444 
DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 
This gives for m = 3, 4, 5, the lines n= 44834'16, 47323'04, 48672‘56. The 0 —C 
for the first is d\ = —'06 whilst the others should be weak and are near to the limits 
of observations. The links are so small that as sounders they produce lines also close 
to the observed region. For w = 1, the difference of the sequent mantissae of 23899 
and 23782 (Djo) is 4144 and 4 A 2 —6^^ = 7l|'(^ = 4141’2, or exact with d\ — '013 on 
two lines. It will be shown later (p. 447) that D 12 depends on the A, multiple. The 
series is, therefore, probably a real doublet series with this for the outer satellites. 
For m = 2 the D^g set with a displacement of about 17 ifis inserted since it recalls 
the order of magnitude in Kr and X, whilst the two Djg satellites for m = 2 and 3 are 
inserted because they show the same displacement of 39f(5. An extrapolated line on 
an observed one [23611’5], 179*5, (2) 23791'0 gives a displacement 175^ for m = 1 
corresponding to that for m = 2. It may also be noted that in Argon the third lines 
of the triplets appear to be missing in this D series. 
The following arrangement would seem to indicate the existence of a set parallel to 
the above:— 
23899-08 
20*74 
(3) 23919-82 
188*73 
(1) 24108-55 
39439-33 
20*65 
[39459-98] 
171*60 
(3) 39631-58 
44835-41 
20*65 
[44856-06] 
177*22 
(4) 45033-28 
[47323-01] 
20-66 
(47343-67) 
178*97 
(1) 47522-64 
The [ ] in the second column are calculated from the first column by adding 20’65. 
The line in ( ) is determined as the mean of the linked lines '?4.(l) 47784’02 = ... 44'55 
and ( 1 ) 46183‘62.w.e = ... 42'80. As 5S on the limit produces a separation of 20‘65, 
the lines in the second column would correspond to the parallel displaced series 
(— 5S) Djj. The separations of the last column increase with the order to a normal 
value of and point to a constant displacement in the sequent. 
With the above D set should be associated a doublet F series whose Fj ( 00) = (l) 
= 51731‘03 —23899’08 = 27831'95 and separation that of the D satellite or 116‘5. In 
searching for this allowance will have to l)e made for the prevalence of displacement 
in the lower orders. As a fact, however, this only appears for m = 3 in Fj, although in 
Fg there are considerable signs of it. The following table with succeeding notes 
contains the data, including also those for the corresponding F series ; also for certain 
lines which show a separation about 150, and which may probably be the analogue of 
the 1864 X series. 
We shall denote this last set by dashing the letters. 
The formula obtained from the two first Fj lines and the given limit is 
n = 27831-95-N y|m + 757701+ 
