IN a previous paper (Trans., 1905, 87, 987) attention was directed t o the fact that the solubility of a sparingly soluble acid is markedly increased in presence of the sodium salt of a weak acid, and the experimental data then communicated showed t h a t the magnitude of the influence of the sodium salt is closely related to the strength of the acid from which it is derived. The solubility of benzoic acid, for Solubility of S p r i n y l y Soluble Acids. Part IT.