ABSTRACT
The effect of the continuous production of the emanation on the radioactivity of radium will now be considered. Solid radium bromide, in a dry atmosphere, gives off very little emanation into the air. This is not due to stoppage of the production of the emanation, but to its inability to escape from the mass of radium. The emanation is stored up or occluded in the solid, and can only be released by heating or dissolving the radium. The activity of the radium is at once diminished, and in the course of four or five hours reaches a minimum value the activity, measured by the rays, possessing only one-quarter of its original value. Let us now consider the emanation which was separated by heating the radium. In a closed vessel, its power of discharging an electrified body at first increases for several hours. The emanation loses its activity in a geometrical progression with the time.
