Jury 29, 1915] 

have to teach advanced students. The 
of greatest interest to electrical engineers is the 
chapter dealing with the theory of coupled elec- 
trical circuits. This subject is now of great 
importance in wireless telegraphy and a simple 
and complete statement of the theory, such as that 
worked out by Prof. Fleming or that contained 
here, is of great value. The tables for determin- 
ing high-frequency resistance and for estimating 
the inductance of coils and for calculating the 
effective capacity of a long antenna should also 
be of importance to radiotelegraph engineers. It 
is impossible, in a ‘short notice, to describe 
adequately the vast field of theoretical work that 
the book covers, or to do justice to the masterly 
treatment of the many problems with which it 
deals. The book has already taken its place as 
a standard work on alternating current theory, 
and the additions made in this new edition will | 
tend to establish it more firmly in the position it 
has already attained. 
(2) The opening chapter of Dr. Baillie’s book 
on electrical engineering contains a useful! sum- 
mary of the pioneer work on which the modern 
practice of electrical engineering rests. Brief 
reference is made to the work of Volta, Galvani, 
Siemens, Ampere, Clerk-Maxwell and many 
others. At the present time it is perhaps of 
interest to note that among those whose names 
are household words in electrical science, only 
two, those of Siemens and Hertz, are of Teutonic 
origin. The following chapters deal with the 
ordinary phenomena of electrical conduction, the 
measurement of resistance power and current, 
about which all elementary students in electrical 
engineering have to learn, together with chapters 
on batteries and the electric light. 
Special mention may be made of chapter vii, 
which deals extremely well with the potentiometer 
and its uses, and to the chapter on batteries, which 
is exceptionally clear and good. The book is 
sufficiently elaborate to meet the needs of students 
taking a first year course in a technical college 
Some doubt may be expressed as to the value of 
such figures as 18, 19, 20, 21, 24, 25, 26, which 
show the outer cases of instruments. This, how- 
ever, is a minor defect; the illustrations do not 
detract from the value of the book, they merely 
add unnecessarily to its bulk. As a text-book for 
elementary courses in electrical engineering it 
should fulfil a useful purpose, a result which is 
greatly assisted by the 125 examples, to be worked 
by the students, which are given at the ends of 
the chapters. 
(3) The book by Messrs. Murdoch and Oschwald 
on electrical instruments is a welcome attempt | 
NO. 2387, VOL. 95] 
NATURE 
addition © 

587 
to discuss the design and construction of electrical 
instruments from the broadest point of view. 
The theory of their action and their mechanism is 
clearly laid down. The opening chapter contains 
a brief summary of the history of exact measure- 
ment together with a short account of some 
absolute determinations of the fundamental elec- 
trical quantities. In this connection it is 
interesting to note that so recently as 1881 Kelvin 
and Bottomley stated that “‘the most accurate 
method of measuring candle power was by 
comparing the shadows of a pencil illuminated by 
the two sources.’? The summary shows clearly 
how the development of electrical instrument con- 
struction is related to the practical needs of the 
industry. 
In an interesting chapter on damping, the 
general theory is laid down and discussed in 
connection with the instruments in which it forms 
an essential feature, the Grassot fluxmeter being, 
of course, the outstanding example. The following 
chapters describe the ordinary form of moving 
coil ammeter, electrostatic and current voltmeters, 
hot wire instruments, dynamometer type instru- 
ments, and energy meters. In the chapter on 
magnetic testing a suggestion is made to resusci- 
tate the old magnetometer method of testing with 
weak fields. This method is an admirable one 
under suitable conditions, but in a laboratory 
within range of an electric tramway or railway, 
or even of electric light mains, it is nearly useless. 
There are numerous figures and results given 
throughout the book which have been obtained 
from the authors’ own requirements, which are of 
value as independent testimony to the accuracy of 
the apparatus with which they have been made. 
The book should be a useful work of reference 
for those who are engaged in the manufacture of 
electrical instruments and in electrical testing. 
(4) The book on alternating current electricity 
and its application to industry by W. H. Timbie 
and H. H. Higbie is an attempt to simplify the 
teaching of alternating current technology for 
engineering students. The teaching of this 
subject has advanced with great strides since the 
time, some twenty years ago, when the study of 
alternating currents was regarded as a branch of 
applied mathematics, to be taken after an elaborate 
introductory mathematical training. Alternating 
current work should form part of a normal 
second year course for all engineering students, 
and this book is one which should be most 
useful as a text-book for helping in the teaching 
of this subject during the early stages. The 
hydraulic analogies in many cases are ingenious 
and enlightening, and explain the apparent incon- 
