455 
DR. W. M. HICKS: 
A CRITICAL STUDY OF SPECTRAL SERIES. 
We are justified by its form in taking this as a D(l) set for a preliminary trial, 
although the satellite separations are not in the usual ratio of 5 : 3. It is not so clear 
that the particular F(co) just obtained is a c? sequent belonging to it, nor, if so, 
whether it is a or a satellite sequent. The latter point, however, will have little 
effect for our immediate object--the attainment A] . Ag. e—as the differences are 
small and may be included in an undetermined The probability is that as this 
seems the only prominent D triplet set, it belongs to the normal group and that our 
F ( 00 ) belongs to it, although on this point something will have to be said later. 
We shall take on trial that F( oo) = In this case 
Dj (oo) = 21230Tl-f 31851-13 = 53081-24 + ^ 
I his should also be Si(co) and should give the separations by oun multiples in the 
denominator of the sequent. The three S or D limits would then be 
53081-24 + £ 49-24 53130-48 + (^.i + ^ 19*71 b^lb0-l9-vdv, + dv, + i 
where £ may be considerable, owing to uncertainty as to 31851 being of cZ^ or satellite 
type. The mantissse of these are 
437428-13-540^, 436752-13-521^, 436485-13*514^ 
which give as differences 
Ai = 666-*019^-t-13-5cZi/i = 46 (14-477 +-29^1^1--0004^) 
A2 = 267--007 (^+cZi/i)+13*5cZi^ 2 = 18^ (14-432+ *73cZi/2--0004^), 
in which it must be remembered that calculations with seven-figure logarithms give 
uncertainties of a unit in the last digit. The direct calculation of 8 from the atomic 
weight has already given ^=14-47±-01. This gives 46(^ = 665-6 +-46, 18|-(^ 
= 267-69 +-18. Thus these limits give without any doubt the true oun multiples 
in Aj, As, and the calculated As then gives a closer value of 267-7±-2. No possible 
change in ^ can affect these results. Further, these multiples are quite in step with 
the march in the other gases. The remarkably close agreement sustains the allocation 
of the F (CO) to the d sequence of this set, although not necessarily to cZ^. 
As a further test the satellite separations should be due to oun displacements in tlie 
sequences. These separations are 29-21 and 45-19, taking the latter because 21224 is 
a good measure (B. and W^. agree) and the observed 1^2 — 19*71 agrees so closely with 
the Ag value and the is subject to the very common triplet modification. These 
separations require displacements in the sequence mantissse of 851 — *040^+29cZ^,* and 
1313--060f+29cZi/. Now 59^= 853-7±l-2, 90f(l = 1313*l±l-8. This is sufficient to 
give the satellite multiples, but as the oun is so small. Si = 3*62, the close agreement 
cannot serve as evidence one way or the other as to the satellite nature of the doublet 
* Watson’s value of the separation 29-30 makes this 2-6 larger = 853-6. 
VOL. CCXX.—A. 3 Q 
