STUDIES ON ELECTROKINETIC POTEKTIALS. The Temperature Coefficient of the l-Potential*
1'11
BY HENRY B. BULL AND ROSS AIKEN GORTNER
Historical Burton' determined the velocity of migration of silver particles in water a t 11.0' and 21.0' C. He found that the velocities of the particles were 19.6 X IO-^ cm./sec. and 25.2 X IO-^ cm./sec., respectively, at these two temperatures, indicating a decided temperature coefficient, However, when these values were multiplied by the corresponding viscosities for these temperatures, he obtained 0.251 and 0.250 respectively. Cruse2 studied the electro-osmosis of distilled water through diaphragms of clay between 10' and 60'. He found a marked maximum for the rate of flow of water at about 38.0'. He did not correct for the change of conductivity, the viscosity, or the dielectric constant with the temperature, which as has been pointed out by Smoluchowski3 must be taken into consideration. Gee and Harrison4found with the streaming potential a decided maximum for H/P around 40' for wool, cotton, and silk against distilled water. Their experiments cover a range from 16' to 84". They made no efforts to correct for the change of the conductance, the dielectric constant, or the viscosity, but they do point out that the factor qK/D, where q is the viscosity, K the specific conductance of water, and D the dielectric constant is approximately a constant from 15' to 70'. These results would indicate that the observed changes in H/P are accompanied by a corresponding change in the
