On the velocities of ions in dried gases

Abstract

An account was recently given of a method by which the velocities of both positive and negative ions produced by Röntgen rays could be measured in very dry gases, and some measurements were given for ions in air. These measurements have now been extended to the cases of carbon dioxide and hydrogen, and some calculations, based on the work of Townsend, show that, while the positive ions retain a large envelope of matter even under the influence of a fairly large field of force, the negative ions become considerably diminished in size when their velocity is increased either by an increased force or by diminished pressure. While these results are in general accord with those of other observers, yet the point which has hitherto escaped notice is that the negative ions are far more readily deprived of their customary envelope in a very dry gas than in a comparatively moist atmosphere.