﻿558 



Mr. D. Coster on the Spectra of X-ray i 

 Table XXII. 





Wave-lengths. 



Frequencies. 



77 



7s 



yr 



78 



78-07 



0i-. 



56 Ba 



2218 



2029 



1942-2 



1859 



1644 



1211 



2218 

 2019 

 1932-2 



1629 

 1202 

 1117 

 1079 



410-82 

 449-22 

 469-20 

 490-20 

 554-18 

 752-32 



410-82 

 451-24 

 47162 



559-23 



758-02 

 815-83 

 844-56 



27-22 

 32-51 

 35-06 



48-47 

 80-96 

 92-53 

 9811 



27-74 

 32-35 

 35-02 



4717 



81-12 

 92-68 

 98-54 



58 Ce 



59 Pr 



60Nd 



63 Eu 



71 Cp 



73 Ta 



74W 





never observed by the author for elements with higher 

 atomic number than 74. y 7 is not only an extremely weak, 

 but also a rather diffuse line, which for the heavier elements 

 lies rather close to the very intense line y lt This makes it 

 nearly impossible to be sure of the existence or non-existence 

 of this line for the heaviest elements. 



§ 11. Tables XXIII. and XXIV. give some lines denoted 

 as j3 u , 79, and y 1Q , which were only observed in the region 

 of the rare earth metals. Their appearance seems to be 

 connected with the change in the X-shell of the atom, which 

 we must expect in this region according to Bohr's theory 

 (compare Part III. § 8). For Ba the lines /3 U ancl y$ do not 

 exist, neither were they observed for La, but here the plates 



Table XXIII. 

 Wave-lengths. 





/3u 



79 



7io 



&.<*) 



55 Cs 



2212-1 

 21220 



2038-8 



1885-1 



1781-4 



1748-1 



16851 



16251 



1567 



1512 



2051 



1962-2 



18804 



1728 5 



1659-3 



1593-6 



1531-4 



1416 



2236-9 

 21402 

 20481 

 1962-3 

 1881-1 

 18022 

 1659-3 



::: 



1987-1 

 1909-2 

 1835-5 

 1765-5 

 1699-2 

 1635-5 

 1575-6 



56 Ba 



57 La 



58 Ce 



59 Pr 



60 Nd. ...;.... 



62 Sra 



63 Eu 



64 Gd 



65 Tb 



66 Dy 



67 Ho 



68 Er 





