X. On the laws governing electric discharges in gases at low pressures

Abstract

The researches of recent years have conclusively settled the general connection between the spark potential and the pressure of a gas. It is now well known that as the pressure of a gas diminishes the difference of potential necessary to produce a discharge between electrodes in the gas, a fixed distance apart, also diminishes, until, at a critical pressure, the spark potential reaches a minimum value. It is further established that below the critical pressure the potential difference required to produce discharge rapidly increases as the pressure is lowered. This connection between the spark potential and the corresponding pressure of a gas has been well illustrated in a series of curves drawn by Peace, who investigated the sparking potentials between a pair of parallel plates at pressures ranging from one-half an atmosphere down to a little below the critical pressure.