376 PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 



the numbers representing the increase in hoiHng points and the 

 lowering in freezing points, are abnormally great. Finally 

 Arrhenius in 1887 advanced his now classical theory, known as 

 the Theory of Ionization or of Electrolytic Dissociation, which 

 endeavors to account for the abnormalities of such solutions upon 

 the assumption that the molecules of acids, bases and salts, when 

 dissolved in water tend to dissociate or ionize into electrically 

 charged particles called ions. Each molecule dissociates into at 

 least 2 ions, the electric charges of the two being equal but 

 opposite in character. The ability of these solutions to conduct 

 the electric current is assumed to be due to the actual passage 

 of these ions with their charge of electricity through the solution. 

 The abnormally high boiling points and the abnormally low 

 freezing points of these solutions are explained upon the assump- 

 tions that each ion has the same effect as a molecule upon these 

 values. The dissociation of a molecule into 2 ions would there- 

 fore have the same effect as doubling the number of molecules. 

 The number of molecules dissociated in any solution increases 

 with dilution reaching a maximum only in very dilute solutions. 

 In ordinary solutions of electrolytes we are dealing, therefore, 

 not only with the molecules of the dissolved substances, but also 

 with the ions formed by the dissociation of a definite number of 

 the molecules present. It was at first supposed that the chemical 

 reactions of these solutions depend entirely upon the properties 

 of the ions present. We now know, however, that the molecules 

 themselves as well as the ions influence the course of the reaction. 

 The theory of Arrhenius has been .strongly contested by a 

 few investigators. Yet it must be said for it, that better than 

 any other theory yet brought forward it furnishes an acceptable 

 basis in accounting for the properties of electrolytes. As one 

 writer puts it, "This theory gives us a working picture of the 

 peculiarities of the class of substances known as electrolytes. 

 This picture has already been considerably modified since it was 

 first drawn and will no doubt be further modified in the future. 

 At many points it is unsatisfactory for it has to do with one of 

 the most complicated provinces of chemistry. It has, however, 

 stimulated a vast amount of research, has greatlv extended our 



