﻿and the Theory of Atomic Structure. 



Table XXIV. 



Frequencies. 



559 



014 



Cs 



13a 



La 



Ce 411-95 



Pr 429 43 



Nd 44696 



Sm 483-40 



Eu 502-08 



Gel ' 521-25 



Tb 54077 



Dy 56076 



Ho ' 581-48 



Er 602-70 



44437 

 464 42 

 484-63 

 527-20 

 549-18 

 57208 

 595-09 



643-56 



7io 



/3 2 -/3 14 



ri-ro 



72-Tio 



407 39 







0-84 



425-78 







1-25 



444-92 







1-44 



46439 



150 



1-37 



1-44 



484-44 



1-45 



1-26 



1-53 



505-64 



1-63 



1-67 



1-58 



54920 



1-82 



1-66 



1-12 





1-89 



1-67 







1-89 



1-52 







1-97 



1-84 







1-83 









1-50 



080 







0-54 







were not especially good. For Ce they are very weak, lying 

 on the long wave-length side of /3 2 and 7^ From Ce down 

 to Tb they get more intense (for Tb they are of about the 

 same intensity as /3 4 ) at the same time as their frequency 

 difference with the lines /3 2 or ry x slowly increases. For the 

 elements with higher atomic number than Tb, these differ- 

 ences rapidly decrease, whereas their intensity relatively to 

 the other lines remains nearly the same. For the elements 

 Ho and Er they could not wholly be separated from /3 2 and 

 7, ; for these elements the values o£ their wave-lengths were 

 roughly calculated from the broadening of /3 2 and y } . For 

 Yb (70) and Lu (71) /9 14 and y 9 had wholly disappeared. 

 For Dy /3 14 could not be observed, as for this element the 

 tungsten Lc^ line was appearing on the long wave-length 

 side of /3 2 As is seen from Table XXIV., the frequency 

 difference 71-79 seems to be somewhat smaller than the 

 difference /3 2 -/3 u . 



A very remarkable line is 7 10 , which appeared for the first 

 time for Cs at the long wave-length side of y 2 . It is a rather 

 intense line, being more sharply limited on its short wave- 

 length side than on the other side. As is shown in 

 Table XXIV. its frequency difference from y 2 increases first 

 with increasing atomic number, but for elements with higher 

 atomic number than Nd the same difference rapidly decreases, 

 so that this line could not be separated from y 2 for elements 

 with higher atomic number than Sm. But up to Er (6$) 

 72 was somewhat broadened and diffuse on the long wave- 

 length side, indicating that also for these elements y 10 is still 

 present. For the elements Nd-Cs, where y l0 was wholly 

 separated from 7 2 , the latter line appeared to be a faint, but 



