May 3, 1901.] 
more complete, but unfortunately the typo- 
graphical errorsare rather annoying. The Hy- 
menoptera occupy 170 pages of Volume III , 
the larger part of which treats of the gallflies 
and sawflies. The Diptera occupy the re- 
mainder of Volume III., and are treated at 
more length than the preceding orders. The 
fleas occupy the position of a family at the end 
of the order. Several Trypetide, especially 
Dacus olezx, Ceratitis hispanica and Rhagoletis 
cerasi are treated in much detail. The Hessian 
fly, which appears under the unfamiliar generic 
name of Mayetiola, occupies fourteen pages. 
In the fourth volume the Neuroptera are 
passed over rather hastily. The Pseudoneu- 
roptera are included under the Orthoptera. 
The Hemiptera receive the fullest treatment of 
all. Over 180 pages are occupied with the Ap- 
hide, and 200 with the Coccide. Phylloxera 
covers 75 pages. Nearly all the Coccide are 
figured. Under the name of Aonidiella per- 
niciosus, a long account is given of the San Jose 
scale. Inthe Orthoptera considerable space is 
devoted to the remedies for grasshoppers ; 
spraying machines and catching machines, 
drawn by two men, seem to be especially 
favored. The volume concludes with a brief 
notice of the Thysanura under the ordinal name 
of Pseudoinsecta. ; 
; | NATHAN BANKS, 
_ An Introduction to Modern Scientific Chemistry, 
‘in the form of popular Lectures suited for 
University Extension students and general 
readers. By Professor LASSAR-CouNn, Ph.D., 
University of Konigsberg. Translated from 
the Second Edition by M. M. ParTrison 
Moir, M.A., Cambridge. New York, D. 
Van Nostrand Company. Pp. viii+ 348. 
Price, $2.00. : 
The author’s preface says: ‘‘In this intro- 
duction to Modern Scientific Chemistry an attempt 
is made to give a succinct and accurate pres- 
entation of chemistry on strictly scientific 
lines, and at the same time in as popular a 
form as is compatible with the vast range of 
the subject. The book can be followed easily 
by any one who takes a serious interest in 
natural science, and will not, I hope, be unwel- 
come to the younger chemists who are still pur- 
suing their studies. A teacher of chemistry 
SCIENCE. 
707 
who may not have paid special attention to the 
methods of presenting his subject will perhaps 
find in the book something useful to himself 
and helpful to his hearers.”’ 
A careful examination of the text impresses 
one with the idea that the author has made a 
particularly happy use of the word modern in 
his title ; and that the promises of the preface 
have been abundantly fulfilled. The author 
has been eminently successful in solving the 
difficult problem of giving the theories and 
facts of chemistry in a form not only popular 
but exact. The keynote of the book is its 
emphasis of the fundamental conceptions of the 
science. 
The style is clear, convincing and always in- 
teresting. While the book is intended primarily 
for University Extension students and general 
readers, to the student and younger teachers of 
chemistry it offers a wealth of valuable, accurate 
information, especially concerning the chemical 
principles involved in the manufactures ofillum- 
inating gas, smokeless powders and other ex- 
plosives, fertilizers, matches, glass, aluminium, 
ete. 
The reader who does not find this book help- 
ful and inspiring must be very well informed in 
scientific chemical subjects. 
The translation is excellent, and will serve to 
introduce Professor Lassar-Cohn’s work to a 
new world of readers. 
The crudeness of the illustrations (by the 
author) is the only unsatisfactory feature of a 
book of rare merit. 
WILLIAM B. SCHOBER. 
LEHIGH UNIVERSITY. 
An Elementary Treatise on Qualitative Chemical 
Analysis. By J. F. SeLuers, Professor of 
Chemistry, Mercer University, Georgia. 
Boston, Ginn & Company. 1900. Pp. ix + 
160. 
The author has attempted in this treatise to 
place qualitative analysis upon a scientific 
basis, to do for this subject what Ostwald has 
done for analytical chemistry in general. It is 
very evident from the nature and arrangement 
of that part of the book devoted to the theory 
of solutions that it is a reflection of Ostwald’s 
‘Foundations of Analytical Chemistry.’ As 
such it isto be commended. The book, how- 
