Frequency Differences in Spectral Series. 343 









Triplets, Vi, v 2 







v obs. 



v calc. 



v calc. 





v obs. v calc. v calc. 



Be .... 





2-50 



2-35 







Mg 



. 1989 



19-59 



19-89 



Mg.... 



.. 19-89 19-62 19-89 



Ca .... 



. 52-11 



52-8 



53-7 



Zn .... 



.. 189-78 191-5 176-7 



Sr 



. 18705 



186-6 



187-1 



Cd.... 



.. 541-86 540-4 541-86 



Ba .... 



. 370-3* 



402-2 



397-6 



Hg.... 



.. 1767'19* 1598 1831'0 



Ka .... 



. 1036-15* 



987-0 



9573 







m- 



= -3552, 



N =--459. 



m- 



= -5227, N = 5-527. 



P ~- 



= 1-94433, 



q =,--79965. 



P = 



=2-38390, q =-1-37403. 



Be .... 





3-67 



4-73 







Mg.... 



. 40-95 



38-06 



40-95 



Mg.... 



.. 40-95* 27-26 45'34 



Ca .... 



. 105-99 



108-6 



111-74 



Zn .... 



.. 388-91 388-9 388-91 



Sr 



. 394-44 



399-3 



394-44 



Od .... 



.. 117105 11710 1171-05 



Ba 



. 878-4 



872-9 



845-03 



Hg.... 



.. 4630-31* 3600-0 3880*0 



Ba .... 



. 2016-64* 



21663 



2054-0 







m- 



= -5312, 



N = -387. 



m- 



= -8055, N =: 5-517. 



P - 



= 1-96502, 



q =--5 



)836. 



P-- 



= 2-34534, q —- -87450. 







338 



3-12 







The v 2 values for 0, S, Se 



s 



. 17-90 



18-89 



m = 



•8382, 



are resp. 2*76, 11*26, and 



Se 



. 10366 



103-0 



N =7-347. 



44-82 cm- 1 . 



Te .... 





2540 









N 



P .... 



. 41-8* 



41-2 









As .... 



. 461-36 



462-5 









Sb .... 



. 1342-26 



1339-1 





m=-8381 



Bi .... 



. 4019-73 



4021-7 









Values marked * are not used in determining m and N . 



Au. The value given is criticised by Quincke, using later measurements. 

 Zt.f. Wiss. Phot, xiv. p. 249 (1914). 



Ba. Later measurements are by Scbmitz, Zt. Wiss. Ph. xi. p. 209. Also by 

 Lorenser, Dissertation. Tubingen, 1913, Beitrtige zur Kenntnis der 

 Erdalkalien. The latter contains a critical study of Mg, Ca, Sr, 

 and Ba. 



Hg. A detailed study of the Hg spectrum is given by Cardaun, Zt. Wiss. Ph. 

 xiv. p. 89. The above values for v lf v 2 are not much altered. 



8b. From later data by Schippers, Zt. Wiss. Ph. xi. p. 241, we have the 

 interval 1341-17 cm. in better agreement with the straight line. 



An examination of the above diagrams and tables shows, 

 in general, an upward curvature of the observed points 

 relative to the straight line, especially for large values of N. 

 We notice further that, with the exception of two lines, 

 N is everywhere positive. This readily suggests that a 

 curve passing through the origin and two of the given points 

 might be an improvement. Runge and Precht's law men- 

 tioned above is in this direction, for, assuming v =AN, 

 where 5 and A are arbitrary, we can choose s nearly equal 

 to 05 and the necessity for passing through the origin gives 



