390 DE. W. M. HICKS : A CRITICAL STUDY OF SPECTRAL SERIES. 



here but (l) 36493'82 is less by 5, i.e. = (,) F(l). We can arrange lines to go with 

 it as a satellite set, viz., 



[36498'90j 1864-50 



25-45 



(3) 36473-45 1863-64 



Here we find the same 6^ for F t and P 2 , whilst in F we had it only for Fj. The 

 set with separation 17 show no F 1( and again is numerically an exact oun multiple 

 displacement, viz., S which gives 17'0. The line found close to the expected (<$i)F, 

 above forms part of a chain 



(1) 32765-29 1864-47 (3) 3462976 1864-06 (l) 36493'82 



It may be the representative corresponding to the satellite displacement S l observed 

 in F for ro = 2, 3. 



Using links 2e + u = 1876T38 and 2e + r = 19056'2 we should find lines at 3967879 

 and 39383"97 with the corresponding lines to P 3 , P 3 beyond the observed region. As a 

 fact, we find lines at (3n) 39683'95 and (l) 39386'98. The first corresponding to a 

 <\ displacement should give 2e.?>.F 1 (l) = 3967970. The second would differ from 

 the same displacement by 3 and is therefore inadmissible. It should be noticed that 

 both the 3e and 2e + u sounders give lines larger by unity than the expected value. 

 This may, of course, be due to combined errors in the sounders and observation errors, 

 but the F are entered in the list as if the sounders are correct. As none of the 

 F(l) or F(l) lines can be observed, their means can have no weight for an accurate 

 determination of the limit. 



m = 2. The F lines are in the ultra-violet, and should be, with the limit chosen, at 42842 '73, 

 44707-23. With sounder e + v = 11742-10 we find the set (4) 31102-16 1863'17 (<1)32965'33 

 with a small separation corresponding to that for 1\. It gives Fj = 42844 -26 and F 2 = 44707 '43. 

 But the set appears to be really Fj (16), F 2 (16). 



m = 3. A displacement 8 1 in F 2 ( oo) produces 5-42. The F line is not observed but (2)39404 is 

 practically an exact ( - Sj) F 3 . In further illustration of this we find (2) 37431 03 linked to it by -d and 

 5-61 (i.e. another &J ahead in the remainder of the triplet (1)37436'64 828'13 (In) 38264-77. The 

 lines in question are ( - Sj) F 3 ; d.( - 2S t ) F 3 ; d.( - 28j) F 3 . 



m = 4. F 2 is(l) 32362- 98 -M = 28229-80 which, as referred to above, is also (1) 26257-20+ 1972.- 60 

 close to d link. For F 3 , (- 8 t ) (4) 29053-89 = 29059-54 or (23J (In) 29071 -03 = 29059 '73 or 

 (SSj) (1) 29076-10 = 29059-15. Take the mean 29059-47 as F 8 . Several other lines in this neighbour- 

 hood show indications of displacement by multiples of 8 1( i.e. that the energy proper to F 3 has gone 

 into a number of collaterals. None of the direct F are observed but there appears a parallel set displaced 

 S, viz., (1)35064-09 1864'34 (1) 36928-45 -with (1)37742-12 due to a further 3^ displacement. 

 The F lines are entered as due to these. 



