and the Theory of Atomic Structure. 



1095 



new lines, which possibly may exist for some elements (one 

 between j3 Q and /3 2 and one between u ± and /9i) will be studied 

 in connexion with an investigation of the elements Ta-Ba 

 and Rb-Cu. 



§ 9. Tables XI. and XII. give the characteristic absorption 

 discontinuities in the L-region for Ba, Cs and Ag, and the 



Table XT. 

 Wave-lengths. 





h 



ft 



L, 



7i 



^3 



73 



74 



56 Ba 



23567 



(2348) 



2399-3 



2198 

 (2194) 



2236-60 



(2063) 



2129-5 



2071-5 



55 Cs 



2466 

 (2459) 



2506-4 



(2299) 



2342-52 



(2157) 



2227-1 



2169-4 



47 Ag 



3684-4 



3893-83 



3504-7 



3514-85 



3260-5 



3299-7 



Table XII. 

 Frequencies -^ 





&i 



fc 



L, 



7i 



L 3 73 



74 



56 Ba 



386-67 

 (388-1) 



379-80 



414-67 

 (415-3) 



407-42 



(441-7) 427-92 



439-91 



55 Cs 



47 Ag 



369-50 

 (370-6) 

 247-33 



363-58 

 246-69 



(396-4) 

 260-01 



389-00 



(422-5) 409-18 



42011 



259-15 



279-48 276-17 



1 



shortest wave-lengths of the emission spectrum which belong 

 to each of them. The absorption wave-lengths of Ba and Os 

 were accidentally found on tlie same plates on which the 

 emission spectra were taken. Tiiey were obviously due to 

 the selective absorption of trie heterogeneous radiation of the 

 copper anticathode, in the Ba and Cs salt used on the anti- 

 cathode. Hertz's values * are added in parenthesis. They 

 differ from ours by about 7 X.U. in the mean. The absorp- 

 tion spectrum of Ag is determined with a gypsum crystal, 



* Zeitschr. fur Physik, iii. p. 19 (1920). 



