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



7 elements (see Table XXII.) has been added, besides some 

 of the lines belonging to the X-series which has recently 

 been detected by Mr, Dolejsek* in this laboratory have been 

 added. The levels falling out between niton and xenon are 

 denoted in the figure with one dash, those which fall out 

 between xenon and krypton with two dashes. The diagrams 

 I, II., and III. have been thoroughly discussed in Part III.. 

 where a comparison of the experimental results and the 

 theory has been given. Here will only be added something 

 in connexion with the line L/3 7 , which has now been measured 

 for a great number of elements. This line is for all elements 

 rather faint, and becomes still fainter for the elements with 

 lower atomic number than Ba (56). As has been stated in 

 Part IV. § 7, for the elements with lower atomic number 

 than Ag, it could not be separated from /3 2 , which for these 

 elements has nearly the same wave-length as the I^-absorp- 

 tion edge. 



Table XXY. 

 Frequencies. 



L3- 



Ln^+Ma-]^ L x 



A, A 2 



66 Dy 571-09 



68 Br 611-91 



57427 (574-56) 

 615-73 (617-03) 

 680-62 (683-30) 

 72612 728-65 

 749-14 750-85 

 846-76 851-28 

 872-13 877-64 

 v 92363 932-16 

 950-26 959-54 

 1236-80 1263-20 



3-18 | (0-29) 

 3-81 (1-30) 

 3-55 (2-68) 

 2-82 2-53 

 2-69 1-71 

 1-83 4-52 

 1-36 5-51 

 0-99 8-53 

 0-04 i 9-28 

 -1-34 ! 26-40 



71 Lu 677-07 



73 Ta 723-30 



74 W 746-45 



78 Pt 844-93 



79 Au 870-77 



81 Tl 922-64 



82 Pb 950-22 



92 r 1238-14 





Table XXV. gives the frequencies of the line L/3 7 for the 

 elements Dy- U, and in the second column the sum of the 

 frequencies of the hx 1 and the Ma 2 line. The third column 

 gives the absorption-edge L 1# For TV to U Duane and 

 Patterson's values are used, for Ta I have used my value of 

 /3 5 , which must have nearly the same value as L|, for Lu, 

 Er, and Dy the values for L ± have been interpolated. Of 

 course, we cannot draw any certain conclusions from the last 

 values, but still it seems to me very improbable that the 

 frequencies of L 2 for Lu. Er, and Dy should be appreciably 



* Dolejsek, •' Nature/ cix. p. 582 (1922). 



