ABSTRACT
The heating effect of 30 milligrammes of pure radium bromide was first measured in a differential air calorimeter. The radium bromide was then heated to a sufficient temperature to drive off the emanation, and the latter was condensed by passing through a short glass tube immersed in liquid air, and then the tubes were sealed off. The amount of emanation from 30 milligrammes of radium bromide, when collected in the tube, was sufficient to cause bright phosphorescence in the tube, but it was too small either to measure or weigh. The amount of heat emitted from the radium emanation is thus enormous compared with the amount of matter involved. Experiments are still in progress to determine the rate of recovery and loss of heating power of the de-emanated radium and the separated emanation respectively, but so far as the observations have gone, the curves of decay and recovery are the same as those for the corresponding a radiation.
