10 



ROYAL SOCIETY OF CANADA 



TABLE IV. See Figure 1. 



Radium in lead 1 cm. thick. 



Aluminium screens. Secondary radiators stated. 



TABLE V. See Figure 2. 



Radium in steel 2.2 cms. thick. 

 Aluminium screens. 



Thickness of screens 

 in mms. 







0.41 

 0.82 

 1.75 

 3.40 

 7.10 



Lead, 5 cms. 



17.8 



4.4 



2.21 



1.02 



.59 



.56 



Iron, 5 cms. 



10.4 

 4.70 

 3.56 

 3.41 

 3 28 

 3.04 



Brick, 6 cms. 



8 00 

 4 09 

 3 91 

 3 80 

 3 35 

 3 OS 



Radium in lead. 

 Lead screens. 



TABLE VI. See Figure 3. 



