35 <? Conductivity of Aqueous Solutions. Part XII. 



and from the usual empirical law in the case of largely ionized substances, 

 may well arise from the presence of a small proportion of molecules of the 

 other type. In the former case, we may indeed with some confidence 

 predict quantitatively that that proportion of electrical molecules will 

 always be present which corresponds for the type of substance in question 

 to the concentration of its ions in the solution. 



A fuller experimental investigation of the properties of dissolved salts, 

 especially of those of polyionic types, and of the phenomena of the solu- 

 bility effect and the distribution into a gaseous or another liquid phase 

 of ionizing substances, if combined with a thorough and persistent study 

 of all the available data, gives promise of suggesting a fuller theoretical 

 explanation of this remarkable behavior of largely ionized substances in 

 aqueous solution. Even if such a theoretical interpretation should not be 

 discovered, one may at least hope to determine with greater accuracy and 

 certainty the laws of the equilibrium between the ions and un-ionized mole- 

 cules, and between the two forms of the latter, in case their existence shall 

 be more fully substantiated. It is my conviction that at any rate we have 

 here to deal with a new kind of equilibrium phenomenon, and not simply 

 with some deviation of a secondary nature, arising, for example from a 

 somewhat abnormal osmotic pressure, or a change in the migration veloci- 

 ties of the ions, as has been assumed by most authors. 



In conclusion I desire to express to the authorities of the Carnegie 

 Institution my great indebtedness for the assistance rendered me in the 

 prosecution of these researches; for without such aid the progress made 

 would have been discouragingly slow. 



Research Laboratory of Physical Chemistry, 

 Massachusetts Institute of Technology, 

 Boston, June, 1907. 



