454 Dr. C. A. Sadler on Homogeneous 



The relative values of k calculated on the above assumption* 

 are given in Table III. 



Table III. 



^ T) o) 



Values of Efc, where L = -q .j- . 





Radiators which act as the source of homogeneous secondary 

 Rontgen Radiation. 



Tertiary 

 Radiators. 



Fe. 



216 

 25-3 

 584 

 131 



1 

 Co. 



53-9 



555 



130 



1 



JS T i. , Cu. Zn. 



As. 



Se. 



218 

 325 

 395 



Sr. 



Mo. 



Rho. 



Ag. 



Sn. 





850 



669 



545 



137 

 491 



278 

 430 

 436 



90-1 

 125 

 256 



39-4 

 56 

 141 



9-80 



1 



24-5 

 30-8 

 70-1 

 6-42 



18-8 j 

 23-1 

 48-8 

 5,2 



107 

 12-8 



44-6 



3-54 



Copper 



Silver 



536 



522 



510 



Aluminium... 



... 12-6 



12-1 11-9 11-2 



The corresponding values of k' for Iron and Copper a 



Tertiary 

 Radiators. 



re 



474 



140 



Iron 20-0 



I 

 Copper 1 ... 



51-4 



526 



403 



307 

 43-0 



137 96-0 

 390 267 



43-9 

 131 



18-3 ... 

 52 ... 



7-95 

 224 



— . 



























For either iron or copper as tertiary radiator, if we plot 

 the values of k corresponding to any particular secondary 

 exciting radiation against the absorption coefficients ot the 

 secondary radiation in aluminium, we get the curve shown 



in it g wiil be seen from the figure that for a given tertiary 

 radiator K 3 the value of k is very small for those secondary 

 Rontgen radiations which are softer than that characteristic 

 of R, When the secondary beam becomes just more pene- 

 trating an increase in the value of k is at once apparent, and 

 for a beam very little more penetrating the value ot k 

 assumes a maximum value many times its previous one. 

 For more penetrating beams the value of * decreases as a 

 linear function of the penetrating power of the exciting 

 radiation, while for more penetrating beams still the value 

 of k decreases more slowly, approaching a zero value tor an 

 exceedingly penetrating beam. It is possible, however that 

 at some later stage a further corpuscular radiation would be 

 emitted when a similar sudden rise and subsequent fall in 



