II. Electrical conductivity in gases traversed by cathode rays

Though it has been known that a gas becomes a conductor when traversed by cathode rays, yet the laws connecting this electrical conductivity have not hitherto been studied. The theory has been put forward by J. J. Thomson and Rutherford* that when a gas becomes a conductor under a radiation, it does so in virtue of the production of positive and negative ions throughout its mass. This view has been established by their experiments on Röntgenised gases, and confirmed by those of Zeleny on the same subject. The recent work of Rutherford on Uranium Radiation also affords another example of such a process in the gases traversed.