ABSTRACT
Author draws attention to the fact that the emanations of radium, thorium, and actinium were completely absorbed by cocoanut charcoal at ordinary temperatures. The have had occasion recently to repeat these experiments with much larger quantities of radium emanation and have found that the actual volume of emanation capable of absorption by charcoal at room temperature is very small. As the temperature of the bath slowly rose, the unabsorbed emanation was allowed to expand into an exhausted receiver of about 50 c cms. capacity. This was pumped out at different temperatures of the charcoal, and the emanation collected and afterwards measured by the δ'ray method. At - 5050˪ C. the amount of unabsorbed emanation was less than To per cent of the total. An experiment was shown to illustrate the rapidity of condensation of pure emanation contained in an exhausted vessel when one point was cooled to the temperature of liquid air.
