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



m = 1. In S(l) cases of the displacement associated with the linked lines have 

 been given above. They also exist in connection with the S lines themselves. Near 

 S 2 (l) are 42448'25 and 42473'49, both of intensity 1 ; the first 14'42 above and the 

 second 10-82 below S 2 (l), or a difference of 25'24 = 2x 12'62. Again (3) 42401'45 

 is 14'38 above S 3 (l). Now 3f 5 = US, displacement on S ( <*> ) produces a separation 

 of 14'42, and of 2|-5 = 10 S l one of 10 '30. If, therefore, the observation errors are 

 very small the lines in question are respectively (-14^) S 3 (l), (105^ S 2 (l), and 

 (-145083(1). There is no corresponding (-14 5,) 8j (l), but (l)42623'93 is 

 (-185j) Sj(l) with d\ = '00. 



TO = 2. In S (2) we find direct displacements on the S (2) lines with a whole set 

 of linked lines. They are indicated in the following table : 



(9) 26806-14 

 (4)26562-08 182'07 (3)26744-15 75'60 19'75 



(1) 26833-37 

 - e (3) 26098 

 -e + 24 -61 (3) 26123 



The line 26562 has been already adduced. It is (-25) 8^2) with d\ = -'02. 

 The lines 26022, 26098 under (e) S 2 and (e) S 3 differ by 75"57 or a normal v a , and 

 refer back to lines which would give the true triplet separations with the first 

 line 26542. 



TO = 3. From Si (3) the two lines (l) 40258'62 and (4) 40273'21 are displaced 

 successively by 14 "57 and 14 "5 9, the same separation as in the case of m = 1. They 

 are (-145,) S, (3) and (-285 t ) S t (3), with 0-C given by d\ = '00 in both cases. 

 The first has a modified e link 7 22 "61 and the second another of 718'46 to observed 

 lines (4) 39536'01 ; (&) 40991 '67. 



The D and F Series. 



It wiD be found that the rare gases show a large preponderance of sets of lines 

 which have all the characteristics of belonging to satellites of D series, or to parallel 

 multiplet F series. In other words where, as in other elements, the d sequences 

 show two displacements from the main d u sequence when triplets are in question, the 

 rare gases show a large number of such displacements, both in the d and the f 

 sequences, many of these being due to large multiples of A 2 . No attempt has been 

 made to determine the whole system of these satellite sets, a problem belonging to 

 an intensive study of individual elements, but a sufficient number have been adduced 

 to prove their existence and to exhibit some of their characteristics. 



