DE. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 
437 
produced in 92246+a: by a decrease of Aj = 72820 in its denominator. The result 
is that 
P ( oo) = S (I) = 92266 = N/{r090264}2 
u = 11191-8 
V = 13680-0 
Si(l) = -41864-3 
The set of S (1) lines would then be 
-41864-3, -36493-6 or 89-7,* -33844-1. 
On the two latter u, e—u, e—v links as sounders should give the following lines. 
22652-3 
(4) 22636±6 (C.K) 
21357-6 
(10) 21357-43 (K.) 6-57 (W.) 
23846 
(2) 23841-9 (W.) 
They are not satisfactory sounded lines, but are given as material at disposal only, 
-M.Sg and e.Sg.w are really good. 
There is a striking triplet which has all the aspect of being a S (l) set except that 
of position. It is 
(2) 18611-7 (W.) 2648-9 (5) 21260-21 (W.) 
(0) ... 09-94 (K) 2652-3 (3) 21262-25 (K) 5371-3 (lO) 26633-64 (K) 
Its separations give support to the values obtained above. It is a parallel set to 
our adopted S (l), separated from it by 15230-7. I have not been able to recognise any 
arrangement of links which give this value although 2h + a, and e—v + b are close 
to it.t 
* Sounded from observed line. 
t There is the possibility to be kept in mind that it may be a real and independent S set of lines, not 
analogous to the set considered in the previous elements. If so, it must have the same limit and 
s(l) = 77036'64 = N/{1 • 193177}2. Now the s sequence depends on the atomic volume, although the 
exact relation is not known. In the next grouji, the alkalies, the denominator is of the form • 987 + kv, 
where v is a number proportional to the atomic volume. If here the group constant be • 99, the 
denominators of the two types of s sequences can be expressed as ‘dd + kv and '99 + 2kv. In other 
words, this new type may depend on twice the atomic volume. 
below which are placed the nearest observed. 
-u- 
-[e — u)- 
-{e—v)- 
25301-8 or 297-3 
(2) 25299-1 ±-7 (W.) 
24007-1 or 3-2 
(20) 23993-82 (E.) 4-45 (W.) 
26495-3 
