116 Dr. Russell and Mr. Chadwick on the y Rays of 



necessary to employ a temperature greater than 1100°, but 

 in hydrogen it can be volatilized in a short time at 900°. 

 The second o£ these facts was used in transferring radium E 

 from metal to metal in connexion with the work o£ Rutherford 

 and Richardson *. 



The apparatus used in volatilizing these substances is 

 shown in the figure. 



rr 



E F 



ABC is a thick porcelain tube, 25 cm. in length and 

 2*4 cm. inside diameter, closed at one end B. The other 

 end is closed by an ebonite cork D through which a brass 

 cylinder passes centrally. The diameter of this cylinder is 



* Phil. Mag. vol. xxvi. p. 324 (1913). 



