﻿566 Mr. D. Coster on the Spectra of X-rays 



slightest indication o£ anomalies in this region for chese 

 satellites. Therefore, we may assume that there exists no 

 simple numerical relation between the satellites on the long 

 wave-length side and those on the short wave-length side of 

 /3 2 and y v 



It is difficult to say whether the line denoted as fy 10 should 

 be connected with y 2 or with <y z . As <y 10 gets closer to y 2 for 

 elements with higher atomic number than Nd, and finally 

 coincides with this line without crossing it, we are inclined 

 to assume that y 10 is only connected with y 2 - 



We might expect to meet such anomalous satellites as 

 those described in this paragraph in other regions of the 

 periodic system where an inner shell of electrons is being- 

 completed. Thus, in the case of the elements in the region 

 of the palladium group, we should expect anomalies for 

 Ly 2 , 3 , L/3 2 , and L71, and for K/3 2 . The authors who have 

 investigated the K-lines in this region do not mention any 

 anomaly for K/3 2 . This line, however, is very faint. As to 

 Ly 2 , 3 , it might be that the lines X = 3651 and 3631 for Rh 

 and A = 3450 and 3433 for Pd are such anomalous satellites of 

 7 2 ,3 (compare Part III. § 5) ; but they lie on the short wave- 

 length side of this line. For the lines L/3 2 and hy l in this 

 region no new satellites have been found up to the present. 

 It should, however, be worth while investigating this region 

 again with quartz * as analysing crystal, making use of the 

 Imperial Eclipse photographic plates. 



Further, we might expect anomalous satellites in the 

 region of the iron group, where, according to Bohr, the 

 M-shell develops from a shell containing four 3 2 electrons 

 into a shell containing six 3 l5 six 3 2 , and six 3 3 electrons. 

 In this region Hjalmar f actually observed a satellite on the 

 long wave-length side of K/3 1? which he denoted as ft'.. 

 Wentzel J has already suggested that the appearance of this 

 line should be connected with the development of the 

 M-shell. In their recent paper Siegbahn and Dolejsek 

 observe that this line is much broader than the breadth of 

 the slit of the spectograph, and that it was not possible to 

 separate this line from Ky^. From this and from the 

 theoretical interpretation of this line (see Part V. § 9) we 

 might conclude that it is hardly probable that this line is 



* As has been pointed out by Prof. Siegbahn, the grating constant of 

 this crystal lies between those of gypsum and calcite, making it especially 

 adapted for the region of wave-length in question. 



t Hjalmar, Phil. Mag. xli. p. 675 (1921). 



% Wentzel, Annalen d. Physik, lxvi. p. 437 (1921). 



