X-Rays from Boron and Carbon. 147 



Apparatus. 

 Two slightly different types of apparatus were used in the 



Fio-. 1. 



• z 



To . electrometer 



To earth 



(N,\) ; 



Q L 





1 



-1-600 volts 



z /8 volts 



-18 volts 



7 



To trap and 

 pump 



To electrometer 



To earth 



To liquid air 



trap and 



pump 



Charcoa/ 



course of the research. In the first type the tungsten leads 



L2 



