304 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



degree of dissociation from molecular weight determinations is 

 in the case of non-aqueous solutions also impracticable, because 

 the molecular weights are, as a rule, normal, or greater than 

 normal, in spite of the fact that the solutions conduct well and 

 that the boiling-point constant of the solvent is so high that dis- 

 sociation certainly ought to be indicated, if present. 



It is a well known fact also that molecular weights determined 

 according to cryoscopic or ebullioscopic methods at times in- 

 crease with the dilution ; again, at other times, they do not 

 change much with the dilution ; and at still other times they de- 

 crease as the dilution increases. The latter behavior only is in 

 harmony with the theory of solutions and the theory of electro- 

 lytic dissociation. Furthermore simple substances occasionally 

 show abnormally low molecular weights and yet their solutions 

 are not conductors of electricity. This I have found to be true, 

 for instance, in the case of solutions of diphenylamine in methyl 

 cyanide, — results as yet unpublished. 



The osmotic theory of the galvanic cell, which uses the disso- 

 ciation hypothesis as a basis, also naturally meets great difficul- 

 ties when applied to chains containing non-aqueous solutions. 1 



In the face of these facts the theory of electrolytic dissocia- 

 tion is untenable in the case of non-aqueous solutions. While 

 chemists have frequently in conversation admitted this to be 

 true, I have also often been told, "But in the realm of aqueous 

 solutions the theory concords with the facts so well". This led 

 me to investigate the behavior of aqueous solutions somewhat 

 further. 



Experimental Part. 



The general plan of the investigation was to determine the 

 boiling-points of aqueous solutions of typical, common chemical 

 compounds from low to very high concentrations, in order to see 

 how the molecular weight changes with the concentration, and 

 at the same time to measure the electrical conductivity of such 

 solutions at or near their boiling-points. This would enable one 

 to make much more accurate comparisons between the values of 

 the degree of dissociation as calculated from conductivity and 



>See Kahlenberg, Jour. Phys. Cheni. 3, 395 (1899). Ibid. 4, 709 (1900). 



