Ionization of mercury vapour by positive ions of mercury and potassium

Abstract

It was postulated by Townsend some thirty years ago that ionization of gases by positive ions played an important part in a self-maintained electric discharge through a gas. There was, however, no direct experimental evidence in favour of this hypothesis. Very few experiments have been done so far in connection with the solution of this problem and it appears that no satisfactory method has been devised to investigate it. The experiments of Sutton which showed that positive ions of potassium of energy above 100 volts ionized neon and argon are not conclusive, since the results obtained can be explained in terms of the secondary effects caused by the impact of primary positive ions and excited atoms upon different parts of the apparatus.