()44 Dr. Marine Siegbahn on 



For comparison, the measurements of other authors are? 

 oiven in the following table : — 



Table IV. 



Ledoux-Lebard 

 and 



de Broglie. Hull & Rice. A. Dauvillier. E. Dershem. Siegbahn.. 



Iv« L> 1 218 212-8 212-4 213-52 



Ka[ J ~ ° 214 205-3 207-6 208"85 



K/3 X 177 192 182-6 183-4 184-36 



K/3 2 — — 176-8 178-4 17940 



The Jj-series. 



The measurements of the L-group were carried out with 

 the vacuum-spec tro graph described in Part I. of this paper. 

 For the exposition of all spectrograms here used, my thanks 

 are due to Mr. Nils Stensson. 



All the stronger lines of the group, namely a. 2 u l fii /3 2 

 and <y l , were separately determined ; in all cases more 

 spectrograms were taken and some of these lines, as shown 

 in the following tables, were analysed both with calcite 

 and rock-salt. As generator for the X-ray spectrum a 

 tube was employed wholly of metal, with hot-wire cathode 

 as described in the earlier paper. The anticathode was 

 plated with a piece of tungsten, which Dr. Waldemar Ponlsem. 

 of Copenhagen, had kindlv placed at my disposal. Some of 

 the fainter lines (marked [ ] in Table VII.) obtained may 

 possibly be due to other substances. 



The results for the stronger lines were as follows : — 



Table V. 



Calcite PI. 5 14° 4' 33"-6 14° 11' 4"-3 



„ PI. 6 14 4 37-8 14 11 5-4 



Rock-salt, ... PL 8 15 10 40-2 15 17 36-1 



... PI. 9 15 10 41 -4 15 17 40 -4 



L&. 'LA. 



Calcite PI. 2 12° 11' 24"-5 11° 49' 48"-0 



„ PL 4 12 11 19-6 11 49 45 -7 



Eock-salt ... PI. 12 13 8 11 -0 12 44 46-0 



... PI. 13 13 8 19 -7 12 44 59 7 



Lyx. 



Rock-salt ... PI. 27 11° 13' 32"-4 



... PI. 28 11 13 31 -8 



... PI. 29 11 13 31 -8 



PL 30 11 13 19 -8 



Mean 11° 13' 29"-0 



