600 
elementary understanding is not so great nor 
so difficult to grasp. The teachings of these 
truths of geology are illustrated on every hand, 
and in fact some of them are already familiar 
to the pupil before he enters upon the study. 
They deal with phenomena in the midst of 
which we dwell, and hence should become a 
part of the mental possessions of every high 
‘school pupil.’’? The second reason for putting 
forth the book is to furnish a companion and 
adjunct to the ‘Elementary Physical Geog- 
raphy,’ by the same author. 
There is much to be said for the view that in 
teaching geology a beginning can best be made 
with the study of the materials of the earth 
and the forces which modify it. Such a method 
transforms the study by substituting observa- 
tion of our environment for book learning of 
past conditions. As the tendency of modern 
geologic interpretation is to seek in the records 
of the past for the effects of causes now opera- 
tive, such a method is scientifically sound. 
Those who have found the author’s work on 
‘Physical Geography’ helpful will, no doubt, 
discover in this ‘Elementary Geology’ an aid 
to further studies. 
To prepare an adequate elementary text- 
book is a task involving the successful reduc- 
tion of three difficulties: the selection of ma- 
terial; the analysis of the subject-matter chosen, 
and the choice of language. 
In the selection of material from the enormous 
mass of available facts the author determines 
the essential character of the book. This is his 
peculiar privilege, and detailed comment would 
only serve to illustrate another point of view. 
The choice for this volume is controlled by the 
emphasis given to the dynamic phase of the 
subject, and by the appropriate preference for 
American instances of world-wide phenomena. 
With reference to the analysis of the subjects 
chosen and the precision of expression, more 
definite standards have been set by the masters 
of scientific exposition. Their example might 
well check too fluent thought and too facile 
pen. The present work is weak in analysis and 
statement. The writing is in a descriptive 
style, which is pleasant to read, but which lacks 
emphasis of leading ideas. Examples chosen 
to illustrate processes appear to have controlled 
SCIENCE. 
[N. S. Vou. VI. No. 146. 
the order of presentation rather than to have 
been controlled by a logical train of thought. 
About one-hundred and fifty pages of the 
four hundred and eighty-seven are given to 
illustrations. The illustrations are, as a rule, 
well chosen, judging by those whose originals 
are familiar, but in reduction to a scale ade- 
quate for this work they have suffered very ma- 
terially, and their value is in many instances 
doubtful Half-tone reductions printed as text 
figures rarely retain sufficient character to 
Justify their use in works of this kind. The 
photograph should either be redrawn as line 
work or it should be printed upon a separate 
plate in a proper press. Hither of these alter- 
natives would limit the number of illustrations 
available for a book of moderate cost, but it 
would be better to have a few good ones than 
many which fail of their purpose. 
The responsibility which rests upon the 
scientific author in attempting to promote the 
study of his subject can scarcely be too seriously 
considered. It is only in recognition of this re- 
sponsibility that this review has been prepared. 
BAILEY WILLIS. 
NEW BOOKS. 
Naturol History. R. LyDEKKER and others. 
New York, D. Appleton & Co. 1897. Pp. 
xvi++-771. $2.00. 
Life Histories of American Insects. CLARENCE 
M. WEED. 
Maemillan Co. 
New York and London, The 
1897. Pp. xii4-272. $1.50. 
J. S. Kinestry. New 
1897. Pp. vii+ 
Comparative Zoology. 
York, Henry Holt & Co. 
357. 
Darwin and after Darwin. GEORGE JOHN Ro- 
MANES. Chicago, The Open Court Publish- 
ing Co. 1897. Vol. III. Pp. viii--181. 
Laboratory Directions in General Biology. HAR- 
RIET RANDOLF. New York, Henry Holt & 
Co. 1897. Pp. vi+-163. 
Quantitative Chemical Analysis. PERCY Norton 
Evans. Boston and London, Ginn & Co. 
1897. Pp. iv-+80. _ 
Kroll’s Stereoskopische Bilder fiir Schielende. 
R. PERLIA. Hamburg, Leopold Voss. 1897. 
26 colored pictures. 
