The Role of the Cation in the Electrical Double Layer

The differential capacity of a number of tenth‐normal aqueous solutions of metallic chlorides has been measured as a function of potential. The results are interpreted to mean that the solvent sheaths on the positive and negative ions are displaced as the ions approach the interface. New explanations are given for several well‐known phenomena connected with the double layer. The surface charge density and integral capacity of the non‐diffuse part of the electrical double layer have been calculated from these data. The ratios of the differential capacities have been found to approach unity at potentials where the concentration of cations within the double layer is at a minimum.