4 Makowkk, Volatility of Radium A and Radium C. 



activity falls to a somewhat lower value before becoming 

 constant than when the exposure is carried out at the 

 temperature of the room. This is no doubt due to the 

 fact that 710^ C. is above the volatilisation point of 



100 





< 



20 Jo 40 5a 



TIME m MINUTES 

 /'isy. 2. 



60 



radium B, which cannot therefore be deposited on the 

 rod. That the temperature of volatilisation of radium B 

 is below 710' C. is further confirmed by the fact that above 



