THE STRUCTURE OF THE SERIES OF LINE- AND BAND-SPECTRA. 563 
geneous character of what to all appearance seems a single series can be proved. 
Leaving this point in abeyance for the present, we shall disregard the two discrepant 
series. 
13. Aluminium. Indium—continued. 
2. Supsmpr1ary Series (1st Component). 2. Sussip1aRyY SERIES (2nd Component). 
Jog a, = 4°94086 — 10 are ag 2 irene Sie aerons 
log 0,=4°82757,-10 9” He GN Sera Re 
Obs. == Tea 
Oe (m+p)|  v obs. PURI ctr K-R. 
(m+ p)| — v obs. CORN her K-R. 
2°45 24379 24379 0 — 333 
2°4 25242°2 | 25242°2 00 — 338° 3°45 36311 36311 0 0 
3°4 37587°3 | 37587°8| —0°5 0:0 4-45 40648 40648 0 0 
4-4 42043°6 | 42043°9| -0°3 0-0 5°45 42730 42729 + 1 0 
54 44172°0 | 44171:4| +06 0:0 6°45 43891 43891 0 - 2 
6°4 45356°7 | 45356°8| -—1:0 + 17 7°45 44611 44609 + 2 + 2 
8°45 45080 45082 - 2 - 6 
9°45 45455 45412 + 43 + 39 
15. Thallium. 
14. Indium. 1, Supsiprary Series (1st Component). 
log a, =4:94304 — 10 
1, Sussm1ary Series (2nd Component). ie 7 2 ee Laie Veo = 415117 
log a, =4°92091 —10 
3) 46 4 | 
log b, = 4°41282,, - 10 ee lee a) pee a eee) Ob” aha 
les ; i Comp. ; 
Obs. — 
(m +p) v obs. vy comp. Garant K-R. Be 98339 98339 0 0 
4:0 34228 34227 | + 1 + 1 
5:0 | 36887 36887 | 0 - 2 
3°0 32900 32900 0 0 6:0) | 38316 |) 38314 + 2 0 
4:0 39060 39060 0 0 %0 39168 39168 0 + 2 
5:0 41847 41847 0 0 8-0 39722 39721 | + 1 + 5 
6:0 43350 43345 +5 +11 90 40096 40098 - 2 + 3 
7-0 44236 44243 -7 + 2 10:0") 40362," 9+ 408635) a1 - 1 
8-0 44825 44823 | +2 +16 11:0 40559 40567 8 - 4 
9:0 45224 45220 +4 +20 12:0 40708 40718 | -—10 - 7 
10°0 45506 45502 +4 +19 13:0 40824 40836 -12 -1l 
11:0 45714 45713 +1 +17 14:0 40916 40929 | -13 -13 
12:0 45871 45872 -l +13 15:0 40991 41005 —14 —16 
To complete our investigation of the line-spectra we will now discuss the line-series 
observed by Runce and Pascuen in the spectra of Oxygen, Sulphur and Selenium 
(Astrophysical Journal, vol. viii.), and in the spectrum of Helium (Kayser, Handbuch, 
pp. 560-1). The comparison of these series with the RypBERG-THIELE formula is specially 
Interesting, not only on account of the extreme accuracy of the observations which 
thereby afford a valuable test of this formula, but still more because it had been 
