DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 
65 
The D Series. 
' (16107-45) 
2050-27 
18157-72 (4) 
832-00 
18989-71 (6) 
12-31 
12-31 
7n = 3 < 
(16119-76) 
2050-27 
18170-03 (8) 
3-34 
16123-10 ( 10 ) 
^ (18510-67) 
2050-27 
20560-94 (2) 
II 
1-75 
18512-42 (8) 
m = 5 
19804-02 (1) 
ni = 6 
(20582-97) (X = 
4857-05) ? hidden by X = 4856 
25 (8) 
m =■ 7 
21089-93 (2) 
m = 8 
21438-12 Exner and ITaschek’s arc. . 
The 
S Series. 
m = 3 
(14728-20) 
2050-26 
16778-46 (10) 
882-05 
17660-51 ( 10 ) 
in = 4 < 
17846-78 (8) 
2050-27 
19897-05 (1) 
, 17879-71 (1) 
2043-50 
19923-21 ( 4 ) 
890-95 
20814-91 (2) 
m = 5 
(19440-00) 
2050-22 
21490-22 (1 + ) 
Exner and Haschek’s arc 
In the above the figures in brackets after the wave-nnmhers represent intensities ; 
the wave-numbers in brackets are those of unobserved lines, put in partly to illustrate 
the arrangement of satellites. 
The lines 16107, 16119 (XX = 6206'6, 6201'9) would be in the region where the 
photographic plates were insensitive ; in fact, the measured lines here are of intensity 
4 at least, whereas X = 6206’6 would certainly he less (by analogy), but 6201'9 (by 
analogy) ought to have been seen if it existed, unless overshadowed by the very 
strong line 16123 (X = 6200‘3). 18510 would certainly be of small intensity, probably 
less than those actually measured, but the convergence (3‘34) and (l’75) of the two 
satellites of the lines looks correct. If 0 ^ 3 ( 3 ) is correctly allotted and 1/3 = 882, there 
must be a satellite D 23 = 18107’66. Its distance from D 32 = 50, which lies in order 
with 12‘31 and 3'34. 
In the S 14728 (X = 6787'86) is extrapolated. The next set (m = 4) appear to 
show satellites. It may be noted that an alteration of 7 in 83 ( 4 ) = 19923 brings 
both i/j and 1/2 into order. The strong line 17846 has been used in the calculation. 
Exner and Haschek give 21490'22 in the arc as a weak line and 19440'58 is extra¬ 
polated from this. The value calculated from this formula in is 19430’58, and 
VOL. CCXII.-A. 
K 
