Secondary y Radiation. 229 



directly by placing the absorber against the electroscope or 

 indirectly by placing the absorber in front of the emanation. 



Fig. 1. 



BALANCE CHAMBER 



S=I 



ijl] $fe-*I9EA/mi 



-$r-^70£**TH, 



Electroscope and Balance- chamber 



Fig. 2. 



RfiDIA TOR 



Experimental arrangement for the examination of the 

 secondary y radiation. 



