DE. W. M. HICKS: A CEITICAL STUDY OF SPECTEAL SEEIES. 
G9 
Ga. 
i 
In. 
Si. 
So. 
Si. 
So. 
(2) 4172-25 
4033-19 
(2) 4511-44 
4101-87 
2780-28 
2718 
2932-71 
2753 - 97 
2481-1 
2601-84 
2460-14 
2468-09 
2340-30 
2399-33 
2278-3 
2357-7* 
2241-6 
2332-2 
2218-3 
2200-0 1 
* 1 8-7 
2191-2 
Tl. 
Si. 
So. 
Pi. 
Ps. 
(2)5350-65 
3775-87 
(2)11513-22 
13013-8 
3229-88 
2580-23 
6549-99 
6713-92 
2826-27 
2316-01 
5528-118 
5584-195 
2665 - 67 
2207-13 
5109-65 
5137-01 
2585 - 68 
2152-08 
4891-3 
4906-5 
2538-27 
2119-2 
4760-8 
4768-7 
2508-03 
2098-5 
4678-3 
2487-57 
2083 - 2 
4617-4 
2472-65 
2072-4 
4574 - 8 
i 
2462-01 
2453-87 
2447-59 
1 
2442-24 
1 
The lines for MgS and CaS were first allotted by PtYDBEEG"^ in his original memoir 
presented on November 13, 1889, to the Swedish Royal Academy. The values are 
the observations of Kayser and Runge (‘ Ann. d. Rhys.’ (3), 43, p. 387, 1891). In 
the same paper Kayser and Runge observed Sr (2, 4, 5), but they were arranged in 
the series by Rydberg (‘ Ann. d. Rhys.’ (3), 50, p. 629), who pointed out that there 
ought to be a set 3865‘39, 3807'37, 3780'47, and that they were probably hidden by 
strong Cyanogen bands. This was afterwards fully confirmed by K. and R. {‘ Ann. 
d. Rhys.’ (3), 52, p. 115). The first lines of the series were first observed by 
Lehmann (‘ Ann. d. Rhys.’ (4), 8, p. 647, 1902), but the more accurate values of 
Saunders (‘Astro. Rhys. Jour.,’ 32, p. 170) are inserted in the list. In the case of 
Ba the second triplet and the first of the next two were observed by K. and R., but 
‘ Kongl. Svensk. Vetens. Akad. Hand.,’ Bd. 23, No. 11. In this memoir, which laid the foundation 
of what is known as to series relationships, the material is chiefly due to the observations of Thalen, of 
Hartley and Adeney, and of Liveing and Dewar. 
