662 Notices respecting New Books. 
A Text-Book of Organic Chemistry. By Wi.it1am A. Novus, 
Professor of Chenistry in the Rose Polytechnic Institute. Henry 
Holt & Company, New York. 1903. Pp. xvi+534. 
THE task of writing a satisfactory elementary text-book of organic 
chemistry is, in view of the extraordinary rapid accumulation of 
new facts in that domain of science, an extremely difficult one, 
and we must confess that in our opinion the author has succeeded 
in accomplishing it admirably. The introductory two chapters, 
on physical measurements, are particularly good. In the general 
arrangement of the subject-matter, the book differs from others 
of a similar kind in the rejection of the old division into “ fatty ” 
and ‘‘aromatic” compounds. A very useful feature is the list of 
laboratory exercises given at the end of each chapter. 
La Moderna Teoria dei Fenoment Fisict (Radioattivita, Loni, Elet- 
tront). Di Aucusto Ricut. Bologna: Nicola Zanichelli. 1904. 
(Attualita Scientifiche—No. 3.) Pp. viii+138. 
Proressor Rieu is to be congratulated on having produced so 
fascinating an account of the new phase in physical science brought 
about by the introduction of the electronic theory. Not only the 
serious scientific worker, but the general reader will find this little 
volume delightful reading. In non-technical yet strictly scientific 
language, the author traces the gradual growth of the electronic 
idea, and describes the remarkable series of experimental researches 
which have gradually led to the general adoption of the electronic 
theory. Electrolytic ions and electrons ; electrons and luminous phe- 
nomena; nature of cathode rays ; ions in gases and solids ; radio- 
activity ; mass, velocity, and charge of ions and electrons ; electrons 
and the constitution of matter—such is the list of subjects dealt with 
by Prof. Righi in his interesting little book, the value of which to the 
serious student will be enhanced by the complete bibliography 
given at the end of the book. 
Essais Industriels des Machines Electriques et des Groupes Hleetrogeénes. 
Par F. Lopré. Paris: Gauthier-Villars. 1904. Pp. 285. 
Tus work is a fine specimen of that lucidity and elegance of style 
for which the best writers of French text-books are noted. The 
testing of electrical machinery and of ‘‘ generating sets” has become 
so important a matter for the modern engineer that a book spe- 
cially devoted to this subject is sure to appeal to a very wide circle 
of readers ; and in the work under review its distinguished author 
has succeeded in giving an interesting and useful summary of the 
large amount of experimental work carried out within recent years 
in connexion with the testing of electrical machinery. 
It is now well known that many of the earlier methods of dynamo 
and motor testing, and of separating the various losses, were based 
on assumptions which subsequent researches have shown to be 
untenable. A clear idea of the nature of the assumptions under- 
lying any particular test is of extreme importance to the engineer, 
and in M. Loppé’s book he will find a systematic and critical 
account of ali the best-known methods relating to the testing of 
