602 Notices respecting New Books. 



Appendix K, on Vector Analysis, was written as a review of 

 Gibbs- Wilson's well-known treatise. 



Chapter X. contains under the title of Waves in the Ether such 

 a multitude of topics, masterly treated and suggestive of new 

 problems, that even a mere enumeration of them would exceed 

 the limited space of a Philosophical Magazine review. We shall, 

 therefore, content ourselves with pointing out that the reader will 

 find in that chapter Heaviside's most important investigations con- 

 cerning the radiation from a moving electron, viz. " Elliptic or 

 any other Orbit " in § 513 and " Theory of an Electric Charge in 

 Variable Motion" in § 514, pp. 432-491, the remainder of this- 

 section (pp. 491-498) being dedicated to the interesting problems 

 connected with spherical sources of energy, i. e. seats of oscillating 

 impressed forces. 



A System of Physical Chemistry. By Professor W. C. M C C. Lewis, 

 Professor of Physical Chemistry in the University of Liverpool. 

 Two volumes. Text Books of Physical Chemistry. Edited by 

 Sir William Eamsat, K.C.B., i\R.S. London : Longmans, 

 Green & Co. 1916. Price 9s. net each. 

 There is probably no other subject which is so progressive at 

 the present time as that of physical chemistry. The seed set by 

 vau't Hoff and by Willard Gribbs developed and grew, and the- 

 plant has began to bear fruit on its many branches. The works 

 of Gribbs were of rather too abstruse a character to be easily 

 assimilated. Those of Nernst are a little too lax in their treatment 

 to be quite satisfactory, though they represent the activities of a 

 very brilliant investigator. Small books there are in plenty which 

 deal more or less satisfactorily with the elementary side of the 

 subject. But there has up to the present been no book which 

 deals with the matter in an absolutely satisfactory way. The 

 present two volumes in a well-known series promise to fill the gap. 

 Professor Lewis has endeavoured to give a sufficiently complete 

 account both on the experimental and the thermodynamic side, 

 and we do not hesitate to say that he has succeeded. 



The first volume deals with the kinetic theory with chief refer- 

 ence to the laws of chemical equilibrium and reaction velocity 

 including catalysis (positive and negative). This is preceded, 

 amongst other things, by an exceptionally good account of the 

 various characteristic equations which have been suggested for 

 fluids. 



It is in the second volume that the unique value of the book 

 will be perceived. The theorems of thermodynamics are not all 

 simple, and in chemical books in particular they have often been 

 badly slurred over. But here it is otherwise. In one or two 

 particulars we might have put the matter otherwise. For example, 

 does not the first law of thermodynamics state more than that 

 " there is always a definite quantitative relationship between the 

 heat that has disappeared as such and the work which has been 



