128 
essential, therefore, to assume a certain amount 
of chemical knowledge in the reader, and we are 
inclined to think, on the whole, that Dr. Allmand 
has not assumed too much. 
It must be remembered however, that the 
student who approaches this subject from the 
electrical side is often seriously lacking in chemical 
grounding and, complete though Dr. Allmand’s 
treatment is, we could not help feeling at times 
that the chemical reasoning and illustrations would 
be above the heads of many readers. This argu- 
ment must not be given undue weight, as it is 
open to all who care to study the subject thor- 
oughly to supplement the volume by the reading of 
other chemical and physico-chemical works, a 
matter which is greatly facilitated by the copious 
references to current literature and the biblio- 
graphical references at the end of each chapter. By 
the time the student has thoroughly mastered the 
theoretical discussion in the first part of the book 
he will be in a position to understand properly 
the reactions and phenomena involved in the 
various practical applications to which the second 
part is devoted. 
The “special and technical” part of the work 
opens with two chapters on primary and secondary 
cells respectively. The treatment here is neces- 
sarily brief—whole volumes have been written 
dealing with each of these subjects—but it is 
clear and covers the more important points. An 
interesting discussion of the “fuel cell,” a cell in 
which coal, or some simple derivative from coal 
such as carbon, or CO, is used to generate elec- 
trical energy, concludes the chapter on primary 
cells. There follow chapters on the electro-metal- 
lurgy of the principal metals, and on electrolytic 
bleaching, etc., and in chapters xxiv. to xxvi. the 
more important electro-thermic processes are dis- 
cussed. The last two chapters deal with the 
oxidation of atmospheric nitrogen and the pro- 
duction of ozone. 
Although, owing to natural conditions, this 
country is not to the fore in electrochemical and 
electrothermal development, the field for English 
engineers is not confined to England. There is 
good reason to hope, moreover, that the future, 
and very possibly the near future, will see much 
greater advances in this direction in England than 
one would have anticipated a few years ago. It 
is becoming more evident every year that not only 
is water power not an indispensable adjunct to 
electrochemical enterprises, but that other sources 
of power may possess decided advantages. The 
appearance of so thoroughly sound a treatise as 
Dr. Allmand’s is therefore very much 
welcomed, . 
(3) Messrs. Barclay and Hainsworth have set 
NO. 2292, VOL. 92] 
NATURE 
to be | 
[OcToBER 2, 1913 
out to write a thoroughly up-to-date handbook 
for the practical electroplater, and have succeeded 
admirably in realising their aim. Rightly insist- 
ing that even the most practical of practical men 
cannot in these days work without a more or less 
thorough groundwork in the theoretical side of his 
| subject, they have devoted the first six chapters 
of their book to a succinct but thoroughly sound 
exposition of the fundamental chemical and elec- 
trical principles. 
well suited to the scope of the book, the elementary 
knowledge assumed being such as can_ hardly fail 
to be possessed by anyone seriously attempting 
to study the volume. 
After two chapters dealing with plant and ap- 
paratus and preliminary processes such as clean- 
ing, etc., the remaining chapters deal with the 
deposition of the various metals. Each of the 
more important metals is considered separately, 
and in each case the theoretical explanation of the 
various reactions involved is not forgotten. The 
composition of the various depositing baths 
having been considered from this viewpoint, the 
methods of making them up and the details of the 
actual electroplating process are dealt with. The 
book covers the deposition of all the metals of 
importance industrially and also of many the 
deposition of which has a very limited application. 
We can thoroughly recommend the book either 
to the practical electroplater or to the student 
anxious to familiarise himself with the details of 
a process of great commercial importance and 
great historical interest. 
(4) Messrs. Barr and Archibald’s volume on 
alternating current machinery is an advanced 
treatise suitable for the use of senior students and 
those actually engaged in the design of such 
machinery. The whole field is well covered : after 
preliminary chapters on complex wave forms and 
insulation, the subject of transformer design is 
dealt with in three chapters. These are followed 
by eight chapters on alternators and three on 
rotary converters. 
(5) Mr. Morecroft’s book is a collection of 
laboratory experiments designed to elucidate the 
more important current phenomena. We are glad 
to see that a method too frequently followed by 
the writers of such laboratory notes, that of con- 
fining the text to the merest statement of instruc- 
tions, has been avoided and a clear exposition of 
the significance of the experiment has been given 
in each case. Although this may render the book 
less convenient for actual use in the test-room, 
it gives it much higher educational value. 
(6) and (7) These two books deal with specific 
developments in the field of telegraphy and 
telephony, and may be regarded more as mono- 
These are treated in a manner 
| 
: 
