﻿Electric Source, and Line Spectra. 



Ill 



observed wave-lengths (to five figures only), with the usual 

 short denominations of the hydrogen lines ; and finally, the 

 fourth column, the differences, A = \ ca i c> — \ oba ,, in Angstrom 

 units. The symbol A B stands for Balmer's " theoretical 

 end," if we are to translate literally the name used by 

 Germans. The constants, at the top of each table, are given 

 in microns. I should like to remark that the tables are 

 numbered, not according to the importance to be attributed 

 to the degree of agreement attained, but simply in their 

 chronological order. 



Table I. 



7=-3660 8 ; 



^ =4-1200 



«= -3-2398. 



i. 



i calc. 



X oba. 



A 



3 



•4336 8 



•4340 7 H y 



-39 



4 



•4097 6 



•4102 3 § 



-4-7 



5 



•3965 2 



•3970 2 e 



-50 



6 



•3884 4 



•3889 2 1 



-4-8 



7 



•3831 6 



•3835 G n 



-4-0 



8 



•3795 5 



•3798! 



-2-6 



9 



•3769 5 



•3770 8 , 



-1-3 



10 



•3750 5 



•3750s K 



+0-2 



11 



•3735 8 



■3734. x 



+ 13 



12 



■3724- 



•3722 p 



+25 



13 



•3715 9 



•3712, v 



+38 



14 



•3708 3 











15 



•3702 5 



•3704 g 



-1-5 



16 



•3697 6 



•3697, 



+04 



17 



•3693 c 











18 



•3690 2 



•3691 7 v 



-1-5 



19 



•3687 3 



•3687, p 



+0-2 



20 



•3684 7 



•3682, ff 



+ 1-8 



00 



•3660 a 



•3661. H 3l 



-0'4 







•3646!= X B 





It will be noticed that the theoretical "lines" \ u and A 17 

 are superabundant * ; such would be also\ 2 iJ ^m coincides 



* The first of these may also be coordinated with ffr, giving 

 A=+4-3. 



