction  when  doped. 

Gasbag  fabric  must  primarily  have  good  gasholding  properties  for 
the  minimum  weight.  The  strength  need  only  be  sufficient  to  with- 
stand handling  when  the  bags  are  being  placed  in  the  ship  or  are 
moving  slightly  with  change  of  fullness. 

Goldbeaters'  skin — a  thin  membrane  from  the  caecum  of  the  ox — 
although  easily  permeable  to  moisture  is  extremely  gaslight  when 
in  good  condition.  The  skins  vary  in  size,  but,  allowing  for  over- 
laps, each  skin  covers  about  10  in.  by  4  in.  In  English  gasbags  the 
skins  are  attached  to  the  fabric  by  rubber  solution,  as  this  gives 
rather  better  gastightness  for  a  given  weight.  The  German  method  is 
to  build  up  the  skins  into  large  sheets  some  10  metres  wide  and  of 
length  equal  to  the  circumference  of  the  bag.  Fabric  is  then  stuck 
to  these  sheets  with  a  form  of  gelatine  adhesive.  Skin  contracts  as 
it  dries,  whereas  fabric  contracts  as  it  absorbs  moisture;  great  care 
has,  therefore,  to  be  taken  that  the  fabric  is  attached  to  the  skin 
sheet  under  correct  humidity  condition.  The  fabric  in  which  rubber 
is  used  as  the  adhesive  is  found  to  give  trouble  in  hot  climates,  owing 
to  the  serious  contraction  of  the  skins  and  the  softening  of  the  adhe- 
sive just  when  good  adhesion  is  most  essential. 

German  experts  are  strongly  of  the  opinion  that  the  use  of  rubber 
in  gasbags  forms  a  non-conducting  surface  apt  to  become  electrically 
charged  by  friction  or  in  the  vicinity  of  an  electric  storm.  The  use 
of  rubber  has,  therefore,  been  abandoned  in  Germany  since  very 
early  days. 

Fabric  made  with  glue  adhesive  appears  satisfactory  even  under 
the  most  extreme  tropical  heat. 

The  envelope  fabric  of  a  non-rigid  or  semi-rigid  ship,  in  addition 
to  being  gaslight,  must  have  an  outer  surface  capable  of  giving  pro- 
leclion  againsl  light  and  heat.  It  is  also  called  upon  to  take  very 
considerable  tensile  stresses.  These  are  due  partly  to  local  tensions 
in  the  neighbourhood  of  rigging  attachments;  partly  to  a  bending  of 
the  envelope  as  a  whole,  but  mainly  to  the  internal  pressure  which 
is  necessary  in  order  to  maintain  the  shape  of  this  class  of  ship.  When 
the  ship  takes  up  a  steep  angle  of  pitch  there  is  considerable  accumu- 
lation of  pressure  at  the  upper  end,  and  if  for  any  reason,  such  as  a 
rapid  rise,  Ihe  pilot  allows  the  pressure  lo  become  excessive  Ihe  len- 
sion  in  Ihe  envelope  is  more  likely  to  approach  the  safe  maximum 
than  from  any  other  cause.  The  tension  induced  by  internal  pres- 
sure is,  therefore,  the  main  consideration  and  must  be  regarded  as  a 
load  thai,  although  not  very  suddenly  applied— the  interval  between 
normal  and  maximum  being  at  least  15  seconds — cannot  be  expected 
to  be  maintained  for  long  periods — say,  more  than  15  minutes.  The 
resistance  of  fabric  to  tension  varies  greatly  with  the  rate  at  which 
the  load  is  applied.  For  a  high  rate  of  loading — say,  150  Ib./in./min. 
— the  load  reached  before  failure  is  10  to  20%  higher  than  the  load 
reached  with  the  comparatively  slow  rate  of  30  Ib./in./min.  or  less. 

A  load  sustained  for  really  long  periods  gives  lower  strength  still. 
A  load  of  only  50  to  60%  of  that  which  the  material  will  stand  for, 
say,  10  minutes  will  break  it  after  a  week. 

Considerably  more  investigation  on  these  points  is  still  required, 
but  they  are  probably  due  to  the  manner  of  failure  of  a  woven  mate- 
rial, being  one  of  gradual  slipping  of  the  fibres  of  the  twisted  thread. 

A  small  local  cut  produces  considerable  reduction  of  tensile 
strength  of  an  ordinary  fabric.  This  is  due  to  the  concentration  of 
stress  at  the  ends  of  the  cut  causing  the  failure  of  individual  threads 
in  succession.  Provided  the  cut  is  more  than  J  in.  long  across  Ihe 
direclion  of  tension  Ihe  reduction  of  strength  is  to  some  30  %  to  40  % 
of  the  unwounded  strength  and  is  no  greater  until  the  size  of  the 
cut  is  such  that  it  becomes  an  important  proportion  of  the  whole 
width  of  fabric  in  tension.  In  order  to  reduce  this  loss  of  strength 
fabric  exposed  to  serious  tension  is  usually  made  of  2  or  3  plies,  of 
which  one  has  its  Ihreads  at  45°  to  those  of  the  other  plies  which  lie 
along  and  normal  to  the  direction  of  tension.  The  threads  of  the 
diagonal  ply  help  to  redistribute  the  concentration  of  stress  at  the 
ends  of  the  cut.  The  extent  of  this  reinforcemenl  depends  upon  Ihe 
comparalive  slrength  of  the  diagonal  ply  and  upon  the  nature  of 
the  material  with  which  the  plies  are  stuck  together.  The  table 
shows  with  an  accuracy  of  about  5  %  the  wounded  and  unwounded 
strengths  of  typical  airship  fabrics  built  up  of  one  or  more  plies  of 
the  same  cotton  and  expressed  as  percentages  of  that  of  single  ply, 
the  adhesive  being  in  each  case  rubber. 




Single  ply 
2-ply  parallel 
2-ply  diagonal  .        .        . 
3-ply  parallel     . 
3-ply  centre-ply  diagonal 




1  20 

Rubber  is  particularly  suilable  as  a  doubling  adhesive  as  it  allows 

the  requisite  movement  of  threads  for  the  reinforcement  to  take 
place.  Glue,  being  a  much  more  rigid  adhesive,  will  allow  of  prac- 
tically no  reinforcing  action  by  the  diagonal  ply. 

Rubber  is  also  a  reasonably  good  gasproofing  material  and  as  it 
combines  these  two  qualities  it  is  almost  universally  employed  in  the 
construction  of  non-rigid  airship  envelopes.  The  fabric  used  for  the 
envelopes  of  the  N.S.  airship  was  made  of  three  plies  of  a  cotton 
weighing  80  grms./sq.  metre.  The  outer  surface  as  a  protection  from 
light  and  heat  was  of  50  grms.  of  rubber  containing  a  proportion  of 
black  litharge  and  a  surface  of  aluminium  powder.  Between  the 
outer  and  diagonal  ply  was  30  grms.  of  rubber  and  between  the 
diagonal  and  inner  ply  100  grms.  of  rubber  as  a  gastight  layer;  some 
more  recent  experiments  show  that  additional  protection  is  given 
to  the  rubber  by  staining  it  with  a  suitable  red  dye. 

Gastightness  of  most  materials  decreases  considerably  (4  or  5% 
per  degree  Centigrade)  with  increases  of  temperature. 

A  film  of  gelatine  gives  the  greatest  gastightness  for  a  given  weight, 
but  its  proteclion  against  the  effects  of  moisture  is  a  matter  of  con- 
siderable difficulty  which  has  only  recently  been  achieved  with  any 
degree  of  success  in  compound  films  now  being  developed. 

Goldbeaters'  skin  is  almost  equally  good,  but  is  liable  to  small 
local  defects  caused  in  the  process  of  preparation  and  building  up. 

An  extract  of  the  plum,  cordia  myxa  or  Turkish  birdlime,  has 
given  satisfactory  results  in  some  respects,  but  its  use  has  not  been 
very  fully  developed. 

It  is  important  to  realize  that  gastight  fabric  for  airships  must 
primarily  stop  the  leakage  of  air  into  the  gas.  Loss  of  hydrogen  is 
too  small  to  be  important,  but  the  ingress  of  a  weight  of  air  definitely 
reduces  the  useful  lift  of  the  ship  by  an  equal  weight  and  this  can 
only  be  partially  got  rid  of  even  by  the  discharge  of  many  times  the 
volume  of  gas. 

Airship  Machinery. — In  the  early  days  the  machinery  of  airships 
and  aeroplanes  had  to  be  extremely  light.  As  development  pro- 
ceeded, the  greater  length  of  flight  of  the  airship  made  fuel  economy 
and  some  other  characteristics  of  greater  importance  in  the  airship 
than  in  the  aeroplane.  In  England  neglect  of  airships  before  the  war 
followed  by  difficullies  of  supply  during  Ihe  war  caused  the  airships 
to  use,  not  a  special  engine  suitable  for  this  requirement,  but  stand- 
ard aeroplane  engines.  This  general  unsuitability  of  the  engines 
used  for  airship  work  caused  the  machinery  to  be  by  far  the  most 
unreliable  part  of  the  airship  as  a  patrol  unit. 

The  advent  of  the  commercial  aeroplane  for  long  flights  is  in 
turn  bringing  a  requirement  more  nearly  that  of  the  airship.  Even 
so,  an  aeroplane  which  flies  10  hrs.  before  refuelling  must  be  com- 
pared with  the  airship  which  flies  TOO  hrs.  on  one  load  of  fuel.  A 
machinery  installation  which  weighs,  say,  5  Ib.  per  H.P.  burns  0-5 
Ib.  of  fuel  per  H.P.  in  one  hour.  An  aeroplane  in  10  hrs.  will  burn 
a  weight  of  fuel  equal  to  that  of  its  machinery.  In  100  hrs.  an 
airship  will  burn  ten  times  its  machinery  weight.  The  importance  of 
saving  fuel  even  at  the  expense  of  increased  machinery  weight  is 
therefore  much  greater  in  the  airship.  During  much  of  the  airship's 
flighl  some  engines  are  run  at  considerably  less  than  their  full  power, 
thus  introducing  the  need  for  good  fuel  economy  at  reduced  power. 
In  an  airship  repairs  of  some  magnitude  can  be  made  in  flight  (a 
cylinder  has  been  changed,  cracked  water-jackets  patched,  magne- 
tos changed  and  retimed,  etc.,  during  long  flights).  The  machinery 
must  therefore  be  arranged  so  that  advantage  can  be  taken  of  this 

Arrangement  of  Power  Units. — The  low  speed  of  an  airship  renders 
desirable  a  larger  airscrew  than  in  the  faster  aeroplane.  Moreover, 
airscrew  size  is  not  restricted  by  the  consideration  of  landing  as  in 
the  aeroplane.  The  large  airscrew  makes  for  fuel  economy,  and  this 
being  cardinal  has  been  found  to  justify  the  use  of  reduction  gearing. 
The  most  efficient  arrangemenl  for  a  rigid  airship  includes  a  fly-wheel 
fitted  to  the  crank-shaft  of  the  engine  driving,  through  a  friction 
clutch,  a  gear  reduction  box  on  which  is  mounled  a  large  two-bladed 
airscrew.  In  R38  350  B.H.P.  is  transmitted  through  a  3-3:1  reduc- 
tion gear  to  a  I7i-ft.  airscrew,  turning  at  600  revs,  for  a  ship's  air 
speed  of  60  knots.  There  is  usually,  in  addition,  a  dog  clutch  and  an 
airscrew  brake,  so  that  the  airscrew  can  be  disconnected  and  locked 
horizontal  when  landing.  The  departure  from  aeroplane  praclice 
is  here  notable. 

In  early  airships  it  was  usually  necessary  to  mount  the  engines  in 
the  car  and  to  transmit  the  power  to  airscrews  carried  on  outriggers. 
The  weight  available  for  this  transmission  was  so  small  that  there 
was  frequent  trouble,  which  could  mostly  be  traced  to  resonance  at 
some  speed  within  the  very  wide  range  (often  from  1 00%  to  50% 
of  the  revolutions  for  full  speed)  over  which  the  airship  engine  was 

Belts,  chains,  bevel-gear  boxes  with  long  lengths  of  shafting  were 
used,  but  all  gave  trouble  within  a  few  hundred  hours'  flight. 

German  rigid  airships  derived  great  benefit  from  the  Maybach 
engine,  which  was  developed  at  the  same  time  as  the  ship's  designs 
progressed,  and  was  devised  primarily  to  be  suitable  for  airship  pur- 
poses. It  departed  from  other  aero-engine  practice  in  many  respects, 
and  though  it  was  not  till  quite  late  in  the  war  that  a  modified  type 
of  a  Maybach  was  used  in  aeroplanes,  the  German  industry  gained 
the  earliest  experience  of  large  light-weight  engines. 

Jn  the  British  airships  constructed  during  the  war  there  was  no 
intermediate  shafting,  the  airscrew  being  mounted  on  the  engine. 



In  some  cases  a  reduction  gear  was  incorporated  in  the  engine  itself. 
In  the  first  ships  of  the  N.S.  class  a  length  of  shafting  was  used  in 
order  to  give  a  better  shape  to  the  engine  car  and  obtain  better  air- 
screw efficiency.  This  shafting  had  ultimately  to  be  abandoned  on 
account  of  torsional  resonance,  and  the  airscrew  mounted  direct 
on  the  engine.  In  the  German  rigid  airships,  however,  where  more 
weight  was  available,  the  reduction  gear  box  and  intermediate  shaft- 
ing were  employed. 

Pre-war  British  airships  and  the  first  few  rigids  were  fitted  with 
swivelling  propellers.  The  airscrews  were  carried  at  the  ends  of 
horizontal  arms  and  driven  through  bevel  gearing  so  that  the  axis  of 
the  airscrew  could  be  rotated  about  a  horizontal  transverse  axis, 
and  the  direction  of  thrust  of  the  airscrew  changed  from  ahead  to 
astern,  up  or  down.  The  ability  to  exert  a  vertical  force  independent 
of  the  headway  of  the  ship  was  often  very  valuable  to  the  then  com- 
paratively inexperienced  pilots  under  the  bad  landing  facilities  then 

Though  engine  failure  has  not  the  same  consequences  as  in  an 
aeroplane,  the  machinery  must  still  be  regarded  as  the  part  of  the 
airship  most  frequently  in  need  of  overhaul.  Experience  shows  that 
the  engine  cars  must  be  easily  detachable  so  that  spare  cars  can  be 
fitted  and  thorough  overhaul  made  possible  without  excessive  delay 
to  the  ship.  They  must  be  as  the  locomotive  to  the  train,  not  as  the 
machinery  to  a  battleship. 

Hydrogen  as  Fuel  and  Recovery  of  Exhaust  Water  as  Ballast. — Dur- 
ing a  long  flight  the  consumption  of  petrol  so  reduces  the  weight  of 
the  ship  that,  in  order  to  restore  her  static  equilibrium  for  landing  or 
to  avoid  the  increase  of  resistance  if  she  is  flown  very  light,  it  is  neces- 
sary either  to  discharge  a  quantity  of  hydrogen  or  to  acquire  weight. 
The  latter  can  be  done  by  condensing  the  steam  in  the  exhaust  gas. 
Petrol  produces  steam  equivalent  to  some  140  %  of  its  weight,  and  the 
proportion  of  this  which  can  be  collected  depends  upon  the  tempera- 
ture and  humidity  of  the  issuing  gas.  The  chief  difficulty  in  the 
condensation  is  due  to  the  fouling  of  the  cooling  surfaces  with  an 
oily  deposit. 

Attempts  have  been  made  to  burn,  as  supplementary  fuel,  the 
hydrogen,  which  must  otherwise  be  discharged.  When  burning  hy- 
drogen alone  in  an  engine  with  a  compression  ratio  of  about  5:1  it 
is  not  possible  to  develop  more  than  25  %  of  the  engine's  full  power 
without  serious  detonation.  When  petrol  and  hydrogen  are  burnt 
together  the  proportion  can  be  so  adjusted  that  any  fraction  up  to 
full  power  can  be  developed.  A  few  of  the  smaller  airships  were  fitted 
in  this  way  but  the  system  was  abandoned  on  account  of  increased 
risk  of  fire. 

Risk  of  Fire. — Apart  from  hostile  incendiary  action  the  risk  of 
fire  in  the  air  is  small  and  is  mainly  due  to  the  petrol.  It  is  thought 
that  the  use  of  heavy  oil  fuel  would  give  added  safety.  The  heavy 
oil  engine  at  present  involves  prohibitive  weight,  but  a  Diesel  en- 
gine capable  of  burning  only  -38  Ib.  of  fuel  per  H.P.-hour  would,  on 
the  basis  of  too  hrs.  flight,  justify  an  increase  of  machinery  weight 
of  12  Ib.  per  H.P.  over  the  5  Ib.  per  H.P.  of  the  petrol  machinery 
which  burns  -5  Ib.  per  H.P.  hour. 

Winches  (for  Kite-Balloons). — The  earliest  form  of  winch  used 
had  a  steam  engine  driving  a  single  drum  on  which  the  wire  was 
wound.  It  was  mounted  on  a  single  chassis  and  was  drawn  by 

In  1915  the  French  adopted  a  steam  winch  of  Col.  Renard's  design 
which  was  fitted  with  surge  drums — a  pair  of  drums  round  which  the 
cable  makes  a  number  of  turns  in  grooves  of  correctly  formed  section. 
These  drums  transmitted  the  whole  of 'the  engine  or  brake  torque 
to  the  cable  and  allowed  it  to  be  stowed  on  a  separate  storage  drum 
under  comparatively  small  tension  and,  therefore,  less  subject  to 
damage.  The  winding  unit  of  this  type  of  winch,  including  the  surge 
drums,  liquid  brake  and  storage  drums,  was  adopted,  with  only  modi- 
fications in  detail,  as  the  standard  for  all  future  winches. 

The  later  winches  were  usually  driven  by  petrol  engines  independ- 
ent of  the  motors  driving  the  chassis  which  carried  them. 

After  1916  the  German  winches  were  made  in  two  separate  units, 
the  motor  on  one  and  the  winding  unit  on  the  other.  These  were 
treated  like  gun  and  limber  and  when  in  use  were  connected  by  a 
flexible  shaft. 

For  naval  purposes  the  standard  winding  unit  was  employed  but 
driven  by  a  steam  engine  in  destroyers,  an  electric  motor  in  light 
cruisers,  and  by  hydraulic  motor  in  capital  ships,  these  being  the 
most  convenient  forms  of  power  available. 

Gas  for  Airship  Purposes. — Hydrogen  is  almost  invariably  em- 
ployed for  airships  and  balloons.  Coal  gas  is  cheaper  and  more  uni- 
versally available.  It  is  sometimes  used  for  free  ballooning,  but  has 
a  lifting  power  of  only  about  half  that  of  hydrogen.  Helium,  al- 
though having  only  93  %  of  the  lifting  power  of  hydrogen  of  equal 
purity,  is  totally  non-flammable  and  has,  therefore,  signal  advan- 
tages for  airships  exposed  to  attack  with  incendiary  bullets. 

Variation  of  Lift. — The  total  upward  force  on  the  airship  when 
at_rest  is  termed  her  "gross  lift."    If  V  be  the  volume  of  gas  in  the 
ship,  ph  its  density  and  pa  the  density  of  the  surrounding  air: 
Lift  =  V(po-pA). 

Variation  with  Height. — The  lift  is  constant  as  the  ship  ascends 
until  a  height — termed  "  thepressure  height  " — is  reached  at  which 
the  gas  spaces  have  become  full  and  further  expansion  involves  the 
loss  of  gas.  When  descending,  the  lift  will  similarly  remain  constant, 

because  V  varies  directly  and  pa  and  ph  inversely  as  the  height,  as- 
suming that  the  temperature  of  gas  and  air  remain  equal.  As  the 
ship  rises  above  pressure  height,  V  remains  constant  but  pa  and  ph 

Variation  with  Barometer  is  nil  until  the  ship  becomes  full;  after 
that  it  varies  directly  with  the  barometric  reading. 

Variation  with  Temperature. — Provided  the  temperature  of  the 
gas  exactly  follows  that  of  the  surrounding  air,  there  will  be  no  change 
of  lift  until  the  ship  becomes  full.  Then,  after  V  has  reached  a  maxi- 
mum the  lift  will  decrease  inversely  as  the  absolute  temperature 
rises.  Radiant  heat  falling  on  the  ship  raises  the  gas  temperature 
sometimes  as  much  as  40°  F.  and  often  20°  F.  above  that  of  the  air. 
The  gas  temperature  changes  comparatively  slowly  as  the  ship  moves 
through  air  of  varying  temperature,  hence  there  may  be  a  consider- 
able difference  between  gas  and  air  temperatures  and  this  will  sub- 
stantially influence  the  lift  of  the  airship. 

Variation  with  Gas  Purity. — Dilution  of  the  hydrogen  by  ingress 
of  air  increases  ph  and  decreases  the  jift. 

Standard  Basis  of  Airship  Calculations. — The  variation  of  atmos- 
pheric density  with  height  is  a  somewhat  complex  relation.  The 
accepted  relation  is  given  in  A.C.A.  Reports,  R.M.  509.  The  condi- 
tions at  sea  level  are  assumed  to  be:  atmospheric  density  -0782  Ib./ 
ft.3;  temperature  282° A;  pressure  1,014  millibars,  i.e.  14-7  lb./in2. 
As  a  standard  basis  of  calculation  of  airship  performance,  the  lift 
of  hydrogen  under  these  conditions  at  sea  level  is  assumed  to  be  68 
Ib.  for  each  thousand  cubic  feet.  This  figure  corresponds  to  a  purity 
of  94  per  cent. 

Determination  of  Purity. — The  apparatus  most  usually  employed 
measures  the  times  taken  by  equal  volumes  of  gas  and  air  to  escape 
through  a  small  hole.  The  densities  are  inversely  proportional  to 
the  squares  of  these  times.  An  accuracy  of  =*=  I  %  can  be  obtained 
with  such  an  instrument. 

The  most  accurate  method  is  by  chemical  analysis. 

Manufacture  of  Hydrogen. — The  choice  of  method  is  governed  pri- 
marily by  the  transport  facilities  and  the  raw  materials  available 
in  any  district.  Those  most  usually  employed  for  airship  purposes 
are: — 

The  Water-Gas  Process^  generally  employed  at  large  fixed  bases 
where  a  supply  of  coke  is  available.  It  yields  a  steady  supply  of 
gas  of  about  99-0%  purity.  Calcined  spathic  iron  ore  is  oxidized  at 
about  800°  C.  by  steam.  Hydrogen  is  given  off  and  the  ore  is 
then  reduced  by  water-gas  and  the  process  repeated.  In  the  Lane 
plant  the  ore  is  contained  in  iron  retorts  heated  externally  by  coke 
or  spent  gas.  In  the  Messerschmidt  plant  the  heating  gas  is  burnt 
actually  in  contact  with  the  ore  itself. 

The  Electrolytic  Method  is  employed  where  cheap  electric  power 
is  available  or  where  the  oxygen  is  valuable  as  a  by-product.  Dis- 
tilled water  must  be  used  and  a  yield  of  5  to  7  cub.  ft.  of  hydrogen 
per  kilowatt  hour  with  a  purity  of  over  99  %  can  be  obtained. 

The  Silicon  Process  is  employed  where  a  rapid  yield  is  required  and 
where  transport  of  raw  materials  is  difficult.  Powdered  ferro-silicon 
(90%  Si)  is  fed  into  hot  40  %  caustic-soda  solution.  One  ton  ferro- 
silicon  and  2  tons  of  caustic  give  about  50,000  cub.  ft.  of  gas  of  99  % 

In  cases  where  transport  of  materials  is  exceptionally  difficult,  hy- 
drolythe  (calcium  hydride  made  by  passing  hydrogen  over  strongly 
heated  metallic  calcium)  is  used  with  water.  About  34,000  cub.  ft. 
of  hydrogen  are  given  off  per  ton  of  hydrolythe. 

Storage. — Hydrogen  is  usually  stored  in  gas-holders  under  a  pres- 
sure of  some  9  in.  of  water.  It  is  transported  in  steel  cylinders  under 
a  pressure  of  some  2,000  lb./in.2  One  ton  of  cylinders  will  carry  some 
2,600  ft.3  of  gas  at  N.T.P.  In  Germany  special  Kesselwagen  (tank 
trucks)  carried  2,600  cub.  ft.  for  a  weight  of  one  ton  of  tank  (see 
T.  A.  Monckton,  Hydrogen  Manual,  Parts  I  and  2,  H.  M.  Stationery 

Helium. — Helium  is  present  in  the  atmosphere  as  -0004%.  It  is 
present  in  certain  natural  gases  in  proportions  up  to  2^5  %.  The  main 
supplies  are,  however,  in  the  natural  gas  in  Texas,  where  the 
strength  is  about  1-8%,  and  in  Canada,  near  Ontario,  where  the 
purity  is  -3  %.  The  process  of  collection  is  by  liquefaction  of  the  gas 
and  by  regenerative  distillation.  The  cost,  therefore,  varies  almost 
inversely  as  the  proportion  of  helium  present  in  the  gas.  The  cost 
of  production  in  a  large  plant  working  in  America  is  about  £12  per 
1,000  cubic  feet. 

Such  technical  detail  as  has  been  published  is  contained  in: — 
Reports  to  the  Advisory  Committee  for  Aeronautics  and  Reports 
to  the  Aeronautical  -Research  Committee;  lectures  to  the  Royal 
Aeronautical  Society,  published  in  Aeronautical  Journal;  two  lec- 
tures to  the  British  Association  in  1919  and  1920;  lecture  by  Air 
Commodore  Maitland  to  the  Royal  Society  of  Arts;  T.  A.  Monck- 
ton ,  Hydrogen  Manual,  Parts  I  and  2  (H.M.  Stationery  Office);  va- 
rious articles  in  the  German  aeronautical  press,  mostly  in  Illustrierte 
Flugwoche,  Luftweg  and  Luftfahrt;  in  the  Italian  in  L' A eronautica 
and  Cazzetta  del  Aviazione,  and  in  the  French  in  L Aeronautique. 

(C.  B.  C.) 


AEROTHERAPEUTICS.— The  term  "  aerotherapeutics,"  as  a 
special  branch  of  medicine,  might  convey  the  idea  that  there  are 
special  diseases  due  to  aviation  which  require  special  treatment. 



But  such  is  not  the  case,  as  there  is  no  special  "  flying  sickness  " 
brought  about  solely  by  the  pursuit  of  aeronautics.  Although 
certain  authorities  have  inclined  to  recognize  some  mechanical 
effects  owing  directly  to  the  reduction  of  atmospheric  pressure 
upon  the  body,  this  is  only  of  importance  in  connexion  with 
the  air  enclosed  within  the  cavity  of  the  middle  ear  and  to  a 
lesser  .extent  as  regards  gas  inside  the  intestines.  Changes  of 
absolute  pressure  of  the  atmosphere  produce  no  mechanical 
effects  since  the  altered  pressure  is  transmitted  equally  in  all 
directions  through  the  semi-fluid  body  tissues.  The  suggestion 
has  also  been  made  that,  owing  to  the  diminution  of  atmospheric 
pressure,  the  airman  may  be  liable  to  a  special  disease,  somewhat 
akin  to  that  experienced  by  the  diver  or  the  worker  in  compressed 
air.  The  cause  of  "  diver's  palsy,"  "  caisson  disease,"  or  "  com- 
pressed-air illness  "  is  now  thoroughly  well  established.  When 
man  is  subjected  to  an  increased  air  pressure  he  dissolves  in  the 
fluid  portion  of  his  blood  a  considerable  amount  of  nitrogen 
from  the  surrounding  air.  When  the  air  pressure  is  diminished, 
this  nitrogen  is  again  given  off.  If  the  diminution  in  pressure  be 
rapid,  then  bubbles  of  gas  are  liberated  inside  the  blood  vessels, 
in  the  same  way  as  bubbles  of  gas  are  liberated  when  fluid  is 
removed  from  a  siphon  of  aerated  water.  These  bubbles  then 
circulate  in  the  blood  and  produce  symptoms,  according  as  they 
become  lodged  in  the  various  parts  of  the  body. 

At  first  sight,  therefore,  it  might  be  supposed  that  an  airman 
making  an  ascent,  in  other  words  subjecting  himself  fairly  rapidly 
to  a  diminution  of  the  surrounding  air  pressure,  might  be  liable 
to  symptoms  arising  from  the  same  cause  as  does  "  diver's 
palsy."  This,  however,  is  not  the  case,  since  the  diminution  in 
pressure  is  not  sufficiently  great  or  rapid  to  bring  about  any 
liberation  of  gases  held  in  the  blood  plasma.  In  "  diver's  palsy  " 
and  "  caisson  disease  "  one  is  dealing  with  a  reduction  of  pressure 
of  from  two  to  five  atmospheres,  whereas  in  flying  one  is  generally 
dealing  at  most  with  a  diminution  of  pressure  of  a  little  more  than 
half  an  atmosphere,  which  is  reached  relatively  slowly,  and  is 
easily  within  the  margin  of  safety  for  the  rate  of  decompression  in 
compressed-air  work.  The  idea,  therefore,  that  airmen  are 
subject  to  any  special  "  flying  sickness  "  of  this  nature  may  be 

Because  it  is  stated  that  there  is  no  "  flying  sickness  "  it  does 
not  mean,  however,  that  flying  may  not  cause  bodily  breakdown. 
Flying  imposes  a  very  definite  stress  upon  the  body,  especially 
when  flights  are  carried  out  for  long  periods  at  high  altitudes. 
When  to  this  is  added  the  stress  of  offensive  and  defensive  war- 
fare in  the  air  it  is  obvious  that  bodily  breakdown  as  the  result  of 
"  strain  "  is  likely  to  ensue.  But  the  signs  and  symptoms  of 
"  flying  strain  "  are  varied  and  might  occur  in  an  individual 
quite  apart  altogether  from  flying.  In  the  World  War  it  was 
found  that  "  flying  strain "  was  most  generally  characterized 
by  a  gradual  loss  of  power  to  fly  high,  associated  in  varying 
degrees  with  symptoms  of  respiratory,  cardiac  and  nervous 
derangement,  such  as  breathlessness  on  exertion,  quickened 
heart-beat,  exaggerated  reflexes,  marked  tremor  of  fingers  and 
eyelids,  and  loss  of  neuromuscular  control  as  exemplified  by 
power  to  balance  on  one  leg.  Mental  symptoms,  generally  in  the 
form  of  anxiety  neurosis,  might  or  might  not  be  present.  In  many 
cases  it  was  difficult  to  say  whether  breakdown  was  to  be  attrib- 
uted primarily  to  the  effects  of  flying  or  to  the  nervous  strain  of 
aerial  warfare,  but  such  symptoms  were  frequently  found  to  occur 
in  those  who  had  taken  no  part  in  active  service  in  the  air. 

In  order  to  appreciate  the  correct  medical  measures  which 
must  be  taken  in  respect  of  the  care  of  flying  personnel,  it  is 
necessary  in  the  first  place  to  consider  the  human  machine  in 
relation  to  flying.  The  aviator  provides  the  controlling  and 
coordinating  mechanism  on  which  the  satisfactory  performance 
of  the  aeroplane  depends.  The  pilot  adds  the  aeroplane  to  him- 
self— the  "  joy-stick,"  engine  controls  and  so  forth  are  append- 
ages to  his  hands,  the  rudder  bar  an  extension  to  his  feet.  By 
appropriate  movements  of  his  upper  and  lower  limbs  man  is  now 
able  to  fly,  just  as  previously  by  appropriate  arm  and  leg  move- 
ments he  was  able  to  indulge  in  games  or  to  control  other  forms 
of  mechanism,  as,  for  example,  a  motor-car. 

To  acquire  the  art  of  flight,  therefore,  a  number  of  controlled 
and  coordinated  movements  are  necessary.  It  is  common  ex- 
perience that  certain  people  are  found  heavy-handed  or  heavy- 
footed  and  not  likely  to  acquire  the  art  of  flying.  In  the  apt 
pupil  these  coordinated  movements  are  at  first  all  made  as  the 
result  of  conscious  effort,  but  later  they  pass  into  the  realm  of  the 
automatic,  so  that  eventually  the  expert  pilot  does  not  have  to 
think  how  he  flies — he  just  wishes  his  machine  to  perform  a 
certain  evolution  and  it  occurs. 

No  elements  come  into  the  mechanical  problem  of  flying  that 
are  not  required  for  driving  a  motor-car  or  taking  part  in  various 
sports;  some  men  have  more  aptitude  for  flying  than  others; 
just  as  some  have  more  aptitude  for  games. 

To  initiate  the  coordinated  movements  necessary  for  flying, 
the  pilot  relies  upon  certain  sensory  impressions.  Vision  is  the 
most  important.  Without  facilities  for  using  his  eyes  a  man  is 
not  able  to  fly.  It  has  been  found  that  experienced  pilots  cannot 
satisfactorily  perform  even  a  simple  evolution  with  the  eyes- 
blindfolded.  It  is  also  well  known  that  pilots  cannot  fly  level  in 
fog  and  may  even  get  upside  down.  This  is  due  to  the  temporary 
eclipse  of  the  sense  of  vision ;  unaided  by  instruments,  man  will 
never  be  able  to  fly  in  a  fog  successfully. 

Besides  good  visual  acuity  it  has  been  found  that  harmonious 
working  of  the  muscles  moving  the  eyeballs  is  necessary,  particu- 
larly for  successful  landing,  and  is  lacking  in  a  great  percentage 
of  bad  landers.  By  careful  training  it  has  been  found  possible  to 
bring  about  good  visual  judgment  of  distance  and  to  turn  bad 
landers  into  good  ones. 

For  successful  flying,  next  to  vision  and  perhaps  almost  equally 
important,  come  the  sensations  from  the  skin  and  muscles.  A 
pilot  flies  very  largely  by  the  "  feel  "  of  his  machine.  In  addition 
to  the  "  feel  "  of  the  controls,  he  derives  much  information  from 
the  "  feel  "  of  his  seat,  from  the  direction  and  change  of  direction 
of  the  wind  on  his  face.  He  is  also  aided  by  hearing  the  singing 
of  the  wind  in  the  wires.  Hearing  is  of  importance  also  in  flying 
in  so  far  as  it  enables  a  pilot  to  detect  a  failing  engine,  to  operate 
wireless  and  to  hear  a  telephone  above  the  roar  of  the  engine. 

According  to  some  people  it  has  been  thought  very  necessary 
that  a  man  should  have  a  good  sense  of  balance,  but  experience 
has  shown,  as  already  mentioned,  that  "  balance  sense  "  is  not 
sufficiently  developed  in  any  man  to  enable  him  to  fly  level  in  a 

But  for  flying  it  is  not  sufficient  to  be  endowed  with  a  mechani- 
cal and  mental  aptitude;  a  consideration  of  prime  importance  is 
physical  endurance  to  resist  the  stress  of  high  flights  or  flights  of 
long  duration.  For  endurance  it  is  particularly  important  that  a 
man  be  fit  as  regards  his  respiratory  and  circulatory  mechanisms. 
This  has  been  shown  by  the  examination  of  fit  pilots  as  well  as  of 
subjects  who  have  been  deemed  in  need  of  a  rest  or  who  have 
broken  down  as  the  result  of  flying  strain. 

The  examination  of  successful  flying  officers  showed  that  they 
were  possessed  of  an  efficient  respiratory  capacity.  The  examina- 
tion of  officers  taken  off  flying  through  "  flying  strain  "  showed 
that  their  capacity  was  very  much  diminished.  It  was  found  by 
careful  observation  that  this  fall  was  due  chiefly  to  ineffective 
working  of  the  "  exhaust  "  or  expiratory  side  of  the  respiratory 
"  bellows."  The  individual  had  lost  his  power  to  expire  fully  to 
the  greatest  extent.  He,  therefore,  could  not  empty  his  lungs 
satisfactorily.  Such  a  condition  makes  for  deficient  ventilation 
and  the  subject  becomes  very  like  a  motor-engine  in  which 
the  exhaust  valves  are  defective  and  incomplete  scavenging  of 
the  cylinders  results.  Hence  we  find  that  the  airman  in  this 
condition  easily  gets  breathless  on  the  ground  and  certainly  can- 
not fly  to  heights  at  which  formerly  he  did  not  notice  anything 
abnormal  in  his  breathing. 

For  endurance  and  high  flying,  therefore,  it  is  especially  im- 
portant that  a  flier  have  an  adequate  "  bellows  capacity  "  and 
that  the  "  bellows  "  be  particularly  effective  on  the  exhaust  side. 
An  efficient  expiratory  force  is,  therefore,  very  necessary  to  the 

Examination  of  successful  flying  officers  also  showed  that  the 
effective  pilot  is  possessed  of  an  efficient  circulatory  system. 



Observation  has  shown  that  there  is  a  marked  difference  between 
the  fit  and  unfit  pilot  in  this  respect.  For  example,  the  fit  pilot 
is  possessed  of  a  regular,  fairly  slow  pulse  which  gives  the  im- 
pression of  a  delightfully  easy-working  piece  of  mechanism.  It 
is  not  greatly  quickened  by  exercise  and  speedily  returns  to  its 
normal  rate.  The  pulse  of  the  man  unfit  for  flying,  or  unfit  to 
learn  to  fly,  is  unduly  quickened  by  exercise  and  takes  con- 
siderable time  to  return  to  normal. 

Circulatory  efficiency  also  depends  upon  the  pressure  main- 
tained in  the  arteries  both  during  and  between  the  beats  of  the 
heart.  With  the  beat  of  the  heart  the  pressure  in  the  arteries 
rises:  during  the  rest  period  it  falls.  In  some  people  it  may  fall 
greatly,  in  others  but  a  little.  The  examination  of  successful  fly- 
ing officers  has  shown  that  in  them  the  fall  is  not  great,  whereas 
in  the  tired  or  inefficient  individual  the  difference  in  the  pressure 
during  and  between  the  beats  is  relatively  large.  The  importance 
of  a  good  pressure  between  the  beats  will  be  appreciated  when  it 
is  realized  that  if  the  fall  of  pressure  be  great  enough,  fainting 
may  result. 

The  efficiency  of  the  circulatory  mechanism  of  the  body  is 
intimately  bound  up  with  the  efficiency  of  the  respiratory 
mechanism.  The  abdominal  cavity  has  sufficient  vessel  capacity 
to  take  the  whole  of  the  blood  of  the  body  and,  in  the  upright  or 
sitting  posture,  blood,  by  virtue  of  the  effect  of  gravity,  will  tend 
to  stagnate  there  unless  its  return  to  the  heart  is  aided  by  the 
movements  of  respiration.  In  inspiration  the  downward  thrust 
of  the  great  muscle  separating  the  chest  from  the  abdomen,  the 
diaphragm,  acts  like  the  piston  of  a  pump  and  squeezes  blood 
upwards  into  the  heart,  since  it  is  prevented  from  escape  in  any 
other  direction  by  means  of  valves  placed  in  the  vessels.  During 
expiration  the  muscles  of  the  abdominal  wall  and  of  the  lower 
ribs  squeeze  inwards  upon  the  abdominal  contents  and  again 
force  blood  upwards  to  the  heart. 

The  importance  of  these  accessory  pumps  to  the  circulation  is 
well  exemplified  in  the  crucifixion  of  a  man.  In  the  vertical 
posture  the  immobilization  of  the  limbs  and  the  restriction  of  the 
action  of  the  respiratory  and  abdominal  muscles  cause  blood  to 
stagnate  in  the  lower  limbs  and  the  abdomen,  thereby  con- 
tributing the  principal  cause  of  death. 

Since  in  the  machine  the  pilot  is  rendered  relatively  immobile 
in  a  sitting  posture,  it  is  of  the  greatest  importance  that  he  be 
possessed  of  efficient  respiration  and  good  abdominal  tone,  in 
order  that  an  adequate  circulation  may  be  maintained.  The 
importance  of  good  abdominal  tone  is  further  emphasized  by  the 
following  experiment.  If  a  hutch  rabbit,  with  its  flabby,  pendu- 
lous abdomen,  be  held  in  the  vertical  posture,  it  will  soon  become 
unconscious  owing  to  the  lack  of  tone  of  its  abdominal  wall;  a 
wild  rabbit,  on  the  other  hand,  will  not  do  so,  owing  to  the  fact 
that,  on  account  of  the  exercise  taken  in  its  free  open-air  life, 
it  has  developed  the  tone  of  its  abdominal  musculature. 

This  emphasizes  the  value  of  sport  in  developing  the  respira- 
tory and  circulatory  mechanisms,  and  for  this  reason  all  airmen 
are  advised  to  take  up  sports  which,  besides  giving  eye  and  limb 
coordination,  also  give  physical  endurance  by  toning  up  the 
respiratory  and  circulatory  mechanisms.  The  importance  of 
sports  and  games  in  the  life  of  the  flying  man  cannot  be  over- 

In  addition  to  the  power  of  endurance  the  pilot  must  also  be 
possessed  of  quick  perception  and  judgment,  which,  besides 
enabling  him  to  learn  to  fly,  will  help  him  to  meet  any  sudden 
emergency  which  may  arise  while  he  is  in  charge  of  his  machine 
in  the  air.  He  must  therefore  possess  good  mental  and  nervous 
stability.  Such  stability  is  of  even  greater  importance  in  the 
service  pilot  who  may  be  called  upon  to  undertake  combatant 
service  in  the  air. 

Since  1878  it  has  been  known  that  the  chief  cause  of  "  mountain 
sickness  "  or  "  altitude  sickness  "  is  lack  of  proper  oxygenation 
of  the  body  owing  to  the  rarefaction  of  the  air  breathed.  Ex- 
periments conducted  in  rarefaction  chambers  as  well  as  at  high 
altitudes,  such  as  Pike's  Peak  and  Monte  Rosa,  have  fully 
proved  this  point.  In  respect  of  life  at  high  altitudes,  however, 
a  certain  degree  of  bodily  acclimatization  takes  place,  which  is 

not  the  case  in  respect  of  flying.  In  an  aeroplane  the  length 
of  sojourn  at  high  altitudes  is  insufficient  to  induce  any  ac- 
climatization, beyond  possibly  a  transitory  concentration  of  the 
blood  plasma.  In  flying  the  effect  of  increasing  altitude  is  in 
the  first  place  a  deepening  of  the  respiration  in  order  to  secure  the 
oxygen  necessary  to  maintain  the  bodily  functions.  At  the  same 
time  the  heart  quickens,  and  thus  is  established  the  beginning  of 
a  "  vicious  circle."  For  an  increase  in  the  rate  of  the  heart-beat 
means  an  increase  in  the  amount  of  work  done  by  the  heart, 
and  this  increased  work  entails  an  increased  oxygen  consumption, 
the  supply  of  which  is  diminishing;  thus  each  factor  reacts 
unfavourably  upon  the  other. 

All  the  devices  to  render  the  respiration  and  circulation 
efficient  will,  therefore,  be  called  into  play  to  meet  the  changing 
conditions,  so  that  with  prolonged  and  repeated  stress  a  break- 
down of  the  respiratory  and  circulatory  mechanisms,  involving 
also  the  nervous  system,  is  to  be  anticipated,  unless  appropriate 
measures  are  taken  to  mitigate  the  ill  effects.  This  has  been 
found  to  be  the  case. 

The  effects  of  flying  at  great  altitudes  were  observed  as 
the  result  of  the  high  flying  which  became  necessary  during  the 
World  War.  In  the  earlier  stages  of  the  war  such  flying  was  the 
exception  rather  than  the  rule.  Owing  to  the  increasing  altitudes 
reached  by  aeroplanes,  however,  it  became  eventually  quite  an 
ordinary  event  for  high-flying  aeroplanes  to  maintain  an  altitude 
of  from  20,000  to  22,000  ft.  for  several  hours.  When  this  first 
took  place  it  was  found  that  after  a  time  the  pilots  and  observers 
began  to  suffer  from  the  effects  of  prolonged  exposure  to  such 
altitudes.  In  the  air  the  chief  among  these  effects  were  breath- 
lessness,  muscular  weakness  and  diminution  of  judgment  followed 
by  great  bodily  fatigue.  This,  when  frequently  repeated,  led 
to  the  signs  of  breakdown  already  given. 

Another  effect  of  high  altitudes  was  the  onset  of  drowsiness  or 
sleepiness.  In  some  cases  this  was  excessive  and  pilots  have 
stated  that  they  have  fainted  at  great  heights  and  cannot  re- 
member landing,  whereas  they  have  actually  been  sufficiently 
awake  to  fly  the  machine  and  land  it  in  their  own  aerodrome 
with  verbal  assistance  from  the  observer. 

At  great  altitudes  there  is,  therefore,  either  a  general  slackening 
of  moral  and  loss  of  offensive  spirit  or  else  a  feebleness  of 
judgment  which  may  lead  a  pilot  into  unnecessary  difficulties. 
The  effects  of  high  altitudes  upon  judgment  are  insidious  and 
constitute  for  the  aviator  a  subtle  danger. 

Some  flying  officers  eventually  complained  of  headaches  which 
at  times  came  on  while  in  the  air,  but  more  usually  after  landing. 
Vomiting  and  bleeding  from  the  nose  were  very  rare  indeed. 
Cases  of  syncope  were  infrequent. 

As  with  "  mountain  sickness,"  the  symptoms  described 
above  are  chiefly  due  to  oxygen  want  and  it  was  found  that 
with  the  provision  of  oxygen  apparatus  on  high-flying  machines 
these  symptoms  were  greatly  alleviated. 

As  is  well  known  it  has  been  shown  that  the  administration 
of  oxygen  (i)  tends  to  keep  an  efficient  slow  pulse;  (2)  tends  to 
keep  up  a  good  arterial  pressure;  (3)  keeps  off  the  onset  of  dis- 
tressful breathing;  (4)  mitigates  any  ill  effect  due  to  excessive 
deep  breathing;  (5)  increases  the  power  for  nervous  concentration 
and  muscular  work. 

In  flying,  particularly  in  high  flying,  it  is  important  that 
the  pilot  be  able  to  accommodate  himself  to  the  effects  of 
diminished  pressure  upon  the  air  enclosed  within  the  middle 
ear  and  the  air  passages  connected  with  the  nose.  Any  hindrance, 
for  example,  to  effective  ventilation  and  drainage  of  the  frontal 
sinuses  in  the  brow  may  lead  to  headaches  of  varying  duration. 
As  regards  the  ear,  the  external  orifice  affords  a  wide  passage 
by  which  alterations  of  air  pressure  are  easily  transmitted  to  the 
ear  drum;  on  the  other  hand  the  Eustachian  tubes,  leading  from 
the  throat  to  the  middle  ear,  are  narrow  passages  which  normally 
open  only  during  the  act  of  swallowing,  and  therefore  do  not  so 
readily  transmit  changes  of  pressure.  Any  catarrhal  condition 
or  congestion  of  these  tubes,  therefore,  tends  to  produce  difficulty 
in  the  equalization  of  pressure  within  and  without  the  tympanic 
cavity.  Generally  speaking,  during  an  ascent  the  ears  are 


unconsciously  "  cleared  "  by  swallowing,  which  under  ordinary 
circumstances  is  sufficient  to  open  the  Eustachian  tubes  and 
equalize  the  pressure  on  both  sides  of  the  ear  drum.  Occasion- 
ally a  very  graduated  self-inflation,  just  sufficient  to  open  the 
tubes,  may  be  required  to  dispel  a  sensation  of  fullness  in 
the  ears.  If,  however,  owing  to  very  marked  obstruction  of  the 
Eustachian  tubes,  no  equalization  of  pressure  has  taken  place, 
then  at  20,000  ft.  the  pressure  in  the  external  auditory  meatus  is 
approximately  380  mm.,  while  in  the  middle  ear  it  is  still  760 
mm.  (ground  level),  a  difference  of  380  mm.  tending  to  push 
the  drum  outwards.  If,  on  the  other  hand,  during  the  relatively 
slow  ascent  to  this  height  equalization  of  pressure  is  made,  but, 
owing  to  Eustachian  obstruction,  little  or  no  equalization  is 
made  during  a  rapid  descent,  then  on  reaching  ground  level  there 
is  through  the  external  ear  a  pressure  of  760  mm.  but  only 
about  380  mm.  in  the  middle  ear,  a  pressure  which  forces  the 
drum  painfully  inwards.  Such  an  "  invagination  "  of  the  drum 
is  sometimes  found  immediately  after  landing  in  pilots  who  com- 
plain of  deafness,  discomfort  or  pain  in  the  ears,  headaches,  dizzi- 
ness, nausea  and,  in  certain  cases,  vomiting  and  fainting  in  the 
air.  In  less  severe  cases,  inspection  of  the  ear  drums  often  shows 
marked  distension  of  the  blood  vessels.  On  enquiry  it  is  usually 
ascertained  that  the  symptoms  complained  of  have  come  on 
during  descent  or  immediately  after  landing,  and  are  in  many 
cases  attributable  to  difficulty  in  equalizing  the  pressure  within 
and  without  the  tympanic  cavity.  It  has  been  found  also  that 
one-sided  obstruction  of  the  Eustachian  tubes  may  cause  vertigo 
and  incoordination  in  the  air.  The  importance  to  the  aviator, 
therefore,  of  adequate  ventilation  and  drainage  of  the  middle  ear 
through  the  Eustachian  tubes  under  rapidly  varying  degrees  of 
atmospheric  pressure  is  manifest.  Broadly  speaking,  any  con- 
dition of  the  nose  or  throat  which  causes  or  is  likely  to  cause 
post-nasal  or  pharyngeal  catarrh  is  a  potential  factor  in  the  causa- 
tion of  Eustachian  obstruction.  Abnormal  conditions  of  the  nose, 
throat  and  ears  which  are  apparently  of  trifling  importance  on 
the  ground  tend  to  become  considerably  aggravated  in  the  air. 
Free  nasal  respiration  and  a  healthy  condition  of  the  upper 
respiratory  tract  are  necessary  in  the  aviator. 

From  what  has  been  written  it  will  be  seen  that  the  medical 
measures  to  be  taken  as  regards  flying  consist  in  (a)  the  careful 
selection  of  flying  personnel;  (b)  the  effective  care  of  those 

In  the  main  the  case  for  careful  selection  has  been  presented. 
The  great  necessity  of  nervous  stability,  efficient  respiration  and 
circulation  has  been  shown.  Attention  has  also  been  directed  to 
the  important  part  played  by  vision,  as  well  as  to  the  necessity  of 
a  healthy  state  of  the  ears  and  upper  air  passages. 

A  word  may  be  added  here  as  to  the  importance  of  vestibular 
stability.  As  already  mentioned,  a  man  cannot  fly  level  in  a  fog. 
In  certain  countries,  particularly  in  the  United  States,  great 
importance  was  at  first  attached  to  the  supposed  "  motion- 
sensing  functions  "  of  the  vestibular  apparatus.  On  them  the 
success  or  failure  of  candidates  for  flying  was  believed  largely 
to  depend.  The  sensitivity  of  the  vestibular  apparatus  was 
tested  by  means  of  "  rotation  tests."  As  the  result  of  special 
investigation,  so  great  an  importance  is  not  assigned  to  these 
tests  in  England.  Generally  speaking,  rotation  tests  therefore 
are  only  employed  when  a  candidate  gives  a  history  of  giddiness, 
train  or  swing  sickness,  suggestive  of  undue  sensitivity  of  the 
vestibular  apparatus. 

At  first  no  special  medical  examination  was  made  for  flying, 
but  early  in  the  World  War  medical  officers  with  squadrons 
collected  considerable  evidence  which  proved  that  a  special 
examination  was  necessary.  They  were  constantly  seeing  pilots 
who  were  breaking  down  or  had  actually  broken  down  from 
causes  which  should  have  precluded  their  admittance  to  the 
flying  services. 

In  addition  to  visual  defects,  olitis  media,  and  conditions 
resulting  in  Eustachian  obstruction,  numerous  instances  of 
gross  nervous  instability  were  observed  amongst  unfit  flying 
officers,  who  could  never  have  been  accepted  for  the  service  had 
details  of  their  past  histories  been  elicited  at  a  medical  examina- 

tion.   In  the  selection  of  flying  personnel  the  importance  of  the 
past  history  of  the  candidate  cannot  be  overestimated. 

Nowadays  candidates  in  England,  both  for  military  and 
civil  aviation,  are  submitted  to: — 

I.  A  surgical  examination,  comprising,  in  addition  to  measure- 
ment of  height  and  weight,  observations  as  to  any  existing  surgical 
abnormality,  congenital  or  the  result  of  injury  or  disease,  which  is 
likely  to  impair  the  efficiency  of  f  he  individual. 

II.  A  medical  examination,  including  enquiries  as  to  previous 
occupation,  family  and  personal  medical  history,  an  investigation  of 
the  various  systems,  including  special  tests  for  flying  efficiency. 

III.  An  examination  of  the  eyes  from  the  point  of  view  of  normal 
acuity  of  vision  and  also  of  good  ocular  muscle  balance.    Normal 
colour  vision  is  also  demanded. 

IV.  An  examination  of  the  ears,  nose,  throat  and  buccal  cavity, 
including  tests  of  hearing,  the  patency  of  Eustachian  tubes,  and, 
when  deemed  necessary,  the  sensitivity  of  the  labyrinthine  apparatus. 

V.  An  assessment  in  which,  after  such  further  examination  as 
appears  necessary,  a  decision  is  formed  as  to  the  candidate's  fit- 
ness for  flying. 

The  special  tests  employed  in  the  assessment  of  efficiency  are  as 
follow: — 

For  respiratory  efficiency : — 

1.  Measurement   of   the   respiratory   capacity   by   means  of  a 

2.  The  length  of  time  during  which  the  breath  can  be  held  after 
full  expiration  and  full  inspiration. 

3.  Measurement  of  the  expiratory  force — that  is,  the  height  to 
which  the  subject  can  force  a  column  of  mercury  with  the  cheeks  and 
lips  held. 

For  circulatory  efficiency: — 

4.  The  pulse  rate  sitting,  standing  and  after  regulated  exercise 
(lifting  the  body  weight  on  and  off  a  chair  five  times  in  fifteen 

5.  Measurement  of  the  systolic  and  diastolic  arterial  pressures. 

For  nervous  stability  and  neuromuscular  coordination: — 

6.  Observation  of  knee  jerks  and  other  reflexes. 

7.  Observation   of   presence   or  absence   of   tremor  of  eyelids, 
tongue  and  fingers. 

8.  The  ability  of  the  subject  to  stand  steadily  on  one  leg  for  15 
seconds  with  the  eyes  closed  and  hands  to  side. 

9.  The  ability  of  the  subject  to  raise  from  table  to  shoulder  level 
and  replace  again  an  unstable  rod  placed  on  a  piece  of  board. 

Tests  for  endurance  and  resolution  (testing  respiratory  and 
circulatory 'efficiency  and  nervous  stability): — 

ip.  After  full  expiration  and  full  inspiration,  the  length  of  time 
during  which  the  subject  can  support  with  the  breath  held,  a 
column  of  mercury  at  40  mm.,  the  rate  of  the  pulse  being  counted 

The  standards  for  these  tests,  which  are  used  as  adjuncts  to 
the  clinical  examination,  have  been  set  by  the  examination  of 
efficient  pilots  who  have  rendered  satisfactory  aerial  service. 
Results  have  also  been  obtained  from  larger  numbers  of  pilots 
who  have  partially  or  wholly  broken  down. 

The  duty  of  forming  a  final  decision  as  to  the  candidate's 
fitness  for  air  work  rests  with  the  assessor,  a  medical  officer  of 
wide  experience.  His  decision  is  based  upon  a  review  of  all  the 
facts  and  observations  recorded  by  the  examiners,  checked  and 
supplemented  by  an  examination  on  his  part  of  such  points  as 
appear  doubtful. 

Apart  from  the  elimination  of  cases  which  fail  to  satisfy  the 
requirements  in  respect  of  the  special  senses  of  sight  and  hearing 
or  show  signs  of  organic  disease  of  a  gross  or  potentially  disabling 
nature,  the  assessor's  main  duty  is  to  ensure  that  the  accepted 
candidate  is  possessed  of  a  mental  aptitude  and  a  degree  of 
stamina  and  nervous  stability  adequate  to  withstand  the  stress 
of  training  and  of  subsequent  service  in  the  air. 

In  forming  an  opinion  on  these  points,  no  attempt  is  made 
to  determine  the  temperamental  suitability  of  candidates  by 
elaborate  psychological  methods.  In  most  cases  the  assessor  is 
able  to  gain  an  insight  into  the  candidate's  general  "  mental 
make-up  "  by  interrogation  as  to  his  motives  for  wishing  to  fly, 
by  ascertaining  his  keenness  for  sports  and  games  and  by  ob- 
taining details  as  to  his  service,  if  any,  in  the  war.  The  evidence 
as  to  the  soundness  of  the  stock  from  which  the  candidate 



comes,  the  illnesses  from  which  he  has  suffered,  the  stresses  to 
which  he  has  been  exposed  and  the  manner  in  which  they  have 
been  borne,  are  of  prognostic  importance.  Reliable  impressions 
are  also  formed  in  many  cases  in  the  course  of  ordinary  clinical 
examination,  additional  aid  in  arriving  at  a  decision  being 
afforded  by  the  candidate's  method  of  performing  the  various 
tests  of  the  cardiovascular,  respiratory  and  neuromuscular  sys- 
tems. When  deemed  necessary  the  psychomotor  reflexes  may 
be  measured. 

After  admission  much  devolves  upon  the  medical  officer  in  the 
way  of  careful  supervision.  As  in  other  branches  of  the  medical 
profession,  the  success  of  the  medical  officer  in  preventing 
breakdown  from  flying  strain  depends  largely  upon  his  mental 
aptitude  for,  and  his  attitude  towards,  his  work.  To  the  medical 
officer  the  flying  officers  under  his  care  are  so  many  human 
engines,  and  it  is  his  duty  to  keep  them  as  far  as  possible  in  fit 
condition,  properly  attuned,  and  to  overhaul  them  periodically 
so  that  he  can  say  whether  they  are  wearing  well  or  showing  signs 
of  strain,  and,  if  the  latter,  to  take  necessary  measures  to  prevent 
any  disaster. 

The  medical  officer  should  live  as  much  as  possible  among  the 
officers  under  his  charge;  by  this  means  he  acquires  an  intimate 
knowledge  of  their  characters,  which  he  may  use  sympathetically 
and  confidentially  as  occasion  arises.  Each  flying  officer  is,  so  to 
speak,  an  individual  unit,  and  requires  his  own  special  study. 
Much  of  the  medical  officer's  best  work,  therefore,  is  done  in 
the  mess,  on  the  aerodrome,  or  at  games.  For  example,  indications 
of  "  fatigue  "  may  be  observed  when  a  pilot,  usually  efficient, 
begins  to  land  badly,  or  returns  from  a  relatively  simple  flight 
unduly  exhausted;  when  a  moderate  drinker  begins  to  take  more 
than  is  good  for  him;  or  when  a  sociable  pilot  prefers  always  to 
sit  alone  quietly  reading  in  the  corner.  A  little  tact  and  sympathy 
on  the  part  of  the  medical  officer  under  such  conditions  may  make 
all  the  difference  between  recovery  and  breakdown. 

It  should  always  be  borne  in  mind  that  a  certain  number  of 
pilots  are  liable  to  develop  an  "  anxiety  "  in  regard  to  their 
occupation,  especially  as  the  result  of  the  stress  of  early  training 
or  of  prolonged  service  in  the  air.  The  first  symptoms  of  such 
anxiety  are  best  detected  by  a  medical  officer  knowing  each  of 
his  pilots  personally.  Thus  during  the  training  stage  much 
information  can  be  gleaned  by  a  quiet  chat  with  an  officer  or 
cadet  in  regard  to  his  sensations  while  in  the  air,  either  when 
receiving  dual  instruction  or  when  learning  to  acquire  pro- 
ficiency at  aerial  acrobatics.  The  stress  of  the  first  solo  flight 
must  always  be  borne  in  mind.  It  must  be  remembered  also 
that  a  young  officer  is  generally  averse  to  showing  any  sign  of 
what  he  fears  may  be  deemed  cowardice.  Yet,  during  the  stages 
of  training,  he  is  probably  constantly  repressing  a  tendency  to  be 
afraid,  which  is  only  natural.  With  such  an  individual  a  frank 
discussion  of  his  fear  with  the  medical  officer  will  frequently 
improve  his  condition.  It  is  a  great  help,  from  the  pilot's  point 
of  view,  to  be  assured  by  a  medical  officer  in  whom  he  has  con- 
fidence that  he  is  in  good  condition,  or  that  he  is  not  a  coward, 
and  that  many  other  pilots  who  have  eventually  "  made  good  " 
have  been  through  the  same  stages  of  "  wind-up."  In  gleaning 
information  as  to  the  "  anxiety  state,"  note  should  be  made  of 
such  points  as  change  of  habits,  restlessness,  irritability,  ten- 
dency to  jump  at  any  sudden  noise,  or  inability  to  concentrate. 
Enquiry  should  be  made  as  to  sleep  and  the  nature  of  dreams  or 
nightmares.  The  "  anxious  "  pilot  is  particularly  liable  to  in- 
somnia, anxiety  dreams  and  nightmares.  In  his  dream  or 
nightmare  he  is  nearly  always  performing  something  connected 
with  his  daily  duties,  and  failing  in  its  performance.  The 
importance  of  good  refreshing  sleep  in  a  flying  officer  cannot 
be  too  strongly  emphasized. 

Periodic  medical  examination  will  also  give  indication  of 
the  onset  of  flying  strain  or  fatigue,  and  if  found,  appropriate 
steps  can  be  taken  to  prevent  or  mitigate  it. 

Attention  has  already  been  drawn  to  the  great  importance 
of  the  use  of  oxygen  for  flights  at  high  altitudes  or  of  long  dura- 
tion, as  well  as  to  the  great  value  of  sports  and  games  in  promot- 
ing flying  skill  and  bodily  endurance  in  pilots.  Periodic  advice 

by  medical  officers  in  respect  of  the  ill  effects  of  too  much  smok- 
ing or  alcohol  also  play  a  part  in  the  effective  care  of  flying 
personnel.  Advice  may  also  be  given  in  regard  to  the  efficient 
protection  of  the  body. 

The  intensity  of  the  cold  varies  with  the  season  of  the  year 
and  with  the  height  attained;  it  is  accentuated  also  by  the 
speed  of  the  machine  through  the  air.  To  prevent  loss  of  body 
heat  while  flying,  special  suits  have  been  designed,  the  cardinal 
principle  of  which  is  to  keep  the  body  surrounded  by  layers  of 
warm  air.  In  most  cases  this  warmth  is  derived  from  the  body, 
but  the  warming  of  clothing  by  electric  means  has  also  been 
tried.  For  warmth  purposes,  great  thickness  of  clothing  is  by 
no  means  necessary.  Underclothing  should  be  loose-fitting;  two 
thin  garments  of  closely-woven  texture,  either  of  wool  or  silk, 
are  better  than  one  thick  one.  Research  has  shown  that  the 
warmth-giving  power  of  clothing  lies  in  the  fineness  of  the  mesh 
rather  than  in  its  thickness.  Care  should  be  taken  to  avoid 
orifices  through  which  the  outside  air  can  permeate.  Tight 
clothing  should  be  avoided,  particularly  clothing  which  tends  to 
hamper  the  movements  of  the  chest  and  abdomen  or  to  restrict 
the  circulation  of  the  limbs.  Frequently,  however,  it  is  necessary 
to  employ  considerable  additional  protection  for  the  legs,  espe- 
cially for  the  feet,  and  for  this  reason  care  should  be  taken  to 
provide  suitable  additional  protection  in  the  form  of  warm, 
loose-fitting  stockings. 

For  the  protection  of  the  face,  a  fairly  close-fitting  head 
and  face  piece  of  non-absorbent  and  non-porous  material  may 
be  made,  the  inner  surface  of  which  will  not  absorb  the  oil  or 
grease  with  which  it  is  advisable  to  anoint  the  face  when  severe 
cold  has  to  be  endured.  Over  such,  a  woollen  balaclava  may  be 
worn,  and  then  a  flying  cap  of  close-fitting  design. 

For  the  protection  of  the  hands  a  series  of  suitable  gloves 
may  be  employed;  for  instance,  thin  silk  gloves  covered  by 
woollen  gloves,  the  whole  enclosed  in  a  leather  gauntlet,  which 
can  be  easily  removed  for  delicate  work.  Gauntlets  provided 
with  a  specially  adaptable  finger  muff  are  to  be  recommended. 
In  certain  cases  electrically  heated  gloves  have  also  been 

For  the  protection  of  the  eyes  well-fitting  fur-lined  triplex 
goggles  should  be  employed.  The  fogging  of  goggles  may  be 
prevented  by  certain  preparations  which  are  on  the  market. 
Some  pilots  prefer  to  employ  tinted  goggles;  this  is  especially 
necessary  for  flying  in  the  tropics,  otherwise  the  effects  of 
glare  are  soon  felt. 

In  regard  to  diet,  gas-producing  foods  are  best  avoided,  since 
altitude  causes  expansion  of  the  gases  of  the  intestines,  but  in 
practice  there  is  little  need  for  the  healthy  person  to  worry  about 
the  constitution  of  his  diet.  It  is  important,  however,  that  no 
flying  should,  under  any  circumstances,  take  place  upon  an 
empty  stomach. 

Before  long  flights  it  is  advisable  not  to  partake  of  food  of 
too  fluid  a  nature  or  of  too  much  liquid.  By  this  means  the 
desire  to  urinate  in  the  air  during  a  flight  is  avoided.  On  very 
long  flights,  a  supply  of  liquid  food,  such  as  sweetened  cocoa  or 
malted  milk,  may  be  carried  in  special  thermos  flasks.  In  addition 
compressed  food  in  the  form  of  tablets  or  chocolate  may  be 

Finally  if  "  flying  strain  "  supervenes  the  treatment  necessary 
is  such  as  would  be  applied  to  the  condition  of  "  fatigue " 
arising  in  any  other  occupation.  According  to  his  chief  symptoms 
the  patient  may  pass  for  treatment  of  an  anxiety  neurosis  to  the 
neurologist  or  for  the  treatment  of  respiratory  and  circulatory 
symptoms  to  the  general  physician.  But  it  is  always  to  be 
remembered  that  the  keynote  of  the  effective  care  of  flying 
personnel  lies  in  prevention  rather  than  cure.  (M.  FL.) 

AFGHANISTAN  (see  1.306).— The  visit  of  the  Amir  Habibulla 
Khan  to  India  at  the  beginning  of  1907  was  destined  to  exercise 
a  powerful  and  beneficial  influence  on  the  attitude  of  the  Afghan 
ruler  during  the  rest  of  his  reign  throughout  periods  of  unusual 
crisis  and  strain.  It  gave  him  the  opportunity  of  making  ac- 
quaintance with  British  officials  and  Anglo-Indian  society,  and 
the  result  was  a  new  development  of  friendship  and  mutual 


confidence.  The  effect  in  Afghanistan  of  the  Anglo-Russian 
Convention  signed  on  Aug.  31  of  the  same  year  was  not  of  a 
similarly  happy  nature.  Articles  III.  and  IV.  of  the  Convention, 
which  provided  respectively  for  the  establishment  of  direct 
relations  between  Russian  and  Afghan  frontier  authorities  and 
the  maintenance  of  equality  of  commercial  opportunity  for 
British  (and  British-Indian)  and  Russian  trade  and  traders, 
were  interpreted  by  the  Afghans  as  an  attempt  to  interfere 
with  the  economic  autonomy  and  political  independence  of  their 
country.  Article  V.  laid  down  that  the  Convention  would  only 
come  into  force  on  the  notification  of  the  Amir's  consent  to  its 
terms.  This  consent,  though  repeatedly  pressed  for,  was  never 
given  by  the  Amir. 

From  1908  to  1914  the  history  of  Afghanistan  remained  peace- 
ful and  uneventful,  and  was  chiefly  remarkable  for  the  gradual 
introduction  into  the  country  of  measures  of  civil,  economic 
and  military  reform. 

Influenced  by  what  he  had  observed  in  India,  steps  were  taken 
by  the  Amir  to  open  schools,  increase  facilities  for  the  education  of 
the  upper  classes,  establish  factories,  introduce  telegraphs  and  tele- 
phones and  to  provide  medical  relief.  The  provision  of  improved 
military  education  and  reforms  in  the  training  of  the  army  were  like- 
wise taken  in  hand.  For  the  above  purposes  a  number  of  foreigners 
were  imported  into  Afghanistan,  and  of  these  the  majority  were 
Turks.  It  was,  however,  in  the  direction  of  public  works  that  the 
Amir  chiefly  directed  his  energies.  Great  efforts  were  made,  largely 
by  means  of  forced  labour,  to  improve  the  internal  communications. 
Metalled  roads  were  constructed  between  the  principal  local  centres, 
and  good  roads,  realigned  and  fit  for  motor  traffic,  were  constructed 
from  Kabul  to  Dakka  and  from  Kabul  to  Kandahar.  Important 
irrigation  canals  were  also  constructed,  notably  the  Nahr-i-Siraj 
from  the  Helmand  river  near  Kala  Bist;  from  the  Kabul  river  near 
Daronta;  and  the  Panjdeh  Argandab  canal  from  the  Argandab  river 
near  Kandahar. 

The  outbreak  of  war  in  1911  between  Italy  and  Turkey  created, 
as  might  be  expected,  a  general  wave  of  sympathy  among  the  Afghans 
for  their  co-religionists  in  Turkey,  and  considerable  sums  of  money 
were  subscribed  by  the  general  public  to  Turkish  funds. 

When  in  Aug.  1914  war  was  declared  between  England  and 
Germany  the  Amir  was  immediately  informed  by  the  Govern- 
ment of  India  and  asked  to  maintain  the  strict  neutrality  of 
Afghanistan,  and  to  this  he  gave  a  solemn  assurance  on  the 
understanding  that  the  safety  and  independence  of  Afghanistan 
were  not  interfered  with. 

On  the  entry  of  Turkey  in  Nov.  1914  into  the  war  on  the  side  of 
Germany,  the  Government  of  India,  in  communicating  the  event  to 
the  Amir,  laid  stress  on  the  non-religious  nature  of  the  struggle,  and 
brought  to  his  knowledge  the  terms  of  a  proclamation  issued  by  the 
British  Government  pledging  immunity  from  attack  of  the  Holy 
Places  of  Arabia.  The  intervention  of  Turkey  under  German  in- 
fluence could  not  fail  to  place  the  Amir  in  a  very  difficult  position. 
Public  feeling  in  Afghanistan  was  profoundly  stirred  by  this  event, 
and  the  trend  of  popular  feeling  under  other  conditions  of  rulership 
might  have  led  to  far  different  results  had  not  the  Amir  Habibulla 
Khan,  faithful  to  his  pledge,  maintained  throughout  the  long  years 
of  the  war  an  attitude  of  strict  and  correct  neutrality  and  enforced 
it  upon  his  country,  notwithstanding  many  temptations  and  induce- 
ments both  from  within  and  without  his  country.  Within  Afghanis- 
tan the  voice  of  religious  bigotry  and  fanaticism  was  loudly  raised 
on  the  side  of  Turkey,  while  the  opportunists  proclaimed  against 
the  folly  of  not  taking  advantage  of  so  favourable  a  moment  for  suc- 
cessful aggression. 

More  seductive  still  were  temptations  from  outside.  Chief  among 
them  were  the  persuasions  of  an  important  mission  which  the 
German  Government  despatched  towards  Afghanistan  in  the  spring 
of  1915.  The  party  were  selected  to  comprise  such  elements  as 
would  be  likely  to  appeal  to  Afghan  sentiment — Indian  sedition- 
ists  were,  both  Mohammedan  and  Hindu,  together  with  German  and 
Turkish  officers.  The  mission  bore  letters  from  the  German  chancellor, 
and  were  charged  to  make  important  revelations  regarding  possible 
future  relations  between  Afghanistan,  Germany,  Austria  and  Tur- 
key. The  mission  reached  Kabul  through  Persia  towards  the  end  of 
1915,  and  were  dismissed  in  May  1916,  without  effecting  their 

The  continuous  and  unwavering  loyalty  of  Amir  Habibulla  Khan 
to  his  pledges  to  the  British  Government  throughout  the  changing 
vicissitudes  of  the  World  War  forms  one  of  the  most  remarkable  in- 
cidents of  that  eventful  period.  He  not  only  maintained  throughout 
the  strictest  neutrality  of  his  country  but  successfully  used  his 
influence  to  preserve  peace  among  the  unruly  tribes  on  the  frontier, 
thereby  diminishing  demands  on  the  depleted  garrison  of  India. 

With  the  Armistice  of  Nov.  1918  the  World  War  came  to  an 
end,  but  Afghanistan  was  not  long  to  enjoy  the  benefit  of  peace. 

At  3  A.M.  on  Feb.  20  1919  Amir  Habibulla  Khan  was  shot  in  his 
bed  in  his  tent  at  Kala  Gosh  while  touring  in  the  district  of 
Lamaghan.  His  brother  Nasrulla  Khan,  then  at  Jalalabad,  at 
once  proclaimed  himself  Amir  of  Afghanistan  in  his  stead.  Prince 
Amanulla  Khan,  the  third  son  of  the  late  Amir  by  his  principal 
wife,  the  Ulya  Hazrat,  who  was  then  residing  at  Kabul  as  gover- 
nor, was  simultaneously  proclaimed  Amir  by  the  people  of  all 
classes  at  the  capital.  His  uncle  Nasrulla  Khan  at  once  abdicated 
in  his  favour,  and  his  elder  brothers,  Inayatulla  Khan  and  Haya- 
tulla  Khan,  and  other  members  of  the  royal  family,  acknowl- 
edged his  succession  to  the  throne.  The  facts  relating  to  the  mur- 
der of  Habibulla  Khan  have  never  been  made  known.  Nasrulla 
Khan  was  charged  with  complicity  and  sentenced  to  imprison- 
ment for  life.  In  a  letter  dated  March  3  1919  to  the  Govern- 
ment of  India,  Amanulla  Khan  announced  his  accession  with 
protestations  of  friendship  to  the  British  Government.  Mischie- 
vous and  unfriendly  influences  however,  so  long  kept  in  check 
by  the  wise,  restraining  hand  of  Amir  Habibulla  Khan,  soon 
began  to  display  themselves.  In  April  the  new  Amir  proclaimed 
the  independence  external  as  well  as  internal  of  Afghanistan. 
In  the  same  month  a  mission  under  Gen.  Wali  Mohammed  Khan 
was  despatched  to  Moscow  to  institute  relations  with  the  new 
Soviet  Government.  Grossly  exaggerated  and  unfounded  reports 
of  rebellions  in  India  and  of  British  tyranny  in  India  and  Meso- 
potamia were  spread  broadcast  by  official  agency  throughout 
the  country  and  frontier  tribes,  and  exhortation  was  addressed 
to  all  to  be  prepared  for  a  call  to  arms.  This  was  quickly  followed 
by  the  proclamation  of  a  jihad  (holy  war)  and  the  cupidity  of 
the  credulous  Afghan  people  and  frontier  tribes  was  aroused  by 
promise  of  an  easy  conquest  of  India. 

Early  in  May  information  accumulated  to  the  effect  that  the  plan 
of  operations  decided  upon  by  the  Afghan  Government  was  to 
attack  simultaneously  on  three  fronts  under  separate  generals 
through  Dakka,  Khost  and  Baluchistan,  by  hordes  of  Ghazis  (reli- 
gious fanatics)  supported  by  regular  troops.  Prompt  measures  were 
accordingly  taken  to  reenforce  British  forces  on  the  Indian  frontier. 

The  arrival  of  Afghan  troops  at  the  western  end  of  the  Khyber 
was  reported  on  May  3,  and  active  hostilities  opened  on  May  8  by 
the  occupation  by  Afghan  regular  troops  of  the  heights  commanding 
Landi  Kotal.  From  there  they  were  immediately  expelled,  and  the 
British  force  in  the  Khyber,  advancing  into  Afghanistan,  occupied 
Dakka  May  13.  This  prompt  measure,  and  the  menace  it  involved 
to  the  safety  of  Jalalabad,  had  an  immediate  and  discouraging  effect 
on  the  Afghan  plan  of  operations,  and  was  shortly  followed  on  May 
28  by  the  capture  of  the  Afghan  fortress  of  Spin  Baldak  which 
threatened  the  security  of  the  southern  capital  of  Kandahar. 

In  a  letter  dated  May  28  the  Amir  addressed  the  Viceroy 
of  India,  definitely  asking  for  peace  and  suggesting  a  cessation 
of  hostilities.  He  was  informed  in  a  reply  dated  June  2  that  an 
armistice  would  be  granted  on  certain  terms,  which  included 
the  withdrawal  of  all  Afghan  troops  from  within  20  m.  of  the 
British  front  and  the  exercise  of  the  Amir's  influence  in  restrain- 
ing the  frontier  tribes  from  further  hostilities.  These  terms  with 
but  slight  modifications  were  accepted 'by  the  Amir  in  a  letter 
of  June  u,  in  which  he  agreed  to  send  delegates  to  India  to 
discuss  terms  of  peace  and  the  reestablishment  of  former  friendly 
relations  between  the  Afghan  and  British  Governments.  These 
delegates  duly  arrived  at  Rawalpindi  on  the  date  appointed, 
July  25,  and  peace  was  formally  signed  on  Aug.  8. 

The  preceding  narrative  of  the  war  has  only  referred  to  the  brief 
operations  in  which  British  troops  were  engaged  with  forces  of  the 
Afghan  regular  army.  Open  hostilities  by  the  latter  against  British 
forces  may  be  said  to  have  ceased  on  June  3.  This,  however,  repre- 
sents but  a  small  portion  of  the  actual  fighting  which  took  place 
between  the  outbreak  of  war  at  the  beginning  of  May  1919  and  the 
signing  of  peace  in  Aug.  1919.  Throughout  the  whole  of  that  period 
continuous  conflict  prevailed,  now  at  one  point,  now  at  another, 
along  the  whole  stretch  of  the  north-west  frontier  of  India  from  Chit- 
ral  to  Chaman.  The  rising  of  the  frontier  tribes  failed,  as  such  ris- 
ings always  have  failed  in  the  past,  to  be  simultaneous,  and  the 
ardour  of  many  tribes  received  a  wholesome  check  from  the  news  of 
British  successes  and  the  capture  of  Dakka  in  the  north  and  of  Spin 
Baldak  in  the  south  at  the  outset  of  the  war.  Nevertheless  the  call  to 
jihad  and  the  cupidity  aroused  by  specious  promises  of  plunder, 
together  with  the  encouragement  and  material  support  given  by 
bodies  small  and  large  of  Afghan  regular  troops  interspersed  along 
the  frontier,  succeeded  in  causing  many  of  the  great  frontier  tribes, 
Mohmand,  Afridi,  Wazir,  Mahsud  and  Shiranni,  to  throw  themselves 
at  one  time  and  another  against  whatever  appeared  to  be  weak  points 



in  the  British  line  of  defence  or  occupation.  Instances  of  loyalty  to 
the  British  Raj  were,  however,  numerous.  In  the  north  the  tribal 
levies  of  Chitral  victoriously  resisted  continuous  Afghan  aggression, 
while  in  the  Kurram  and  Swat  valleys,  and  farther  south  in  Baluchis- 
tan, all  but  a  few  tribes  remained  firm.  Military  operations  through- 
out this  period  of  struggle  were  of  an  exceptionally  severe  and  ardu- 
ous nature,  owing  not  only  to  the  great  heat  that  prevails  at  that 
season  of  (he  year  in  the  frontier  tracts,  but  to  the  severe  outbreak 
of  cholera  which  occurred  along  the  whole  front  and  caused  serious 
losses  among  the  troops  engaged.  The  armistice  of  June  II,  which 
terminated  hostilities  between  the  regular  troops  on  either  side,  had 
but  little  effect  on  the  guerrilla  warfare  raging  along  the  frontier,  and 
this  continued,  notably  in  VVaziristan,  until  even  after  the  signing  of 
peace  on  Aug.  8. 

The  treaty  of  peace  laid  down  that  the  British  Government,  in 
view  of  the  circumstances  which  led  to  the  war,  would  on  their  part 
withdraw  the  privilege,  hitherto  enjoyed  by  former  Amirs,  of  import- 
ing arms,  ammunition  and  warlike  munitions  through  India;  would 
confiscate  the  arrears  of  the  late  Amir's  subsidy  and  grant  no  subsidy 
to  the  present  Amir,  but  would  be  prepared,  if  the  Afghan  Govern- 
ment gave  proof,  by  good  conduct  in  the  meantime,  of  a  genuine 
desire  for  friendship,  to  receive  another  Afghan  mission  after  a  period 
of  six  months,  to  discuss  the  settlement  of  matters  of  mutual  interest 
and  the  reestablishment  of  friendly  relations.  The  Afghan  Govern- 
ment on  their  part  agreed  to  adhere  to  the  Indo-Afghan  frontier 
accepted  by  the  late  Amir,  and  also  to  assent  to  the  early  demarca- 
tion of  the  hitherto  undemarcated  portion  of  the  line  to  the  west  of 
the  Khyber;  British  troops  were  to  remain  in  their  present  positions 
until  this  demarcation  be  effected. 

Demarcation  was  satisfactorily  completed  and  British  troops  ac- 
cordingly evacuated  Dakka  on  Sept.  13.  The  Afghan  fort  of  Spin 
Baldak  had  been  previously  evacuated  on  Aug.  14. 

It  will  be  noticed  that  the  treaty  of  peace  marks  an  important 
departure  from  previous  practice  in  that  no  mention  is  made  in  it 
of  the  dependence  of  Afghanistan  on  the  British  Government  in 
external  affairs,  in  regard  to  which  previous  Amirs,  'Abdurrahman 
and  Habibulla  Khan,  had  bound  themselves  to  follow  the  advice  of 
that  Government.  In  a  letter  handed  by  the  Foreign  Secretary  to 
the  Government  of  India  to  the  Afghan  delegate  immediately  after 
the  signature  of  the  treaty  it  was  expressly  stated  that  that  treaty 
left  Afghanistan  free  and  independent  in  its  affairs  both  internal  and 

Reference  has  been  made  to  the  despatch  in  April  1919  of  an 
Afghan  mission  to  the  Soviet  Government  at  Moscow.  This  mis- 
sion, under  Wali  Mohammed  Khan,  reached  Moscow  in  Oct.,  and 
were  well  received.  Meanwhile,  in  Sept.  1919  the  Soviet  Government 
of  Turkestan  despatched  a  mission  to  Kabul  under  M.  Bravin,  a 
former  member  of  the  Russian  imperial  consular  service.  In  Nov. 
1919  the  Soviet  Government  of  Moscow,  desiring  to  establish  a  more 
direct  control  by  themselves  of  foreign  relations  in  Asia,  also  sent 
a  mission  under  M.  Suritz,  which  reached  Kabul  in  Jan.  1920.  M. 
Suritz,  superseding  M.  Bravin,  at  once  commenced  negotiations  with 
the  Afghan  Government,  and  in  the  course  of  the  summer  despatched 
to  Moscow  the  draft  of  a  treaty  which,  it  is  understood,  provided  for 
the  grant  of  a  subsidy  to  the  Amir,  the  supply  of  material  assistance 
and  expert  instructors  and  the  establishment  of  Russian  consulates  in 
both  eastern  and  northern  Afghanistan. 

In  the  meantime,  after  a  lengthy  correspondence  between  the 
Indian  and  Afghan  Governments,  it  was  decided  that  an  Afghan 
mission,  as  arranged  in  the  treaty  of  peace  of  Aug.  8  1919,  should  be 
sent  to  India.  They  arrived  at  Mussporieon  April  14  1920,  under  the 
charge  of  Sardar  Mahmud  Beg  Tarsi,  the  Afghan  Foreign  Minister, 
and  were  met  by  a  British  delegation  under  Sir  Henry  Dobbs,  the 
Foreign  Secretary  to  the  Government  of  India.  The  conference 
lasted  until  July  24,  when  the  Afghan  delegation  were  presented  with 
a  statement  of  the  general  lines  on  which  the  British  Government 
were  prepared  to  discuss  a  formal  treaty.  Throughout  this  period 
the  attitude  of  the  Afghan  Government  in  respect  to  questions  under 
discussion  was  swayed  backwards  and  forwards  by  outside  concur- 
rent events,  notably  by  the  steady  strengthening  of  the  Turkish 
Nationalist  position  in  Anatolia,  the  change  of  Government  and  the 
growth  of  Bolshevik  influence  in  Persia,  the  outbreak  of  revolt  in 
Mesopotamia,  and  by  the  increase  of  political  agitation  in  India. 
Nearer  home  also,  a  renewed  outbreak  of  hostilities,  fostered  and 
assisted  by  Afghan  agency,  on  the  Indo-Afghan  frontier  in  Waziris- 
tan,  led  to  lengthy  military  operations,  and  raised  hopes  in  the  mind 
of  the  Afghan  Government  that  the  British  Government  would  not 
be  indisposed  to  consider  the  question  of  changes  in  favour  of  Afgha- 
nistan of  the  Indo-Afghan  boundary. 

On  Oct.  16  1920  the  Soviet  Government  of  Moscow  signed  a  treaty 
with  Afghanistan,  subject  to  ratification  by  the  Amir.  The  exact 
terms  of  this  treaty  were  still  unknown  in  Nov.  1921,  but  were  under- 
stood to  be  on  the  lines  of  the  draft  prepared  in  April  by  the  Suritz 
mission.  In  Nov.  1920  the  Turkish  general,  Jemal  Pasha,  arrived  in 
Kabul  on  a  special  politico-military  mission;  and  in  1921  a  British 
mission  under  Sir  Henry  Dobbs  was  also  sent  to  Kabul. 

(A.  H.  McM.) 

AFRICA  (see  1.320). — Territorial  changes  in  Africa  between 
1910  and  1921  resulted  in  a  repartition  of  large  areas  of  the  con- 

tinent; knowledge  of  its  physical  features  largely  increased  and 
means  of  communication  developed.  Social  and  economic 
factors,  affecting  all  races,  acquired  new  values.  The  present 
article  surveys  these  matters  broadly  under  the  headings: 
(i)  Exploration;  (2)  Communications;  (3)  History. 

I.  Exploration. — The  largest  unknown  area  of  Africa  in  1910  was 
in  the  Sahara,  of  which  the  central  part  only  had  been  adequately 
explored.  French  officers  had  begun  as  early  as  1904  to  make  itiner- 
aries in  the  Western  Sahara.  These  were  continued  by  Gen. 
Laperrine,  Capt.  Martin,  Capt.  Mpugin,  Capt.  Augieras  and  others. 
A  long-cherished  design  was  realized  on  Christmas-day  when,  in 
nnd  desert,  a  column  under  Capt.  Augieras  coming  from  Algeria 
effected  a  junction  with  a  column  under  Maj.  Lauzanne  which 
had  started  from  Atar  in  Mauretania.  The  result  of  these  18 
years  of  work  was  that  by  1921  a  roughly  accurate  knowledge  of 
the  region  had  been  obtained.  The  Western  Sahara  consists  of  a 
central  dome  (the  Eglab)  of  moderate  elevation,  almost  surrounded 
by  great  tracts  of  sand  dunes.  The  "central  dome,"  though  unin- 
habited, contains  habitable  regions,  and  is  regularly  traversed  by 
organised  bands  of  brigands  who  set  out  from  Southern  Morocco  to 
pillage  the  tribes  of  Mauretania  and  the  middle  Niger.  Abundant 
traces  of  ancient  human  occupation  in  the  Western  Sahara  have 
been  discovered ;  except  that  they  are  pre-Islamic  it  has  been  impos- 
sible even  approximately  to  fix  their  age.  The  great  depression  known 
as  the  Juf,  to  the  N.E.  of  Timbuktu,  remained  unexplored  UD  to 

But  it  was  in  the  region  bordering  the  southern  end  of  the  Eastern 
Sahara,  and  in  the  Libyan  desert  itself  that  the  greatest  gaps  existed 
in  the  map  of  Africa  in  1910.  Several  of  these  gaps  wore  filled,  and 
the  chief  remaining  problems  in  the  hydrography  and  orography 
of  Africa  were  solved  by  Lieut.-Col.  Jean  Tilho  and  his  colleagues 
in  an  expedition  extending  from  1912-7.  The  main  object  of 
Col.  Tilho  was  to  ascertain  whether  the  basin  of  the  Chad  was 
closed  or  belonged  to  that  of  the  Nile,  and  that  thus  there  was, 
as  tradition  asserted,  a  water  connexion  between  the  Niger  and 
the  Nile  (see  19.676).  In  a  previous  expedition  (1908-9)  Tilho 
had  found  that  the  Soro  (the  Bahr-el-Ghazal  channel  running  E. 
of  the  Chad)  was  of  the  same  level  as  the  lake  for  a  very  consider- 
able distance.  The  1912-7  expedition  discovered  that  a  mountain- 
ous barrier  encirclc-d  the  basin  of  the  Chad  from  N.  to  S.E.,  that  is, 
it  had  no  fluvial  connexion  with  the  Nile  basin.  But  N.E.  of  the 
lake  is  a  low-lying  zone  of  which  the  lowest  point  is  520  ft.  below 
the  level  of  Chad.  This  point  is  in  the  recently  dried-up  bed  of 
the  lake  of  Kirri  and  is  some  250  m.  from  Lake  Chad.  Thus  Chad 
was  proved  to  be  but  the  remains  of  a  vast  lake  comparable  in  size 
to  the  Caspian.  The  Tilho  expedition  also  explored  the  Tibesti  and 
Ennedi  (End!)  mountains,  and  discovered  another  massif,  that  of 
Erdi,  connecting  Tibesti  and  Ennedi.  It  also  learned  of  the  existence 
in  the  Libyan  desert  of  another  mountain  mass,  the  Jebel  el  Auniat 
(about  150  m.  S.E.  of  Kufra),  with  heights  probably  exceeding  4,000 
feet.  Hypsometric  determinations  enabled  the  expedition  to  ascer- 
tain the  heights  of  the  chief  summits  of  the  mountain  chains  between 
Chad  and  the  Nile.  The  highest  points  are  Emi  Kussi,  11,200  ft. 
(an  extinct  volcano),  and  Tussidc,  10,700  ft.,  in  Tibesti,  and  (the) 
Jebel  Marra,  9,800  ft.,  in  Darfur.1  The  exact  longitude  of  many 
places  was  determined  by  wireless  time  signals  from  the  Eiffel 
Tower,  and  a  chain  of  astronomical  positions  completed  the  con- 
nexion of  the  maps  of  the  Niger,  Chad  and  Nile.  Some  7,000  m.  of 
surveys  were  made  by  the  expedition.  Particular  interest  centred 
in  the  exploration  of  Tibesti,  which  had  been  seen  by  one  European 
only  (Nachtigal  in  1869)  until  it  was  reached  by  Comdt.  Loftcr 
in  Dec.  1913.  It  had  l>een  thought  that  Tibesti  might  prove  a 
well-watered  fertile  region,  but  though  it  contains  pasture  lands, 
palm-groves,  and  flowing  rivers  it  is  mainly  arid — a  magnificent 
mountain-mass  with  deep  gorges  and  serrated  ridges,  falling  east- 
ward in  giant  steps;  westward  overlooking  a  boundless  plain. 

Of  the  Libyan  desert  Mr.  W.  J.  Harding  King  collected  much  in- 
formation from  native  sources  and  himself  investigated  its  north- 
western fringe.  Early  in  Jan.  1921  Mrs.  Rosita  Forbes,  a  young 
Englishwoman,  reached  Kufra  from  Cyrenaica,  and  the  following 
month  travelled  to  Jarabub  by  a  new  route.  Except  by  a  French 
prisoner  of  the  Senussites  who  was  interned  there  in  1916,  Kufra 
had  only  once  before  been  visited  by  Europeans — by  Rohlfs  and 
Anton  Stecker  in  1879 — and  Mrs.  Forbes  showed  that  the  extent 
of  the  oases  was  less  than  supposed  and  their  position  incorrectly 
mapped.  Evidence  of  increasing  desiccation  of  the  desert  was 
obtained — one  stretch  of  350  m.  traversed  was  without  a  well  or 
water  of  any  sort. 

In  the  upper  Nile  basin  Capt.  H.  D.  Pearson,  director  of  sur- 
veys in  the  Sudan,  explored  (1911-2)  in  part  the  head  streams  of 
the  Pibor,  the  main  western  branch  of  the  Sobat.  Captain  H.  A. 
Darley  investigated  other  parts  of  the  Sobat  system  and  Capt. 
R.  H.  Leckc  in  1912-4  explored  the  adjacent  southern  region — 
that  between  the  Bahr-el-Jcbel  (Mountain  Nile)  and  Lake  Rudolf. 
The  chief  feature  of  the  country  was  shown  to  be  the  escarpment 

1  These  figures  are  subject  to  rectification  on  the  full  working-out 
of  the  data  obtained  by  the  expedition. 


forming  the  Nile-Rudolf  watershed,  which  drops  abruptly  into  the 
Turkana  plain  on  the  Rudolf  side,  but  slopes  gradually  westwards 
to  the  Nile.  It  has  heights  of  10,000  feet.  The  expeditions  named 
nearly  completed  the  exploration  of  the  region  between  the  Nile  and 
Abyssinia.  In  1915—6  Maj.  Cuthbert  Christy  made  a  ten  months' 
journey  along  the  Congo-Nile  divide,  where  it  forms  the  frontier 
of  the  Anglo-Egyptian  Sudan.  The  divide  proved  to  be  "  a  continu- 
ous and  more  or  jess  level  strip  of  bush-covered  country  (mostly  of 
ironstone  formation),  sometimes  as  much  as  two  miles  in  width 
but  often  only  a  few  yards."  In  Maj.  Christy's  opinion  the  divide 
was  perfectly  suitable  for  the  building  of  a  railway,  a  roundabout 
link  in  the  Cape-to-Cairo  scheme. 

Mr.  I.  N.  Dracopoli  in  1912-3  explored  part  of  southern 
Jubaland.  He  reached  the  Lorian  Swamp — which  receives  the 
waters  of  the  Uaso  Nyiro — and  solved  the  problem  of  its  outflow. 
He  found  that  the  Lake  Dera  issues  from  Lorian  in  a  well-defined 
bed  and,  though  usually  dry  in  its  lower  course,  is,  through  Lake 
Wama,  a  tributary  of  the  Juba  river.  Mr.  (afterwards  Sir)  G.  F. 
Archer  completed  in  April  1912,  after  over  two  years'  work,  surveys 
connecting  the  triangulation  of  British  East  Africa  with  Maj. 
Gwynn's  Abyssinian  boundary  survey.  Captain  R.  E.  Salkeld  in 
1913-4  further  explored  Jubaland,  drawing  attention  to  the  over- 
running of  that  region  by  the  Somalis — the  most  recent  instance  of 
the  migration  of  African  races. 

In  east  central  Africa  a  survey  by  Capt.  E.  M.  Jack,  in  1911.  of 
the  region  N.E.  of  Lake  Kivu  and  W.  of  Victoria  Nyanza  resulted  in 
making  known  a  healthy  highland  region  and  added  to  the  knowl- 
edge of  the  Mfumbiro  range  of  active  volcanoes.  Karissimbi  was 
found  to  be  14,780  ft.  high.  In  Dec.  1912  Sir  A.  Sharpe  and 
Mr.  M.  Elphinstone  witnessed  the  formation  of  a  new  volcano, 
named  Katarusi,  which,  following  an  earthquake,  rose  out  of  an 
old  grass-covered  lava-field,  sending  into  the  N.E.  corner  of  Kivu 
a  river  of  lava  which  filled  up  a  "  large  bay." 

The  first  survey  along  its  whole  length  of  the  Congo-Zambezi 
watershed  was  made  in  1911-4  by  Anglo-Belgian  and  Anglo- 
Portuguese  boundary  commissions,  the  principal  commissioners 
being  Capt.  Everest  (killed  by  a  lion),  Maj.  E.  A.  Steel  and 
Mai.  Reginald  Walker  (British),  Maj.  Begraud  and  Capt.  Web- 
er (Belgian)  and  Capts.  C.  V.  Cago  Coutinho  and  V.  da  Rocha 
(Portuguese).  As  in  the  Congo-Nile  watershed,  it  was  found  that 
many  rivers  ran  for  considerable  distances  parallel  to  the  divide, 
which  is  largely  bush-covered.  Major  Walker  discovered  that  the 
Luapula  (the  main  eastern  headstream  of  the  Congo)  did  not,  as 
was  believed,  issue  from  Lake  Bangweulu,  but  was  a  continuation 
of  the  Chambezi,  which  passes  through  the  great  swamp  S.  of 

Another  boundary  commission,  under  Capt.  W.  V.  Nugent 
and  Oberleutnant  Detzner,  in  1912-3  demarcated  the  Nigeria- 
Cameroon  frontier  between  Yola  and  the  Cross  river.  The  frontier 
followed  roughly  the  edge  of  the  highlands  overlooking  the  fertile 
plains  of  the  Benue  and  was  an  instance  where  the  straight  lines 
drawn  on  the  map  by  diplomatists  to  mark  international  boundaries 
worked  out  fairly  well  in  practice. 

During  the  World  War  exigencies  of  campaigning  led  to  many 
additions  to  exact  knowledge  of  the  topography  of  tropical  Africa, 
partly  through  the  use  of  aircraft  for  survey  purposes.  Thus  very 
useful  maps,  showing  routes  unsuspected  on  the  ground,  were  made 
of  Portuguese  Nyasaland  by  airmen.  In  1920  Dr.  P.  Chalmers 
Mitchell,  who  passed  over  the  whole  length  of  the  Nile  basin  in  an 
aeroplane,  proved  the  value  to  geology  of  air  reconnaissances  by  the 
discovery  in  the  Bayuda  desert  N.  of  Khartoum,  of  the  volcanic 
character  of  a  range  of  hills.  Between  Old  Merowe  and  Atbara  the 
aeroplane  crossed  "  a  high  and  irregular  range  of  hills  running  east 
and  west.  In  the  middle  of  them  was  a  great  plain  looking  like  toffee 
poured  out  on  a  plate.  From  this  a  number  of  craters  rose,  two  large, 
one  with  a  sandy  interior  with  thorn  bushes,  the  other  with  a  second 
peak  and  crater  inside  the  outer  rim."  From  pieces  of  tufa  recently 
obtained  from  the  Nile  Valley,  N.  of  Khartoum,  the  existence  of 
some  unknown  Tertiary  volcanic  field  in  that  region  had  been  sus- 
pected. Exploration  on  the  ground  remained  to  be  undertaken, 
but  Dr.  Chalmers  Mitchell's  observations  would  appear  to  be  the 
first  important  geological  discovery  made  from  the  air. 

2.  Communications. — The  first  railway  and  steamer  route  across 
Africa  was  completed  by  the  opening  in  March  1915  of  a  railway 
from  Kabalo  on  the  Lualaba  (Upper  Congo)  to  Albertville  on  the 
west  shores  of  Lake  Tanganyika.  The  year  before  (1914)  the  Ger- 
man railway  from  Dar  es  Salaam  had  reached  Kigoma,  on  the  east 
shores  of  Tanganyika.  A  part  of  this  Atlantic-Indian  Ocean  route 
is  by  the  Congo,  the  non-navigable  stretches  of  the  river  being 
bridged  by  railway.  An  all-rail  east-west  route  across  South  Africa 
had  also  been  effected  in  1915,  when  a  line  was  built  from  Prieska 
to  Kalkfontein  connecting  the  S.A.  system  with  that  of  German 
South-West  Africa.  By  this  means  Walfish  Bay  and  Delagoa  Bay 
were  linked  by  railway.  A  second  east-west  all-rail  route  across 
Africa  will  be  provided  by  the  railway  from  Lobito  Bay  to  Katanga, 
where  it  will  join  the  lines  to  Beira  and  other  east-coast  ports,  as 
well  as  to  Cape  Town.  In  1920  some  600  m.  of  rails  remained  to 
be  laid  on  this  route.  The  surveys  had  been  completed  in  1920  and 
construction  began  in  1921. 

None  of  these  lines  was  designed  as  a  transcontinental  route, 

though  the  Dar  es  Salaam-Congo  route  was  so  used  for  passenger 

With  the  Cape-to-Cairo  scheme  little  progress  was  made  in  the 
period  1910-21.  The  railway  from  Cape  Town  via  Bulawayo  and 
the  Victoria  Falls,  which  had  reached  the  Belgian  Congo  frontier 
in  1009,  was  however  continued  N.  across  Katanga  to  Bukama  on 
the  Lualaba  (Upper  Congo),  the  line  being  completed  in  May  1918 
— an  addition  of  442  m.  in  ten  years,  making  a  through  service  from 
the  Cape,  on  the  same  gauge  (3  ft.  6  in.),  of  2,598  miles.  In  1921 
the  construction  of  a  further  section  of  the  railway  to  a  more  north- 
erly point  on  the  Lualaba.  where  navigation  was  easier  than  at 
Bukama,  was  begun.  But  from  1918  it  was  possible,  by  utilizing  the 
Congo  and  Tanganyika  systems,  to  travel  alternately  by  train  and 
steamer  from  the  Cape  to  Cairo,  with  only  two  breaks — together 
not  more  than  300  m. — to  be  covered  on  foot.  The  southern  break 
was  from  Tabora  (on  the  Tanganyika  railway)  to  Mwanza,  on  Vic- 
toria Nyanza;  the  northern  from  Nimule  to  Rejaf,  along  the  banks 
of  an  unnavigable  stretch  of  the  Upper  Nile. 

These  cross- Africa  routes  were  valueless  for  through  goods  traffic ; 
their  function  was  to  bring  the  produce  of  Central  Africa  direct  to 
the  nearest  seaport.  Thus  the  Tanganyika  railway  made  Dar  es 
Salaam  the  natural  outlet  for  the  trade  of  a  large  portion  of  the 
eastern  part  of  the  Belgian  Congo.  With  these  mam  routes  may 
be  mentioned  the  line  (built  1916-8)  from  Qantara  on  the  Suez 
Canal,  across  the  Sinai  peninsula  to  Gaza,  which  put  Africa  and 
Asia  in  direct  railway  communication,  Cairo  being  linked  with 
Jerusalem,  Damascus,  Aleppo,  etc. 

With  regard  to  trans- Saharan  railways,  from  Algeria  to  the  Niger 
countries,  surveys  made  in  1912-3  showed  that  there  were  routes 
presenting  no  engineering  difficulties.  From  Msala,  in  the  Algerian 
Sahara,  the  route  is  by  Anhet,  W.  of  the  Ahaggar  (Hoggar)  massif 
to  the  Niger  at  Tosaye  (Burem),  some  200  m.  below  Timbuktu. 
What  was  regarded  as  the  first  section  of  the  trans-Saharan  was  the 
line  from  Biskra  to  Tuggurt,  opened  in  1914.  From  Tuggurt  to 
Tosaye  by  the  route  indicated  is  1,470  miles.  A  line  from  Blida  to 
Jelfa,  on  the  way  to  Laghwat,  was  also  built. 

French  projects  to  connect  the  Middle  Niger  with  the  ports  of 
the  Guinea  Coast  were  hindered  by  the  World  War.  The  scheme 
was  for  railways  from  Dakar  (Senegal),  Konakry  (French  Guinea), 
Abidjan  (Ivory  Coast)  and  Kotonu  (Dahomey)  to  be  carried  inland 
to  the  French  Sudan  (Upper  Senegal  and  Niger  colony),  and  there 
united  by  a  transverse  line.  Political  and  economic  considerations 
induced  the  French  to  neglect  the  Gambia  river  (as  being  British), 
the  natural  outlet  for  the  French  Sudan — the  Gambia  is  navigable 
from  the  ocean  by  vessels  drawing  13  ft.  up  to  153  m.  inland.  Of 
the  lines  proposed,  that  from  Thies  (Dakar)  to  Kayes,  on  the  Sene- 
gal, begun  in  1907,  has  a  length  of  682  m.,  of  which  about  100  m. 
remained  to  be  built  in  1920.  The  French  Guinea  line  from  Kon- 
akry reached  Kurussa  (365  m.)  in  1910  and  Kankan,  in  the  French 
Sudan,  411  m.  from  Konakry,  in  1915.  This  led  to  much  of  the 
trade  of  the  countries  in  the  Niger  bend  going  to  Konakry.  The 
Ivory  Coast  railway  from  Abidjan,  traversing  a  dense  forest  region, 
reached  Buake  (193  m.)  in  1913.  No  progress  northward  had  been 
made  by  1921.  The  Dahomey  railway  had  reached  Save  (162  m.) 
in  1912.  All  four  lines  are  of  the  French  standard  West-African 
gauge,  namely  one  metre.  Besides  the  railways  the  French  built 
many  hundreds  of  miles  of  metalled  roads,  on  which  motor  services 
connecting  with  the  Niger  countries  were  established. 

In  British  West  Africa  local  lines  and  extensions,  on  differing 
gauges,  were  built  during  1910-20;  there  was  no  unity  of  plan 
such  as  marked  the  French  programme  in  West  Africa.  The  bridging 
of  the  Niger  at  Jebba,  completed  1914,  gave  the  chief  Nigerian  rail- 
way, that  from  Lagos  to  Kano  (704  m.  long),  an  uninterrupted 
service.  In  1913  a  new  railway  was  begun  from  Port  Harcourt,  at 
the  mouth  of  the  Bonny  river.  It  was  completed  to  the  Udi  coal- 
fields (151  m.)  by  May  1916.  From  Zaria,  on  the  Lagos-Kano  rail- 
way, a  branch  line,  built  across  the  tinfield  area  to  Bukuru  (143  m.), 
was  completed  in  Dec.  1914.  Surveys  were  made  for  an  exten- 
sion of  the  Port  Harcourt-Udi  line  northward  across  the  Benue 
river  and  thence  north-west  to  a  point,  Kaduna,  on  the  Lagos- 
Kano  line.  The  building  of  this  extension,  some  450  m.  in  length, 
was  begun  in  1921.  Motor  services  are  maintained  in  connexion 
with  the  railways,  which  are  Government  owned. 

In  Morocco  the  French,  from  1912  onward,  built  narrow-gauge 
railways  for  military  purposes.  By  1920  these  connected  (l)  Sallee 
with  Fez,  and  (2)  Ujda,  on  the  Algerian  frontier,  with  Taza,  while 
the  section  Fez-Taza  was  under  construction.  From  Rabat  via 
Casablanca  another  line  was  built  to  Marrakesh.  The  river  divid- 
ing Sallee  and  Rabat  was  not  bridged,  but  a  ferry  service  was  insti- 
tuted. In  1918  the  French  Government  decided  to  reconstruct  the 
lines  on  the  normal  gauge.  Up  to  1921  no  progress  had  been  made 
on  the  Tangier-Fez  railway.  In  North-East  Africa  the  decade 
1910-20  saw  the  completion  of  the  railway  from  Jibuti  to  Addis 
Abbaba,  the  capital  of  Abyssinia. 

The  greatest  mileage  of  railways  built  in  the  period  under  consid- 
eration was  in  South  Africa  (see  SOUTH  AFRICA).  A  line  from 
Beira  to  the  Zambezi  (in  construction  1920)  gave  Nyasaland  direct 
access  to  the  ocean.  The  Germans  provided  their  South-West  Africa 
Protectorate  with  an  extensive  system  of  railways.  In  Uganda  the 
British  built  a  short  railway  linking  Jinja,  on  Victoria  Nyanza,  with 



the  first  navigable  stretch  of  the  Nile,  and  during  the  World  War  a 
line  connecting  the  Uganda  railway  with  the  Usambara  railway  in 
German  East  Africa  was  constructed. 

The  telegraphic  system  was  greatly  extended  between  1910  and 
1920,  while  from  the  first-named  year  gaps  in  the  telegraph  lines 
were  increasingly  filled  by  wireless  telegraphy.  The  first  wireless 
station  in  South  Africa  (at  Durban)  was  opened  in  1910.  The 
Germans  by  the  middle  of  1914  had  just  completed  powerful  wire- 
less stations  in  Togoland,  South- West  and  East  Africa.  The  French 
built  stations  in  West  and  North  Africa  (Dakar,  Algiers,  etc.)  and 
in  1920  had  a  trans-S.aharan  wireless  service,  there  being  two  sta- 
tions in  the  desert.  Wireless  stations  in  Egypt  and  the  Sudan  con- 
nected with  Mombasa,  Tabora  and  South  Africa. 

The  World  War  gave  a  great  impetus  to  aerial  communications, 
and  Cairo  became  the  junction  for  services  to  and  from  Europe, 
Asia  and  the  Cape.  In  1919  an  air  route  was  laid  out  by  British 
officers  from  Cairo  to  Cape  Town,  aerodromes  being  built  at  24 
different  places.  The  distance  by  the  air  route  was  5,206  m.,  com- 
pared with  6,823  m-  by  tj16  Cape-to-Cairo  land  route.  The  first 
attempt  to  fly  across  Africa  was  made  in  Feb.  1920  by  Dr.  P. 
Chalmers  Mitchell  in  an  aeroplane  chartered  by  The  Times.  At 
Tabora,  a  little  over  half  way,  the  machine  crashed  (Feb.  27). 
The  first  to  succeed  in  the  enterprise  were  Col.  Sir  H.  A.  van 
Ryneveld  and  Maj.  Sir  C.  J.  Brand,  of  the  South  African  forces. 
They  reached  the  Wynberg  aerodrome,  Cape  Town,  after  many 
delays  and  having  had  to  use  three  machines,  on  March  20 
1920.  Their  actual  flying  time  from  Cairo  to  Cape  Town  was 
72  hours,  40  minutes.  At  the  same  time  (Feb.-March  1920) 
French  airmen,  Maj.  Vuilleman  and  a  comrade,  flew  from  Algiers 
across  the  Sahara  to  the  Niger  at  Gao,  and  thence  to  Dakar.  The 
first  regular  air  service  in  Africa  was  established  in  1921,  with 
seaplanes  along  the  Congo  from  Stanley  Pool  to  Stanleyville,  a  dis- 
tance of  1 ,000  miles.1 

3.  History.— A  summary  statement  of  recent  territorial 
changes  affords  a  guide  to  the  course  of  events  in  Africa.  In 
1910  the  British  self-governing  colonies  of  the  Cape,  Natal, 
Transvaal  and  Orange  Free  State  were  formed  into  the  Union  of 
South  Africa,  with  a  single  government  and  one  legislature. 
In  1911  a  considerable  area  of  French  Equatorial  Africa  was 
transferred  to  the  German  protectorate  of  Cameroon,  and 
in  return  Germany  acknowledged  a  French  protectorate  over 
the  greater  part  of  Morocco,  the  protectorate  treaty  between 
France  and  Morocco  being  signed  in  April  1912.  In  Nov. 
1912  a  Franco-Spanish  treaty  defined  the  Spanish  zones  in 
Morocco.  In  1912  also  Italy  annexed  the  Turkish  vilayets  of 
Tripoli  and  Bengazi  (Cyrenaica),  to  which  they  gave  the  common 
name  of  Libya.  In  the  same  year  the  United  States  acquired 
financial  control  of  Liberia,  part  of  its  hinterland  having  passed 
to  France  in  1910.  In  Dec.  1914  a  British  protectorate  over 
Egypt  was  proclaimed.  In  June  1919,  by  the  Treaty  of  Versailles 
(which  came  into  force  Jan.  10  1920),  Germany  renounced 
possession  of  all  her  oversea  protectorates  in  favour  of  the 
principal  Allied  and  Associated  Powers.  These  protectorates 
were  placed  under  mandatories.  The  Union  of  South  Africa 
became  mandatory  for  German  South- West  Africa,  which  her 
troops  had  conquered  in  1915.  It  was  renamed  the  South- West 
Protectorate.  Togoland  was  divided  between  France  and  Great 
Britain  (it  had  been  conquered  by  British  and  French  troops  in 
Aug.  1914).  France  became  the  mandatory  for  Cameroon, 
but  a  small  portion  was  transferred  to  (British)  Nigeria.  Came- 
roon had  been  conquered  by  Anglo-French  forces  in  1915-6. 
Britain  became  mandatory  for  German  East  Africa,  renamed  the 
Tanganyika  Territory.  A  small  fragment  (the  Kionga  triangle) 
of  German  East  Africa  was,  however,  added  to  Portuguese  East 
Africa,  and  the  greater  part  of  the  provinces  of  Ruanda  and 
Urundi  to  the  Belgian  Congo.  German  East  Africa  had  been 
conquered,  as  to  the  greater  part  in  1916,  by  British  and  Belgian 
troops.  An  Anglo-French  convention  of  Sept.  1919,  rati- 
fied in  1921,  settled  the  boundary  between  Wadai  and 
Darfur,  which  had  been  in  dispute  since  1899.  In  1920-1 
Italy  gained  additions  to  Tripoli  and  Cyrenaica  by  arrangements 
with  France  and  Great  Britain;  also  the  promise  of  an  addition  to 
Italian  Somaliland  at  the  expense  of  British  East  Africa.  British 
East  Africa,  up  to  then  a  protectorate,  was  in  1920  annexed 
to  the  British  Crown  and  renamed  Kenya  Colony. 

As  a  result  of  these  changes  Africa  was  divided  among  the 

1  A  mail  air  service  from  Toulouse  to  Casablanca  had  been  in- 
stituted in  1920. 

following  Powers,  territories  governed  under  a  mandate  being 
reckoned  in  the  possessions  of  the  Powers  named: — 

sq.  m. 

Great  Britain     .        . 4,364,ooo2 

France 4,200,000 

Portugal 788,000 

Italy  650,000 

Spain 140.000' 

Belgium 930  ooo 

Liberia 40,000 

Abyssinia  (Independent) 350,000 

These  figures  give  a  total  of  11,462,000  sq.  m.  as  the  area 
of  Africa.  In  the  absence  of  definite  surveys  of  large  areas  of  the 
continent  this  may  be  regarded  as  a  close  approximation  to 
accuracy.  In  1914  the  German  possessions  in  Africa  had  an 
area  of  approximately  1,030,000  sq.  m.;  the  Turkish  possessions 
(not  reckoning  the  legal  suzerainty  it  possessed  over  Egypt) 
an  area  of  some  400,000  sq.  miles. 

'The  extinction  of  Turkish  rule  in  North  Africa  had  long 
been  foreseen  and  was  no  matter  for  regret.  It  ended  a  connexion 
which  had  lasted  five  centuries  and  had  been  almost  wholly 
evil  in  its  effects.  German  sovereignty  in  Africa  had  dated  from 
1884  only  and  had  been  rapidly  enlarged.  Endeavours  further 
to  extend  it  had  been  a  prominent  factor  in  German  policy  for  a 
decade  before  the  World  War  began,  and  closely  affected  very 
large  areas  of  Africa.  Germany  desired  to  secure  a  footing  on  the 
African  coast  of  the  Mediterranean  and  a  port  on  the  Atlantic 
coast  of  Morocco.  These  desires  conflicted  with  Italian  and 
French  ambitions,  and  in  1911  the  issue  on  both  points  was 
decided  against  Germany.  As  to  Morocco  the  Franco-German 
convention  of  Feb.  9  1909  had  recognized  the  privileged  posi- 
tion of  France  in  Morocco,  but  not  a  French  protectorate 
over  that  country,  and  the  sending  of  the  German  gunboat 
"  Panther  "  to  Agadir  in  July  1911  was  a  protest  against  what 
Germany  considered  an  unwarranted  extension  of  French  influ- 
ence in  Morocco,  and  an  intimation  that  if  German  treaty  rights 
in  Morocco  were  to  be  renounced  France  must  make  com- 
pensation. According  to  Prince  Billow,  Germany — in  1911 — 
"  never  had  any  intention  of  taking  possession  of  any  part  of 
Morocco  .  .  .  England  and  Spain,  besides  France,  would 
have  opposed  us  there  "  (Imperial  Germany,  1913  ed.).  Although 
this  statement  may  be  an  after-the-event  reflection  the  inter- 
vention of  Britain  on  the  side  of  France  was  decisive.  Germany 
withdrew  her  opposition  to  the  establishment  of  a  French 
protectorate  over  Morocco,  and  accepted  compensation  in 
Central  Africa.  While  the  Franco-German  negotiations  were 
still  in  progress,  Italy,  by  abruptly  declaring  war  on  Turkey  and 
invading  Cyrenaica  and  Tripoli,  deprived  Germany  of  her  last 
opportunity — short  of  war — of  gaining  a  footing  in  the  Mediter- 

The  alternative  scheme  to  territorial  acquisitions  in  North 
Africa  which  Germany  had  prepared  were  indicated  in  a  note 
addressed  to  France  on  July  15  1911,  during  the  Agadir 
crisis.  Germany  then  proposed  that  France  should  cede  the 
greater  part  of  the  coast  and  the  interior  of  French  Equatorial 
Africa  as  far  as  the  Sanga  tributary  of  the  Congo  river,  and 
further  renounce  in  favour  of  Germany  her  right  of  preemption 
over  the  Belgian  Congo.  These  proposals  Germany  was  com- 
pelled greatly  to  modify,  but  by  the  convention  of  Nov.  4 
1911  large  tracts  of  French  territory  were  added  to  Cameroon. 
On  the  south  these  additions  made  Spanish  Guinea  an  enclave 

2  Including  Egypt  and  the  Anglo-Egyptian  Sudan. 

3  Including  the  Spanish  zones  in  Morocco. 

4  In  view  of  the  position  publicly  assumed  by  Germany  in  1898 
of  friendship  to  Moslems  in  general  and  to  Turkey  in  particular, 
Germany  had  not  sought  direqt  rule  over  the  Ottoman  provinces 
in  question.   Turkish  sovereignty  was  to  be  respected,  but  an  Austro- 
Hungarian  chartered  company  had  been  formed  under  German  aus- 
pices for  the  exploitation  of  Tripoli  and  Cyrenaica,  and  under  the 
charter  Austrian   (in  effect  German)   authority  would  have  been 
imposed  upon  those  vilayets.   Italy,  however,  ever  since  the  establish- 
ment of  the  French  protectorate  over  Tunisia  in  1881,  had  "  ear- 
marked "  Tripoli  and  Cyrenaica  for  herself.    See  the  Memoirs  of 
Francesco   Crispi   (London,    1914)   and   H.    H.   Johnston   in   Geog. 
Jnl.  (vol.  44,  pp.  280-1). 






A  F  F 

Natural  Scat 


International  Bour, 

»i  »' 

German  Colonies 
Main  ftaL 




in  Cameroon  and  gave  Germany  the  southern  shores  of  the  Muni 
estuary.  In  the  east  the  additions  to  Cameroon  included  two 
tongues  of  land  which  gave  the  protectorate  direct  access  to 
the  Congo  river  and  its  great  northern  tributary  the  Ubangi. 

The  Mittel  Afrika  scheme  foreshadowed  in  1911  aimed  at  se- 
curing Germany's  supremacy,  primarily  economic  and  ultimately 
political,  in  central  equatorial  Africa.  The  aim  was  to  reserve 
the  Belgian  Congo,  Angola  and  Mozambique  N.  of  the  Zambezi 
as  a  German  sphere  and  thus  to  link  up  Cameroon  with  the 
South-West  and  East  Africa  protectorates.  German  industries 
had  need  of  the  raw  material  tropical  Africa  produces,  and 
moreover  southern  Angola  was  a  good  field  for  European  settle- 
ment. British  statesmen  were  not  unfavourable  to  German 
expansion  in  equatorial  Africa — so  long  as  it  was  confined  to  the 
economic  sphere.  In  1898 — the  year  of  Fashoda — Mr.  A.  J. 
Balfour  and  Count  Hatzfeldt  had  concluded  an  agreement  which 
divided  Angola  and  Mozambique  into  zones  in  which  Britain 
and  Germany  respectively  were  to  give  financial  and  economic 
assistance  to  the  Portuguese.  This  agreement  was  capable  of 
various  interpretations  and  in  the  following  year  (1809)  another 
agreement,  known  as  the  Treaty  of  Windsor,  renewed  the 
ancient  Anglo-Portuguese  alliance,  the  object  being  to  reassure 
Portugal  that  the  Balfour-Hatzfeldt  agreement  was  not  in 
derogation  of  her  sovereign  rights  in  Africa.  Neither  the  agree- 
ment with  Germany  nor  that  with  Portugal  was  published. 

After  the  settlement  of  the  Morocco  crisis  of  1911  Germany 
endeavoured  to  come  to  a  further  understanding  with  Great 
Britain.  Negotiations  in  regard  to  the  Portuguese  colonies  in 
Africa  were  reopened  by  Baron  Marschall,  then  ambassador  to 
Britain,  and  were  energetically  taken  up  by  Prince  Lich- 
nowsky,  who  came  to  London  as  ambassador  in  Nov.  1912. 
A  new  agreement  was  drawn  up  and  its  terms  fixed.  It 
affirmed  the  intention  of  the  signatories  to  respect  the  sovereign 
rights  of  Portugal  and  went  on  to  delimit  the  region  in  which 
each  party  was,  as  far  as  the  other  party  was  concerned,  to  have  a 
free  hand  in  respect  to  economic  development.  By  Prince 
Lichnowsky,  and  by  the  German  Foreign  Office,  the  new  agree- 
ment was  looked  upon  as  a  stepping-stone  to  political  rights  in 
the  regions  concerned.  By  this  agreement  the  whole  of  Angola 
up  to  long.  20°  E.  became  a  German  sphere,  together  with  the 
cocoa-producing  islands  of  San  Thome  and  Principe.  On  the  E. 
coast  the  whole  of  Mozambique  province  N.  of  the  river  Likungo 
also  became  a  German  sphere.1  Originally  Belgian  Congo 
was,  according  to  Lichnowsky,  to  have  been  included  in  the 
agreement,  but  Germany  refused  the  offer  "  out  of  alleged 
respect  for  Belgian  sensibilities." 

In  Aug.  1913  the  agreement  was  ready  for  signature. 
But  Sir  Edward  Grey,  then  British  Foreign  Minister,  made 
it  a  condition  of  signing  that  the  1898  and  1899  agreements  as 
well  as  the  new  agreement  should  be  made  public,  with  the  obvious 
object  of  again  reassuring  Portugal.  The  German  Foreign 
Office  objected  to  publication,  as  detrimental  to  negotiations 
for  concessions  then  proceeding  with  Portugal,  and,  as  Herr  von 
Jagow  (then  Foreign  Secretary)  said,  because  the  German  press 
would  regard  the  terms  of  the  Treaty  of  Windsor  and  the 
Lichnowsky  agreement  as  contradictory.  Von  Jagow  said  that 
publication  of  the  agreement  would  be  better  delayed  until  the 
Bagdad  railway  treaty — which  was  looked  upon  as  a  genuine 
triumph  for  Germany — could  also  be  published.  In  July  1914 
German  consent  to  the  publication  of  the  agreement  was  given — 
but  before  the  document  could  be  signed  the  World  War  had 

During  the  period  of  these  Anglo-German  negotiations  the 
French  in  Morocco,  under  Gen.  Lyautey  as  resident  general,  had 
adopted  both  a  bold  and  conciliatory  policy  and  had  won 
the  respect  of  the  majority  of  the  Moors;  the  French  also 
steadily  developed  their  West  African  colonies  and  had  brought 
under  control  the  region  between  Lake  Chad  and  the  Nile  basin. 

1  The  Likungo  lies  about  120  m.  N.  of  the  Zambezi.  The  Zambezi 
valley  and  all  the  territory  S.  to  and  including  Delagoa  Bay  was 
reserved  as  the  British  sphere.  Britain  already  had  the  right  of 
preemption  over  Delagoa  Bay. 

In  the  German  colonies  there  was  likewise  considerable  develop- 
ment, notably  in  the  building  of  railways.  It  was  a  period  too  of 
material  development  in  the  British  colonies  and  of  prosperity 
in  Egypt  and  the  Sudan,  accompanied  in  Egypt  by  manifestations 
in  favour  of  self-government.  In  South  Africa  the  alliance  of 
Dutch  and  British,  which  had  brought  about  union,  had  been 
followed  by  a  reaction  among  a  section  of  the  Dutch,  but  the 
majority  of  the  people  followed  the  Prime  Minister,  General 
Botha,  and  his  colleagues  in  their  loyal  adherence  to  the  British 
connexion.  When  the  World  War  broke  out  it  was  found  that 
the  German  authorities  in  South-West  Africa  had  maintained 
for  years  clandestine  relations  with  a  number  of  Boer  leaders 
and  that  they  counted,  at  the  least,  on  South  Africa's  neutrality 
in  the  war;  Germany  had  also  established  relations  with  elements 
in  North  Africa  inimical  to  France  and  Great  Britain. 

But  the  British  command  of  the  sea  rendered  it  impossible 
when  hostilities  began  for  Germany  to  succour  her  colonies. 
And  this  led  to  proposals  for  neutrality  in  various  parts  of 
Africa.  The  first  such  proposal  was  made,  on  instructions  from 
Berlin,  by  the  acting-governor  of  Togoland  to  the  French  and 
British  authorities  on  Aug.  4  and  5,  reasons  of  humanity 
and  the  presumed  need  of  the  white  races  to  exhibit  solidarity 
in  face  of  the  negroes  being  alleged.  This  proposal,  purely  local 
in  scope,  was  not  entertained  (see  TOGOLAND).  Later  in  the 
month — Aug.  23 — Germany  made  an  offer  of  neutrality  in 
the  conventional  basin  of  the  Congo  as  defined  in  Article  I. 
of  the  Act  of  the  Berlin  Conference  of  1884-5.  The  Congo 
Free  State,  in  accordance  with  the  permission  given  by  Article  X. 
of  the  Act,  had  proclaimed  its  perpetual  neutrality,  and  when 
the  Free  State  became  a  Belgian  colony  the  obligation  of  neutral- 
ity was  retained.  No  other  state  exercising  jurisdiction  within 
the  conventional  basin  of  the  Congo  had,  however,  exercised 
the  option  given  by  Article  X.  of  proclaiming  its  neutrality  within 
that  area,  which  included  besides  Belgian  Congo  about  half  of 
French  Equatorial  Africa,  a  third  of  Cameroon,  all  German  East 
Africa,  all  British  East  Africa,  all  Uganda,  all  Nyasaland, 
Mozambique  N.  of  the  Zambezi,  a  small  part  of  Northern 
Rhodesia  and  the  northern  part  of  Angola.  Belgium  had  desired 
to  preserve  neutrality  in  the  Congo.  At  the  outbreak  of  the  war 
M.  Fuchs,  governor-general  of  Belgian  Congo,  had  been  in- 
structed to  observe  a  strictly  defensive  attitude,  and  on  Aug. 
7  M.  Davignon,  then  Belgian  Foreign  Minister,  asked  the 
British  and  French  Governments  if  they  intended  to  proclaim 
the  neutrality  of  their  territories  in  the  conventional  basin  of 
the  Congo.  The  bombardment  of  Dar  es  Salaam  by  British 
warships  on  Aug.  8  was  a  sufficient  demonstration  of  the 
British  attitude;  but  at  first  the  French  Government  seemed 
disposed  to  entertain  the  proposal;  so  the  Belgian  minister  in 
Paris  informed  M.  Davignon  on  Aug.  9.  But  the  French 
commander  in  Equatorial  Africa  had  opened  hostilities  on  Aug. 
6,  and  on  Aug.  17  Comte  de  Lalaing,  Belgian  minister  in 
London,  informed  M.  Davignon  that  neither  Great  Britain 
nor  France  could  adopt  his  suggestion. 

Hostilities  in  the  conventional  basin  of  the  Congo  had  thus 
been  proceeding  for  over  two  weeks  when  Germany  made  her 
neutrality  offer;  on  the  day  before  it  was  made  the  Germans  in 
East  Africa  had  committed  the  first  act  of  war  in  the  Belgian 
Congo  by  bombarding  Lukuga,  a  port  on  Tanganyika.  The 
German  demarche  was  made  by  Herr  Zimmermann,  Under- 
secretary in  the  Foreign  Office,  to  Mr.  Gerard,  the  American 
ambassador  in  Berlin,  in  a  note  which  asked  the  aid  of  the 
United  States  to  procure  the  neutralization  of  the  conventional 
basin  of  the  Congo.  In  a  later  note,  dated  Sept.  15  1914, 
Herr  Zimmermann  stated  that  Germany's  object  was  "  to 
prevent  an  aggravation  of  the  war  which  could  serve  no  purpose," 
which  was  not  the  view  of  Von  Lettow  Vorbeck,  the  German 
commander  in  East  Africa, "  while  prejudicial  to  the  community 
of  culture  of  the  white  race."  The  Department  of  State  at 
Washington  confined  itself  to  forwarding  the  German  notes, 
without  comment,  to  the  governments  concerned.  Spanish  aid 
was  also  sought  by  Germany.  But  France  and  Great  Britain 
refused  to  entertain  the  proposals,  while,  the  Belgian  Congo 


having  been  attacked,  M.  Fuchs  had  been  given  permission,  on 
Aug.  28,  to  aid  the  French  in  the  Cameroon  campaign. 
The  efforts  of  Dutch  nationalists  in  South  Africa  to  save  German 
South- West  Africa  from  invasion  were  equally  fruitless. 

In  process  of  time  the  whole  of  Africa,  except  Abyssinia  and 
the  Spanish  protectorates,  was  involved  in  the  war  (for  the 
operations  see  the  articles  on  the  various  countries).  The  con- 
quest of  the  German  colonies  was  foreseen  in  the  negotiations 
which  preceded  Italy's  entry  into  the  war,  and  Article  XIII. 
of  the  agreement  signed  in  London  on  April  26  1915  between 
France^  Russia,  Great  Britain  and  Italy,  said: — 

In  the  event  of  France  and  Britain  increasing  their  colonial  terri- 
tories in  Africa  at  the  expense  of  Germany,  those  two  Powers  agree 
in  principle  that  Italy  may  claim  some  equitable  compensation, 
particularly  as  regards  the  settlement  in  her  favour  of  the  ques- 
tions relative  to  the  frontiers  of  the  Italian  colonies  of  Eritrea, 
Somaliland  and  Libya,  and  the  neighbouring  colonies  belonging  to 
France  and  Great  Britain. 

At  a  meeting  of  the  Supreme  Council  at  Versailles  on  May  7 
1919  it  was  agreed  to  form  an  inter-Allied  Committee  to  consider 
the  application  of  Article  XIII.,  which  had  already  been  the 
subject  of  negotiations.  Italian  desires  went  beyond  the  re- 
adjustment of  frontiers.  In  north-east  Africa  she  sought  a 
position  which  would  give  her  all  the  seaward  approaches  to 
Abyssinia.  In  particular  Italy  desired  to  acquire  Jibuti,  the  port 
of  French  Somaliland,  whence  a  railway  ran  to  Addis  Ab- 
baba.  This  desire  was  intimated  to  France  in  the.  negotiations 
preceding  the  signing  of  the  London  agreement  of  1915.  But 
Jibuti  was  the  only  French  port  on  the  Suez  Canal  route  to  the 
East  and  to  Madagascar,  as  well  as  the  only  approach  to  Abys- 
sinia France  possessed,  and  she  declined  to  entertain  proposals 
for  its  surrender.  Italy,  however,  obtained  from  France  a  wel- 
come rectification  of  the  Tripoli-Tunisia  frontier,  besides 
valuable  railway  and  commercial  privileges  in  Tunisia.  The 
claim  to  extend  the  hinterland  of  Tripoli  to  Lake  Chad  was 
refused.  With  Great  Britain  the  negotiations  were  prolonged; 
the  British  Government,  however,  assented  in  1919  in  principle 
to  a  considerable  readjustment  of  territorial  claims  in  the 
Cyrenaican-Egyptia'n  hinterland,  that  is  in  those  regions  of 
the  Libyan  Desert  in  which  lay  Kufra  and  other  Senussi  strong- 
holds. The  oasis  of  Jarabub  was  assigned  to  Italy.  In  East 
Africa  the  British  offered  an  addition  to  Italian  Somaliland  by 
the  transfer  to  it  from  Kenya  Colony  of  the  western  part  of  the 
valley  of  the  Juba — a  rich  cotton-growing  area — together  with 
the  port  of  Kismayu.  This  offer  was  accepted  in  Sept.  1919, 
but  the  Italians  desired  a  larger  concession  and  this  led  to  delays 
in  the  final  settlement.  The  proposal  to  transfer  Kassala  from 
the  Sudan  to  Eritrea  was  not  entertained.  Meanwhile  the  area 
administered  by  the  Sudan  Government  had  been  enlarged  by  the 
conquest  of  the  tributary  sultanate  of  Darfur  in  1915. 

The  distribution  of  the  German  colonies  after  the  war  has 
already  been  stated.  The  change  of  masters  was  readily  accepted 
by  the  natives.  The  war  itself  stimulated  trade  in  various  parts 
of  Africa  and  led  to  a  development  of  communications  (see  page 
67,  Communications). 

Politically  the  greatest  movements  in  Africa  in  1919-21 
were  the  continuance  of  the  separatist  campaign  by  the 
Dutch  Nationalist  party  in  South  Africa,  and  the  insistent 
demand  of  the  Egyptians  for  independence.  These  movements 
are  described  in  the  articles  SOUTH  AFRICA  and  EGYPT. 

Another  subject  which  raised  large  issues  was  the  position  of 
Indians  in  South  and  East  Africa,  but  it  was  of  less  importance 
than  the  growth  of  race  consciousness  among  the  negroes.  In- 
crease of  education  and  of  Christianity,  the  employment  of  large 
numbers  of  Africans  in  industries,  and  the  lessons  taught  by  the 
World  War,  were  among  the  factors  which  intensified  the  feeling 
of  racial  unity,  and  led  to  manifestations  of  a  new  anti-white 
movement — a  movement  different  from  the  simple  objection  to 
interference  by  Europeans  or  Arabs  previously  displayed.  The 
new  movement  had  a  consciousness  of  the  need  of  self-develop- 
ment and  progress.  Not  all  the  ferment  among  the  negroes 
was  however  anti-white,  nor  was  there  by  1921  any  clear  indica- 
tion what  form  negro  nationalism  would  ultimately  take. 

BIBLIOGRAPHY. — Exploration:  Jean  Tilho,  "  The  Exploration  of 
Tiberte,  Erdi,  Borkou  and  Ennedi  in  1912-1917,"  Geog.  Jnl.,  vol. 
Ivi.  (1920) ;  Capt.  Augieras,  Le  Sahara  Occidental  (1919) ;  F.  JR. 
Cana,  "  Problems  in  Exploration:  Africa,"  Geog.  Jnl.,  vol.  xxxviii. 
(1911);  "  The  Sahara  in  1915,"  ibid.,  vol.  xlvi.  (1915);  I.  N.  Dracopoli, 
Through  Jubaland  to  the  Lorian  Swamp  (1914);  Sir  A.  Sharpe,  The 
Backbone  of  Africa  (1921);  Rosita  Forbes,  "Across  the  Libyan 
Desert  to  Kufara,"  Geog.  Jnl.,  vol.  Iviii.  (1921). 

Geography,  Climate,  etc.:  A.  Knox,  The  Climate  of  Africa  (1911); 
H.  Hubert,  Mission  Scientifique  au  Soudan  (1916);  Documents 
Scientifiques  de  la  Mission  Tilho  (1906-9),  3  vols.  (1910-4);  J.  W. 
Gregory,  "  African  Rift  Valley,"  Geog.  Jnl.,  vol.  Ixi.  (1920) ;  E.  H.  L. 
Schwarz,  The  Desiccation  of  Africa  (N.  D.  1918);  K.  Dove,  Wirt- 
schaftsgeographie  von  Afrika  (1917);  R.  Tjader,  The  Big  Game  of 
Africa  (1911);  T.  Roosevelt,  African  Game  Trails  (1910). 

Peoples  and  Languages:  Oric  Bates,  The  Eastern  Libyans  (1914); 
C.  Meindorf,  Introduction  to  Study  of  African  Languages  (1915); 
A.  Werner,  Introductory  Sketch  of  the  Bantu  Languages  (1919); 
Sir  H.  H.  Johnston,  A  Comparative  Study  of  the  Bantu  and  Semi- 
Bantu  Languages  (1919) ;  G.  Foucart,  Introductory  Questions  on 
African  Ethnology  (1919). 

History,  Politics,  etc.:  C.  H.  Stigand,  Administration  in  Tropical 
Africa  (1914) ;  Sir  H.  H.  Johnston,  History  of  Colonization  of  Africa 
by  Alien  Races  (new  ed.  1913);  ibid.,  "  Political  Geog.  of  Africa 
before  and  after  the  War,"  Geog.  Jnl.,  vol.  xlv.  (1915);  Evan  Lewin, 
The  Germans  and  Africa  (1915);  The  Disclosures  from  Germany 
(1918)  contains  Prince  Lichnowsky's  pamphlet,  with  translation, 
Herr  yon  Jagow's  reply,  and  notes;  L.  Woolf,  Empire  and  Com- 
merce in  Africa  (N.  D.  1920);  J.  H.  Harris,  Dawn  in  Darkest  Africa 
(1912);  D.  Crawford,  Thinking  Black  (1912);  N.  Maclean,  Africa  in 
Transformation  (1913) ;  F.  Baltzer,  Die  Kolonialbahnen,  mit  beson- 
derer  Beriicksichtigung  Afrikas  (1916);  Col.  Godefroy,  Transsahariens 
et  Transafricains  (1919). 

See  also  the  bibliographies  under  SOUTH  AFRICA,  EGYPT,  etc. 
For  current  affairs  consult  the  Geog.  Jnl.  and  the  Jnl.  of  the  African 
Society,  and  L'Afrique  Fran$aise  (Paris,  monthly).  (F.  R.  C.) 

AGA  KHAN  III.  (1877-  ),  Indian  Moslem  leader  (see  1.363). 
During  1910-21  the  Aga  Khan's  widening  influence  both  on 
Indian  and  international  affairs  was  shown  in  various  directions. 
He  had  headed  the  Moslem  deputation  in  1906  to  the  Viceroy, 
Lord  Minto,  which  submitted  the  case  for  encouraging  abandon- 
ment of  the  studied  aloofness  of  their  community  from  Indian 
political  life;  and  he  was  president  of  the  All-India  Moslem 
League  thereupon  formed  during  its  first  constructive  years. 
He  initiated  the  fund,  and  personally  collected  more  than  Rs.3o 
lakhs,  for  raising  the  Mahommedan  college  at  Aligarh  to  univer- 
sity status,  which  was  effected  in  1920.  In  the  immediate  pre- 
war years  he  did  much  to  soothe  Indian  Moslem  sentiment  in 
respect  to  the  Turco-Italian  and  two  Balkan  wars.  He  was  tour- 
ing amongst  his  followers  in  East  Africa  when  the  World  War 
broke  out,  and  immediately  cabled  to  the  jamats  or  councils 
of  the  millions  of  Ismailiahs  within  British  territories  and  on 
their  borders  directing  his  followers  to  place  themselves  un- 
reservedly at  the  disposal  of  the  British  authorities.  Both  in 
East  Africa  and  on  arrival  in  England  he  pleaded  for  combatant 
participation  in  the  war,  but  Lord  Kitchener  reserved  him  for 
services  no  one  else  could  render.  When  Turkey  was  drawn 
into  the  struggle  the  Aga  Khan  issued  a  stirring  manifesto  show- 
ing that  the  Allies  had  no  overt  designs  on  Islam,  and  calling 
upon  the  Moslems  of  the  Empire  to  remain  loyal  and  faithful  to 
their  temporal  allegiance.  His  immediate  followers  provided  a 
solid  phalanx  of  whole-hearted  support  of  Britain,,  which  had  a 
most  steadying  influence  in  sterilizing  the  efforts  of  impatient 
headstrong  elements.  Secret  missions  of  great  diplomatic  im- 
portance in  Egypt,  Switzerland  and  elsewhere  were  entrusted 
to  His  Highness,  and  enemy  anger  found  scope  not  only  in 
bitter  newspaper  attacks  but  in  designs  upon  his  life.  His  great 
influence  was  rcenforced  by  his  close  and  intimate  contact  with 
leading  Allied  statesmen  and  the  breadth  and  liberality  of  his 
outlook  on  the  problems  of  reconstruction.  His  remarkable 
study  of  Indian  and  Middle  Eastern  affairs  in  India  in  Transi- 
tion (1918)  was  not  without  considerable  effect  in  the  final  shap- 
ing of  reforms  under  the  India  Act  of  1919,  and  was  consistent  in 
broad  principle  with  his  post-war  criticisms  of  the  British  Gov- 
ernment's Mesopotamian  and  Arabian  policy. 

The  Aga  Khan  laboured  unceasingly  to  secure  mitigation  of 
the  Allied  terms  toward  Turkey,  and  joined  in  many  repre- 
sentations, public  and  private,  both  at  the  Peace  Conference 
and  subsequently,  as  to  the  immense  importance  to  Great 


Britain,  the  ruler  of  the  greatest  aggregation  of  Moslems  in  the 
world,  of  not  depriving  Turkey  of  a  real  independent  existence. 
But  the  issue  was  complicated  by  many  considerations,  and 
British  statesmen  seemed  less  ready  to  accept  his  advice  in 
peace  than  to  use  his  influence  in  war.  To  the  G.C.I.E.  and  the 
G. C.S.I,  there  was  added  in  1916  a  salute  of  n  guns  and  the 
rank  and  status  of  a  first-class  chief  of  the  Bombay  Presidency, 
the  only  previous  instance  of  the  grant  of  a  salute  outside  the 
Indian  territorial  ruling  families  being  that  of  the  first  Sir  Salar 
Jung.  (F.  H.  BE.) 

AGLIARDI,  ANTONIO  (1832-1915),  Italian  cardinal  and 
diplomatist  (see  1.377).  Noted  for  his  strongly  patriotic  senti- 
ments, he  actively  opposed  the  Temporalist  tendencies  which 
prevailed  at  the  Vatican  during  a  part  of  the  pontificate  of  Leo 
XIII.  At  a  time  when  clerical  influences  in  France  aimed  at 
a  restoration  of  the  Temporal  Power,  Agliardi  was  frankly 
favourable  to  the  Triple  Alliance  as  the  best  guarantee  of 
Italy's  territorial  integrity,  and  he  eventually  succeeded  in 
convincing  the  Pope  of  the  hopelessness  of  his  schemes.  With 
Leo's  subsequent  social-Catholic  activities  he  was  in  hearty 
sympathy,  and  contributed  much  to  their  Success.  He  enjoyed 
the  personal  friendship  of  many  of  the  most  eminent  men  in 
Italy,  including  Luigi  Luzzatti,  Antonio  Salandra  and  the 
Marquis  di  San  Giuliano.  He  died  in  Rome  March  19  1915. 

AGRICULTURE  (see  1.388).  In  the  separate  articles  on 
different  countries  of  the  world,  their  agricultural  progress 
between  1910  and  1920  is  dealt  with.  Here  will  be  considered 
(i)  the  progress  of  scientific  research  generally,  (2)  the  agricul- 
tural administration  and  regulations  in  the  United  Kingdom, 
and  (3)  the  developments  in  the  United  Kingdom  during  the 
World  War.  Developments  in  the  United  States  1910-21  are 
described  under  the  heading  Agriculture  in  the  article  UNITED 


During  1900-20  scientific  research  upon  the  soil  was  in  the 
main  directed  to  two  sets  of  phenomena — the  interaction  of  the 
various  groups  of  organisms  living  in  the  soil,  and  secondly  the 
relation  of  the  various  soil  constituents  to  water  as  a  means  of 
interpreting  the  physical  behaviour  of  the  soil  under  cultivation. 

Soil  Research. — Dealing  first  with  the  latter  question,  it  has 
long  been  obvious  that  the  crude  view  which  regards  the  soil  as  a 
mere  mechanical  foundation  for  the  plant  containing  a  certain 
amount  of  plant  food — nitrogen,  potash  and  phosphoric  acid 
determinable  by  analysis — must  be  abandoned.  Infertile  soils 
disclose  in  the  surface  layer  sufficient  plant  food  for  a  hundred 
full  crops,  and  even  the  later  modification  of  the  hypothesis 
which  laid  stress  not  on  the  "  total "  plant  food  in  the  soil  but  on 
the  amount  that  was  "available,"  i.e.  soluble  in  some  dilute 
medium  such  as  carbon-dioxide-charged  water  and  a  solution  of  an 
organic  acid  akin  to  the  cell  sap  of  the  plant,  failed  to  provide  a 
means  of  measuring  fertility  by  chemical  analysis.  It  was  the 
failure  of  this  chemical  theory  of  the  soil  that  led  the  American 
investigators,  Whitney  and  Cameron,  to  propound  the  view 
that  what  really  matters  in  the  soil  is  its  water  relationships. 
The  plant's  roots  feed  in  the  soil  solution,  the  liquid  medium 
held  on  the  surface  of  and  between  the  soil  particles  by  surface 
tension,  and  as  this  solution  is  always  saturated,  e.g.  with 
phosphoric  acid  and  potash  of  which  any  soil  contains  more  than 
the  soil  solution  is  capable  of  dissolving,  then  the  actual  amount 
of  these  constituents  in  the  soil  (above  a  certain  very  low  mini- 
mum) and  the  extra  amount  supplied  by  fertilizers  are  matters 
of  indifference.  Apart  from  some  other  factors,  it  is  the  water 
supply  that  determines  the  growth  of  the  plant  and  therefore 
the  fertility  of  the  soil.  In  its  turn  this  hypothesis  breaks  down, 
because  it  takes  too  simple  a  view  of  the  process  of  solution  in 
the  soil,  which  it  regards  as  a  mixture  of  definite  compounds 
possessing  a  definite  solubility  like  sodium  chloride  or  other 
inorganic  salts.  Actual  experiment  showed  that  whenever  soil 
extracts  were  prepared  from  soils  of  different  fertility  or  when 
even  the  solutions  actually  existing  within  the  soils  could  be 
removed  by  mechanical  means,  they  displayed  a  varying  con- 
centration in  phosphoric  acid  and  potash.  Moreover  the  growth 

of  plants  in  such  extracts  is,  within  limits,  proportional  to  the 
amounts  of  the  nutrient  constituents  they  contain. 

The  value  of  Whitney's  and  Cameron's  suggestion  lay  in  the  way 
it  directed  attention  to  the  soil  solution  as  the  seat  of  nutrition  of 
the  plant,  and  our  ideas  as  to  the  character  and  formation  of  that 
solution  have  to  be  revised  in  the  light  of  our  more  recent  conceptions 
of  the  nature  of  colloids.  A  study  of  the  behaviour  of  any  soil  towards 
water,  whether  we  examine  such  a  character  as  the  rate  at  which 
water  will  drain  through  the  soil  or  the  rate  at  which  successive 
portions  of  water  will  be  removed  from  it  by  evaporation  under 
constant  conditions,  shows  that  the  soil  does  not  behave  as  if  it 
were  a  mixture  of  mere  rock  particles  of  various  grades  of  fineness. 
An  artificial  soil  built  up  of  particles  of  ground  quartz  of  the  same 
order  of  sizes  as  the  soil  behaves  quite  differently  towards  water,  so 
again  does  a  soil  that  has  been  ignited  to  a  red  heat.  In  the  natural 
soil  a  number  of  the  particles,  especially  those  of  the  smallest  size, 
exhibit  colloid  properties,  which  roughly  means  that  they  have  a 
special  power  of  holding  water  on  their  surfaces  more  and  more 
tightly  as  the  amount  of  water  diminishes,  and  also  of  holding  and 
withdrawing  from  solutions,  the  ions,  sometimes  basic,  sometimes 
acid,  of  salts.  These  colloids  are  probably  the  particles  of  compound 
aluminium  silicates  resulting  from  the  decomposition  of  the  felspars 
in  the  original  rock  basis;  they  are  akin  to  the  zeolites  which  can  be 
found  in  a  pure  state.  The  humus  or  organic  matter  of  the  soil  is 
also  largely  colloid,  but  the  inorganic  colloids  themselves  will  ac- 
count for  most  of  the  properties  of  the  soil. 

As  regards  the  water  itself,  the  colloid  theory  explains  certain 
facts  which  had  much  occupied  the  attention  of  the  American 
investigators  who  have  been  studying  the  relation  of  plants  to  soil 
under  arid  conditions  as  a  means  of  extending  cultivation  upon  the 
bad  lands.  Sachs  had  long  ago  shown  that  a  plant  would  begin  to 
wilt  and  be  unable  to  take  water  from  the  soil  before  the  soil  was 
absolutely  dry,  again  that  a  clay  soil  would  hold  water  against  the 
plant  much  more  strongly  than  a  sandy  soil,  wilting  occurring  when 
the  clay  soil  has  still  8  °0  or  more  of  water  in  it,  whereas  the  sand  will 
lose  water  down  to  I  %  before  the  wilting  begins.  Various  attempts 
have  been  made  to  correlate  the  "  wilting  coefficient  "  of  the  soil, 
i.e.  its  proportion  of  moisture  when  wilting  sets  in,  with  the  "  hy- 
groscopic moisture,"  i.e.  the  amount  of  water  a  dry  soil  will  absorb 
when  in  contact  with  a  saturated  atmosphere,  and  with  the  amount 
of  water  the  soil  holds  when  wetted  and  allowed  to  drain.  But 
none  of  these  conceptions  mark  any  change  of  state;  for  example 
the  curve  expressing  the  rate  at  which  evaporation  will  take  place 
from  soil  is  a  perfectly  smooth  one  without  any  discontinuities,  and 
the  points  defining  the  wilting  coefficient  or  the  hygroscopic  moisture 
are  only  particular  positions  of  equilibrium  between  the  water- 
holding  power  of  the  soil  particles  and  the  external  set  of  forces 
tending  to  remove  water.  In  the  same  way  the  distinction  between 
the  water  held  by  the  colloids  and  the  "  free  water  "  in  the  soil, 
the  latter  being  regarded  as  something  different  in  kind  and  sharply 
marked  off  from  the  colloid  water,  cannot  be  maintained.  The 
colloid  "  gels  "  must  be  regarded  as  imbibing  water  and  exercising 
some  attractive  action  on  all  the  water  in  the  soil,  though  that 
attraction  is  infinitesimal  when  the  soil  is  saturated  and  only 
becomes  a  measurable  force  when  the  water  has  shrunk  to  small 

The  colloids  that  hold  water  in  the  soil  are  also  the  agents  which 
control  the  composition  of  the  soil  solution  upon  which  the  plant 
feeds.  If  the  soil  colloids  are  brought  into  contact  with  a  solution 
of  any  of  the  fertilizer  salts  (except  the  nitrates  with  which  the 
action  is  very  slight)  there  is  an  instantaneous  absorption  of  ammonia, 
phosphoric  acid  or  potash  as  the  case  may  be,  that  is  never  complete, 
the  extent  being  determined  by  such  factors  as  the  relative  mass  of 
the  soil  and  the  fertilizer,  the  concentration  of  the  solution  and  the 
nature  of  the  accompanying  ions,  e.g.  carbon  dioxide  in  the  soil 
solution.  Speaking  broadly,  a  fertile  soil  is  one  possessing  a  high 
absorptive  capacity,  that  is  as  it  were  pretty  fully  charged,  so  that 
the  equilibrium  with  the  soil  solution  is  mobile  and  the  soil  colloids 
part  freely  with  their  nutrients  to  the  solution  as  its  strength  is  re- 
duced through  withdrawals  by  the  plant's  roots.  The  analytical 
methods  which  attempt  to  determine  say  the  "  available  "  phos- 
phoric acid  by  attacking  the  soil  with  weak  acids  really  determine 
something  much  more  complex  in  which  the  absorptive  power  of 
the  soil  plays  a  part.  The  acid,  whatever  its  nature,  first  dissolves 
all  the  phosphoric  acid,  and  then  there  is  a  reabsorption,  the  amount 
of  which  is  conditioned  by  the  nature  and  strength  of  the  acid  em- 
ployed. Thus  the  result  obtained  is  an  empirical  one,  valid  only  for 
comparisons  of  soils  of  similar  type  and  constitution,  to  which  limited 
degree  it  is  of  service. 

Lining  Organisms. — The  study  of  the  living  organisms  of  the 
soil  has  resulted  in  some  reconsideration  of  the  views  formerly 
held  as  to  the  relative  importance  and  function  of  the  different 
groups.  Among  the  earliest  of  the  organisms  associated  with  the 
soil  to  be  specifically  studied  were  those  concerned  with  the 
process  of  nitrification  and  responsible  for  the  conversion  of 
ammonia  (resulting  from  the  breaking  down  of  organic  compounds 
of  nitrogen  by  other  bacteria)  first  into  nitrites  and  then  into 


nitrates.  It  was  held  that  as  plants  (other  than  the  legumes) 
practically  take  in  all  their  nitrogen  as  nitrates,  then  the  rate  of 
nitrate-making  or  the  nitrifying  power  of  a  soil  would  be  on  one 
side  at  least  a  measure  of  its  fertility.  In  the  course  of  the 
experiments  on  the  partial  sterilization  of  soil  by  heat  or  anti- 
septics it  has  become  apparent  that  the  nitrification  organisms 
are  very  susceptible  and  may  be  killed  off  while  the  ammonia- 
making  organisms  are  still  active.  Again  acid  soils  have  been 
found  in  which  nitrates  are  not  produced.  Yet  in  such  soils 
plants  grow  freely,  taking  in  their  nitrogen  as  ammonia,  not  as 
nitrate.  It  becomes  clear  that  nitrification  is  only  the  end 
process,  and  the  rate  at  which  it  will  proceed  is  determined  in  a 
normal  soil  by  the  rate  at  which  the  other  organisms  supply 
ammonia.  This  is  seen  from  the  fact  that  nitrates  will  heap  up 
in  the  soil,  whereas  the  ammonia  remains  comparatively  con- 
stant at  a  very  low  level  provided  that  the  soil  is  normal  and 
nitrification  is  going  on. 

For  a  long  time  the  only  organisms  capable  of  "  fixing  " 
nitrogen,  i.e.  bringing  the  free  gas  from  trie  atmosphere  into 
combination,  were  the  so-called  "  nodule  "  organisms  (Pseit- 
domonas  radiclcola)  discovered  by  Hellriegel  and  Wilfarth,  which 
live  in  symbiosis  with  the  leguminous  plants.  More  recent  in- 
vestigations have  discovered  methods  whereby  these  organisms 
can  be  grown  and  made  to  fix  nitrogen  independently  of  a  host 
plant,  and  have  also  cleared  up  the  forms  in  which  they  exist  in 
the  soil  and  find  their  way  into  the  roots  of  the  leguminous  plant. 
The  attempts  to  improve  the  growth  of  leguminous  crops  by 
inoculation  with  strains  of  the  particular  organism  have  not 
been  attended  with  any  practical  success,  though  soils,  generally 
of  the  new  or  reclaimed  order,  destitute  of  the  nodule  organism, 
can  now  be  effectively  inoculated  and  thereby  made  to  grow 
good  crops  of  legumes,  provided  always  that  the  soil  is  first  made 
a  fit  medium  for  the  organism  by  a  supply  of  lime  and  appropriate 
mineral  manures.  Without  this  preliminary  acid  heath  or  peat 
soils  would  neither  support  the  nodule  organisms  nor  the  legu- 
minous crops  and  inoculation  would  be  of  no  avail.  But  as 
"  fixers  "  of  nitrogen  apart  from  the  leguminous  plants  Pscu- 
domonas  radicicola  is  ineffective  compared  with  a  widespread 
group  of  organisms  isolated  by  Beijerinck,  to  which  he  has  given 
the  name  of  Azotobacler. 

Azolobacler. — These  organisms,  found  in  both  virgin  and 
cultivated  soils  from  all  parts  of  the  world,  are  comparatively 
large  oval  bodies  4  to  5  /t  in  length  and  3  /i  in  width,  which 
differ  from  normal  bacteria  in  containing  glycogen  and  act  as 
powerful  agents  for  the  oxidation  of  the  sugars  and  other  carbo- 
hydrates. From  the  carbohydrates  they  produce  in  the  main 
carbon  dioxide  and  water,  but  also  small  quantities  of  organic 
acids  and  of  a  characteristic  deep  brown  pigment.  It  is  by  means 
of  the  energy  derived  from  the  oxidation  that  they  are  able  to 
bring  nitrogen  into  combination  and  the  nitrogen  fixed  under 
favourable  laboratory  conditions  may  amount  to  i%  of  the 
carbohydrate  oxidized.  To  be  effective  Azotobacler  requires 
certain  conditions — a  neutral  medium  with  calcium  carbonate 
present  to  neutralize  the  acids  produced,  for  which  reason  the 
organism  is  generally  absent  from  acid  soils,  also  the  presence  of 
such  nutrients  as  phosphoric  acid  and  potash,  and  finally  a 
favourable  temperature.  It  has  been  found  at  Rothamsted  that 
a  soil  will  accumulate  nitrogen,  as  evidenced  by  an  increased 
crop,  after  the  application  of  starch  or  sugar,  carbohydrates 
containing  no  nitrogen,  if  these  materials  are  mixed  with  the 
soil  in  the  early  autumn  when  the  land  is  still  warm  and  Azolo- 
bacler is  active.  On  the  other  hand  spring  applications  of  carbo- 
hydrates are  followed  by  a  diminished  crop,  because  at  a  low 
temperature  other  organisms  in  the  soil  which  are  consumers  of 
combined  nitrogen,  attack  the  carbohydrate  and  by  their 
multiplication  withdraw  some  of  the  soil  nitrogen  from  circula- 
tion and  so  reduce  the  supply  for  the  crop. 

The  great  significance  of  these  observations  of  the  mode  of  action 
of  Azolobacler  is  that  they  afford  a  solution  of  the  problem  of  how  the 
great  stocks  of  combined  nitrogen  came  to  be  accumulated  in  virgin 
soils,  especially  in  certain  black  soils  such  as  occur  on  the  prairies 
and  in  the  Canadian  North-West.  Of  itself  the  mere  growth  and 
dying  down  of  vegetation  for  however  many  years  repeated,  could 

not  add  to  the  stock  of  combined  nitrogen  in  the  soil.  The  plant 
itself  fixes  no  nitrogen,  but  only  draws  upon  the  capital  in  the  soil, 
restoring  whatever  it  took  out  when  the  vegetation  is  allowed  to 
die  back  to  the  soil  without  loss.  But  the  falling  vegetation  contains 
carbohydrates  derived  from  the  air  and  if  they  are  added  to  a  soil 
containing  A  zotobacter  under  conditions  favourable  to  its  growth,  the 
carbohydrate  supplies  the  energy  whereby  the  Azolobacler  can  fix 
some  more  nitrogen  from  the  air  and  add  to  the  stock  in  the  soil. 
In  this  way  the  annual  cycle  of  vegetation  when  the  leaves  fall  back 
to  the  soil  can  result  in  a  yearly  accretion  of  nitrogen  which  in  time 
may  amount  even  to  the  remarkable  accumulation  found  in  the 
deep  black  soils  of  Manitoba  and  similar  "  steppe  "  lands,  soils  that 
are  invariably  found  to  be  well  supplied  with  carbonate  of  lime  and 
also  to  contain  the  Azotobacter  organism.  The  clue  to  this  interpreta- 
tion of  the  accumulation  of  nitrogen  in  virgin  steppe  and  forest 
soils  was  derived  from  the  examination  of  the  soils  of  the  wheat 
field  at  Rothamsted.  The  soil  of  the  unmanured  plots  which  has 
been  in  arable  cultivation  for  over  half  a  century  shows  a  steady 
decline  in  the  amount  of  nitrogen  it  contains,  a  decline  which  is 
approximately  equivalent  to  the  nitrogen  which  is  known  to  have 
been  removed  in  the  crops  harvested  year  by  year.  Doubtless  the 
soil  has  suffered  other  losses  of  nitrogen  by  drainage,  removal  of 
weeds,  etc.,  that  cannot  be  estimated,  but  the  analysis  of  the  soil 
shows  that  any  recuperative  processes  which  may  have  been  at 
work  restoring  nitrogen  to  the  soil  have  only  been  able  to  repair 
these  minor  losses  butvnot  to  restore  any  of  the  nitrogen  removed  in 
the  crops.  A  portion,  however,  of  the  same  plot  was  allowed  to  go 
to  waste,  i.e.  it  was  allowed  to  cover  itself  with  a  natural  vegetation 
of  weeds  and  grasses,  which  were  neither  cut  nor  grazed  but  allowed 
to  die  back  to  the  soil.  After  30  years  an  examination  of  the  soil 
of  this  wilderness  showed  it  had  been  accumulating  nitrogen  at  the 
rate  of  nearly  100  Ib.  per  ac.  per  annum,  the  greater  part  of  which 
must  have  been  due  to  the  action  of  Azotobacter  working  upon  the 
carbonaceous  matter  supplied  by  the  decaying  vegetation  reaching 
the  soil  in  the  autumn  and  winter. 

On  the  arable  land  where  the  vegetable  matter  reaching  the  soil  is 
minimal,  only  the  roots  and  stubble  of  the  crop,  there  is  a-  steady 
loss  of  nitrogen ;  on  the  wilderness  which  may  be  compared  to  a 
natural  prairie,  the  return  of  the  vegetation  to  the  soil  causes  nitro- 
gen to  accumulate  not  because  of  the  nitrogen  contained  in  its 
material,  but  because  its  carbonaceous  matter  supplies  the  energy 
whereby  the  Azotobacter  fixes  nitrogen.  The  Azotobacter  group  of 
organisms,  though  not  the  only  ones  capable  of  bringing  free  nitrogen 
gas  into  combination,  constitute  the  group  which  has  played  the 
fundamental  part  in  building  up  not  merely  the  vegetable  soil  but 
the  whole  substratum  of  organic  life  in  the  world. 

Soil  Protozoa. — The  outlook  on  the  organisms  in  the  soil  has 
been  entirely  changed  since  Russell  and  Hutchinson  showed  the 
part  played  by  the  protozoa  in  limiting  the  development  of 
bacteria  in  the  soil.  The  soil  protozoa,  which  are  large,  definitely 
animal  organisms  of  varied  character — amoebae,  ciliates  and 
flagellates — exist  in  large  numbers  in  all  cultivated  soils,  and  as 
they  feed  upon  bacteria,  any  conditions  which  encourage  the 
development  of  bacteria  by  increasing  their  food -supply  stimulate 
the  multiplication  of  the  protozoa  which  thereby  put  a  check  to 
the  increase  of  the  bacteria.  Thus  normally  the  number  of 
bacteria  in  a  soil,  however  rich  and  favourable  to  bacterial 
development  the  conditions  may  be,  does  not  pass  a  certain 
limit  because  it  is  kept  in  check  by  the  increasing  number  of  the 
protozoa.  As  the  fertility  of  the  soil  among  other  things  depends 
on  the  rate  of  production  by  bacteria  of  ammonia  and  nitrates 
from  the  nitrogenous  residues  in  the  soil,  the  fertility  of  the  soil 
is  also  limited  by  the  presence  of  the  protozoa.  Certain  processes 
of  partial  sterilization  of  the  soil,  such  as  heating  to  the  tempera- 
ture of  boiling  water  or  even  to  1 70°  F.  or  again  treatment  for  a 
time  with  some  antiseptic,  e.g.  chloroform  or  toluene  vapour, 
effects  a  selective  destruction  of  the  soil  organisms.  The  protozoa 
are  almost  entirely  killed  off,  but  many  groups  of  bacteria,  notably 
the  ammonia-makers,  resist  destruction  though  they  may  be 
reduced  in  numbers.  But  if  after  treatment  the  treated  soil  is 
placed  under  normal  conditions  for  growth,  the  bacteria  that 
remain  multiply  with  great  rapidity  and  rise  to  a  level  of  numbers 
and  activity  they  were  unable  to  attain  before,  because  now  the 
protozoal  check  to  their  multiplication  has  been  removed. 
In  consequence  the  fertility  of  the  soil  is  greatly  increased,  in 
fact  the  yield  from  a  given  soil  may  be  doubled.  This  discovery 
suggests  immense  potentialities  of  increased  production  from 
the  land  but  as  yet  it  has  not  been  found  possible  to  apply  the 
method  of  partial  sterilization  to  ordinary  field  soils  in  the  open. 
Heating  would  be  inordinately  expensive  and  the  difficulty  is  to 
find  an  antiseptic  that  combines  cheapness  with  the  right  degree  of 



volatility  and  stability  against  the  attack  of  bacteria.  In  green- 
houses, however,  where  the  soil  soon  becomes  "  sick  "  through  the 
excessive  development  of  protozoa  under  the  favourable  con- 
ditions of  moisture,  temperature  and  manurial  enrichment,  the 
sterilization  of  the  soil  by  heat  has  been  worked  out  as  a  com- 
mercial process  and  is  now  part  of  the  routine  of  all  progressive 
cultivators  under  glass. 

Microfungi. — Great  as  is  the  attention  that  is  now  being"  given 
to  the  soil  organisms  in  all  agricultural  laboratories  there  would 
appear  to  be  room  for  more  work  upon  one  group — the  micro- 
fungi,  of  which  there  is  a  large  flora  in  the  soil. 

It  has  been  shown  that  when  from  one  cause  or  another  a  soil 
becomes  acid,  many  bacteria  concerned  in  the  decay  of  vegetable 
matter  are  entirely  inhibited  and  may  disappear.  Fungi  instead 
take  up  the  work,  but  the  broad  character  of  the  process  thereby 
changes,  the  vegetable  matter  is  not  burnt  away  as  carbon  dioxide 
but  in  part  accumulates  in  the  form  of  peat.  The  formation  of  a 
peaty  material  is  in  fact  a  concomitant  of  an  acid  reaction  in  the  soil 
and  the  activity  of  microfungi  rather  than  of  bacteria,  and  this 
generalization  fits  in  with  many  observations  of  the  character  of 
peat  deposits. 

Often  trees  are  found  at  the  base  of  these  beds  where  trees  no 
longer  grow;  and  it  may  be  surmised  that  the  trees  grew  on  the 
original  neutral  land  surface  when  it  became  fit  for  vegetation  after 
the  close  of  the  glacial  epoch.  That  soil  being  of  a  non-calcareous 
nature  gradually  accumulates  acids  arising  from  the  decay  of  the 
vegetation  falling  upon  it,  whereupon  under  the  prevailing  climatic 
conditions  the  further  vegetable  debris  reaching  the  soil  began  to 
form  peat.  This  accumulation  of  peat  in  its  turn  brought  about  the 
death  of  the  forest. 

Nitrogen. — During  1910-20  agriculture  received  great  benefit 
from  the  working  out  of  processes  on  a  large  scale  for  bringing 
nitrogen  into  combination,  processes  which  thus  supplement  the 
comparatively  limited  sources  of  nitrogen  compounds  afforded 
by  the  Chile  deposits  of  nitrate  of  soda  and  the  ammonia  which 
is  recovered  as  a  by-product  from  the  distillation  or  combustion 
of  coal. 

Prior  to  the  World  War  two  processes  had  been  established  com- 
mercially. At  Notodden  in  Norway  air  is  driven  into  a  specially 
formed  electric  arc  which  results  in  the  combination  of  nitrogen  and 
oxygen  so  that  the  issuing  gases  contain  about  I  -25  %  of  oxides  of 
nitrogen  which  are  then  absorbed  by  passing  up  towers  where  they 
meet  an  absorbing  stream  of  water  or  milk  of  lime.  The  product, 
nitrate  of  lime,  contains  about  13-5%  of  nitrogen,  and  is  a  most 
valuable  fertilizer,  quite  as  effective  as  nitrate  of  soda  and  on  some 
soils  more  suitable. 

At  about  the  same  time  as  synthetic  nitrate  of  lime  was  in- 
troduced, another  nitrogenous  fertilizer  began  to  be  manufactured 
on  a  large  scale,  calcium  cyanamide  or  nitrolim.  The  body  arises 
from  the  combination  which  ensues  at  a  temperature  of  about  600" 
C.  between  calcium  carbide  and  pure  nitrogen  gas  under  slight 
pressure,  with  the  resulting  formation  of  a  compound  which  in  the 
soil  decomposes  mainly  into  ammonia  and  calcium  carbonate. 
Cyanamide  as  a  fertilizer  requires  a  certain  amount  of  care  in  use 
and  on  the  majority  of  soils  has  not  proved  so  effective  as  nitrate  of 
soda  or  sulphate  of  ammonia.  Its  manufacture,  however,  received  an 
immense  impetus  during  the  World  War,  as  it  was  the  simplest  and 
most  readily  available  process  for  bringing  nitrogen  into  combination, 
from  which  by  further  steps  ammonia  and  then  the  nitrates  and 
nitric  acid  required  in  explosives  could  be  obtained.  The  United 
States  and  many  European  countries  have  immensely  developed 
the  manufacture  of  cyanamide,  which  must  in  future  be  available 
as  fertiliser  either  used  directly  or  after  prior  conversion  into  some 
convenient  compound  of  ammonia. 

The  war  period  was  also  marked  by  the  development  on  a  gigantic 
scale  of  a  new  process,  which  had  only  been  finally  worked  out  to  the 
manufacturing  stage  in  Germany  in  1913 — the  Haber  process  of 
bringing  nitrogen  and  hydrogen  into  combination  as  ammonia.  In 
the  presence  of  a  suitable  catalyst  of  activated  iron  these  elements 
will  unite  at  pressures  of  250-300  atmospheres  and  a  temperature 
approaching  600°  C.  to  the  extent  of  8  %  or  so  of  the  mixed  gases. 
The  ammonia  can  be  removed  and  the  remaining  gases  passed 
round  again  into  the  catalyser.  Great  as  are  the  difficulties  of  work- 
ing at  these  temperatures  and  pressures  the  Haber  process  is  cheap 
in  power  and  materials.  It  was  the  mainstay  of  the  supply  of  com- 
bined nitrogen  for  explosives  to  Germany  during  the  war,  and  should 
become  a  most  important  future  source  of  fertilizer  to  the  agricul- 

During  the  war  the  demand  for  nitrogenous  fertilizers  greatly 
increased  in  all  countries ;  the  United  Kingdom  for  example  increased 
her  consumption  of  sulphate  of  ammonia  from  60,000  tons  to 
269,000  tons  per  annum,  part  of  this  being  of  course  substitution 
for  the  pre-war  use  of  80,000  tons  of  nitrate  of  soda,  which  was  no 
longer  available.  Potentially,  however,  the  establishment  of  so 
many  war  plants  for  the  manufacture  of  synthetic  nitrogen  products 

has  increased  the  supply  of  nitrogen  available  as  may  be  seen  from 
the  following  table:  — 

Metric  Tons  of  Nitrogen. 




Chile  Nitrate 
Ammonium  sulphate 
(by-product)  . 
Haber  process    . 
Arc  process 












It  should  be  noted,  however,  that  the  1920  figures  are  not  actual 
but  only  potential  supply,  if  existing  plants  are  worked  up  to  their 

Potash. — As  the  only  extensive  potash  deposits  in  the  world 
that  had  been  commercially  developed — Stassfurt  and  Alsace — 
were  in  German  hands,  there  was  during  the  war  a  great  shortage 
of  potash  fertilizers  outside  central  Europe.  Great  efforts  were 
made  to  develop  processes  for  the  extraction  of  potash  from 
felspars  and  other  natural  sources,  but  without  much  success. 

The  only  method  which  proved  of  value  was  the  discovery  made 
in  the  United  States  that  the  dust  which  accumulates  in  the  flues 
through  which  the  gases  from  blast  furnaces  are  led  contains  a  not 
inconsiderable  amount  of  potash  in  a  readily  soluble  form,  one-half 
indeed  consisting  of  sulphates  and  carbonates  soluble  in  water. 
Different  grades  of  flue  clust  can  be  collected  :  the  finest  is  a  cream- 
coloured  material  containing  as  much  as  60%  of  potash.  The  dust 
was  collected  and  used  for  agricultural  purposes  during  the  war 
though  only  some  15,000  tons  per  annum  were  obtainable  in  Great 
Britain.  It  is  now  worked  up  for  industrial  purposes,  but  the  output 
of  potash  salts  from  this  source  cannot  exceed  a  few  thousand  tons 
per  annum  in  the  United  Kingdom.  The  supply  of  potash  salts  for 
agricultural  purposes  since  the  war  has  been  .entirely  changed  by 
the  transfer  to  France  of  the  Alsatian  deposits  which  occupy  an  area 
of  some  77  sq.  m.  between  Miilhausen  and  Colmar  in  Alsace.  This 
deposit  consists  of  two  beds,  the  upper  about  4  ft.  thick,  the  lower 
about  llj  ft.,  which  form  practically  unbroken  strata  at  an  approxi- 
mate depth  of  1, 800  ft.  and  present  no  difficulties  in  mining.  The 
material  is  very  uniform  in  composition,  consisting  in  the  main  of 
sylvinit,  mixed  chlorides  of  potassium  and  sodium,  containing  about 
20  %  of  potash  reckoned  as  K2O.  It  can  be  used  for  agriculture  in  its 
crude  state  and  though  the  development  of  the  field  is  still  very  in- 
complete the  former  German  monopoly  of  potash  supplies  is  thereby 
broken  down.  Another  extensive  deposit  is  known  in  Spain,  but  it 
has  not  reached  the  stage  of  commercial  development  and  is  generally 
considered  to  be  controlled  by  the  German  company  which  works  the 
Stassfurt  deposits. 

Superphosphates. — During  the  war  the  manufacture  of 
superphosphate  in  the  United  Kingdom  was  considerably  re- 
stricted, on  the  one  hand  by  the  withdrawal  of  sulphuric  acid  for 
the  manufacture  of  explosives,  and  on  the  other  by  the  shortage 
of  tonnage  for  the  importation  of  phosphate  rock.  American 
supplies  were  completely  cut  off  and  receipts  from  the  North 
African  deposits  fell  to  something  like  500,000  tons  per  annum. 
In  consequence  British  farmers  were  compelled  to  resort  mainby 
to  basic  slag  of  which  this  country  produced  about  400,000 
tons  per  annum,  though  prior  to  the  war  only  some  280,000  tons 
had  been  consumed  by  British  agriculturists.  With  the  extended 
programme  of  arable  farming  the  demand  for  phosphatic 
fertilizers  was  greatly  increased  and  the  whole  of  the  basic  slag 
produced  at  home  was  absorbed,  though  the  output  was  in- 
creased to  as  much  as  565,000  tons  from  the  year  ending  May 
1919.  Unfortunately  this  increase  in  amount  was  accompanied 
by  a  decline  in  character,  owing  to  changes  in  the  processes 
generally  adopted  for  making  steel. 

The  Bessemer  process  has  been  almost  displaced  by  the  open- 
hearth  process  which  produces  a  slag  less  rich  in  phosphoric  acid. 
The  practice  has  also  been  adopted  of  adding  fluor-spar  to  the  furnace 
in  order  to  induce  the  formation  of  a  more  fusible  slag,  but  thereby 
the  solubility  of  the  phosphoric  acid  of  the  slag  in  the  weak  citric 
acid  generally  used  in  testing  its  quality  becomes  impaired.  The 
bulk  of  the  basic  slag  now  sold  contains  only  about  10  %  of  phosphoric 
acid  against  15  to  20%  in  the  older  types  of  slag  and  the  phosphoric 
acid  is  no  longer  soluble  in  weak  acids.  The  new  type  of  basic  slag 
proves,  however,  little  less  effective,  unit  for  unit  of  phosphoric 
acid,  as  a  fertilizer,  but  freight  charges,  always  a  large  item  in  the 
cost  of  basic  slag  to  the  farmer,  now  become  doubled  for  the  amount 
of  phosphoric  acid  that  is  carried,  apart  from  the  increase  in  these 



charges  per  ton.  Attempts  were  in  1921  being  made  to  replace  basic 
slag  Dy  finely  ground  mineral  phosphates  as  a  fertilizer  for  grass 
land.  American  experience  has  always  been  favourable  to  these 
ground  phosphates,  and  recent  experiments  in  England  have 
demonstrated  that  they  effect  in  poor  pastures  the  same  encourage- 
ment of  clover  as  is  obtained  from  basic  slag,  even  upon  such  un- 
promising land  as  the  clays  in  the  dry  Essex  climate.  The  phosphate 
rock  from  Nauru  Island,  that  has  passed  from  German  hands  into 
the  control  of  the  British  Government,  may  prove  of  special  value 
for  application  in  this  finely  ground  but  otherwise  untreated  con- 

Plant  Breeding. — Probably  the  plant  breeders  have  during 
1900-20  rendered  the  greatest  services  to  agriculture,  inasmuch 
as  improvements  in  this  direction — the  introduction  of  new 
varieties  giving  large  yields,  better  quality  and  more  resistant 
to  disease — are  at  once  appreciated  by  the  farmer  and  require  no 
alterations  in  the  methods  of  cultivation.  It  has  been  found 
possible  to  apply  Mendelian  principles  with  comparative  sim- 
plicity and  accuracy  to  the  breeding  of  new  varieties  of  plants, 
especially  of  cereals,  and  the  results  achieved  have  already 
experienced  considerable  commercial  development  in  the  case  of 
wheat,  barley,  oats,  maize,  sugar-cane  and  cotton.  The  value  of 
the  Mendelian  principle  lies  in  the  power  it  gives  of  combining  in 
one  of  the  selected  descendants  of  a  cross-bred  individual  un- 
related valuable  characters  possessed  by  the  parents  separately. 

In  the  case  of  wheat  Biffen  has  shown  that  among  the  Mendelian 
characters  that  are  transmitted  as  unchanged  units  are  such  quanti- 
tative properties  as  the  resistance  to  disease,  the  normal  percentage 
of  nitrogen  in  the  grain  and  the  "  strength  "  of  the  flour  resulting 
from  it,  the  stiffness  of  the  straw,  etc.  One  of  the  chief  desiderata 
as  regards  English  wheat  has  been  an  improvement  in  its  strength, 
i.e.  the  capacity  to  yield  a  spongy  elastic  dough  which  will  .bake  into 
a  light  loaf  of  large  volume.  This  strength  factor  which  is  connected 
with  the  amount  of  gluten  and  therefore  with  the  percentage  of 
nitrogen  in  the  flour  is  as  a  rule  the  property  of  spring  wheats  grown 
in  a  "  steppe  climate  "  with  a  short  period  of  growth,  with  consider- 
able rainfall  in  the  early  months  exchanged  for  great  heat  and  al- 
most complete  dryness  before  harvest.  Wheats  from  Hungary, 
South  Russia,  Manitoba  and  the  great  plains  of  North  America 
possess  this  quality,  and  Leclerc  ana  Leavett  have  shown  by  sowing 
the  same  seed  in  different  states  how  potent  is  the  effect  of  environ- 
ment and  climate  in  determining  the  percentage  of  nitrogen  and 
the  strength  of  wheat.  As  a  rule  any  of  the  strong  wheats  brought 
either  from  continental  or  American  sources  lose  their  strength 
completely  when  grown  under  English  conditions.  One  wheat, 
however,  of  Galician  origin  but  widely  grown  in  America  under  the 
name  of  Red  Fife,  so  widely  indeed  as  to  be  the  dominant  constituent 
of  such  commercial  grades  as  Manitoba  and  No.  I  Northern,  does 
to  a  large  measure  retain  its  strength  in  England,  the  strength  in  this 
case  being  congenital  and  not  the  product  of  environment.  Red 
Fife  is,  however,  a  poor  cropper  on  most  English  soil,  yielding  but 
3  qr.  per  ac.  where  the  typical  English  wheats  will  yield  four  or  five. 
Biffen  has,  however,  employed  it  as  a  parent  in  the  hope  of  combin- 
ing the  strength  of  the  one  parent  with  the  cropping  power  of  the 
other  and  one  of  the  results  of  this  cross,  a  wheat  called  Yeoman, 
issued  to  the  public  in  1915,  is  on  its  congenital  soils — the  warmer 
and  better  soils  of  the  east  and  south-east  of  England — probably  the 
heaviest  cropper  grown.  Further,  the  quality  of  the  grain  is  so  high 
that  the  miller  can  use  it  without  any  mixture  of  strong  foreign 
wheats,  such  as  are  necessary  to  the  extent  of  40%  or  more  with 
ordinary  English  wheat.  Another  of  Biffen's  wheats,  Little  Joss, 
by  its  power  of  resisting  rust,  has  proved  a  very  heavy  cropper  and  is 
now  extensively  grown  on  soils  that  remain  fairly  dry  and  warm 
throughout  the  winter.  Saunders  in  Canada  has  effected  a  very  con- 
siderable extension  of  the  wheat  area  by  the  introduction  of  a 
wheat  called  "  Marquis,"  another  hybrid  with  Red  Fife  as  one 
parent,  which  combines  the  good  quality  of  Red  Fife  with  a  shorter 
period  of  growth  and  an  earlier  ripening  habit,  thus  rendering  wheat- 
growing  safe  in  wide  areas,  as  in  parts  of  Alberta,  where  the  crop 
was  liable  to  ruin  through  the  onset  of  early  autumn  frosts  before 
harvest  had  been  completed.  On  the  average  Marquis  ripens  six 
days  earlier  than  Red  Fife  and  thus  in  the  Central  Prairie  region 
where  firsts  are  expected  between  Aug.  27  and  Sept.  2  Marquis  can 
generally  be  grown  safely  though  Red  Fife  is  liable  to  be  caught. 
In  part  the  extension  of  Marquis  may  be  put  down  to  its  superior 
cropping  powers,  but  for  one  reason  or  another  it  has  largely  dis- 
placed all  other  spring  wheats  in  the  North-West.  In  1918  the  area 
under  Marquis  in  Minnesota,  the  Dakotas,  Montana,  Manitoba, 
Saskatchewan  and  Alberta  was  estimated  to  amount  to  20,000,000 
ac.  and  the  crop  in  Canada  alone  to  129,000,000  bus. — all  the  produce 
of  what  was  but  a  single  plant  in  1903! 

Immunity  from  Disease. — The  inheritance  of  immunity  from 
disease  is  best  illustrated  by  the  discovery  of  potatoes  immune 
to  wart  disease. 

About  1897  attention  was  drawn  to  the  prevalence  in  certain 

parts  of  England  and  Wales  of  a  disease  of  potatoes,  generally  found 
in  old  cottage  gardens  and  allotments,  which  causes  the  potatoes  to 
degenerate  into  a  mass  of  dark  corky  excrescences  and  will  in  bad 
cases  destroy  the  crop  entirely.  The  disease  is  due  to  the  attack  of  a 
lowly  organised  fungus,  and  the  difficulty  of  dealing  with  it  is  due 
to  the  fact  that  once  established  in  the  soil  the  spores  or  some  resting 
form  of  the  fungus  retain  their  life  for  an  indefinite  period  of  many 
years.  Once  the  soil  has  become  infected  no  practicable  means  has 
been  found  of  cleaning  it;  even  leaving  the  land  down  to  grass  for 
ten  years  has  been  found  ineffective.  Considerable  areas  in  the 
industrial  districts  of  Lancashire,  Cheshire,  Stafford  and  Shrop- 
shire, North  and  South  Wales  are  subject  to  the  disease  and  it 
became  more  widely  distributed  throughout  the  West  of  England 
as  a  result  af  the  great  shortage  of  seed  potatoes  in  1917,  which 
caused  men  to  plant  anything  that  was  available  without  inquiring 
into  its  origin. 

The  consequences  would  undoubtedly  have  been  the  complete 
destruction  of  potato-growing  in  those  districts  had  it  not  been 
observed  that  one  or  two  types  of  potatoes  could  be  found  growing 
unharmed  in  some  of  the  old  infected  gardens.  Further  examination 
proved  that  these  varieties  were  really  immune  to  the  disease,  how- 
ever heavily  infected  the  soil,  and  though  in  themselves  they  pos- 
sessed little  commercial  value  they  were  at  once  employed  as  seed 
parents  and  have  become  the  source  of  a  new  race  of  potatoes 
immune  to  wart  diseases.  Many  of  these  are  now  proving  to  be  good 
market  varieties  of  heavy  cropping  power  and  by  their  aid  potato- 
growing  has  been  rendered  possible  in  the  infected  areas  which  other- 
wise inevitably  would  have  spread  until  the  whole  country  would 
have  been  involved.  As  the  disease  has  also  obtained  a  foothold 
(its  original  habitat  is  unknown)  in  North  America,  Holland,  Bel- 
gium and  Germany,  the  value  of  this  discovery  of  immunity  is 
difficult  to  overestimate.  From  the  study  of  this  and  other  cases 
the  conviction  gains  ground  that  the  most  fruitful  method  of  dealing 
with  plant  disease  will  always  be  by  the  search  for  immunity  rather 
than  by  methods  of  treatment. 

Selection. — In  the  improvement  of  cereals  considerable 
advantages  have  been  derived  by  working  on  another  principle 
than  that  of  breeding,  i.e.  pure  line  selection.  Very  little  im- 
provement in  a  variety  can  be  effected  by  what  may  be  called 
"  mass  selection."  If  in  going  over  a  field  of  wheat  a  collection  is 
made  of  the  longest  ears,  or  again  if  the  heaviest  grains  are  sorted 
out,  no  perceptible  improvement  is  visible  in  the  crop  grown 
from  the  selection,  not  even  if  the  process  is  repeated  generation 
after  generation.  The  superiority  of  the  individuals  selected  has 
been  due  to  some  accident  of  nutrition  and  is  not  transmissible 
to  the  offspring.  If,  however,  the  selected  individuals  are  sown 
separately,  here  and  there  among  them  will  be  found  one  which 
in  the  next  and  succeeding  generations  still  preserves  some 
superiority  which  is  congenital  to  it  and  is  maintained  in  succeed- 
ing generations  even  when  the  seed  is  worked  up  to  a  large  crop. 

An  ordinary  variety,  say  of  wheat,  really  consists  of  an  indefinite 
mixture  of  sub-varieties  each  of  which,  for  many  generations  at 
least,  breeds  true  in  the  case  of  cereals  which  are  self-fertilized. 
Thus  "  pure  lines  "  may  be  selected  from  single  seeds  of  such  self- 
fertilized  plants  and  worked  up  to  commercial  stocks  of  seed.  These 
pure  lines  may  have  some  superiority,  never,  however,  great,  in 
cropping  power  over  the  mixed  variety  from  which  they  are  derived, 
and  are  also  appreciably  more  uniform  in  such  details  as  time  of 
ripening  and  length  of  straw. 

It  has  become  evident  that  every  commercial  variety  of  cereals, 
even  if  of  deliberately  cross-bred  origin,  will  be  improved  by  pure 
line  selections  from  time  to  time. 

Nutrition. — It  was  still  difficult  in  1921  to  discuss  in  any 
detail  the  progress  that  is  being  made  in  the  study  of  animal 
nutrition,  in  regard  to  which  the  teachings  of  the  scientific  man 
have  had  much  less  effect  upon  the  practice  of  the  farmer  than 
has  been  the  case  when  the  nutrition  of  the  plant  has  been 

The  great  shortage  of  cattle  food  during  the  war,  notably  in  1917 
and  1918  when  no  tonnage  could  be  spared  for  cattle  food,  did  reveal 
two  things,  first,  the  dependence  upon  imported  corn  and  oil  seeds 
that  British  meat  and  milk  production  had  fallen  into,  and  secondly, 
the  enormous  waste  that  had  been  going  on.  It  was  estimated  that 
the  normal  output  of  meat,  milk  and  other  animal  products  did  not 
represent  one-half,  possibly  not  more  than  a  third,  of  the  amount 
that  could  have  been  obtained,  not  merely  theoretically,  but  even  in 
properly  informed  practice.  At  the  same  time  certain  lacunae  in 
our  theory  were  disclosed,  which  prevent  the  scientific  man  from 
setting  out  with  any  accuracy  the  limits  within  which  the  fattening 
of  animals  will  proceed  most  economically.  It  will  be  seen  that  the 
problem  is  a  very  complex  one.  On  the  one  hand,  as  regards  the 
amount  of  food  fed  over  and  above  the  maintenance  ration,  the  law 
of  diminishing  returns  is  found  to  hold  for  the  amount  of  daily 
increase;  on  the  other  hand,  the  slower  the  rate  of  fattening,  the 



greater  must  be  the  non-productive  consumption  of  food  on  main- 
tenance only. 

Again  in  the  later  stages  of  fattening  the  law  of  diminishing  re- 
turns operates  in  another  fashion,  in  that  the  increase  of  weight 
may  be  put  on  as  offa!  fat  of  comparatively  low  value  instead  of  as 
edible  fat  in  the  "  meat  "  portions  of  the  carcass.  Much  more 
exact  information  is  therefore  being  sought  as  to  the  relations 
of  the  live  weight  increase  to  the  progress  in  consumption  of  food 
and  again  to  the  changes  in  the  composition  of  the  carcass  as  the 
fattening  process  advances. 

On  the  other  side  of  the  nutrition  question  recent  work  upon  "  vita- 
mines  "  and  accessory  food  factors  is  found  to  have  its  application 
to  questions  of  animal  nutrition.  Not  only  the  health  and  growth 
of  certain  animals,  notably  pigs,  is  in  practice  affected  by  the 
deficiency  of  the  foods  habitually  used  in  these  accessory  factors,  but 
again  the  fats  arising  from  the  animals,  e.g.  lard,  bacon,  even  milk 
and  butter  fat,  may  in  their  turn  become  deficient  as  human  foods 
because  of  the  lack  of  the  accessory  substances  in  the  food  of  the 
animal.  Enough  work  has  been  done  to  show  that  in  certain  special 
cases  of  indoor  feeding  of  animals  not  only  the  broad  energy-  and 
tissue-forming  properties  of  the  food  have  to  be  considered,  but  also 
the  supply  of  certain  accessories — energizers  or  detonators,  whatever 
may  prove  to  be  their  function.  In  practice  the  path  of  safety  for 
all  farm  animals  lies  in  a  reasonably  mixed  diet,  which  includes  some 
proportion  of  uncooked  green  food.  Pigs  and  poultry  have  not  in- 
frequently been  sufferers  from  diets  insufficiently  supplied  with 

Animal  Breeding. — Although  in  1921  such  progress  had  not 
yet  been  made  with  the  very  complex  subject  of  animal  breeding 
as  to  enable  economic  results  to  be  obtained  similar  to  those 
which  had  accrued  in  plant  breeding,  still  the  ground  was  being 
prepared  by  certain  initial  investigations  for  the  mode  of  in- 
heritance of  some  of  the  desiderated  qualities  in  domestic 
animals,  e.g.  size,  prolificacy,  quality  of  wool,  etc. 

Punnett,  for  example,  in  England  has  thrown  some  light  on  the 
inheritance  of  size  in  fowls  and  rabbits,  and  again  on  the  inheritance 
of  fur,  but  by  far  the  most  important  work  in  this  direction  has  been 
done  by  Pearl  in  Pennsylvania.  In  studying  the  inheritance  of  milk 
yields  he  has  first  of  all  endeavoured  to  obtain  a  single  figure  char- 
acterizing the  performance  of  a  cow,  a  sort  of  index  number.  By  a 
study  of  commercial  milk  records  he  has  constructed  a  type  curve 
showing  the  variation  in  milk  yield  for  a  cow  during  successive  cal- 
vings,  whereby  if  its  milk  yield  in  any  one  year  is  known  this  figure 
can  be  corrected  to  give  the  milk  yield  in  the  standard  year  used  for 
comparison.  A  similar  type  curve  can  be  constructed  for  the  period 
of  a  lactation,  whereby  the  yield  for  the  whole  period  can  be  de- 
duced from  the  yield  ascertained  during  a  particular  month  or  less. 
Having  thus  obtained  characteristic  figures  for  cows,  Pearl  was  in  a 
position  to  compare  the  performances  of  cows  with  their  offspring  by 
different  bulls.  By  tabulating  all  such  comparisons  obtainable  with 
regard  to  a  particular  bull  a  characteristic  mark  is  obtained  for  the 
bull.  Some  bulls  are  found  always  to  bring  about  an  increase  in  the 
milk  production  of  the  daughter  over  the  dam ;  other  bulls  which  had 
a  great  repute  in  their  day  and  a  fine  record  in  the  show  yard  equally 
invariably  gave  progeny  yielding  less  milk  than  their  dams.  The 
value  of  this  work  in  connexion  with  milk  recording  and  breeding 
is  evident;  indeed  in  Denmark  for  some  years  the  underlying  prin- 
ciple has  been  appreciated  in  that  prizes  are  offered  for  bulls,  the 
award  being  based  upon  the  milk  tests  of  the  bull's  progeny.  The 
difficulty  attaching  to  the  application  of  these  results  lies  in  the 
disinclination  of  farmers  to  retain  bulls  for  service  for  more  than  two 
or  three  years ;  they  are  cast  before  there  is  any  opportunity  of  test- 
ing the  milk-producing  quality  of  their  offspring.  (A.  D.  H.) 


As  was  inevitable,  the  World  War  gave  rise  in  all  countries  to 
a  great  body  of  emergency  enactments  and  temporary  legisla- 
tion affecting  agriculture.  Beyond  these,  however,  the  years 
1917-21  saw  a  large  volume  of  legislation  which  aimed  at  the 
reorganization  of  agriculture  in  Great  Britain,  and  also  inaugu- 
rated a  definite  agricultural  policy,  the  main  features  of  which 
found  expression  in  the  Corn  Production  Act  of  1917  and  the 
Agriculture  Act  of  1920.  The  principles  underlying  these  Acts 
first  were  set  out  in  the  report  of  the  commission  appointed  in 
1915  under  Lord  Milner,  and  still  more  fully  in  the  report  of  the 
sub-committee  of  the  Reconstruction  Committee  under  the 
chairmanship  of  Lord  Selborne. 

Briefly,  these  committees  found  that  the  position  of  the  United 
Kingdom  had,  as  demonstrated  by  the  war,  fallen  into  great 
insecurity  in  consequence  of  the  neglect  of  agriculture  which  had 
been  going  on  during  the  previous  40  years.  In  1872  the  arable 

land  in  the  United  Kingdom  amounted  to  nearly  24,000,000  ac., 
and  this  had  become  by  1914  little  more  than  19,000,000  acres. 
The  loss  had  been  experienced  chiefly  in  England  and  Wales, 
where  the  shrinkage  had  been  nearly  4,000,000  ac.,  from  14,943,- 
oooto  10,998,000  acres.  This  represents  a  great  decline  in  the  gross 
production  of  food,  because  it  has  been  abundantly  demonstrated 
that  an  acre  of  medium  land  under  grass  does  produce  only  about 
one-third  of  the  meat  or  milk  that  can  be  obtained  from  the 
same  land  if  it  is  put  under  the  plough  and  the  crops  are  con- 
sumed by  stock.  Moreover,  whenever  there  is  a  definite  shortage  of 
food  the  production  of  meat  is  in  itself  a  wasteful  process,  from 
seven  to  ten  pounds  of  real  food  being  consumed  by  the  animal 
in  making  one  pound  of  food  in  the  shape  of  meat  or  milk.  The 
only  gain  in  meat  production  is  that  the  animal  is  able  to  convert 
coarse  fodder  like  straw  and  waste  materials  like  millers'  offals 
into  human  food,  but  an  animal  like  a  pig,  which  is  largely  fed 
upon  barley  and  maize  meal,  equally  edible  by  human  beings, 
becomes  definitely  wasteful  of  the  resources  of  the  country  when 
a  real  food  scarcity  is  declared.  The  comparison  between  the 
productiveness  of  grass  and  arable  land  may  perhaps  be  illus- 
trated most  markedly  by  a  consideration  of  the  potato  crop.  Art 
average  yield  of  potatoes  in  England  is  about  6j  tons  per  ac., 
which  represents  over  2,000  Ib.  of  dry  food  when  all  allowances 
have  been  made  for  waste.  Under  grass  the  same  land  would  not 
produce  more  than  120-150  Ib.  of  meat,  i.e.  about  100  Ib.  of  dry- 
food,  or  160  gal.  of  milk,  i.e.  170  Ib.  of  dry  food.  Nor  does 
the  animal  food,  pound  for  pound  of  dry  matter,  possess  more 
than  a  slight  superiority  over  the  potatoes  in  its  power  of  main- 
taining human  beings. 

Before  the  War. — Roughly  speaking,  in  the  years  immediately 
preceding  the  World  War  the  United  Kingdom  was  only  pro- 
ducing about  42%  of  the  food  consumed  by  its  people.  The 
greater  portion  had  to  be  imported,  and  this  applied  particularly 
to  wheat  of  which  only  about  one-fifth  of  the  normal  consump- 
tion was  produced  at  home.  This  dependence  of  the  nation 
upon  external  supplies  of  food  was  its  great  weakness  revealed 
by  the  war.  Not  only  was  there  the  danger  that  the  German 
submarine  campaign  might  prove  successful  and  force  submission 
by  starvation,  but,  even  as  it  was,  the  country's  effort  was  ham- 
pered by  the  necessity  of  allocating  to  food  supply  so  large  a 
proportion  of  the  available  tonnage  needed  for  other  purposes 
and  of  employing  part  of  the  naval  strength  to  protect  it.  Again, 
the  purchasing  power  and  credit  of  the  country  were  continually 
impaired  by  the  enormous  sums  spent  abroad  for  food. 

The  external  food  bill  amounted  to  over  £220,000,000  a  year 
before  the  war,  and  during  its  latter  stages  this  had  risen  to  three 
times  that  sum.  The  enemy  was  not  slow  to  realize  that  this  was 
Britain's  vulnerable  spot.  The  attack  failed,  but  the  economic 
consequences  pressed  grievously  upon  Great  Britain  after  the 
war.  The  recovery  of  Britain  was  deferred  by  the  enormous 
purchases  it  must  continue  to  make  abroad  in  order  to  keep  its 
people  fed,  and  the  sacrifices  it  must  make  in  order  to  maintain 
the  foreign  exchange  at  a  high  level  in  order  to  meet  these  pur- 

It  had  often  been  argued  that  in  case  of  emergency  the  grass 
lands  of  Britain  constituted  a  great  reserve  of  fertility  which 
could  be  drawn  upon  for  the  growth  of  corn  and  other  crops, 
but  when  the  occasion  came  it  was  proved  how  little  of  this 
reserve  was  immediately  available.  Neither  the  men  nor  the 
horses,  not  even  the  buildings  or  the  implements,  required  for 
arable  farming,  existed  any  longer.  All  the  inertia  of  the  farming 
community  came  into  play  against  conversion,  and  despite  the 
efforts  of  the  State,  armed  with  compulsory  powers,  proffering 
compensation  against  loss  and  assisting  with  fertilizers,  seeds 
and  machines,  less  than  a  further  2,000,000  ac.  of  grass  lane1 
got  broken  up  during  the  fateful  years  of  1917  and  1918.  Once 
the  art  and  means  of  arable  farming  have  been  lost,  it  is  only 
slowly  and  at  great  expense  that  they  can  be  improvised. 

Concurrently  with  the  decline  in  the  production  from  British 
land  in  consequence  of  the  conversion  from  arable  into  grass 
there  had  been  a,  corresponding  decrease  in  the  agricultural  pop- 
ulation, which  in  England  and  Wales  alone  had  fallen  from 


1,269,371  in  1871  to  951,674  in  1901,  though  by  1911  it  had 
again  risen  somewhat,  to  1,002,743. 

This  reduction  of  the  agricultural  community  was  not  to  be 
viewed  with  equanimity.  A  population  dependent  entirely  upon 
manufactures  gives  rise  to  an  unstable  State,  subject  to  violent 
fluctuations  of  prosperity  because  the  causes  that  determine 
employment  are  apt  to  affect  all  industries  simultaneously. 
Politically  a  country  population  is  more  sober  and  cautious, 
just  as  it  is  healthier  and  more  reproductive  and  both  physically 
and  temperamentally  better  fitted  for  steady  enduring  work. 
It  was  these  two  motives  then  that  led  to  the  legislation  under 
review — the  desire  to  ensure  a  greater  production  of  food  and  the 
better  cultivation  of  British  land,  and  the  desire  to  increase  the 
rural  population,  neither  of  which  could  be  attained  if  the  old 
laissezfaire  policy  were  persisted  in. 

New  British  Policy. — What  had  been  the  origin  of  the  danger- 
ous situation  in  which  the  nation  found  itself  in  1914?   Taking 
extent  of  the  arable  land  as  an  index,  the  high-water  mark  of 
English  agriculture  was  reached  in  1872.    The  later  seventies 
were  marked  by  bad  seasons  culminating  in  the  disastrous  ex- 
perience of  1879.    At  the  same  time  rapid  progress  was  being 
made  with  the  opening  up  of  the  American  prairies  for  corn- 
growing  and  with  the  cheapening  of  ocean  freights.   This  was  a 
period  of  immense  expansion  in  the  new  lands  of  the  world;  it 
saw  the  growth  of  the  Middle  West  both  in  the  United  States 
and  Canada,  the  agricultural  settlement  of  the  Argentine  and 
other  South  American  lands,  the  development  of  Australian 
wheat-growing    areas    and    the    commercial    exploitation    of 
southern  Russia.    As  a  consequence,  prices  of  the  great  agri- 
cultural commodities,   corn  and   meat,  fell  rapidly  and  con- 
tinuously during  the  eighties  and  nineties.   Wheat  from  an  aver- 
age of  543.  8d.  per  qr.  in  1871-5  fell  to  223.  lod.  in  1894;  the 
average  return  per  acre  on  an  arable  farm  for  both  corn  and  meat, 
estimated  at  1653.  in  the  first  period,  dropped  to  about  iocs, 
between  1894  and  1900.    As  the  rate  of  wages  rose  during  the 
period  and  no  great  compensating  factor  was  at  work  (other 
than  the  perfecting  of  the  self-binder,  which  had  made  wheat- 
growing  for  export  possible  in  the  new  countries),  British  farm- 
ing was  unable  to  adjust  itself  with  sufficient  rapidity  to  the  vastly 
diminished  returns.    The  great  depression  resulted  in  the  ruin 
of  a  large  proportion  of  the  old  farmers,  in  a  wholesale  loss  of 
capital,  and,  worst  of  all,  in  an  entire  loss  of  confidence  in  an 
industry  that  had  ceased  to  control  the  prices  of  its  main  prod- 
ucts.  The  industry  met  the  situation  by  a  drastic  reduction  of 
expenditure  and  the  conversion  of  arable  land  into  grass  on 
which  the  labour  bill  was  small.    The  process  was  aided  by  the 
continued  development  of  the  milk  trade.    From  1900  onwards 
the  course  of  prices  turned  upwards — the  world's  population 
was  growing  up  to  the  food  supply,  and  the  new  farming  adjusted 
to  the  changed  conditions  began  to  become  steadily  prosperous. 
But  the  memory  of  the  great  depression  remained,  confidence 
was  small  and  capital  mistrustful.    Men  hesitated  to  adventure 
their  money  in  a  business  which  was  liable  to  a  break  of  prices 
such  as  had  occurred  within  all  too  recent  a  date.    Such  were 
the  conditions  that  had  led  to  the  dependence  of  the  nation  upon 
foreign  food  and  particularly  upon  foreign  corn;  hence  the  object 
of  the  policy  was  to  give  the  arable-land  farmer  security  that  he 
should  not  in  future  be  subjected  to  a  devastating  break  in 
prices  such  as  had  occurred  in  the  eighties  and  nineties  of  the 
last  century.  With  this  security  in  the  background  it  was  thought 
the  current  conditions  would  be  favourable  enough  to  bring 
about  an  extension  of  the  arable  area. 

As  the  Prime  Minister  said  in  his  famous  speech  to  agricultur- 
ists in  Oct.  1919: — 

"  The  Agricultural  industry  is  the  greatest  industry  in  the  State. 
It  ought  therefore  to  be  a  primary  concern  of  every  Government  and 
of  every  Statesman  to  do  what  in  them  lies  to  promote  that  industry. 
I  regret  to  say  that  in  no  civilized  country  has  the  State  done  so  little 
during  the  last  generation  to  foster  agriculture.  I  hope  that  record 
will  now  be  rolled  up  and  that  there  will  begin  a  new  era  in  the 
relations  of  the  State  with  the  greatest  and  the  most  important  of  its 
industries  .  .  .  The  question  is  '  Are  we  going  back  to  the  dismal 
pre-war  conditions  or  are  we  merely  going  to  maintain  the  progress 
which  has  been  made?'  Are  we  not  going  further?  There  can  be  but 

one  answer  from  every  man  who  loves  his  country.  We  must  go 
forward.  How  is  it  to  be  done?  You  must  have  a  settled  policy  with 
regard  to  agriculture.  The  first  condition  is  security  to  the  cultiva- 
tor :  security  in  the  first  place  against  ruin  through  the  violent  fluc- 
tuations of  foreign  agriculture." 

Acts  of  igij,  i gig,  1920. — The  method  by  which  this  security 
was  given  in  the  "  Corn  Production  Act  "  of  1917  and  the 
"  Agriculture  Act  "  of  1919  embodies  a  novel  principle.   Instead 
of  a  protective  duty,  which  enhances  the  price  to  the  consumer, 
a  bounty  was  given  to  the  producer  if  the  average  market  price 
of  wheat  or  oats  fell  below  certain  guaranteed  figures.    In  the 
Corn  Production  Act  certain  guaranteed  prices  were  set  down 
for  six  years  ahead,  but  at  that  time  it  was  vain  to  make  forecasts 
of  the  trend  of  prices,  and  actually  none  of  the  guarantees  then 
given  ever  came  into  operation.   By  the  Agriculture  Act  of  1920 
basal  prices  of  68s.  for  wheat  and  465.  for  oats  were  taken  for  the 
year  1919,  and  commissioners  were  appointed  who  were  charged 
to  determine  from  year  to  year  how  far  the  average  costs  of 
production  of  wheat  and  oats  had  changed  in  that  year  from 
those  of  the  basal  year  1919,  whereupon  the  guaranteed  figure  of 
68s.  or  465.  was  varied  in  like  proportion.    If  for  example  the 
commissioners  found  that  in  1923  the  cost  of  production  of  a 
quarter  of  wheat  was  on  the  average  20%  less  than  in  1919,  the 
price  guaranteed  by  the  Act  would  become  545.  sd.   Should  then 
the  average  price  actually  obtained  by  farmers,  as  ascertained 
by  the  official  corn  market  returns  from  Sept.  i  to  March  31, 
amount  to  525.  nd.  and  thus  leave  a  difference  of  is.  6d.  per 
quarter  between  the  guaranteed  and  realized  price,  the  Govern- 
ment would  be  liable  to  pay  is.  6d.  per  quarter  on  all  the  wheat 
produced.    But  since  the  verification  of  the  actual  quantities 
grown   presents   great   administrative    difficulties   the   crop   is 
assumed  to  be  4  qr.  to  the  acre,  and  the  undertaking  of  the 
Act  was  to  pay  four  times  the  difference  between  the  average 
realized  price  and  the  guarantee  on  every  acre  of  wheat  grown, 
five  times  the  difference  in  the  case  of  oats,  on  the  assumption  of 
an  average  crop  of  5  qr.  to  the  acre.   It  will  be  seen  .that  the  pay- 
ments made  to  any  individual  were  independent  of  the  actual 
price  he  happened  to  obtain  for  his  particular  sample.   The  nor- 
mal course  of  trade  is  not  interfered  with  and  the  grower  gets  the 
benefit  of  any  superiority  of  quality  or  favourable  market  con- 
ditions he  may  possess. 

The  guarantees  were  confined  to  wheat  and  oats,  not  so  much 
to  increase  the  specific  production  of  those  cereals  as  to  en- 
courage arable  farming,  since  one  or  both  of  these  crops  formed 
an  inevitable  part  of  every  rotation  in  the  United  Kingdom. 

Inevitably  the  State  was  involved  in  a  considerable  liability  in 
any  year  in  which  a  break  in  prices  might  occur  after  harvest  but  in 
which  the  costs  of  production  had  not  been  affected.  These  are, 
lowever,  precisely  the  occasions  dreaded  by  the  farmer  mindful  of 
the  past,  and  the  Act  was  designed  to  give  the  farmer  such  assistance 
as  might  save  him  from  ruin,  though  it  would  not  provide  a  profit. 
The  State,  however,  only  accepted  this  liability  in  order  to  bring 
about  an  increase  of  production ;  it  recognized  an  obligation  towards 
agriculturists,  but  on  the  other  hand  it  required  that  the  land  should 
be  put  to  proper  use.  In  the  Corn  Production  Act  the  Board  of 
Agriculture  was  given  power  to  enforce  proper  cultivation  where  the 
rules  of  good  husbandry  were  being  neglected  and  also  to  dictate  the 
mode  of  cultivation  or  the  use  to  which  the  land  should  be  put  for 
the  purpose  of  increasing  the  production  of  food  in  the  national 
interest.  In  case  of  failure  to  comply  with  the  directions  the  Board 
could  cause  the  owner  to  terminate  the  tenancy,  or,  if  the  occupier 
were  the  owner,  could  enter  itself  and  cultivate. 

These  somewhat  drastic  provisions,  which  were  exercised  under 
the  Defence  of  the  Realm  Act  during  the  war,  were  strongly  opposed 
by  both  owners  and  occupiers  and  became  greatly  modified  when  the 
Agriculture  Act  of  1920  replaced  the  Corn  Production  Act.  Prac- 
tically under  the  new  Act  the  powers  of  the  Ministry  of  Agriculture 
were  limited  to  the  enforcement  of  cultivation  according  to  the 
rules  of  good  husbandry. 

Where  an  estate  is  grossly  mismanaged  to  such  an  extent  as  to 
prejudice  materially  the  production  of  food  thereon  or  the  welfare  of 
persons  engaged  in  the  cultivation  of  the  estate,  the  minister  may, 
after  holding  a  public  inquiry,  appoint  some  person  to  act  as  re- 
ceiver and  manager  of  the  whole  or  a  portion  of  the  estate,  an  appeal 
being  allowed  to  the  High  Court.  The  Ministry's  powers  were  dele- 
gated to  cultivation  sub-committees  of  the  agricultural  committees 
of  the  county  councils  which  had  been  set  up  by  the  Ministry  of 
Agriculture  Act  of  1919. 

There  was,  however,  another  public  interest  to  be  considered — 



the  condition  of  the  labourers  engaged  upon  the  land.  In  order 
to  give  them  security  the  Corn  Production  Act,  whose  provisions 
were  renewed  in  the  Agriculture  Act,  provided  for  the  setting  up  of 
an  agricultural  wages  board,  empowered  to  fix  minimum  rates 
of  wage  for  persons  engaged  in  agricultural  work,  no  such  rate  to  be 
less  than  255.  a  week  for  able-bodied  men.  The  wages  board  con- 
sisted of  an  equal  number  of  representatives  of  employers  and 
workmen,  together  with  certain  appointed  members  nominated  by 
the  Board  (Ministry)  of  Agriculture.  District  wages  committees  were 
set  up  for  administration  of  the  Act  within  their  areas,  and  these 
committees  proposed  local  rates  of  wage  and  incidental  regulations 
regarding  their  area  for  the  confirmation  of  the  central  wages  board. 
As  the  setting  up  of  the  wages  board  coincided  with  a  time  of  rapidly 
advancing  wages  in  all  industries  the  minimum  rates  of  wage  were 
repeatedly  advanced  under  its  orders.  In  June  1921  the  lowest  rate 
amounted  to  433.  6d.  per  week  of  52  hours  in  summer  and  48  in 
winter,  and  this  rate  prevailed  in  the  English  counties  where  the 
average  rate  of  wages  before  the  war  was  not  more  than  153.  An 
incidental  result  of  the  wage  regulation  was  the  practical  abolition 
of  all  allowances  which  in  many  parts  of  the  country  were  made  to 
labourers  in  lieu  of  cash,  e.g.  milk,  potatoes,  bacon,  coal,  etc.  A 
deduction  may  still  be  made  for  cottages  but  the  amount  of  deduc- 
tion allowable  is  fixed  by  the  wages  board  and  may  not  exceed  35.  a 
week.  It  may  be  noted  that  with  one  or  two  comparatively  small 
exceptions  the  minimum  wage  regulations  succeeded  in  avoiding 
strikes  in  the  agricultural  industry  during  a  period  in  which  labour 
conditions  were  very  disturbed. 

The  Corn  Production  Act,  and  in  its  turn  the  Agriculture  Act, 
thus  represent  a  definite  attempt  on  the  part  of  the  State  to  frame  a 
constructive  policy  for  agriculture  in  the  national  interest.  The  two 
main  interests  concerned,  the  farmers  and  the  labourers,  were  given 
some  security  of  a  return  for  their  work,  the  State  obtained  increased 
production  and  some  control  over  the  use  of  the  land.  Should  it 
prove,  however,  that  even  with  guaranteed  prices  the  occupiers  of 
land  were  not  responding  by  an  increase  of  production  to  any  pay- 
ments made  by  the  State  under  the  guarantees,  the  purpose  of  the 
Act  would  be  unfulfilled.  To  meet  this  the  Act  gave  the  Ministry 
power  by  Order  in  Council  to  give  four  years'  notice  of  the  determi- 
nation of  its  powers  under  Part  I.  of  the  Act,  which  dealt  with 
the  system  of  guarantees,  the  control  of  cultivation  and  the  regula- 
tion of  wages. 

It  should  be  noted  that  the  Agriculture  Act  contemplated  the 
delegation  of  the  powers  of  the  Ministry  to  control  cultivation  to 
committees  of  the  county  agricultural  committees  which  were  set 
up  by  the  Ministry  of  Agriculture  Act  of  1919.  This  was  a  continua- 
tion of  the  procedure  adopted  during  the  war,  when  the  Board  of 
Agriculture  appointed  county  executive  committees  in  order  to 
carry  out  the  orders  under  the  Defence  of  the  Realm  Act  for  the 
increase  of  food  production. 

The  second  part  of  the  Agriculture  Act  of  1920  also  contained  a 
series  of  provisions  amending  considerably  the  Agricultural  Hold- 
ings Acts.  The  main  feature  of  this  legislation  entitles  a  tenant  who 
is  given  notice  to  quit  to  compensation  for  disturbance.  This  com- 
pensation amounts  to  one  year's  rent,  or,  if  greater,  to  the  proved 
loss  and  expenses  incurred  in  quitting  the  holding,  up  to  a  maximum 
of  two  years'  rent.  Compensation  is  not  payable  to  a  tenant  who 
was  not  cultivating  his  holding  according  to  the  rules  of  good  hus- 
bandry, or  who  had  failed  to  comply  with  an  order  to  pay  arrears 
of  rent  or  to  repair  a  breach  of  covenant.  The  landlord  may  also 
demand  that  the  question  of  the  rent  payable  for  the  holding  shall  be 
submitted  to  arbitration  and  if  the  tenant  refuses  to  agree  to  this  de- 
mand may  then  give  him  notice  to  quit  without  compensation  for 
disturbance.  The  Agriculture  Act  applied  to  Great  Britain  only, 
and  the  procedure  of  the  Corn  Production  Act  in  setting  up  an 
agricultural  wages  board  for  England  and  Wales  was  somewhat 
modified  as  regards  Scotland  and  Ireland. 

In  1919  the  Ministry  of  Agriculture  and  Fisheries  Act  was  passed, 
which,  besides  changing  the  title  of  the  Board  of  Agriculture,  set  up  a 
council  of  agriculture  for  England  and  Wales,  partly  elective  and 
partly  representative,  which  should  meet  at  least  twice  a  year  for 
the  purpose  of  discussing  matters  of  public  interest  relating  to 
agriculture  and  of  making  representations  to  the  minister.  From 
these  councils  are  selected  the  members  of  the  Agricultural  Ad- 
visory Committee,  which  has  the  duty  of  advising  the  Ministry  on 
all  matters  (except  as  regards  fishing)  relating  to  the  exercise  of  the 
powers  of  the  Ministry.  These  two  bodies  resemble  in  many  respects 
the  Council  and  Board  of  Agriculture  in  Ireland,  though  neither 
of  them  possesses  that  control  over  expenditure  which  the  Board  of 
Agriculture  in  Ireland  can  exercise  over  the  expenditure  of  the 
endowment  fund  enjoyed  by  the  Department  of  Agriculture  in 
Ireland.  The  Act  also  provides  for  the  setting  up  by  the  county 
council  in  each  county  and  in  certain  county  boroughs  of  an  agricul- 
tural committee.  These  committees  must  set  up  sub-committees  to 
deal  with  small  holdings  and  allotments,  with  the  powers  to  regulate 
cultivation  delegated  to  them  by  the  Ministry  under  the  Corn 
Production  and  Agriculture  Acts,  and  with  drainage  under  the  Land 
Drainage  Act  of  1918.  This  committee  may  also,  by  the  direction 
of  the  county  council  and  with  the  concurrence  of  the  Board  of 
Education,  take  over  from  the  Education  Committee  the  control  of 
agricultural  education. 

Land  drainage  for  generations  has  been  the  subject  of  legislation, 
but  it  was  evident  that  existing  powers  were  inadequate  to  provide 
for  the  efficient  management  of  the  drainage  of  the  majority  of  the 
river  basins  of  England  and  Wales.  In  many  areas  there  was  a 
multiplication  of  authorities,  many  of  whom  possessed  insufficient 
rating  powers  to  be  able  to  carry  out  works  falling  within  their 
area  but  vital  to  the  whole  river  basin.  In  other  cases  the  area  was 
inadequate  or  the  existing  commissioners  of  sewers  failed  to  execute 
their  duties.  The  Drainage  Acts  of  1914  and  1918  gave  the  Ministry 
of  Agriculture  powers  to  make  orders  constituting  drainage  districts, 
altering  the  boundaries  of  existing  drainage  areas  or  enlarging  their 
powers  of  levying  rates  or  borrowing.  The  Ministry  may  also  act 
itself  in  default  of  any  drainage  authority  or  may  delegate  its  powers 
to  a  committee  of  the  county  council  or  councils  of  the  area  con- 
cerned, though  its  power  of  executing  any  such  work  of  drainage  and 
of  recovering  from  the  owners  affected  is  limited  to  schemes  costing 
not  more  than  £5,000.  By  means  of  these  Acts  and  of  the  Defence 
of  the  Realm  Act  powers  possessed  by  the  county  executive  commit- 
tees, much  valuable  work  had  been  accomplished  by  1921  in  cleaning 
out  the  smaller  watercourses  and  improving  the  drainage  of  many 
minor  areas  subject  to  flood  or  unfertile  because  of  waterlogging. 
Larger  schemes  exist  for  dealing  comprehensively  with  important 
areas  like  the  Ouse  basin,  which  embraces  some  of  the  most  valuable 
land  in  the  Fens,  but  these  schemes  are  likely  to  remain  in  abeyance 
while  the  difficulties  of  financial  stringency  and  high  cost  of  labour 

One  of  the  heaviest  tasks  which  was  assigned  to  the  Board  of 
Agriculture  at  the  close  of  the  war  was  the  settlement  upon  the  land 
of  such  ex-service  men  as  desired  holdings  and  could  show  their 
suitability  to  occupy  land.  Under  the  Small  Holdings  and  Allot- 
ments Act  of  1908  county  councils  had  been  empowered  to  purchase 
land  and  equip  it  for  small  holdings,  but  it  was  necessary  that  the 
schemes  they  framed  for  this  purpose  should  show  a  reasonable 

Frospect  of  being  self-supporting  on  the  rents  that  could  be  expected, 
t  was  evident,  however,  at  the  close  of  1918  that  little  settlement  of 
ex-service  men  could  be  effected  upon  such  terms.  Not  only  had  the 
price  of  land,  especially  of  land  suitable  to  small  holders,  increased 
very  largely,  but  the  cost  of  buildings,  equipment  and  adaptation, 
necessary  in  the  majority  of  cases  before  a  small  holder  can  be  placed 
upon  the  land,  had  grown  to  three  or  four  times  its  pre-war  magni- 
tude. No  such  rents  could  be  charged  as  would  make  the  small 
holdings  pay,  nor  could  county  councils  be  expected  to  burden  their 
rates  with  the  losses  that  would  accrue  if  the  holdings  were  let  at 
reasonable  rents.  Accordingly,  by  the  Land  Settlement  Act  of  1919, 
the  State  accepted  this  liability  and  allotted  a  sum  of  £20,000,000  for 
the  provision  of  holdings  for  ex-service  men..  The  Act  retained  the 
county  councils  as  the  agencies  for  the  provision  of  small  holdings, 
and  strengthened  their  powers  to  acquire  land  compulsorily  for  the 
purpose  by  purchase  or  by  hiring.  In  the  main  the  £20,000,000  men- 
tioned above  has  been  lent  to  the  county  councils  in  order  to  enable 
them  to  acquire  land  and  adapt  it  for  letting  as  small  holdings. 

The  county  councils  could  not  take  up  such  loans,  did  not  the 
Act  further  empower  the  Ministry  for  seven  years  after  the  passing 
of  the  Act  to  pay  to  the  county  councils  any  losses  they  had  incurred 
in  the  provision  of  holdings  under  approved  schemes.  The  loss  each 
year  consists  of  the  excess  of  the  loan  charges  over  receipts  for  rent 
together  with  administrative  expenses.  Then  on  April  I  1926  a 
valuation  is  to  be  made  of  all  the  land  acquired  by  county  councils 
under  the  Small  Holdings  Act,  and  this  valuation  will  be  compared 
with  the  liabilities  incurred  by  the  council.  The  Ministry  will  then 
assume  the  responsibility  of  paying  such  portion  of  the  loan  charges 
due  from  the  council  as  represented  the  excess  of  liabilities  over  the 
valuation.  Finally  the  councils  will  be  left  as  owners  of  the  small 
holdings  that  have  been  set  up,  with  only  such  charges  to  meet  as 
might  reasonably  be  expected  to  be  covered  by  the  rents  in  the 
then  conditions  of  the  land  market. 

By  the  end  of  May  1921  some  34,000  applications  for  holdings  had 
been  received  in  England  and  Wales  alone,  29,000  of  which  had  been 
approved  by  the  county  councils;  277,000  ac.  of  land  had  been 
acquired,  and  15,000  men  had  already  been  placed  upon  it.  Slow  as 
this  progress  may  at  first  sight  appear  it  has  to  be  remembered  that 
land  cannot  be  acquired  at  short  notice  nor  sitting  tenants  displaced 
except  at  the  cost  of  burdening  the  scheme  with  impossible  charges 
for  compensation.  The  work  of  building  and  adaptation  had  also 
had  to  be  carried  out  under  the  most  difficult  and  burdensome  con- 
ditions, at  a  time  when  both  labour  and  materials  of  all  kinds 
were  abnormally  deficient.  In  the  great  majority  of  cases  the  holding 
created  was  inevitably  uneconomic,  in  the  sense  that  the  capital 
outlay  on  land,  buildings  and  roads,  fencing  and  other  incidentals, 
cannot  be  repaid  by  the  rents  which  can  be  paid  under  anything  like 
existing  conditions.  The  total  cost  of  the  scheme  to  the  State,  i.e. 
the  expenditure  that  would  have  to  be  written  off  as  not  represented 
by  the  market  value  of  the  resulting  holdings,  can  only  be  estimated, 
but  seemed  likely  to  amount  to  about  £8,000,000.  Undoubtedly  the 
State  accepted  a  very  heavy  financial  responsibility  in  this  scheme 
of  land  settlement  for  ex-service  men,  but  it  had  to  be  taken  as  a 
partial  repayment  of  the  debt  due  from  the  State  to  the  men  who 
fought  for  it.  As  part  of  the  national  policy  they  were  promised 
access  to  the  land,  and  the  conditions  prevailing  at  the  close  of  the 
war  made  it  impossible  to  redeem  that  promise  except  at  a  loss. 


Education  and  Research. — From  the  administrative  point  of 
view  the  chief  advance  effected  during  1900-20  was  the  organiza- 
tion throughout  the  United  Kingdom  of  a  scheme  of  agricultural 
education  and  research.  State  assistance  to  agricultural  educa- 
tion may  be  said  to  have  begun  with  the  Technical  Instruction 
Act  of  1889,  but  organized  research  remained  practically  un- 
provided for  until  the  setting  up  of  the  Development  Com- 
mission in  1908.  The  scheme  then  adopted  was  furthered  by  the 
allocation  of  fresh  funds  for  the  purpose  after  the  end  of  the  war, 
and  most  of  the  institutions  contemplated  were  at  work  in  1921. 
The  essential  feature  of  the  scheme  is  the  provision  of  institutes, 
each  dealing  with  a  particular  aspect  of  the  subject  and  as  a 
rule  associated  with  a  university  possessing  an  agricultural  de- 
partment. The  State  exercises  no  direct  control  over  the  nature 
of  the  investigations  conducted,  other  than  the  sanction  ac- 
companying its  annual  contribution,  which  is  in  the  nature  of  a 
grant  in  aid.  General  policy  is  also  reviewed  at  the  meetings  of  a 
research  council  composed  of  the  directors  of  the  institutes  and 
officials  of  the  Government  departments  concerned.  The  staff 
of  the  research  institutes  are  not  civil  servants  but  are  engaged 
by  the  respective  governing  bodies;  the  State  does,  however,  pro- 
vide for  a  stated  scale  of  salaries  with  increments  and  superan- 
nuation allowances.  The  annual  expenditure  on  the  scheme 
amounted  to  £140,000  for  England  and  Wales  for  the  year  1921- 
2,  and  to  £5,400  for  Scotland  for  the  same  period,  but  the  Irish 
expenditure  cannot  so  easily  be  differentiated  from  the  other 
commitments  of  the  Department  of  Agriculture. 

The  Experimental  Station  at  Rothamsted,  the  oldest  in  the 
world,  has  been  greatly  enlarged  and  developed  as  the  Institute  of 
Research  in  problems  of  soil  and  plant  nutrition,  to  which  has 
recently  been  added  a  second  institute  dealing  with  plant  pathology, 
embracing  entomology,  mycology  and  helminthology.  At  Cambridge 
is  situated  the  main  institute  for  research  in  animal  nutrition,  and  a 
second  station  also  exists  in  connexion  with  the  university  of  Aber- 
deen. At  Cambridge,  also,  investigations  have  been  made  dealing 
with  animal-breeding  from  the  genetic  side  and  with  problems  of 
reproduction,  and  the  plan  was  to  draw  all  these  threads  together  so 
as  to  make  at  Cambridge  an  institute  dealing  broadly  with  animal 
husbandry  in  all  its  aspects. 

Research  in  dairying  problems  is  provided  for  by  an  institute  in 
connexion  with  the  University  College  at  Reading;  and  a  second 
station  was  projected  in  1921  in  connexion  with  the  Agricultural 
College  at  Glasgow.  The  plant-breeding  station  and  institute  proper 
are  situated  at  Cambridge;  a  second  station,  specializing  mainly  on 
grasses,  clovers  and  fodder  crops  appropriate  to  the  moister  climates 
of  the  west,  is  associated  with  the  University  College  at  Aberystwyth ; 
and  a  third  station  was  planned  in  1921  in  Scotland.  The  commercial 
development  of  the  products  of  the  plant-breeders  is  provided  for 
by  the  National  Institute  of  Agricultural  Botany,  which  has  also 
recently  been  set  up  at  Cambridge  largely  by  contributions  from 
trade  sources. 

Research  in  fruit-growing  problems  is  dealt  with  by  an  institute 
associatecl  with  the  university  of  Bristol  (Long  Ashton)  and  a  second 
station  situated  at  East  Mailing  in  Kent,  further  sub-stations  being 
in  contemplation  at  Cambridge  for  the  eastern  counties  fruit  district 
and  elsewhere.  The  Bristol  centre  also  deals  with  cider-making  and 
with  the  various  processes  of  fruit  preservation,  to  which  end  a  small 
commercial  factory  is  maintained  at  Chiming  Camden. 

The  Imperial  College  of  Science  in  London  maintains  an  institute 
for  work  in  problems  of  plant  physiology,  utilizing  for  its  experi- 
mental cultures  various  institutions  near  London,  such  as  Roth- 
amsted, the  Lea  Valley  Experimental  Station  which  deals  with 
glass-house  problems,  the  East  Mailing  Fruit  Station,  and  the  Experi- 
mental Gardens  of  the  Royal  Horticultural  Society  at  Wisley.  Men- 
tion should  also  be  made  of  the  John  Innes  Horticultural  Institute 
at  Merton,  which  under  Mr.  W.  Bateson  deals  mainly  with'genetic 
problems,  though  this  institution  derives  its  income  entirely  from 
trust  funds. 

Schemes  for  dealing  with  research  on  problems  of  agricultural 
machinery  and  again  with  veterinary  science  were  under  considera- 
tion in  1921.  As  regards  the  latter  subject  the  only  institution  main- 
ly concerned  with  research  is  the  laboratory  maintained  by  the 
Ministry  of  Agriculture. 

The  complete  scheme  also  provided  an  annual  sum  for  grants  in 
aid  of  particular  investigations  set  on  foot  by  individuals  who  might 
not  be  attached  to  a  research  institute,  and  again  for  postgraduate 
scholarships  in  order  to  ensure  a  supply  of  properly  trained  workers. 

Higher  instruction  in  agriculture  is  provided  for  by  agricultural 
colleges,  which  as  a  rule  are  attached  to  one  of  the  local  universities 
and  have  a  distinct  regional  responsibility  as  to  the  provision  of 
information  and  technical  advice  to  farmers  occupying  land  in  the 
area  allocated  to  the  college. 

In  Scotland  three  such  colleges  are  attached  to  the  universities 
of  Aberdeen,  Edinburgh  and  Glasgow;  in  England  there  are  de- 
partments of  agriculture  attached  to  the  universities  of  Durham 
(Newcastle),  Leeds,  Cambridge.  Reading  (Oxford),  and  in  addition 
four  residential  agricultural  colleges — the  Harper  Adams  College  at 
Newport,  Salop;  the  South-Eastern  Agricultural  College  at  Wye, 
Kent;  the  Midland  College  at  Sutton  Bonington  and  the  Scale 
Hayne  College  at  Newton  Abbot,  Devon.  In  Wales  the  University 
Colleges  of  Bangor  and  Aberystwyth  maintain  similar  agricultural 
departments.  In  Ireland  higher  instruction  in  agriculture  is  given 
at  the  Royal  College  of  Science  in  Dublin  and  the  Albert  Agricultural 
College  at  Glasnevin,  while  there  are  professors  of  agriculture  at  the 
Queen's  Universities  of  Cork  and  Belfast. 

Intermediate  education  in  agriculture  is  in  Scotland  organized  by 
the  agricultural  colleges  through  extension  lecturers  attached  to  the 
various  counties.  In  England  and  Wales  the  county  councils  are 
the  responsible  authorities,  and  the  Ministry  of  Agriculture  pro- 
vides an  agricultural  organizer  for  each  county  and  gives  assistance 
towards  the  setting  up  of  a  farm  institute,  intended  to  give  instruc- 
tion by  means  of  short  courses  for  the  sons  of  farmers,  etc.,  who 
cannot  leave  the  farm  for  the  long  periods  demanded  by  the  agri- 
cultural colleges.  In  Ireland  intermediate  instruction  in  agriculture 
is  given  at  the  Munster  Institute,  Cork,  the  Ulster  Dairy  School  and 
the  four  regional  agricultural  stations  at  Athenry,  Ballyhaise,  Clon- 
akilty  and  Strabane. 

Steady  progress  has  been  made  in  all  parts  of  the  United  Kingdom 
in  the  schemes  for  the  improvement  of  live  stock,  by  the  dissemina- 
tion among  the  smaller  farmers  of  improved  sires.  In  Ireland,  where 
the  scheme  came  into  operation  in  191 1,  premiums,  to  which  both  the 
Department  and  the  local  authorities  contribute,  are  given  towards 
the  purchase  of  approved  bulls  and  other  sires,  and  the  success  of 
the  scheme  is  manifest  in  the  improvement  effected  in  the  quality 
of  the  store  cattle  exported  for  fattening  to  Great  Britain.  In 
England  and  Wales  farmers  are  encouraged  to  form  societies  for  the 
purchase  of  a  bull  or  the  hire  of  a  stallion,  and  a  grant  is  made 
towards  the  cost  of  the  sire,  which  in  the  case  of  a  bull  may  not  ex- 
ceed /2O  or  one-third  of  its  cost.  The  work  of  forming  societies  for 
recording  the  milk  yield  of  the  cows  of  the  members  has  been 
vigorously  prosecuted,  and  the  growth  of  the  movement  is  shown  by 
the  fact  that  637  cows  obtained  certificates  in  1915  and  16,211  in 
1921.  The  high  prices  obtained  for  recorded  cows  and  their  progeny 
show  the  value  that  farmers  attach  to  milk  records. 


For  a  long  time  after  the  declaration  of  war  no  special  effort 
was  made  in  the  United  Kingdom  to  develop  agriculture  and 
increase  production  of  food.  A  measure  to  prevent  the  slaughter- 
ing of  calves  and  pregnant  animals  was  passed  in  1914,  but  no 
other  legislative  action  was  taken  until  the  close  of  1916.  Pro- 
posals which  had  been  made,  such  as  those  of  the  Milner  Com- 
mittee, to  guarantee  a  price  for  wheat  or  to  give  other  bounties 
on  production,  were  turned  down  on  the  broad  principle  that  any 
interference  with  the  free  play  of  the  market  would  impair  the 
confidence  of  the  trader  and  reduce  importation  to  a  greater 
degree  than  the  increase  in  production.  In  1915  in  response  to 
the  general  feeling  farmers  had  increased  their  acreage  of  wheat 
by  430,000  ac.  and  of  oats  by  200,000,  but  this  increase  had 
chiefly  been  attained  at  the  expense  of  the  barley  crop,  for  there 
had  been  no  increase  in  the  total  extent  of  land  under  the  plough. 
In  1916,  however,  the  wheat  area  went  back  by  280,000  ac., 
and  a  low  yield  per  acre  was  obtained.  The  potato  crop  also  was 
much  below  average.  It  may  be  noted  here  that,  speaking 
generally,  except  in  the  magnificent  harvest  of  1914,  the  seasons 
during  the  World  War  were  very  adverse  to  arable  cultivation, 
being  characterized  by  wet  seeding-times  and  harvests,  with 
spring  droughts.  It  was  not  until  1917-8  that  there  was  a  favour- 
able autumn  and  spring  for  sowing,  but  that  promise  was  belied 
by  a  disastrous  harvest-time  for  all  the  western  and  northern 
parts  of  the  kingdom,  with  rains  so  heavy  and  protracted 
that  no  inconsiderable  proportion  of  the  corn  crops  were  never 

Intensified  Production. — It  was  not  until  the  close  of  1916  that 
any  action  was  taken  to  stimulate  production.  By  that  time  the 
effects  of  the  enemy  interference  with  the  free  play  of  the  market 
and  the  indifferent  output  began  to  be  apparent  in  rapidly  rising 
prices  for  all  the  prime  food  products — corn,  potatoes,  meat  and 
milk.  At  the  same  time  the  withdrawal  of  labour  from  agricul- 
ture was  bringing  about  a  still  further  diminution  in  the  area 
under  wheat,  of  which  at  the  close  of  1916  it  was  estimated  that 
15%  less  had  been  sown  than  at  the  corresponding  season  in  the 
preceding  year.  The  appointment  of  a  Royal  Commission  on 



Wheat  Supplies,  which  assumed  complete  control  of  the  purchases 
of  wheat  and  the  operations  of  the  milling  trade,  was  followed  by 
the  appointment  of  a  Food  Controller  and  a  promise  in  Dec.  of 
certain  guaranteed  prices  for  wheat,  oats  and  potatoes.  At  this 
time  Rowland  Prothero  (afterwards  Lord  Ernie)  had  become 
President  of  the  Board  of  Agriculture,  and  he  proceeded  to  set 
up  a  Food  Production  Department  which  would  take  charge  of  a 
national  effort  to  obtain  more  food  from  the  land.  To  this 
department  came  as  chief  Sir  Arthur  Lee  (afterwards  Lord  Lee 
of  Fareham). 

The  policy  adopted  aimed  at  obtaining  an  increased  acreage 
of  arable  land  and  as  large  a  proportion  of  wheat  and  other 
bread  corn  as  possible.  Success  depended  upon  the  cooperation 
of  the  farmers,  upon  securing  additional  labour  and  upon  assisting 
the  farmer  to  obtain  supplies  of  all  kinds — horses,  tractors,  seeds 
and  manures. 

The  first  step  was  to  set  up  War  Agricultural  Committees 
in  each  of  the  counties  of  England,  Wales  and  Scotland;  in 
Ireland  the  existing  statutory  County  Council  Committees  on 
Agriculture  were  available  for  the  same  purpose.  In  England 
smaller  executive  committees  were  afterwards  appointed,  to 
whom  were  entrusted  in  the  main  the  special  powers  which  had 
been  conferred  by  D.O.R.A.  on  the  Board  of  Agriculture.  Dis- 
trict committees,  and  even  in  some  cases  parish  committees, 
were  further  appointed.  The  staffs  required  for  the  executive 
committees  were  made  up  from  the  county  council  staffs  and 
officers  of  the  Land  Valuation  Department  and  Inland  Revenue, 
while  district  commissioners  appointed  by  the  central  depart- 
ment for  small  groups  of  two  or  more  counties  served  to  bind  the 
whole  organization. 

As  it  was  already  Jan.  1917  before  the  Food  Production 
Department  was  set  up,  it  was  impossible  to  effect  much  increase 
in  the  crops  of  that  year,  and  in  practically  all  cases  it  was  ob- 
tained by  voluntary  response  to  the  appeal  for  greater  production. 
In  England  and  Wales  a  further  286,000  ac.  were  put  under  the 
plough;  the  increase  in  wheat  was  50,000  ac.,  in  oats  616,000  ac. 
and  in  potatoes  220,000  acres.  Scotland,  having  suffered  less  loss 
of  arable  land  in  the  generation  prior  to  the  war,  had  smaller 
opportunities  for  reconversion  from  grass  into  arable,  but  added 
some  50,000  ac.  to  the  plough  land.  In  Ireland,  however,  the 
greatest  extension  was  possible  because  of  the  much  smaller 
draft  that  had  been  made  on  its  man-power.  An  Order  in  Council 
was  made  requiring  all  Irish  occupiers  of  more  than  10  ac.  to  add 
10%  to  their  area  under  tillage,  except  in  cases  where  the  arable 
already  amounted  to  50%  of  the  total  cultivable  area  of  the 
farm,  and  this  resulted  in  an  addition  of  nearly  650,000  ac. 
to  the  plough  land  of  that  country. 

While  this  was  going  on  during  the  spring  of  1917  the  county 
executive  committees  with  the  help  of  their  district  committees 
carried  out  a  survey  from  farm  to  farm  which  revealed  in  all  too 
many  cases  into  what  a  state  of  neglect  the  land  had  been  allowed 
to  fall.  Notices  were  served  calling  for  improved  cultivation, 
and  in  the  worst  cases  the  tenancies  were  determined,  the  execu- 
tive committees  either  approving  a  new  tenant,  or  taking  the 
land  under  their  own  control.  The  central  department  framed  a 
programme  for  1918  which  provided  for  the  ploughing-up  in 
England  and  Wales  of  2,000,000  ac.  of  permanent  grass  as  com- 
pared with  1916,  and  in  Scotland  of  350,000  acres.  A  quota  was 
fixed  for  each  county,  based  upon  such  considerations  as  the  area 
which  had  been  converted  from  arable  into  grass  land  since  1872, 
the  existing  proportion  of  arable  in  the  county,  the  labour  still 
upon  the  land,  etc.  Each  county  in  its  turn  divided  its  quota 
among  districts  and  eventually  among  the  parishes  and  the  in- 
dividual farms,  orders  to  plough  certain  fields  being  served  upon 
the  occupiers.  These  "  ploughing  orders  "  in  many  cases  excited 
violent  opposition,  and  sustained  attacks  were  made  upon  the 
Department  on  the  specious  plea  that  ignorant  officials  were 
ordering  grass  land,  which  was  providing  meat  and  milk,  to  be 
converted  into  plough  land  which  would  yield  nothing.  Time 
considerations  alone  permitted  of  no  appeal  from  the  order  of 
the  committees,  who  had  perhaps  acted  in  some  cases  on  the 
principle  of  making  every  man  do  a  share  proportional  to  his 

acreage  without  consideration  of  the  character  of  the  land.  But 
the  mistakes  made,  if  one  is  to  judge  by  the  mass  of  the  results 
afterwards  realized  upon  the  broken-up  land,  affected  but  a  small 
proportion  of  the  land  ordered  to  be  put  under  the  plough.  The 
opposition  both  of  occupiers  and  owners  to  the  plough  policy 
must  be  set  down  to  the  grass-land  tradition,  which  the  great 
depression  of  1880-1900  had  so  firmly  impressed  on  English 

None  the  less  the  programme  was  adhered  to,  and,  aided  by 
favourable  weather  in  the  winter  and  spring  of  1917-8,  a  re- 
markable increase  in  the  cultivated  area  was  achieved.  The 
disturbed  state  of  Ireland  prevented  the  realization  of  the  plans 
which  had  been  formed  for  a  still  further  increase  of  5%  in  the 
cultivated  area.  The  tables  show  what  was  actually  obtained 
in  each  of  the  three  countries. 

England  and  Wales 





Arable  land 
Oats    .... 
Potatoes     . 
All  crops  other  than 
temporary  grasses 
and  fallow 












1916             1917 


Arable  land 
Oats    .... 
All  crops  other  than 
temporary  grasses 
and  fallow 



i  ,8o5;35o 
















Arable  land 
Oats    .... 
All  crops  other  than 
temporary  grasses 
and  fallow 












United  Kingdom 





Arable  land 
Wheat   -     ... 
All  crops  other  than 
temporary  grasses 
and  fallow 











Speaking  roughly,  about  40%  more  grain  was  produced  in 
1918  than  in  1916,  and  if  the  potato  crop  is  also  taken  into  ac- 
count the  1918  crops  represent  a  saving  in  tonnage  (and  shipping 
was  the  limiting  factor  in  the  prosecution  of  the  war  at  that  time) 
of  2,600,000  tons.  Results  would  have  been  even  better  had  it 
not  been  for  the  disastrous  harvest  weather,  which  caused  the 
total  loss  of  something  like  5  %  of  the  grain  crop,  and  rendered 
even  more  unfit  for  any  other  purpose  than  cattle-feeding.  The 
occurrence  of  so  continuous  a  succession  of  heavy  rains  was 
naturally  regarded  by  the  opponents  of  "  ploughing  up  "  as  a 
justification  of  their  adhesion  to  grass.  It  did  indeed  put  an  end 
to  the  plans  which  had  been  made  for  a  further  extension  of  the 
arable  area  in  1919.  Work  on  most  farms  had  fallen  badly  into 
arrears,  and  land  had  become  foul  and  weedy,  so  that  it  seemed 
preferable  to  concentrate  the  available  labour  on  the  existing 



tillage  land  rather  than  to  attempt  to  increase  its  area  in  the 
face  of  the  general  opposition  of  the  agricultural  community. 
Labour  Supply. — Turning  now  to  the  means  by  which  this  in- 
creased production  was  realized  in  war-time,  the  prime  difficulty 
experienced  was  the  lack  of  labour.  Grass  land  had  often  been 
described  as  a  reserve  of  fertility  that  in  case  of  need  could  be 
converted  into  crops,  but  this  view  had  ignored  the  facts  that 
laying  down  to  grass  is  accompanied  by  the  permanent  loss  of 
men  and  horses,  implements  and  even  buildings.  When  the  need 
comes  tillage  cannot  be  resumed  at  pleasure;  the  men  and