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POPULAR SCIENCE REVIEW. 
and card playing, and last, but by no means least in importance, money for 
science, a brilliant essay which appeared, if we mistake not, in the “ Con- 
temporary Review.” All of these several chapters are of interest, but that 
on “ Have we two Brains?” strikes us as of especial importance. We 
remember reading the report of Brown-Sequard’s lecture on the subject, 
which has formed the basis of Mr. Proctor’s chapter ; but it was so exceed- 
ingly badly reported that we could make nothing .of it as a physiological 
argument. We have read Mr. Proctor’s pages on this subject with great 
interest, therefore ; and while we differ from him on some points we agree 
with him on others; and we would especially commend his mode of dealing 
with the question to our readers. All through his book is of more than 
general interest and value. 
NE would have thought that the ordinary British Mollusca of our ponds, 
streams, and groves had been described enough. However, there is, 
we suppose, still room for a good cheap popular description, with fairly 
coloured plates ; and such a book is that before us, by Mr. J. E. Harting. 
The present work is an enlarged reprint from the u Field ” newspaper, and 
it deals with the subject in such a manner that any person of ordinary 
intelligence can identify the species described. The author has adopted the 
plan of grouping the shells according to the soils which they inhabit, thus 
giving the reader an opportunity of finding a number of specimens on each 
excursion. We thick the idea is good for a popular book of the kind. The 
volume has had the advantage of the revision of the late Dr. J. E. Gray, 
E.R.S., and it is one we can commend. 
O NE who did not understand chemistry would hardly comprehend 
how it was that a whole book was required to answer the ques- 
tion in the above heading. Yet so it is, and Mr. W. N. Hartley has 
given us a very excellent and scientific, yet popular account of air in the 
243 pages which form this volume. It is, in fact, but a species of report of 
his lectures, which were last year (1874) delivered before the Royal Institu- 
tion, on the subject of Air in its relation to Life. However, the author 
has doubtless expanded many of the points he referred to in his discourses, 
* u Rambles in Search of Shells, Land and Fresh Water.” By James 
E. Harting, F.L.S., F.Z.S. With coloured illustrations. Van Voorst. 
1875. 
t u Air, and its relation to Life; being, with some additions, the sub- 
stance of a Course of Lectures delivered at the Royal Institution in the 
year 1874, by W. N. Hartley, F.C.S.” London: Longmans. 1875. 
POPULAR CONCHOLOGY.* 
WHAT IS AIR ? t 
