188 
obvious what these constructions should be. On 
the other hand, we can easily get covariant sets of 
points by construction, but it is then troublesome 
to find their analytical equivalents. The results 
for the cubic and quartic are so simple and elegant 
that one would like to have some development, if 
possible. 
It should be noted that Prof. Glenn has given, 
as an appendix, forty-eight very good and instruc- 
tive exercises ; and we may add that, in spite of its 
conciseness, the book seems as easy to read as the 
subject will permit. G. B. M. 
THE GROWTH OF TELEPHONY. 
The Telephone and Telephone Exchanges: their 
Invention and Development. By J. E. Kings- 
bury. Pp. x+558. (London: Longmans, 
Green and Co., 1915.) Price 12s. 6d. net. 
6 Bice book covers most of the ground relating 
to telephony from its earliest stages to the 
present time. It may, indeed, be regarded as a 
“Short History ” df telephony, and, as a matter of 
fact, the author’s original intention was to write 
a history, but circumstances were not favourable 
to the project. However, the future historian 
will find in Mr. Kingsbury’s volume much useful 
historical matter and many finger-posts indicating 
different avenues of development which merit 
much fuller treatment than has been possible in 
this work. 
A marked and valuable feature of the book is 
the numerous extracts from circulars of early 
telephone companies and from unpublished reports 
of experts and of telephone conferences, held 
principally in the United States. Only a person 
very intimately connected with the industry from 
its infancy could have obtained this exclusive in- 
formation and made such judicious selection of 
material. Telephone engineers interested in the 
growth and development of their instruments and 
systems will feel indebted to Mr. Kingsbury for 
the masterly way in which the subject is dealt 
with in the work under review. If ever “scissors 
and paste” can be justified, this is a case in 
point; for here one gets the views of inventors 
and pioneers in their own words, “hot from the 
anvil” as it were, and free from any form of dis- 
tortion due to narration by a second party. The 
work is not of the text-book order; persons desir- 
ing technical details of the latest instruments and 
appliances should consult other treatises, but 
those who wish to study early telephonic devices 
and the way they developed into present-day 
models will find in the volume much that they 
require presented in a very readable form. 
The book is conveniently divided into thirty- 
three chapters and two appendices, one of the 
latter giving telephone statistics of the world, and 
the other relating to the increased telephone rates 
inGreat Britain. In the first six chapters—headed, 
respectively, i., Introductory; ii., The Spoken 
Word; iii, The Growth of an Idea; iv., The 
Undulating Current; v., The Solution of the 
NO. 2454, VOL. 98] 
NATURE 
[NovEMBER 9, 1916 
Problem; and vi., Development and Demonstra- 
tion—the author traces the early uses of the word 
“telephone”’ for speaking-trumpets and speaking- 
tubes, for instruments depending on the trans- 
mission of sound through rods of glass, wood, ete., 
as in the “‘enchanted lyre,” to, the electrical trans- 
mission and reproduction of musical sounds, and 
eventually of human speech, by currents of varying 
strengths. 
Subsequent chapters relate how the beautiful 
scientific instrument patented by Alexander 
Graham Bell in 1876 was, by the prevision and 
business acuity of the inventor and his American 
associates, made the basis of a new branch of 
electrical industry of enormous benefit to the 
public, and in a few decades permeated all 
parts of the civilised world and utilised capital 
amounting to some 400 millions sterling. The 
headings of these chapters are as follows :— 
vii., The Production of a Commercial Instrument ; 
viii., The Application to Commercial Uses; ix., 
The Telephone Exchange; x., The Battery or 
Variable Resistance Transmitter; xi., The Micro- 
phone; xii., Philipp Reis and his Work; xiii., 
Call Bells; xiv., The Telephone Switchboard; 
xv., The Organisation of the Industry in the 
United States; xvi., Competition, Consolidation, 
and Development; xvii., Introduction of the Tele- 
phone in Europe and Abroad; xviii., Public 
Apathy and Appreciation; xix., The Multiple 
Switchboard; xx., Outside or Line Construction ; 
xxi., Ten Years’ Progress; xxii., The Develop- 
ment of Dry-core Cable; xxiii., Early Exchange 
“Systems”; xxiv., Telephone Engineering on a 
Scientific Basis; xxv., The “Branching” Sys- 
tem; xxvi:, The Common Battery System; xxvii., 
Automatic. and Semi-Automatic Switchboards; 
xxviii., Long-Distance Service; xxix., Instru- 
ments; xxx., Rates; xxxi., The Economics of the 
Telephone; xxxii., The Telephone and Govern- 
ments; xxxiii., Conclusion. 
Chap. xii., on Reis’s work, should, chrono- 
logically, be near the beginning of the book, but 
it is put later because ‘its consideration is facili- 
tated by the preceding chapters.”” On the ques- 
tion of priority the author maintains that Reis 
invented a musical telephone and not a talking 
telephone, and that ‘his work had no direct effect 
on the invention of the speaking telephone, for 
Bell fortunately went on entirely independent lines 
and without any reference to the prior work of 
Reis.” Throughout the book the work of Bell 
and his colleagues is given especial prominence, 
sometimes to the detriment of others, such as 
Reis, Hughes, Gray, and Edison. In fact, the 
“pro-Bellism” of the author is a feature to which 
some exception might be taken. In a similar 
way, when dealing with long-distance service, 
Pupin’s work is highly and deservedly appre- 
ciated, whilst that of O. Heaviside (who made the 
discovery that by increasing the inductance of 
lines their speaking qualities could be improved) 
is insufficiently recognised. These, however, 
are minor blemishes in an exceptionally valuable 
book: T. MaTHER. 
