This subject has occupied a dominant position in physico-chemical research since the investigations of van't Hoff and Arrhenius.
Van Hoff pointed out that measurements of osmotic pressure confirmed this value in the case of dilute solutions of cane sugar.
Van 't Hoff's formula is equivalent to taking the frequency of dissociation as proportional to the square of the concentration of the molecules, and the frequency of recombination as proportional to the cube of the concentration of the ions.
This influence extended from Germany to Denmark, where it was embraced by Hoff ding, and to England, where it was accepted by Romanes, and in a more qualified manner as " a working hypothesis " by Stout.
The conception of a semi-permeable membrane, permeable to the solvent only, was used by van't Hoff as a means of applying the principles of thermodynamics to the theory of solution.