20b* Geological Society. 



introduced into analysis by Sarrus in his prize memoir," Eecherches 

 eur le Caleul des Variations " (1846). 



Solution and Electrolysis. By "W. C. Dampier Whetham, M.A. 



Cambridge, University Press, 1895. 

 In choosing the title of this volume Mr. "YVhetham has very aptly 

 indicated the connexion of his subject with both physics and 

 chemistry ; for while solution is essentially a chemical process 

 electrolysis is quite as closely allied to purely physical phenomena. 

 Such borderland subjects, apart from the fact that they interest two 

 sections of scientific workers, derive additional importance as being 

 the meeting- point of two theories, which, although originally 

 framed to explain phenomena totally different in nature, must 

 now be made to harmonize. The process of adjustment is not 

 usually an easy one, and many are the discussions which it 

 provokes, even when the experimental data have been carefully 

 ascertained. The subject of solution is passing through this stage 

 at the present time, but the accumulation of experimental evidence 

 has received a great stimulus by the adoption of a provisional 

 theory. Accordiug to this theory the molecules of a dissolved 

 substance move through the sohent independently of the latter, in 

 a manner comparable with the motion of gas molecules through 

 the space containing thern ; in the case of electrolytes it is further 

 assumed that the molecules are dissociated into their constituent 

 ions to a greater or less degree according to the concentration of the 

 solution. The reconciliation of this so-called physical theory with 

 other doctrines of chemistry and physics is, however, not yet 

 complete. The author proposes to accept the hydrate theory of 

 solution, according to which solvent and dissolved substance form 

 a large complex molecule, making the assumption that the chemical 

 forces acting within the molecule do not interfere with the physical 

 independence of its constituents. 



Mr. Whetham has followed Ostwald in giving an account of the 

 general properties of solutions, but his materials for the portion of 

 the treatise dealing with electrolytes were much more scattered, 

 the only previous attempts to collect them having been made by 

 Wiedemann (1883), and by the Electrolysis Committee of the 

 British Association. The author has selected the more important 

 parts of these reports and presents them, together with other and 

 more recent matter, in a form suited to the needs of students. 

 The book is issued as a volume of the Cambridge Natural Science 

 Manuals. James L. Howard. 



XIX. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 123.] 



April 29th, 1896.— Dr. Henry Hicks, F.R.S., President, in the Chair. 



The following communications were read: — 



1. ' Descriptions of New Fossils from the Carboniferous Lime- 



Btone. — I. On Pemmatites constipatus, sp. nov., a Lithistid Sponge. 



