G4 



SPECTRUM ANALYSIS OF FLAMES. [MEMOIR IL 



Spectra of Various Flames. 



Figr. 8. 



red and orange are deficient, and the more refrangible 

 colors predominate, and, indeed, it is the excess of these 

 that gives the flame its characteristic blue tint. This 

 agrees with what has been observed as to anthracite and 

 charcoal; for with carbonic oxide a limited supply of 

 oxygen can bring about the maximum chemical action, 

 and therefore liberate in abundance rays of maximum 

 refrangibility. 



This condition of things is inverted in the case of cy- 

 anogen. It is the nature of its flame to be enveloped, as 

 it were, in a sheet of nitrogen arising from its own burn- 

 ing, and this necessarily impedes the access of air and 

 checks the intensity of the chemical change : a check 

 which is at once betokened by the emission of a predom- 

 inant number of rays of low refrangibility or of a red 

 color. 



But there is a striking difference in the chemical con- 

 ditions under which carbonic oxide and cyanogen burn. 

 In the case of the former the whole gas is combustible, 

 in the latter the carbon alone, and we have, in reality, 



