The dependence of the measured electric strengths of liquids on electrode spacing

For some twenty-five years the decrease in the measured electric strength of liquids with increasing electrode spacing has been an important subject of study because of its practical as well as theoretical significance. Early investigators were handicapped by the lack of reproducibility of electric strength values as well as their inability to measure accurately small electrode spacings. With the recent development of a reproducible pulsed-voltage technique (1) and a means of determining small electrode separations (1-10μ) by capacitance measurement, we have re-examined this phenomenon using several carefully purified hydrocarbons as the liquid dielectric. Our measurements extend and, in some cases, supplant those of Edwards (1) and Goodwin and MacFadyen (2).