208 
NATURE 
[NovEMBER 16, 1916 
OUR BOOKSHELF, 
Economics in the Light of War. By Prof. R. A. 
Lehfeldt. Pp. 56. (Johannesburg: The South 
African School of Mines and Technology; 
London: Wm. Wesley and Son, 1916.) Price 
IS. 
In this slight, but well-reasoned, essay Prof. 
Lehfeldt contemplates the influence which the 
present war has had on economic theory. He 
deals only with consumption and production, 
“not,” he says, “because the problems of distri- 
bution are not urgent, but because there seems to 
be less that is novel to say about them.” This 
is surely a remarkable finding in view of the ex- 
periments in Germany and France. If there be 
little novel to say, there must then be many 
striking new proofs of old tenets of belief. 
More attention will, Prof. Lehfeldt thinks, 
have to be given in the future to the human 
factor in economics. We are beginning to 
realise the necessity of a qualitative as well as a 
quantitative analysis of consumption. The 
human powers of production are more dependent 
than we have supposed on the human will to 
produce. 
The essay is strikingly sound, if somewhat un- 
inspiring ; and it is refreshing after the cant which 
has been talked on the former and the absurdities 
which have been written on the latter to read the 
sound common sense of the author on the two 
problems of the size of the family and social wel- 
fare, and of the influence of taxation for the war 
loan on supplies of capital. It is, however, pre- 
sumably popular in purport, and Prof. Lehfeldt 
does not venture on the treacherous currents of 
finance. A. L. 
Interpolated Six-Place Tables of the Logarithms 
of Numbers and the Natural and Logarithmic 
Trigonometric Functions. Edited by H. W. 
Marsh. Pp. xii+155. (New York: John 
Wiley and Sons, Inc. ; London: Chapman and 
Hall, Ltd., 1916.) Price 5s. 6d. net. 
Tue publication of these tables helps to mark a 
change in the use of logarithms, both for teaching 
and practical purposes. Nowadays most teachers 
use four-figure tables for teaching purposes, even 
in the laboratory; on the other hand, the reason 
given for the issue of this volume is that in many 
technical problems five significant figures are 
essential, so that a six-figure table is necessary. 
The contents of the book are: (1) logs of 
numbers, with differences and full tables of pro- 
portional parts; (2) logarithmic sines, etc., inter- 
polated to the second; (3) natural sines, etc., 
tabulated to the minute, with proportional part 
for the second; (4) lengths of circular arcs to 
radius unity; (5) various tables of length, specific 
gravity, etc. Change of a leading figure in a 
mantissa is indicated in an unusually clear way; 
the figures used are mostly ‘old faced,” and, 
although rather fine cut, do not seem to be tiring. 
But in using the tables it will be almost unavoid- 
NO. 2455, VOL. 98] 
able to use a card to guide the eye along the lines ¢ 
this is suggested in the introduction, which gives 
other useful hints. It seems to us that it would 
add considerably to the convenience of the book 
to give the values and the logarithms of certain 
constants, such as 7, e, /7, Euler’s constant, and 
so on; this would not require more than a page. 
The World’s Wonder Stories for Boys and Girls, 
By A. G. Whyte. Pp. xiv+270. (London: 
Watts and Co., 1916.) Price 6s. net. 
THESE stories take the form of brightly written 
and interesting answers to a number of questions 
propounded by the author. How was the world 
made? Where did the plants and animals come 
from? Who was the first man? are specimens 
of questions which provide the opportunity for 
giving much biological and geological inform- 
ation, and for introducing a simply worded 
explanation of evolution. 
A second type of question is made to serve 
another and additional purpose. Where did all 
the religions come from? Where did the Bible 
come from? Where did right and wrong come 
from? are questions asked to enable the author 
primarily to give moral instruction on a rational 
basis. 
The chapters throughout are written in easy 
English which young children can understand; 
the information is correct and modern; and the 
language is dignified and circumspect. Orthodox 
teachers and parents whose teaching of morality 
follows conventional lines would undoubtedly 
derive benefit from the method of presentation 
adopted, while no child could read the book with- 
out. understanding something of the scientific 
method and what it has accomplished. 
Petit Atlas Céleste. By G. Bigourdan. Five 
charts. Pp. 59. (Paris: Gauthier-Villars et 
Cie, 1915.) ‘Price! 2:75° francs: : 
An admirable introduction to the study of the 
heavens is provided by this little book, which has 
been prepared by a distinguished member of the ~ 
staff of the Paris Observatory. The constella- 
tions over the entire sky are represented in con- 
siderable detail in five excellent maps, the stars 
being shown in black on a white ground, and 
names and index letters in red. The introductory 
text includes a brief history and description of 
the constellations, and two very useful lists of 
stars. One of the catalogues is arranged: in 
order of right ascensions, and is notable as indi- 
cating the spectra, in addition to the proper 
names, positions, and magnitudes, of 195 of the 
principal stars. The other is arranged according 
to constellations, in alphabetical order, and will be 
convenient as a means of quickly finding par- 
ticulars of a star which is indicated only by its 
constellation and letter. The book is of a con- 
venient size (9 in. x 54 in.), and may be recom- 
mended as a handy work of reference for use in 
the observatory as well as to beginners in observa- 
tional, astronomy. 
