406 
POPULAR SCIENCE REVIEW. 
Professor Pettenkofer gave the three lectures. How admirable an institu- 
tion, and what an honourable example for us, the leaders of Western civili- 
zation, to follow. These lectures are not merely popular expositions of old 
and well-known facts, but they are a series of facts of the utmost importance 
to the health of the community, which have been arrived at by careful 
study of the hygienic requirements of an ordinary mansion. Of the three 
portions into which the volume is divided, and which are all of exceeding 
value, one portion is extremely interesting. Sanitarians who have given 
any study to the subject, are aware that the author of this work differs from 
many able men in his views as to the mode in which cholera is transmitted. 
Water is, in the opinion of most, a customary channel for the diffusion of 
the cholera poison. He, however, stands apart by asserting that the poison 
is not alone transmitted by water, but that soils have much to do with 
its conveyance. We do not say that we ourselves incline towards his 
theories in this respect, but we are bound to say they are well supported 
by various careful experiments. Look for example at the following in- 
genious argument. He says, pointing to an apparatus that is represented in 
the book: ^^You see this high glass cylinder, with a smaller glass tube 
inside, open at both ends. The cylinder is filled with gravel, and the glass 
tube connected with a manometer by some india-rubber tubing. As soon 
as I blow gently on the upper surface of the gravel you see the liquid in 
the manometer moving. The motion of the air which I produce acts in the 
first instance on the surface of the gravel, propagates itself through the 
same to the bottom of the cylinder, enters the lower end of the tube, rises 
through it, and through the tubing into the manometer, where it presses on 
the column of liquid and sets it in motion.” He further shows that the 
force of the air is nearly sufficiently strong to blow out a candle. This 
experiment goes far to convince us of the force of the author’s view, but he 
has many more experiments in hand. Indeed he has produced an excellent 
little work, which X)r. Hess has done well to translate, and has performed 
his portion of the work in a most estimable manner. 
GEOLOGICAL SURVEY OF INDIANA.* 
rpiIIS volume contains the results of the Indiana Survey made by the 
-L State geologist and his assistants during the years 1871 and 1872, and 
forms the third and fourth Reports on the geology of this State. Some of 
the counties of the State have been fully surveyed, whilst of others only a 
preliminary examination has been made. Besides the geological structure 
and typographical features, the distribution and character of the various 
economical substances are also given, as well as tables of the analyses and 
calorific power of coals. The carboniferous rocks and coal-measures are 
more or less extensively developed in Perry, Dubois, Parke and Pike coun- 
ties, occasionally covered by beds of gravel and glacial drift and other more 
* Geological Survey of Indiana.” By E. T. Cox, State Geologist ; 
assisted by Professors j. Collett, B.C. Hobbs, R. B. Warder, and Dr. 
Levette. Indianapolis, 1872. 
