ON THE DIELECTRIC CONSTANTS OE PURE 



SOLVENTS. 



Introduction. 



In 1893 Nernst, 1 from theoretical considerations based upon 

 the theory of electrolytic dissociation, deduced his well known 

 rule, that — other things being equal — the greater the dielectric 

 constant of a medium the greater is its dissociating power. In 

 the same year J. J. Thomson 2 also pointed out this relation, 

 saying that if we accept the view that the forces between the 

 atoms are electrical in their origin then the effect of surrounding 

 the molecules of a substance by a medium possessing a very 

 high dielectric constant like water, would be to practically dis- 

 sociate them. According to Nernst, proportionality between the 

 dielectric constant and dissociating power need not necessarily 

 exist, but a close parallelism between the two doubtless pre- 

 vails. He adds that other factors besides the dielectric constant 

 doubtless exist, which probably influence the dissociating power 

 of the solvent. The experimental facts, Kernst 3 says, show 

 beyond a doubt that a marked parallelism exists between the dis- 

 sociating power and the dielectric constant. Exceptions to the 

 rule he explains by assuming the existence of specific influences, 

 of which the association of the ions with the molecules of the 

 solvent is probably of prime importance. 



The existing experimental data at the time the above relation 

 between the dielectric constant and dissociating power was 

 pointed out accorded well with it, and subsequent investigations 

 furnished numerous additional examples in support of it. But 



1 Gottinger Nachrichten No. 12, (1393) ; Zeit. phys. Cham. 13, 531, (1894). 



* PhiL Mag. 36, 320. (1893). 



3 Theoretische Chernie p. 355. (Dritta Auflage). 



