THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



LSpiTIf SERIES.] 



v , ^ ^x — - 



<A S. ?K$* 



Y 1920. 



XLVI. The Spectrum of Copper. 

 ByWM.E.iCKs,F.R.S* 



IN the following pages similar methods are applied to the 

 discussion of the copper spectrum as have already been 

 successful in dealing with those of silver and gold f . The 

 arc spectrum of copper differs from those of the other metals 

 of the group in that it is very rich in lines. It is, however, 

 similar to them in general plan, and the similar conclusions 

 arrived at in each receive greater support in combination. 



Strong well defined sets are given for the orders m = 2, 3 

 in both the S and D sets and for the first order of P. Those 

 for S (2) are in the red and in step with those for silver. 

 The others show the Zeeman patterns proper for their 

 respective types. These may therefore be adopted definitely 

 as normal series lines. For the higher orders, however, the 

 intensities fall off more quickly and irregularly than usual 

 and there is also evidence, as will be shown below, for 

 numerous displacements. In fact these are apparently the 

 cause of the low intensities and the large number of weak 

 lines. In consequence the determination of the S and D 

 limits with any exactness from the series lines alone is 

 rendered impossible. The doublet separations of the S (2) 

 and D(2) sets are the same within at least *01. For S (2) 



* Communicated bv the Author. 

 t Phil. Mag. Sept. 1919— July 1919. 



Phil Mag. Ser. 6. Vol. 39. No. 233. May 1920. 2 H 



