JuNE 6, 1912] 
and ecological, under the several families, the 
helpfulness of which is much increased by the pro- 
fusion of admirable illustrations, by numerous 
bibliographical references, and by a very full 
index. 
PHYSICAL TEXT-BOOKS. 
(1) Grundriss der Naturlehre fiir Gymnasien und | 
Realschulen. By E. Mach. Bearbeitet von 
Dr. Karl Habart. Unterstufe. Siebente 
Auflage. Pp. 181. (Wien: F. Tempsky, 
191.) Price 2.50 marks. 
(2) An Elementary Course on Practical Applied 
Electricity and Magnetism. By D. H. Ogley. 
With a preface by Dr. W. G. Rhodes. Pp. 
xi+134. (London: Longmans, Green and 
Co., 1911.) Price 2s. 6d. net. 
(3) An Introductory Course of Mechanics and 
Physics for Technical Students. By W. M. 
Hooton and A. Mathias. Pp. vii+148. 
(London: W. B. Clive, University Tutorial 
Press, Ltd., 1911.) Price 1s. 6d. 
(4) The Ontario High School Physics. By Dr. 
F. W. Merchant and Prof. C. A. Chant. Pp. 
viii+504. (Toronto: The Copp, Clark Com- 
pany, Ltd., n.d.) Price go cents. 
(5) The Ontario High School Laboratory Manual 
in Physics. By Dr. F. W. Merchant and Prof. 
C. A. Chant. Pp. viiit+128. (Toronto: The 
Copp, Clark Company, Ltd., n.d.) Price 35 
cents. 
(6) Lehrbuch der Physik. Nach Vorlesungen an 
der Technischen Hochschule zu Miinchen, von 
Prof. H. Ebert. Erster Band :—Mechanik— 
Warmelehre. Pp. xx+661. (Leipzig and 
Berlin: B. G. Teubner, 1912.) Price 14 marks. 
(Naturwissenschaft und Technik in Lehre und 
Forschung, herausgegeben von Prof. F. Doflein 
und Prof. K. T. Fischer.) 
(7) An Intermediate Course of Practical Physics. 
By Rajanikanta De. Pp. xii+284. (Calcutta: 
The International Publishing Co., 1911.) 
(1) HIS little book comprises introductions 
to the various sections of physics, in- | 
| inexpensive apparatus. 
cluding mechanics and astronomy. The treat- 
ment is almost entirely qualitative, as is to be 
expected in an elementary-school book. For such 
purposes it appears to have many good points. 
The statements of the fundamental principles are | 
clear, the printing is excellent, and the diagrams | 
with which the various experiments are profusely | 
illustrated are very good, particularly those bear- 
ing on the movements of the heavenly bodies. 
Perhaps the order in which the subjects are taken 
is a little peculiar, the treatment of mechanics 
being given towards the end of the book. This | 
NO. VOL. 89] 
s 
2323, 
NATURE 343 
would be a serious defect in a work of wider 
scope, in which quantitative measurements in 
electricity and magnetism were described; here, 
however, the order of the subjects is compara- 
tively indifferent. 
(2) It is probable that most teachers of prac- 
tical physics have experienced the difficulties to 
help to remove which this book has been pro- 
duced. The difficulties arise from the small 
amount of individual attention which it is possible 
for a demonstrator to give in large practical 
classes. As the writer of the preface points out, 
this is especially so in cases where the number of 
hours devoted by students to practical work is 
very small. The method which the author adopts 
for lessening this undoubted defect in teaching 
is as follows:—Not only are instructions as to 
procedure in a given experiment stated, but the 
observations are also explained — theoretically. 
Thus a student can prepare beforehand for the 
experiment assigned to him, and need not work 
unintelligently even in the absence of the demon- 
strator. This book should certainly serve the 
purpose for which it was written. It consists of 
a collection of some sixty experiments in mag- 
netism and electricity which have been carefully 
and clearly treated after the manner above 
referred to. There are, however, no experiments 
in electrostatics described—an omission which 
somewhat reduces the value of the book. Com- 
paratively few teachers realise that many simple 
yet instructive experiments in that department 
can be performed with very inexpensive appara~ 
tus. With regard to the standard of the work, it 
is pointed out that it is suitable for the elementary 
examination in electrical engineering of the City 
and Guilds of London Institute. 
(3) This book is similar in many respects to the 
one commented upon above, and most of the 
remarks apply to it also. The subjects treated 
are mechanics and heat, and all the experiments 
are quite simple and can be performed with very 
Sets of examples at the 
ends of the various chapters are given, and a 
table of some physical constants is to be found at 
the end of the book. 
(4) There appears to be a tendency in recently 
published text-books of physics—particularly 
those emanating from America—to crowd: too 
much into too small a volume. Of such this is 
a typical example. It is true that it is elemen- 
tary in character and scarcely touches upon the 
exact side of the science; nevertheless the impres- 
sion of “hurry” is very markedly felt in reading 
it. Instead of clearly dealing with and laying 
stress upon the essential and fundamental points, 
the authors, in many places, do no more than 
