350 



Conductivity of Aqueous Solutions. Part XII. 



of neutral salts of the same ionic type instead of being several per cent 

 larger as is the conductance-ratio A/A taken in the usual way. 



Reference may also be made to the measurements of Dr. Wilhelm 

 Bottger, presented in Part X, of the solubility of some difficultly soluble 

 salts. This constitutes only the beginning of a more extended investiga- 

 tion of the solubility of substances at high temperatures by means of con- 

 ductance measurements. Results have thus far been obtained at 100 

 with silver chloride, bromide, and sulphocyanate, whose solubilities 

 expressed in equivalents per million liters at 100 and 20 have been 

 found to be as follows: 



In the preceding pages have been summarized the generalizations to 

 be drawn from the results of these investigations, in regard to the beha- 

 vior of the various types of chemical substances in aqueous solutions 

 through a wide range of temperature. In conclusion, it seems, however, 

 desirable to draw attention again to a theoretical principle of even more 

 general import, which has been already presented in a previous article 

 by the author as a conclusion apparently justified by a study of the 

 then existing data; for this principle has now received a further con- 

 firmation through the demonstration of the fact that certain purely 

 empirical laws relating to the ionization of salts in water still continue 

 to be valid, even when the physical condition of that solvent is greatly 

 altered by a large change in its temperature. This principle is that the 

 ionization of salts, strong acids, and bases is a phenomenon primarily 

 determined not by specific chemical affinities, but by electrical forces aris- 

 ing from the charges on the ions; that it is not affected (except in a 

 secondary degree) by chemical mass-action, but is regulated by certain 

 general, comparatively simple laws, fairly well established empirically, 

 but of unknown theoretical significance; and that, therefore, it is a 

 phenomenon quite distinct in almost all its aspects from the phenomenon 

 of dissociation ordinarily exhibited by chemical substances, including 

 that of the ionization of weak acids and bases. 



The most important facts leading to this conclusion are the approxi- 

 mate identity of the ionization-values for salts of the same ionic type; 



