140 Notices respecting New Books. 



The aim of the author has been to produce a work bearing the 

 same relation to electrical theory as a treatise on thermodynamics 

 bears to the theory of heat. Temperature in the one case, electric 

 force in the other, are regarded as fundamental quantities ; the 

 rest consists entirely of experiment and mathematical deduction. 

 A closer study of the behaviour of heated gases gives us a clue to 

 the physical meaning of temperature ; may we not hope to learn 

 from the electrical properties of matter something more definite 

 concerning electric force ? James L. Howard. 



Molecules and the Molecular Theory of Matter. By A. D. Eisteen, S.B. 

 Boston, U.S.A. : Ginn & Co., 1895. 



This volume is the outcome of a lecture on the same subject, 

 which the author has greatly amplified, retaining, however, the 

 lecture style, which involves the frequent use of the first person 

 singular. The introduction of this personal element enables 

 Mr. Eisteen occasionally to put forward his own views without 

 leading students to suppose them orthodox — if such a term is 

 permissible in connexion with the theory of the constitution of 

 matter. He thus imparts to his subject a greater interest and a 

 more vigorous treatment than it has previously received, except in 

 Maxwell's discourse on ' Molecules,' and Lord Kelvin's lecture on 

 the ' Size of Atoms.' 



The first part of the work is devoted to the kinetic theory of a 

 perfect gas ; the gaseous laws are explained, and Maxwell's law of 

 distribution of molecular velocities is enunciated and discussed. 

 This is followed by the statement of Boltzmann's theorem and 

 the deduction of the relation between the number of degrees of 

 freedom of the molecules of a gas and the ratio of its specific heats, 

 after which diffusion and viscosity are treated according to the 

 principles of the kinetic theory, and molecular free path is 

 illustrated by the radiometer and Crookes's tubes. The second 

 section of the volume deals with the molecular theory of liquids 

 and solids, and is necessarily more superficial and sketchy than the 

 previous one; it concludes with a good account of the various 

 methods for the determination of molecular magnitudes. The 

 rest of the volume contains short descriptions of the various 

 theories concerning the nature of atoms and molecules. 



The author has endeavoured to give an outline of the whole 

 subject rather than a detailed mathematical treatment of a portion 

 of it, so that formulae are occasionally quoted without proof. In 

 these cases the student might with advantage be referred to a 

 treatise or memoir where the proof is to be found. 



James L. Howard. 



