384 Mr. H. C. Jones on the Cryoscopic Relations 



molecular lowerings as found by Arrhenius, Kaoult, and 

 myself, for the same concentrations of some or all of these 

 compounds, are greater than the theoretical value. That 

 more work on this problem was necessary was further shown 

 by the fact, that no two of the observers above cited had 

 been able to obtain the same results for even one non-electro- 

 lyte. It is, however, gratifying to know that w.ith electrolytes 

 our knowledge seems to be far more satisfactory. The dis- 

 sociation of a comparatively large number of acids, bases, and 

 salts, as calculated from Kohlrausclr's conductivity-determi- 

 nations* ( a— J, agrees as well as could be expected with 



the dissociation of the same dilutions of these same compounds, 

 as calculated from my results f from the lowerings of the 



freezing-point of water, (a = i — l when the molecule dis- 

 sociates into two ions, a= -^— when into three). 



Noyes and Abbot J have recently shown that the dissocia- 

 tion of thallous chloride, sulphocyanate, and bromate, as 

 calculated from solubility-experiments, agrees with the dis- 

 sociation of these compounds as calculated from conductivity- 

 results. In their words, " Die Loslichkeits und die Leit- 

 fahigkeitsmethode der Bestimmung der Dissociation auf die 

 gleichen Resultate fiihren." The authors recognize that this 

 conclusion is based on a small number of facts, only three 

 compounds having been investigated, yet three which differ, 

 chemically, very widely from one another. Noyes and 

 Abbot conclude, "Die Veraligemeinerung dieses Resultates 

 beziiglich anderer ahnlichen bin'aren Salze, scheint daher 

 berechtigt." We have then the three methods — conductivity, 

 lowering of the freezing-point, and solubility — having to do 

 with such widely different properties of the ions as the lower- 

 ing of the freezing-point of the solvent, carrying electricity, 

 and their mass action on each other's solubility, giving results 

 for the number of ions present in any solution (the dissocia- 

 tion) which agree satisfactorily with one another. Some not 

 inconsiderable difference appeared between my results and 

 those of Kohlrausch for certain compounds §, but these 

 seemed to have admitted of at least a rational explanation. 



In the midst of the uncertain state of our knowledge as to 

 the true lowerings produced by non-electrolytes, a paper 



* Wied. Ami. xxvi. p. 161. 



t Phil. Mag. xxxvi. p. 483 (1893); Zcit.f.phijs. C/iem. xii. p. G39. 



] Zeit. f. phys. Chan. xvi. p. 130. 



§ Phil.' Mag. xxxvi. p. 483 (1893) ; Zeit. f. phys. Chem. xii. p. C39. 



