ITS 



tion is probably less than that of the simpler ones, but also with more com- 

 plex ions, whose velocity is probably less than that of the simpler ones. 

 If, however, the ionization resulting from dilution proceeds at a greater 

 rate than does the change in complexity, increase in molecular conductiv- 

 ity would then be the rule. This actually happens for a certain range in 

 the case of lithium chloride, then later the increasing complexity of the 

 ions perhaps gains the ascendancy and molecular conductivity decreases 

 with further dilution. The effect of dilution upon molecular conductivity 

 will necessarily be somewhat complicated, if the preceding reasoning is 

 correct, involving at least the following changes: (a) Increase in mole- 

 cular complexity, through increase in the active mass of ethyl amine. 

 (b) change (probably decrease) in ionization constant because of increas- 

 ing complexity, (c) increase in ionization of any one form, since at any 

 dilution a considerable number of different complexes are probably pres- 

 ent, and (d) probable decrease in migration velocity on account of in- 

 creasing complexity of the ions. 



This would seem to be merely another special case of the influence 

 of solvate formation upon conductivity, and such influences have long been 

 known. The formation of hydrates, for example, has a very marked 

 effect upon the conductivity and upon the lowering of freezing point and 

 vapor pressure of aqueous solutions. 



In the case of solutions of ammonium chloride in ethyl amine it is 

 by no means certain that the entire amount of salt is converted at once 

 into ethyl amine hydrochloride when brought into a solution of any con- 

 centration. We should certainly expect that equilibrium will result when 

 a certain amount of ammonium chloride remains as such in the solution, 

 this amount becoming smaller as dilution proceeds. The molecular con- 

 ductivity will then depend upon (a) the ratio of ethyl amine hydro- 

 chloride to ammonium chloride, (b) the relative ionization constants of 

 the two compounds and (c) the relative migration velocities of the two 

 (or more) cations involved. 



The theory of electrolytic dissociation has proven of so great value 

 to physical chemistry and has piloted the way to so many valuable in- 

 vestigations that one cannot fail to realize its importance. This does not 

 mean that its imperfections should be ignored or that there should be any 

 cessation in the search for facts which will test it to the extreme. But 

 so many supposed objections have been urged against it that, on closer 



