The problem of the electrical pumping of a dielectric liquid along lines of the applied field is considered experimentally. The pressure generated by typical pumps are studied in detail, often in novel fashions; e.g., by varying the liquid flow velocity, the electrode spacing, or the liquid temperature while the applied field is held constant. It is shown that the experimental data are consistent with an ion emission model of the phenomenon, but that the emission is not necessarily space‐charge‐limited; photomicrographs are presented to show the effects of the emission process on the electrodes.