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IX. Notices respecting New Books. 



Traite d' Eleclricite Statique. Par M. E. Mascaet, Professeur de 



Physique au College de France. 2 vols. Paris : Gr. Masson. 1876. 

 QI]N T CE the publication of Eiess's Reibungs-Electricitdt in 1853, 

 ^ enormous strides have been made in electrical science, and not 

 least in those regions of it comprehended by M. Mascart under the 

 title Eleclricite Statique. The theory of the potential has been 

 widely extended and applied ; and the various new forms of elec- 

 trometer have given us the means of performing electrical measure- 

 ments with a precision unattainable twenty-five years ago. Im- 

 portant researches involving new methods have been carried out 

 and published both in this country and on the continent, while 

 the mathematical theories connecting the observed phenomena 

 have been developed in an admirable manner by Professor Clerk 

 Maxwell and others. 



The work before us is undoubtedly the most complete and im- 

 portant treatise on statical electricity, considered from the experi- 

 mental point of view, that has been published since Eiess's work 

 appeared. It supplies a want widely felt. It brings before us 

 concisely, but in a well connected and interesting manner, the re- 

 sults obtained by the labours of the less-recent workers, Coulomb, 

 Poisson, Snow Harris, Paraday, &c, and, though not professing 

 to furnish a complete history of the science, or to cite all the 

 physicists who have contributed to its progress, describes the most 

 recent advances made in all lines of research connected with its 

 subject. We have here, in fact, together with the most valuable 

 part of Eiess's work, to which the author acknowledges his great 

 obligations, a lucid and sufficiently detailed account of the ideas 

 and methods developed since his time. Nor is Prof. Mascart 

 satisfied with mere description or abstraction. His expositions of 

 the researches of others are generally accompanied by discussion 

 and criticism, always trenchant and suggestive, and for the most 

 part, as we think, just. # 



The title of the book Electricite Statique must not be understood 

 in its restricted sense. It includes here not only the matter com- 

 prised under this heading in the ordinary text-books, i. e. the 

 general conditions of equilibrium of electrified bodies, &c., but 

 gives an account also of the principles of the Voltaic pile, the pheno- 

 mena of the thermoelectric circuit, and other matters belonging 

 strictly to the department of dynamical electricity. 



Professor Mascart regards his subject from an experimental 

 rather than from a mathematical point of view, nearly the whole 

 of the mathematical investigations in the two volumes being con- 

 tained in two chapters, the sixth and seventh, styled respectively 

 " Theory of Electrical Phenomena " and " Applications of the 

 Theory." 



The first of these gives a sketch of the potential theory and of 

 the properties of the potential function. Green's transformation 



