Radium Emanation hij Coconut Charcoal. 787 



shown in the accompanying diagram (fig. 3). When the 

 brine had been boiling for some time the clip T was opened, 



Fig. 3. 



air bubbled through the solution, and the emanation drawn 

 off from the solution and collected in the aspirator A and 

 tested in the usual way. 



Table IV. gives the results, the leaks being reduced to the 

 same electrometer sensitiveness as before. The last column 

 is calculated from the second, by the help of tables similar 

 to those given in my earlier papers *. 



Table IV. 



Interval solution 

 had been resting 

 since last heating. 



Emanation 

 generated in 

 this interval. 



Emanation 



generated in 



21 hours. 



20£ hours. 



71 



7-3 



m „ 



200 



67 



23* „ 



8-4 



7-4 



2-H „ 



8-4 



7-4 



47^ „ 



140 



67 



Mean 



71 



The radium generates therefore an amount of emanation 

 represented by 7"1 in 21 hours ; and with an air-stream of 

 •48 litre per minute the charcoal in (silica) tubes catches only 

 * See also Kolowrat, Le Radium, 1909, pp, 193-5. 





