NOVEMBER 30, I1916| 
whereas it is really a portion of what is prac- 
tically a sphere, with radius equal to its distance 
from the earth’s centre, and hence quite definite. 
Advantage should have been taken of a new 
edition to correct such mistakes, but, even as it is, 
Mr. Hoover’s work still remains the authoritative 
text-book on this subject. Like all text-books 
dealing with a branch of technology in active 
development, it suffers from the fact that it falls 
behind the times even whilst it is passing through 
the press, but this is a disadvantage that the 
writer of such books must make up his mind to 
endure. His chief consolation is that it is the 
production of such books which contributes as 
much as anything else to the rapid advance of 
the art that leaves the written page behind. 
(2) With true journalistic instinct Mr. Rickard 
has produced his book on “The Flotation Pro- 
-cess”” at a moment when this method is attract- 
ing a very large share of attention from the 
mining profession; the book cannot, however, be 
said. to form a contribution of any real 
value to the literature of the subject, seeing that 
jit is a typical example of a form of. book- 
making that appears to be in some favour on the 
other side of the Atlantic, though fortunately not 
in this country. It consists of a series of mis- 
cellaneous articles on the subject of flotation by a 
number of different writers, gathered from various 
sources, though all have appeared already in the 
pages of the Mining and Scientific Press; these 
have been strung together on no particular sys- 
tem, forming just such a scrap-book as anyone 
interested in flotation might put together for him- 
self—very useful, no doubt, to the man who had 
compiled it for his own purpose, far less so to 
anyone else, and practically useless to the student 
who demands a systematic presentment of the 
‘subject. The articles vary in length from a few 
lines to many pages, and are as unequal in value 
as they are in extent. The best article in the 
book is probably Mr. Rickard’s own introductory 
chapter, which is itself a paper presented at a 
meeting of the Canadian Mining Institute. 
Whilst Mr. Hoover’s book can be recom- 
mended to the student who wishes to know what 
the various flotation processes are, how they are 
carried out, and what results are obtained by 
them, Mr. Rickard’s compilation gives informa- 
tion on none of these points, but exhibits the 
different and often widely divergent opinions of a 
number of writers who approach the subject of 
flotation from very varied points of view, and most 
of which possess little more than an ephemeral 
interest. EGE. 
OUR BOOKSHELF. 
The Drink Problem of To-day in its Medico- 
Sociological Aspects. Edited by Dr. T. N. 
Kelynack. Pp. xii+318. (London: Methuen 
and Co., Ltd., 1916.) Price 7s. 6d. net. 
Tuts book comprises a number of essays by well- 
known authorities dealing with various aspects 
of the alcohol question. Dr. Harry Campbell dis- 
cusses the biology of alcoholism, and asks, What 
NO. 2457, VOL. 98] 
NATURE 
247 
is the nature of the peculiar attraction which alcohol 
exercises over mankind? He considers that the 
essential factor is the power to intoxicate and 
narcotise. Doubtless this is so for the drunkard, 
but as regards the moderate drinker we do not 
believe it: it is the flavour, and the flavour alone, 
and it is noteworthy that no non-alcoholic drink 
has yet been manufactured which reproduces to any 
extent the flavour of an alcoholic one. Prof. Wood- 
head deals with the pathology, and Dr. Claye 
Shaw with the psychology, of alcoholism, Mrs. 
Sharlieb with alcoholism in relation to women 
and children, Sir Thomas Oliver with alcohol and 
work, and the Rev. J. C. Pringle, of the Charity 
Organisation Society, with alcohol and poverty. 
In the last essay Dr. Kelynack, the editor, dis- 
cusses the arrest of alcoholism, and considers that 
the most effective work in limiting the worst 
manifestations of intemperance has been accom- 
plished by the action of the Central Control Board, 
and certainly the statistics of the decline of 
drunkenness in London since it has been at work 
bear this out. 
The book is largely a partisan one, but, with 
this limitation, all the social problems connected 
with the consumption of alcohol seem to be 
covered by it. The vexed question of moderate 
drinking is not altogether burked, and Dr. Claye 
Shaw admits that in the present war the 
teetotalers do not appear to have come out of the 
ordeal better than those who have a preference 
for alcohol. “Moderate drinking” is an elastic 
term: we would lay down that the maximum 
daily consumption of alcoholic drink should not 
exceed an equivalent of two fluid ounces of abso- 
lute alcohol for a weight of ten stones, and that 
it should be taken in a dilution not stronger than 
10 per cent. It is interesting to note that a 
weighty committee of the French Academy of 
Medicine has advocated a moderate ration of wine 
in the French Army on the ground that it replaces 
a certain amount of meat (protein) and actually 
diminishes the risk of alcoholism ! 
Results of Meteorological Observations in the 
Five Years 1911-1915, also of Underground 
Temperatures in the Twelve Years 1898-1910. 
Made at the Radcliffe Observatory, Oxford. 
Vol. li. Pp. xv+215. (Oxford: Humphrey 
Milford, 1916.) Price 15s. net. 
Tue first part of this volume contains daily 
meteorological data, for the five years 1911 to 
1915, in regard to barometric pressure, tempera- 
ture, wind, cloud, sunshine, rain, ozone, weather 
notes, and occasional phenomena, according to a 
plan adopted in previous years. The figures re- 
lating to wind are from two instruments of 
different dimensions, and a detailed comparison 
would be interesting, as the instruments are at 
very nearly the same height above ground, though 
not quite so nearly as the table makes them 
appear, since the higher one, given at 114 ft. 
in all the tables, is really at 116 ft. For this 
comparison, however, we must wait, as it cannot 
be made from the figures in the volume before us. 
In the appendix, which forms the third section 
