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Full text of "(1) Camp Fire Yarns of the Lost Legion (2) Social Welfare in New Zealand"

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28 


NATURE 


[March 12, 1914 


DYNAMICS: OLD AND NEW. 


(1) Legons stir la Dynamique des Systemes 
materiels. By Prof. E. Delassus. Pp. xii + 421. 
(Paris : A. Hermann et Fils, 1913.) Price 14 
francs. 

(2) The Theory of Relativity. By Prof. R. D. 
Carmichael. Pp. 74. (New York : John Wiley 
and Sons, Inc. ; London: Chapman and Hall, 
Ltd., 1913.) Price 45. 6 d. net. 


(1) A I "'HIS volume is the result of an experi- 
X ment made by the author to improve 
on the usual methods of introducing students to 
the study of dynamics. The first respect in which 
this has been essayed is in presenting the subject 
from the beginning in a general form, instead of 
beginning with those problems which are geo¬ 
metrically most simple. Thus the volume has 
rather the appearance of a treatise on what is 
usually known as analytical dynamics. But the 
object which the author has in view is not so much 
the development of the advanced analytical theory, 
which becomes largely a study of differential equa¬ 
tions, as a unification of method which shall ob¬ 
viate the feeding of the student on a multiplicity 
of isolated problems in which the dynamical pro¬ 
perties are essentially of the same type. 

Special attention is paid to the class of systems 
the equations of motion of which can be integrated 
by quadratures. An elaborate study is made of two 
special questions in respect of which the author 
considers wrong notions to be prevalent. The first 
of these is the assumption usually made in respect 
of a unilateral constraint, such as that which occurs 
when a body rolls or slides on another body, that 
the constraint will cease to be conformed to at 
the moment when the force required to maintain 
it vanishes and changes sign; examples are given 
in which the assumption that this is true where 
there is more than one point of contact between 
two bodies leads to wrong conclusions. 

The other point which is called in question is 
the assumption, which the author considers to be 
often tacitly made, that if the constraint imposed 
on a system is realised by means of auxiliary 
bodies of negligible mass, these auxiliary bodies 
Jiave no influence on the motion of the system. 
An example given is that of a heavy particle con¬ 
strained to move in a horizontal plane by attach¬ 
ment to an axis bearing two weightless wheels 
which roll and slide respectively on a fixed hori¬ 
zontal plane. It is clear that if the wheels and 
axis have ever so little inertia and are set in motion 
with a rotation about the vertical, the particle 
cannot describe a straight line, but the example 
points to such an obvious objection to the assump- 
NO. 2315, VOL. 93] 


tion referred to that it is difficult to believe that 
as a general rule it has really been commonly 
asserted. 

(2) After reading this careful course on classical 
dynamics, it is an abrupt transition to the first 
book published in English on the principle of 
relativity, and to read of a revision of the funda¬ 
mental concepts, not only of space and time, but 
also of mass. Prof. Carmichael sets out to 
give a popular account of the way in which these 
magnitudes are regarded by the exponents of this 
most up-to-date of generalisations, without going 
! into the details of its origin in electrical theory. 

The project is well carried through, but it seems 
doubtful whether even yet the public mind is 
prepared to face the shock of the postulate (p. 20) : 
“ The velocity of light in free space, measured on 
an unaccelerated system of reference S, is inde¬ 
pendent of the velocity of S.” But less objection 
seems to be taken to one of the consequences of 
j the assumption of the complete relativity of all 
[ physical phenomena, namely, the dependence of 
the mass of a body upon its velocity, in spite of 
its reducing the status of Newtonian mechanics to 
that of an approximate theory. 

The reason for this is probably that experiment 
seems to have demonstrated without doubt that 
the mass of the electron must be admitted to be 
variable, and we can find no reason for denying 
the possibility of the mass of any body varying 
within the limits of error admitted by astronomical 
theory. 

The real obstacle to the acceptance of the theory 
of relativity is the carrying over of a conception 
of space and time, which is based on, or rather 
part of, Newton’s dynamical theory into regions 
where that theory is certainly no longer tenable 
in its entirety. Prof. Carmichael’s book deals 
entirely with these fundamental matters and will 
help to make more familiar a more logical and 
less metaphysical view of space and time in their 
physical bearing. 


NEW ZEALAND: THEN AND NOW. 

(1) Camp Fire Yarns of the Lost Legion. By 
Col. G. Hamilton-Browne. Pp. xiii + 301. 
(London: T. Werner Laurie, n.d.) Price 
1 2S. 6 d. net. 

(2) Social Welfare in New Zealand. By Hugh H. 
Lusk. Pp. viii + 287. (London: William 
Heinemann, 1913.) Price 6 s. net. 

T HESE two books present a most vivid pic¬ 
ture of the progress which has occurred 
in New Zealand during the last fifty years. The 


© 1914 Nature Publishing Group 












March 12, 1914] 


NATURE 


29 


first is essentially personal, the account of strange 
and curious adventures of individuals; the second 
is largely impersonal, the account of the develop¬ 
ment of a system of State Socialism. Both works 
tell the story of the reaction between outsiders 
from overseas and the environment which they 
found awaiting them in these distant islands. 

(1) The gallant colonel, typically a frontiersman, 
presents a picture of the Maori wars, and 
■demonstrates the dangers of the trackless bush. 
The Maori regarded war as essentially the work 
for men; their curious outlook caused them to 
regard the shot which landed in their “ pah ” 
during a bombardment and failed to explode as 
the enemy’s method of supplying them with 
powder with which to continue fighting. Mr. 
Lusk, formerly a member of the New Zealand 
Parliament, states that Maoris nowadays receive 
old-age pensions on the same terms as the white 
men. 

The camp-fire yarns are racy, redolent of the 
soldier’s vocabulary, and make excellent reading; 
the parliamentarian account (2) of organised atten¬ 
tion to the well-being of the community as a 
whole community, and not as a cong-eries of 
classes of society, is calm, dispassionate, careful, 
and on this account eminently readable. 

Steadily, step by step, the State interfered with 
manifestations of private enterprise, prevented the 
permanent establishment of a landed gentry, or 
of a body of yeomen tenant farmers; established 
systems of communication by rail, by telegraph, 
and by telephone, which have contributed greatly 
to a feeling of national unity ; freed the country 
from outside influences as regards fluctuations in 
coal prices; secured loans of capital for all the 
people at advantageous rates, so preventing the 
exploitation of the farmers because they were 
necessitous; and, by controlling the development 
of the country, secured a high average of pros¬ 
perity to all members of the State, without caus¬ 
ing the growth of either a wealthy or a poverty- 
stricken caste. 

Mr. Lusk is of opinion that New Zealanders 
grew, without definite intention, or without definite 
leadership, to regard the welfare of all as para¬ 
mount, and he is further of the opinion that New 
Zealand sets an object-lesson to the whole world 
in its regard for all members of the body politic; 
lie pays more attention to the principle which 
underlies these progressive movements than to 
the fact that New Zealand is a special case. 
Regarded as a contribution to the knowledge of 
the world, New Zealand’s progress is a striking 
illustration of the unique reaction to its own local 
environment, which occurs in a more or less 
NO. 2315, VOL. 93] 


isolated community. More than a thousand miles 
from its nearest neighbour, with a small popula¬ 
tion of a million souls, with a large area of cul¬ 
tivable land, in the happy position of having one 
market only, and that a certain one for its surplus 
of food-stuffs and raw material, almost outside 
the stress and strain of international competition, 
New Zealand has developed along lines which 
were only possible in such comparative isolation. 
But it is hazardous to generalise from so specific 
an example; while, on one hand, it is possible 
to note the fact of New Zealand’s prosperity, it 
is incorrect, on the other, to infer from 
New Zealand’s experience principles of State 
activity which shall be regarded as of general 
application. 

It does not necessarily follow that what is good 
for one million people on the edge of the modern 
business world and mainly occupied and depen¬ 
dent upon the cultivation of the soil is equally 
good both in method and in result for more than 
forty millions of people, with an industrial popu¬ 
lation in ratio to that employed on the land of 
roughly four to one, situated at the hub of world 
commerce and the centre of concentration of a 
world-wide competition. B. C. W. 


OUR BOOKSHELF. 

Camping in Crete: With Notes upon the Animal 
and Plant. Life of the Island. By Aubyn 
Trevor-Battye. Including a Description of Cer¬ 
tain Caves and their Ancient Deposits. By 
Dorothea M. A, Bate. Pp. xxi + 308 + plates. 
(London: Witherby and Co., 1913.) Price 
10s. 6 d. net. 

This pleasant record of camping experiences in 
Crete falls into two parts. In the body of his 
book Mr. Trevor-Battye, who declines to discuss 
questions of politics and excavations, describes a 
series of tours through the island. With Canea 
as his headquarters, he made trips by steamer 
along parts of the coast, journeyed so far as Sitia 
on the east, traversed the island to Sphakia, and 
again to Retimo, with a long and arduous march 
from Sphakia, vid Mt. Ida, to Candia. The main 
object of these excursions was the collection of 
zoological and botanical specimens, many of 
which have been valuable additions to the South 
Kensington Museum. He succeeded in bringing 
home two ibex kids to the Zoological Society, one 
of which, the male, died from an accident, but the 
female is now at Regent’s Park, and has given 
birth to twins. He gives a delightful account of 
these charming animals. 

He finds that a narrow waist, which appears 
in the Minoan frescoes, is quite characteristic of 
the islanders. He gives useful accounts of the 
geology, describing the curious high-level plains 
of Homalo and Nidha, Mt. Ida, and Kurnas, the 


© 1914 Nature Publishing Group