45G 
DE. W. M. HICKS; A CEITICAL STUDY OF SPECTEAL SEEIES. 
and triplet lines in question. The points against the allocation of these lines to the 
normal D group are, (l) the satellite separations are not in the usual ratio 5 ; 3 (they 
are in fact close to the ratio 3:5), (2) there is no appearance of satellite lines 
corresponding to the parallel F lines noted above, and (3) the limit 53081 is somewhat 
larger than we should expect from the march of the limits in the other gases. 
Taking it, however, as the limit, it is possible with the given value of Aj to 
calculate the link e. The result is 197 + 4dj/]. The occurrency curve as found from 
B.’s and W.’s observations is given in Plate 2, fig. 6. The dotted line is the result 
when the numerous rough measures by L.D. are included. As is seen the maxima 
occur at 195’6 and 198, the calculated, at a minimum. The peaks look as if analogous 
to corresponding peaks found in other elements, but the analogy is doubtful. In the 
other elements these (much larger ones) are produced by the prevalence of displace¬ 
ments by a few ouns, and by Aj operating oji {xS) S Such changes here would 
be very small and the corresponding effects are really shown by the flattened tops of 
the peaks. The peaks themselves are due in all probability to another cause to be 
considered shortly (p. 458). 
In the region in which the S triplets should be expected are found (all interferential 
measures) 
(6) 28787-86 49-81 (5) 28837*67 18-61 (4) 28856-28 
with intensities in the proper order, although the rj, v .2 are slightly different from 
those obtained in the D set. The interferential measures of Meggers and of B.M.M. 
differ considerably ('008) and are not so reliable therefore as usual. Baly and 
Watson agree in giving the separations as 49*72, 18*64. The third line, however, 
has already appeared in the quite definite relation 1429 + 417 ahead of F (4). It 
cannot be S (2), but the latter may be a weak line close to it. 
There is also another doublet set 
(10) 27818*89 
47-75 
(1) 27866*641 
49-93 
(1) 
68*82 j 
(8) *73 
48-07 
(1) 
6*80 
The suggested Sg line is abnor 
mally weak. 
There 
are, however, here a 
number of other weak lines which have the appearance of displaced debris. If the 
first set form a S group, th.e second would belong to a group with smaller limit, 
which is also indicated by the smaller triplet separations. The limit 53081*24 was 
obtained from apparently the only stable D set, whilst the first set are apparently 
the only stable strong S group. It is natural therefore to take its limit as the same. 
If so, the limit for the second, being 969*03 (or *35 di/) less, is 52112*20. The two 
mantissm are 437420—13*54^ and 450723 —13*92^+13*92dj/. Their difference is 
13303-*38^+13*92dr = 20 (665*15-*019^+*7dv) = 20Ai. 
