Notices respecting New Books. 757 
ftecherches sur VEffet Magnétique des Corps Electrises en Mouvement. 
Par M. N. Vasiuusco Karpun, Paris: Gauthier-Villars. 1904. 
Pp. 114. 
To all whose equanimity has been seriously disturbed by the 
heretical announcements of M. Crémieu, directed against one of 
the foundations of modern electromagnetic theory, we can cordially 
recommend M. Karpen’s monograph on the subject. In addition 
to a very full account of the author’s own interesting experiments, 
it contains a connected historical account of the ‘matter, and 18 
sure to be read with deep interest by all physicists. 
Saggio di Una Teoria Generale det Fenoment Naturali. Di Dre 
Parisino Perrine. Bertoletto eC.: Savona. 1904. Pp.79. 
Un Nuove Procedimento per Trovare Molte Relazioni Note ed Ignote 
fra le Quantiia Fisiche. Di Dre Paristno Pertinent. Fratelli 
Isoardi: Cuneo. 1902. Pp. 70. 
In these two pamphlets, the author deduces a large number of 
new and interesting relations between physical quantities by the 
aid of dimensional equations. The simple manner in which some 
of the results arrived at are obtained is very striking. Part of 
the first pamphlet contains a section dealing with social, moral, 
and even theological questions. 
Lecons sur LElectricité. Par Ertc Gurarp. Tome Premier. 
Neptiéme Edition. Paris: Gauthier-Villars. 1904. Pp. xii 
+ 882. 7 
THE seventh edition of the first volume of this standard treatise, 
so deservedly popular, fully maintains the reputation of its pre- 
decessors. The work of revising and bringing it up to date seems 
to have been carried out with exceptional thoroughness, and in its 
present form it is an essentially modern text-book, in the best 
sense of the term. The happy combination of a sound basis of 
theory with technical detail is the most striking feature of the 
book, and no doubt largely accounts for its phenomenal success. 
The exposition is characterized by elegance and clearness, and the 
reader’s interest is maintained throughout; there is further a 
certain atmosphere of freshness about the book which is altogether 
lacking in some rival treatises. In dealing with problems involving 
more or less complicated calculations, the author seems to have 
sueceeded in choosing the simplest and most direct inethods; and 
any reader who has mastered the elements of the differential and 
integral calculus should be in a position to follow all the mathe- 
matical developments contained in the book with the greatest 
ease. It is a thoroughly practical book for practical men, and 
exhibits that peculiar restraint, that instinctive appreciation of what 
to retain and what to reject, which at once reveal the practised 
touch of the expert teacher. The result is a work which, while 
