DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 
359 
Here again the links to the line observed near normal S 3 are had, whereas the links treated as good refer 
back to a line exactly vo ahead of So. Further the 12 or G separation is again in evidence. Also the links 
2 e, - 2 e + - e-u refer back to lines differing by about 6 from So. 
[45179-30] 
#(1) 45618 --02 
--y (4) 44735 -07 
2e + v(2) 44175 --16 
S(4). 
[45358] 
e-iy (1) 45635 -00 
-?;(3) 44913 -12 
[45434-40] 
-e-#(1) 44996 --09 
-e-#(1) 44275 --01 
Heie the calculated lines agree remarkably wth the sounded. The calculated are therefore adopted. 
[47501-68] 
S(5). 
[47681-18] [47756-78] 
®(1) 48126 --12 
# + 6(1) 48126 -00 
Ihe only links apparent are for So, again with the 6 displacement. These lines are all close to the limit 
of observed region. 
S ( 6 ). 
[48776-74] [48956-34] 
-2e + ?;(l) 47784 -16 - 2e- 12 (1) 47522 -09 
[49031-94] 
-e + « (1) 48753 -06 
- 2e - # (1) 47155 - -10 
The lines are now so far out of the observed region that the links are too small to refer back to well 
observed regions even if such lines are really existent. 
The foregoing discussion of the S series affords evidence of the existence of dis¬ 
placements of about 12 (or 6). This requires further consideration as affording 
material on which additional knowledge may be obtained regarding the laws which 
such displacements follow. The presence of the same displacements in successive 
terms of the series jDoints to a modification on the limit—either a pure displacement, 
a linkage effect, or, as the separation is small, possibly the difference of two links. 
The further evidence to follow points decisively to the existence of displacement. 
Whether they are due to displacements by multiples of the oun on the limit is, of 
course, not so convincing. The numerical relations are very closely represented on 
this hypothesis, but in the case of argon the is so small that it produces in Sj 
separations of 1‘03 only. In lines whose wave-numbers lie about 40,000 or greater, 
this produces changes in X of ’06 and therefore comparable with observation errors. 
In the case of S (2) only—wave-numbers of order 26700—Hoes it produce d\ = ‘15. 
The measurements here are by Kayser, whose errors are probably < ‘02, almost 
certainly < '05, and a close agreement between calculated and observed lines will 
give evidence of some weight. 
VOL. CGXX.-A. 3 D 
