ABSTRACT
The method employed to determine the energy required to produce an ion in gases exposed to Rontgen rays depended on the measurement of the heating effect of the rays, and of the total number of ions produced by the radiation in the gas. The ionization due to the more penetrating rays is in general a small part of the total, especially for thin layers of uranium. From this it follows that the energy required to produce ions in the gases examined was, roughly, the same. The results on the ionization of different gases by the agency of Rontgen, Becquerel, and cathode rays all strongly point to the conclusion that the same energy is required to produce an ion whatever the gas. It is intended to continue these investigations on ionic energy for other gases besides air and carbonic acid. Some experiments made to see if a thermopile is suitable for a measure of the heating effect of X-rays.
