﻿214 Prof. A. Lielegg on the Spectra of the 



teresting investigations also of Frank! and *, according to which 

 the intensity of light of a flame depends upon the density of the 

 ignited vapours, cannot but lead us to hesitate in supposing 

 carbon to exist in a state of vapour in such flames ; so that it 

 appears simpler to refer the flame-spectrum of the compounds 

 of carbon with hydrogen, and of oxygen with carbon and hy- 

 drogen, to the ignited vapours of carbon combined with hydrogen 

 than to those of carbon alone. 



Since, then, it would seem that no independent spectrum of 

 carbon exists, and that, instead of this, every gas containing 

 carbon has its own peculiar spectrum, and since the quantitative 

 proportions of any compound have no effect upon the character 

 of the spectrum, we have a sufficient explanation why it is that 

 the flames of spirits of wine, wax-lights f, coal-gas, and olefiant 

 gas exhibit the same spectrum, whilst, on the contrary, cyanogen 

 and carbonic oxide, in which bodies of a different nature become 

 the sources of light, manifest an essential difference in their spectra. 



In support of this view, similar cases may also be adduced in 

 combinations which have a different nature in their chemical 

 constitution — for instance, the spectra of the compounds of 

 copper with chlorine, bromine, and iodine, observed by A. Mits- 

 cherlich J and, on account of their characteristic differences, 

 proposed by him to be applied to analytical purposes. There 

 is no question that these spectra are due, not to the copper, 

 but to the combinations in question, and that the difference 

 shown by them is produced by the substance united with the 

 copper, as in the combinations of carbon it is produced by hy- 

 drogen, oxygen, and nitrogen. 



Spectrum of Carbonic Oxide, 



When combustion of carbonic oxide with atmospheric air or 

 with oxygen is produced, a continuous spec f rum is obtained 

 without bright or dark lines, ip 'vhich )-±2 gret_^ and blue parts 

 are especially well developed. A flame, however, of carbonic 

 oxide, caused by the combustion of charcoal in a blast-furnace, 

 in which carbonic oxide is consumed at a tolerably high tem- 

 perature, shows in the continuous spectrum some bright lines ; 

 the higher the temperature of the carbonic oxide the more lines 

 appear; and it is evident that the conditions, under which the 

 formation and combustion of the carbonic oxide takes place 

 during a " charge " in the Bessemer-process, are particularly 

 favourable for the production of a spectrum with complete lines. 



* Polytechnic Journal; vol. clxxxv. p. 279. 



f The lowest blue part of the flame of a wax-light shows, if a cold body 

 be held in it, a white border. 



J Fresenius, Zeitschrift fur analytische Chemie. 1865, p. 153, [Phil. Mag. 

 Dec. 1865, p. 449.] 



