206 t/. Stanley Rogers: High Frequency Spectra. 



difference between the two configurations, the following formula 

 is obtained: — 



a' 



where>4 = 3,/-8,F, = (N-S,.l)^ F,=^(N - k+l-S,^,)\F,= {^ -S,)\ 

 and the S terms are obtained from 



For Pt. this gives the values of X.Ka^ as 1841 x 10^ cm. The 

 agreement with the observed value is remarkable, as the formula 

 is a rational relation. This lends additional support to the Bohr- 

 Sommerfeld theory of the atom. 



Sommerfeld has also obtained the following formula for the 

 difference in wave number Av for the lines of the Ka doublet : — 



^^ _A,, n ■5al( N-3-5) ^ 53aM N-3>5r . 



(N - 3-5) 

 where Az^h= frequency difference for hydrogen = -^♦ 



From the results of the experiment, given in Table II., Az; x 10* 

 = -126d=-008, while the above formula gives Az; x 10^=:-135±-002. 



It will be seen that the agreement is again fairly good. 



In conclusion, the author wishes to express his indebtedness 

 to Prof. T. H. Laby, M.A., Sc.D., F. Inst. P., for his invaluable 

 guidance and advice throughout the whole of the research, and 

 in the writing of this paper. 



The Gundelach tube used in these experiments was presented 

 to the Natural Philosophy Department, Melbourne University by 

 W. Watson and Sons. 



