410 



Dr. Barkla and Mr. Sadler on Secondary 



The curves obtained are given in fig. 1. The true relative 

 absorptions by various substances are not here exhibited as 



Fig. 1. 



50 



55 60 65 



/froM/c We/ cut of /?aoi/}tor 



the] absorbing plates varied in thickness. The thickness of 

 each is given in the figure. The absorption of the radiation 

 from nickel by each absorbing substance is shown by a 

 horizontal line cutting the corresponding absorption curve. 

 Thus, by interpolating the experimentally determined absorp- 



