52 SPECTRUM ANALYSIS OF FLAMES. [MEMOIR II. 



MEMOIR II. 



SPECTRUM ANALYSIS OF FLAMES. PRODUCTION OF LIGHT 

 BY CHEMICAL ACTION. 



From the American Journal of Science, Second Series, Vol. V., 1848; Philosophical 

 Magazine, London and Edinburgh, Feb., 1848; Harper's New Monthly Maga- 

 zine, No. 323. 



CONTENTS : Spectrum analysis of a candle flame. Examination of 

 various other flames. Spectrum analysis of the light of a burning 

 solid. Flames consist of a succession of shells. Spectrum of cyano- 

 gen. Combustion of flames in oxygen. Effect of air in the interior 

 of a flame. The blowpipe cone. General result, the more energetic 

 the chemical action the higher the refrangibility of the resulting light; 

 the vibrations increase in frequency as the chemical action is more 

 violent. Fraunhofer's fixed lines. 



THE production of light and heat by the combustion 

 of various bodies is, of all chemical processes, that which 

 ministers most to the comfort and well-being of man. 

 By it the rigor of winter is abated, and night made 

 almost as available for our purposes as day. 



One would suppose that, of a phenomenon on which 

 so much of our personal and social happiness depends, 

 and which must have been witnessed by every one, all 

 the particulars ought to have been long ago known. 

 Among scientific men its importance has been universal- 

 ly recognized. The earlier theories of chemistry, such as 

 those of Stahl and Lavoisier, are essentially theories of 

 combustion. 



It is nevertheless remarkable how little positive 

 knowledge, until quite recently, was possessed on this 

 subject. Some chemists thought that the light emitted 

 by flames is due to electric discharges ; others, regarding 



