334 



Dr. J. R. Rydberg on the Structure of the 



As an example of the series and their calculation, the prin- 

 cipal series of IA is as follows : — 



109721-6 



Formula: n=4348 



t ( 



(wi+0-9596) 2 



m... 1. 2. 3. 4. 



5. 6. 7. 



8. 9. 



\ obs. 



6705-2 



3232-0 2741-0 2561-5 



2475 -0 2425-5 2394-5 



2373-5 



2359-0 



X calc. 



6704-8 



3229-S 2740-5 2562 3 



2475-3 2425-9 2394-9 



2374-1 



2359-5 



Diff. 



-0-4 



-2-2 -0-5 +0-8 



4-0-3 +0-4 4-0-4 



+0-6 +0-5 



3. The different series of the elements are related to each 

 other in a way which proves that they all belong to one system 

 of vibrations. .To show these relations. I will cite as an 

 example the formulae of the diffuse and sharp lines of Xa : — 



First series 



Second series 



Diffuse Group. 

 .... n =24451 -5- 



... »=24496-4- 



109721-6 

 (//> 4-0-9887) 2 * 



109721-6 

 {m +0-9887)- 



=24485 



n= 24500-5- 



Sharp Group. 



109721- 



(/7*+0-6445) 2 

 il 9721-6 



| .;; -0-6445,-' 



The series of the same group) (diffuse or sharp) have the 

 same value of fi ; the difference of their values of ??,-, is equal 

 to v or (y x and v. 2 ). This follows from the fundamental pro- 

 perty of the doublets. With Xa we have i*=14'6. 



The series of the same order {first, second, third) have the 

 same value ofn Q in the different groups', they are distinguished 

 by the values of /i. The difference, for instance, of the num- 

 bers 24481*8 and 24485"9 3 which are perfectly independent of 

 each other, amounts only to 0*7 tenth-metre. TVe find in all 

 the revised spectra the same accordance when we calculate 

 the values of n . using only the last terms of the series. For 

 example, if we denote the values obtained from the diffuse 

 series by n t and those from the sharp series by n 2 : — 



Element .. 



Li. 



Mfr 



Ccl. 



Tl. 



7 h 



n 2 



28598-5 

 286011 



39777-9 

 39779-9 



40775-9 

 40789-1 



414559 

 41456-5 



