Prof. W. M. Hicks 



the 



The arc spectrum of gold has been touched upon by me in 

 [III. p. 405] and the spark spectrum has been more fully 

 discussed in its linkage relations in [IV.]. It does not 

 afford data for the direct determination of series constants. 

 The two strong lines usually taken to correspond to the P(l) 

 doublet give the doublet separation to be looked for in the 

 P, S, or D series. The mean from measures by Kayser and 

 Punge, Exner and Haschek, and by Eder and Valenta gives 

 z/ = 3815*58. The most reliable is that obtained from the 

 inverse D set above referred to, viz., W = 5064*75, 6278*37 

 P. A., giving ^ = 3815*54. These two were the only sets 

 giving the separation in K. R.'s original measures of the 

 arc spectrum. Since then E. & H. have observed a line at 

 \ 4811*81, which K. R. appear to have missed and which has 

 a separation 3815*57 with X4665'22. Aiso Lehmann * has 

 observed in the ultra red a line at 7509*8 giving with K. P/s 

 5837 a separation of 3813 + 13, and allocated by him to S (2) 

 — an allocation justified by their position relatively to the 

 corresponding lines in Cu and Ag and by the Zeeman pattern 

 for 5837 as determined by Hartmann. The Zeeman effects 

 for certain lines have been observed by Michelsonf, Purvis J, 

 and Hartmann §. They are given in the notation suggested 

 by me || in the following list : — 





X. 



n. 



Hartmann. 



Purvis 



D' 2 o(D 



6278-37 



15923-38 



0/5 ? 





J»i(l)-i?i(2) 



5957-24 



16781-73 



o/7| 





S a (2) 



5837-64 



17125-54 



4/8 





D'xxd) 



5230-47 



19113-51 



0/61 







4811-81 



20776-50 



0/5 ? 







4792-79 



20858-97 



0/6 



0/6 





4065-22 



2459207 





0/3^ 





3898-04 



25646-81 





0/6* 





3804-22 



26279-28 





0/6* 





358666 



27873-33 





0/5 





3122-88 



32012-59 





0/5 





3029-32 



3300133 





8/6* 





2913-63 



3431167 





0/6 





2748-30 



36374-87 





0/61 



P 2 (l) 



2676-05 



3735762 





34-/6 



* Ann. d. Phys. xxxix. p. 75 (1912). 



t Nat. lix. p. 440 (1899). 



% Proc. Camb. Phil. Soc. xiv. p. 217 (1907). 



§ Dissertation Halle (1907). Sc. Abstracts 



|| Phil. Mag. xxxi. p. 171 (1916). 



