June 18, 1914] 
NATURE 
401 
OUR BOOKSHELF. 
Interpretations and Forecasts: a Study of Sur- 
vivals and Tendencies in Contemporary Society. 
By Victor Branford. Pp. v+411. (London: 
Duckworth and Co., 1914.) Price 7s. 6d. net. 
“THE city,” said Aristotle, ‘exists for the sake 
of the good life.” But only by the good life is 
the ideal city, the perfect state, to be realised. In 
other words, social organisation is necessary for 
individual achievement, but individual achieve- 
ment reacts creatively upon the social organisa- 
tion. Mr. Victor Branford, one of the founders 
of the Sociological Society, has with his spiritual 
father, Prof. Geddes, done much to illustrate this 
essential interaction, and still more to infuse a 
sense of enthusiasm into our appreciation of it. 
He shows in these lectures the spirit of the 
medieval guildsmen, who knew themselves to be 
citizens of no mean city. On their work and 
ideals he writes a delightful and instructive essay. 
The text of the whole book is Aristotle’s theory 
of the city. The author well shows how, as a 
result of the statecraft of the Renascence and 
subsequent centuries, a “capital literary fraud” 
was perpetrated upon that theory. Aristotle saw 
the city as “‘a process in which four types of social 
operation tended to co-adjustment. He saw the 
Labour of the People, who maintain the outer life 
of the city; he observed the Public Functions of 
the citizens, who direct the polity of the city; he 
perceived the Meditations of Philosophers, who 
study and compare the polities of cities in order 
to discover the ideal polity; he recognised the 
Efforts of Teachers to educate for citizenship. In 
proportion as all these—the four natural elements 
of civic life—work together harmoniously, the city 
comes into being and creates for its citizens the 
conditions of the good life.” The fraud per- 
petrated upon this. theory is the substitution of 
‘ state” for 5 city”; “politician” for “citizen”; 
_ Constitution” for “polity”; “political’’ for 
civic”; and “for the science and art of Civics 
they have substituted Politics.” A reaction to- 
wards the original and sounder view is to be seen 
in the decentralising movement of to-day. The 
author is familiar with the life both of North 
and South America, and his comparisons of the | 
working of a new spirit in the western republics 
and in European countries are marked by insight. 
The place of education in developing the ideal and 
therefore most efficient relation between man and 
society, in 1ts most practical because closest and 
best realisable form, the city, is very fully worked 
out. 
The book is an eloquent example of the practical 
application of sociological theory. 
A. E. Craw ey. 
The Country Month by Month. By J]. A. Ow 
and Prof. G. S. Boulger. Pp. ies (Por. 
don: Duckworth and Co., 1914.) Price 6s. net. 
Twenty years ago Mrs. Owen, better known, 
perhaps, by her works under the signature “A Son 
of the Marshes,” prepared, with Prof. Boulger, a 
series of twelve volumes in which the natural 
characteristics of the country month by month 
NO. 2329, VOL. 93] 
_ of the British Association in 1912? 
were described. The series was published in a 
single volume in 1901, and was given an apprecia- 
tive notice in these columns (vol. Ixv., p. 125). 
The late Lord Lilford sent the authors a number 
of valuable notes which were added to the original 
work, and are also included in the present volume. 
The new edition has been revised, and is embel- 
lished with twelve coloured plates and twenty half- 
tone plates reproduced from photographs. The 
result is a very attractive book on popular natural 
history. Many similar books have been published 
in recent years, but for pleasantly-written descrip- 
tion of country life, interesting alike to the general 
| reader and the working naturalist, this volume is 
among the best. In its present form the book 
should be acceptable to a wide circle of readers. 
LETTERS FO’ THE EDITOR. 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
can he undertake to return, or to correspond with 
the writers of, rejected manuscripts intended for 
this or any other part of Nature. No notice is 
taken of anonymous communications. | 
Migration Routes. 
On November 27, 1913, Nature published a letter 
from me in which the suggestion was made that birds 
when migrating may find it advantageous to follow 
coast lines or rivers, because of the up-air currents 
produced by the difference of temperature of the sur- 
face of the land and water. 
Mr. McLean has recently flown up the Nile, and 
he tells me that the vertical air currents were fre- 
quently very marked. | When the wind was only 
slightly different in direction from the line of the river 
there was a down current on the side from which the 
wind came and an up current on the other side. When, 
however, the river split up into several channels the 
air was generally descending over the whole neigh- 
bourhood and was disturbed. These down currents 
were at times so strong that his aeroplane when 
climbing at its greatest speed would descend steadily 
at 3 ft. per second. He estimates that the maximum 
rate of climbing of his machine in still air was 4 ft. 
per second. This observation is of great interest as 
showing that a down current may exist of about the 
velocity of 4-8 miles per hour. 
Horace Darwin. 
The Orchard, Cambridge, June 8. 
Aeroplane Wings. 
In connection with the apparently growing practice 
of constructing the wings of aeroplanes so that their 
inclination can be modified (a scheme which I recom- 
mended in the first edition of my book, ‘‘ The Problem 
of Flight,’ published in April, 1907), may I direct 
attention to my paper read at the Dundee meeting 
Therein I referred 
to the fact that the propeller axis (to which the in- 
clination is, or should be, referred) does not run hori- 
zontal so that the propeller thrust has a vertical com- 
ponent. The use of a mechanism by which the wing 
inclination can be varied enables this vertical com- 
ponent to be annulled, i.e. the propeller axis can be 
kept horizontal, thus greatly increasing the efficiency. 
With reference to the question of acceleration in the 
air and its effect on the reactions, which was discussed 
some time ago in NATURE in connection with Mr. 
Walkden’s book, a recent paper of mine in Flight on 
oscillating wings may be of interest. It was shown 
| therein that if the reactions during oscillation of the 
