Spectroscoped and Spectrometed in 1879. 



113 



primarily either of those (carbo-oxygen or carbo-nitrogen) 

 compound gases and burn it in a blowpipe, then if the smallest 

 trace of carbo-hydrogen ; merely as an unavoidable impurity, 

 be present, its spectrum will overpower that of the gas proper 

 to the occasion, and may lead to some unfortunate genera- 

 lizations. 



Postsckipt. — By the kindness of Prof. Alexander S. Her- 

 schel I am now enabled to add the veritable lineai* spectrum of 

 carbon as given by M. Thalen in Nova Acta R. S. Sc. Upsala, 

 Series iii., vol. ix. 1875, in both description, number, and 

 graphical representation. 



It was obtained apparently by the disruptive discharge of 

 electricity of high tension and in large quantity (" decharge 

 disruptive d'un grand condensateur, bobine de RuhmkorfF 

 grande dimension "),and records only eleven lines in the whole 

 spectrum ; but each of them is remarkable for strength and 

 clearness, thus : — 



Colour. 



Scarlet 



Yellow 



Yellow and 

 Citron . 



Green 



Green 



Violet .... 



Subject. 



Grand double /1st component 



line [2nd 



Single line 



{1st component 

 2nd „ 

 3rd 



Single line 



f 1st component 

 Triple group... \ 2nd „ 



I 3rd 

 Very broad line 



-£ s o 

 '55 ■"" ' 

 fl o 



8 

 9 



5 

 5 

 6 

 4 

 3 

 5 

 6 

 4 

 10 



Appear- 

 ance. 



}« 



Wave- 

 Number 

 Place per 

 Brit. inch. 



38,584 

 38,616 



44,607 

 44,869 

 44,983 

 45,046 

 47,220 

 49,315 

 49,376 

 49,483 

 59,540 



Hence these are the lines which should be alluded to, with 

 all the responsibility of their fearfully high temperature of 

 production, whenever any one in future speaks of " carbon 

 lines." 



Indeed M. Thalen goes further, and declares that this is 

 the one, and only, spectrum that carbon alone is capable of 

 under any circumstances whatever ! But as he allows that 

 his demonstration of that point is not yet quite complete, and 

 as he does not seem to have discovered the peculiar micro- 

 scopic arrangement of the linelets in what I have ventured to 

 call the vacuum-tube carbon's band, or lower-temperature, 

 spectrum, I conclude here with giving my recent measures 

 of them in their green band ; thus — 



