340 



Hartley and Ramage — Banded Flame-Spectra of Metals. 



which accompanies the two strong lines which are common to flame and spark 

 spectra. The bands are apparently of two kinds : those in the visible spectrum 

 are of the nature of flutings, but those in the ultra-violet are groups of distinct 

 lines. The intervals between the component lines are smaller as they approach 

 the stronger edge of the band which is situated at the more refrangible end of the 

 spectrum. The flutings in the visible spectrum have not hitherto been resolved 

 into lines by the instrument at our command, and undoubtedly will require a much 

 higher dispersion. 



We have found that the flame-spectra of copper and gold are even more 

 beautiful than that of silver : the lines forming the bands are sharper and more 

 widely separated than in the spectrum of silver, and the bands of this character 

 are more numerous. The spectra of copper and gold have a much closer similarity 

 in constitution than that of silver to either of them, but the complete details of 

 these spectra have not yet been quite fully examined. In the three spectra there 

 is this character in common, all the bands are degraded towards the red. 



Banded Flame-Spectra of Copper, Silver, and Gold. 

 Measurements of the Edges of the Bands. 



The following are measurements of some lines which have been observed in the 

 spark-spectra of these metals : — 



Copper, 



Silver, 



Gold, 



(Eder & Valenta.) 

 4649-31 sbarp, 3777-17 diffuse. 



3358-79 not sharp, 3329-84 sharp. 



3976-8 diffuse. 3650-9 sharp. 



(Exner & Haschek.) 

 4051-3, 4003-1, 3777-3. 



3639-7, 3581-5, 35190, 3329-3. 



3457-05. 



A careful comparison of spark- with flame-spectra has led to the conclusion that 

 the measurements quoted do not represent lines in the banded flame-spectra, 

 although near to them. 



The flame-spectra of copper and silver contain, in addition to the bands, two 

 very strong lines in the same region of the spectrum, which appear also as 



