1920. No. 2. 



ON THE X-RAY SPECTRA. 



35 



Puttincr: 





Vi — I = c- 



d = N 



.c-\-(gj— i)b —Qj a c2 4- {Qj — i) 62 — g^. a'- 



,(26b) 



In the case of Ko, K^ and L^^ we get : 



This formula shows that the quantity d is not constant but increases 

 with atomic number. The formula is not exact, because the variation of 

 mass it disregarded. 



Having previously calculated the frequencies for the three lines we 

 can from these values find d. Now on the other hand the frequencies 

 derived from observations do not fulfil Kossel's relation identically. 

 They show, in fact, a deviation which is too great to be due to errors 

 of experiment. 



In the Table XVIII are given calculated and observed values of the 

 deviation d for the lines Kg, K^ and L^. 



Table XVIII, 



I appears from the table that the calculated and observed values of 

 d both as regards sign and absolute magnetude agree in a very striking 

 manner. The observed values of d increas with atomic number in the 

 way required by theory. 



This fact that our theory is able to explain the deviation from 

 Kossel's relation is a matter of the greatest importance and weighs 

 heavily in favour of the assumption of recombination from secondaries 

 in its modified form. 



