The double layer theory of Otto Stern may be briefly summarized as follows (7, 12,14). The theory of Helmholtz gives values for the capacity of the double layer which agree approximately with those obtained from electrocapillary experiments. However, owing to kinetic heat motion, the double layer ions facing the liquid cannot have the distribution postulated by Helmholtz. On the other hand, Gouy's (6) theory, which is based on the existence of a diffuse double layer, gives values for the capacity which are far too great. Stern develops his concept of the double layer in this manner: 311