THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JULY 1897. 



I. The Ionizing Power of Solvents. By W. C. Dampier 

 "Whetham, H.A., Fellow of Trinity College, Cambridge* '. 



THE exceptionally high power which water possesses of 

 making many substances dissolved in it good conductors 

 of electricity was noticed as soon as solutions in other liquids 

 began to be studied. Even in cases where some conductivity 

 is produced, as in those of salts and acids dissolved in alcohol, 

 the electrical resistance is much greater than if water were 

 used as solvent. 



Now the dielectric constant of water is about 75, a number 

 greater than that of any other substance which has been 

 examined, and it seems likely that there is a relation between 

 these two properties. Thus J. J. Thomson f and "W . Nernst X 

 have pointed out that the effect of immersing a system 

 formed of two oppositely electrified bodies in a medium of 

 high dielectric capacity is to diminish the attractive force 

 between the bodies. The result will be that the oppositely 

 charged ions, which we must suppose to make up a salt or 

 acid, can, under favourable circumstances, separate from each 

 other, and the number of molecules thus dissociated at any 

 instant, and therefore the conductivity, will depend on the 

 dielectric constant of the solvent. 



Several experimental investigations on the relative conduc- 

 tivities of substances when dissolved in different solvents have 



* Communicated by Prof. J.J. Thomson, F.R.S. 



t Phil. Mag. 1893, xxxvi. p. 320. 



X Zeita. physikal. Chem. 1894, xiii. p. 531. 



Phil. Mag. S. 5. Vol. 44. No. 266. July 1897. B 



