OCTOBER 27, 1899. ] 
sively the state of experimental geology. The 
critical student to whom experiments are the 
last resort will find from footnotes that most of 
the author’s tests are more completely de- 
scribed in the Comptes rendus de l’ Academie des 
Sciences. 
The grouping of the subject matter is good, 
experiments relating to epigene processes com- 
ing first and those pertaining to the theory of 
hypogene actions following. An introductory 
chapter of 384 pages is an apology for and 
defense of ‘La Geologie experimentale,’ a 
frank statement that the methods and its re- 
sults are scorned in certain quarters. While 
this admission seems not inappropriate, the 
frequent references in the body of the work 
to the distinction between experimental geol- 
ogy and geology as ordinarily pursued, ap- 
pear somewhat pathetic and out of place in 
a book designedly published in the inter- 
ests of science and for the popularization of 
this subject. Notwithstanding the fact that 
many of the author’s attempted explanations of 
natural phenomena would probably not be ac- 
cepted by geologists, it cannot but be instruc- 
tive to many who have not grasped the facts of 
the earth’s structure to see how by some simple 
mechanical contrivance phenomena simulating 
mountains, the action of volcanoes, the effects 
of earthquakes and the like may be produced. 
However far removed the apparatus employed 
may be from the exact processes in nature, 
analogies described in the text must displace 
much misconception which prevails in the pop- 
ular mind concerning the operations of the 
earth forces. 
It is to be regretted that the author did not 
state the principles governing experimentation 
and something of the limitations of the method. 
Though the objections to certain experiments 
are briefly referred to, there is much which has 
been said on the subject of which we find no 
echo in this book. A text-book giving a com- 
prehensive view of the subject with critical 
notes would be a welcome addition to our geo- 
logical laboratories. 
As for the experiments, many of them illus- 
trate everyday changes which it is customary 
in all favorably situated colleges to demonstrate 
in the field where the natural process and its 
SCIENCE. 
609 
product may be seen under more favorable cir- 
cumstances than in the laboratory. That ex- 
perimentation without accurate knowledge of 
the facts to be explained is not infallible, is well 
illustrated by the different conclusions reached 
by Daubrée and Meunier in regard to the rec- 
tangular courses of rivers. Daubrée, it will be 
recalled, sought to explain the right-angled 
courses of streams by postulating preéxistent 
faults as guiding lines for the drainage. Atthe 
time he did his work this explanation had many 
adherents. It is manifestly no difficult matter 
for a clever artisan to devise a model in which 
the conditions of the hypothesis and the ex- 
pected results are satisfactorily demonstrated. 
Professor Meunier, evidently familiar with the 
current view that such rectangular courses 
arise in the development of a river system upon 
certain geological structures unaffected by 
faults, performs an experiment through which 
he comes to disbelieve in Daubrée’s conclusion. 
Incidentally the phenomena of the headwater 
gnawing of streams, the recession of falls, and 
river-capture, are artificially reproduced. It is 
to be noted that in the discussion the reference 
to 35,000 years as the time required for the re- 
cession of Niagara Falls indicates an oversight 
on the part of the author of all recent investi- 
gations on that subject. 
Some of the experiments intended to illus- 
trate the phenomena of meanders in streams 
seem hardly legitimate, or at least there is no 
endeavor to imitate nature in the employment 
of a stream of mercury and in the production 
of meanders onaslope of 20 degrees! The 
object of the experiment seems here to have 
been lost sight of! Likewise the agitation of a 
flexible cord, substituted for a stream with me- 
anders, in the attempt to illustrate the control 
of the meander is amusing, but it may be ques- 
tioned whether it is convincing. 
Other experiments are described as designed 
to prove the competency of running water to 
excavate valleys and with the further purpose of 
combating the lingering notion in France that 
‘we are now ina period of geologic tranquility.’ 
Under the head of marine and lacustrine 
denudation, M. Stanislas Meunier treats of the 
mechanical action of waves and the chemical 
action of water. The experiments with wave 
