348 



Mr 0. A. Sadler on 

 Table IV. 



Tertiary 

 Radiator. 



Density 



of 

 Tertiary 

 Radiator. 



Atomic 

 Weight of 



Tertiary 

 Radiator. 



Absorption 



CoefRcient in 



Aluminium 



of the 



Homogeneous 



Secondary 



Radiator 



characteristic 



of the 



Absorption Coefficient in Air 

 of the corpuscular radiation 



excited by the Secondary 



Homogeneous Radiator from 



the following metals. 









Tertiary 

 Radiator. 



As. 

 296 



Sr. 

 200 



Mo. 







15-2 



Rho. 



Ag. 

 8-90 



Sn. 

 654 



Alumiuium . . 



27 



27 



* 



Iron 



779 



8-95 



55-9 

 636 



239 

 128-9 



30-2 

 30-4 



21-5 



20-8 



15-5 

 152 



10-9 



10-8 



8-84 

 8-81 



6-41 

 667 



Copper 



Silver 



10-57 



107-9 



6 75 



302 



21-2 



15-4 



103 



8-78 



6-63 





* The absorption coefficient of the homogeneous radiation from aluminium 

 has not yet been determined. 



Since the absorption coefficients o£ the radiation from 

 aluminium when both radiating surfaces are of aluminium 

 are the same as the corresponding coefficients when one of 

 the surfaces is replaced by iron, copper, and silver, respec- 

 tively, no correction is necessary in the determination of the 

 absorption coefficients of the radiation from these substances 

 due to the superposition of the corpuscular radiation from the 

 remaining aluminium surface. 



However, this point was tested for separately; the secondary 

 rays from silver were allowed to fall upon a copper ter- 

 tiary radiator, after passing through a thin copper window 

 substituted for the aluminium window used in the previous 

 experiments. No difference in the value of the absorption 

 coefficient could be detected. These results are shown in 

 Table V. 



Table V. 



Secondary 

 Radiator. 



/3, Absorption Coefficient in Air. 



Al Window. Cu Window. 





8-81 8-84 



i 





