The potential difference, E, between the two ends of a capillary, through which a steady flow of liquid was maintained, was measured by means of unpolarizable electrodes connected to a potentiometer circuit, and at the same time shunted through a known resistance, R. The value of R was varied from 1 to 98000 megohms. For each value of R there was a corresponding value of E, and a current, I (=E/R), through the resistance. The electrokinetic current, Ie, was obtained by extrapolating the plot of E/R versus R to the limit R=O