C. C. Hutchins — Notes on Metallic Spectra. 475 



of Rowland's tables. The true wave-length of the metallic 

 line can then be computed from a previously determined mi- 

 crometer constant. As a check to the result so ' obtained the 

 metallic line has been interpolated, with the micrometer, be- 

 tween two of the standard lines in the same field of view, and 

 the whole process has been repeated on different days until it 

 became assured that positions of the metallic lines were as pre- 

 cise as those of the standard lines themselves. 



Copper Spectrum. 



The subjoined table gives the results as obtained for the 

 spectrum of copper. The first two columns contain respectively 

 the wave-lengths and intensities as given by Thalen ; the third, 

 the wave-lengths as determined in the present work. 



Copper Spectrum. 



Thalen a. 



Corrected a. 



Remarks. 





6379-7 



2 



6380-899 



Surrounded by continuous spectrum. Reversed in 



sun 



6218-3 



5 





No line seen. 





5781-3 



2 



5782-285 



Reversed in arc. Reversed in sun. 





5700-4 



1 



5700-442 



5535-64 



5555-119 



Reversed in arc. Reversed in sun. 

 Reversed in sun. Seen only in the arc. 

 Seen only in the arc. 





5292-0 



2 



529268 



Reversed in sun. 





5217-1 



1 



5218-308 



Reversed in arc. Reversed in sun. 





5152-6 



1 



5153-345 



Reversed in arc. Reversed in sun. 





5104-9 



1 



5105-663 



Reversed in sun. 





5011-4 



4 



5016-86 



No line seen. 



Seen only in the arc. 





4955-5 



3 





No line seen. 





4932-5 



3 



4933-181 



Reversed in sun. 





Zinc Spectrum. 



The examination of the zinc spectrum is here limited to five 

 lines ; many of the remaining lines being mere dots close to 

 the poles of the metal, others very broad and nebulous, and in 

 general too ill defined to admit of measurement with the ap- 

 paratus employed. In strong contrast to the remaining lines 

 these five are very bright and sharp, and may be called the 

 representative lines of the metal within those limits. 









Zinc Spectrum. 



Thalen a. Corrected a. Remarks. 



6362-5 



5893-5 

 48097 

 4721-4 



1 



2 

 1 

 1 



6362-566 

 6204-708 

 5894-454 

 4810-671 

 4722306 



Reversed in sun. 



Faint but very sharp. Reversed in sun 



Very bright. Reversed in sun. 

 Very bright. Reversed in sun. 



