ABSTRACT
This chapter provides the results of detailed investigation of the radioactivity and emanating power of thorium compounds. The results have led to a theoretical interpretation of the processes involved which give rise to the phenomenon of natural radioactivity. If the recovery of the activity of thorium with time is due to the production of ThX, the active constituent of thorium, it should be possible to obtain experimental evidence of the process. The first point to be ascertained is how far the removal of ThX by the method given reduces the total radioactivity of thorium. The curves of the recovery and decay of the activities of thorium and ThX with time suggested that the radioactivity of thorium was being maintained by the production of ThX at a constant rate. Uranium and thorium possess the property in whatever molecular condition they occur, and the former also in the elementary state.
