On the Combustion of Hydrogen and Carbonic Oxide, fyc. 309 



I suppose, much the brightest. A suspicion also of the red hydrogen- 

 line C. I was much surprised at the brightness of the continuous 

 spectrum, in which all the principal prismatic colours were brilliant. 



June 11. — Lieut. -General Sabine, President, in the Chair. 



The following communication was read : — 



"On the Combustion of Hydrogen and Carbonic Oxide in Oxygen 

 under great pressure." By E. Frankland, F.R.S., Professor of 

 Chemistry in the Royal Institution and in the Royal School of Mines. 



In a former communication to the Royal Society* I described some 

 researches on the effect of a diminution of pressure on some of the 

 phenomena of combustion, and deduced therefrom the law that the 

 diminution in illuminating-power is directly proportional to the di- 

 minution in atmospheric pressure. 



Further experiments, made more than a year ago, on the nature 

 of the luminous agent in a coal-gas flamef, led me to doubt the cor- 

 rectness of the commonly received theory first propounded by Sir 

 Humphry DavyJ, that the light of a gas-flame and of luminous 

 flames in general is due to the presence of solid particles. In refer- 

 ence to gas- and candle-flames, it is now well known that the fuligi- 

 nous matter produced when a piece of wire-gauze is depressed upon 

 such flames, and the sooty deposit which coats a piece of white por- 

 celain placed in a similar position, are not pure carbon, but contain 

 hydrogen, which is only completely got rid of by prolonged expo- 

 sure to a white heat in an atmosphere of chlorine. On pursuing the 

 subject further, I found that there are many flames possessing a 

 high degree of luminosity which cannot possibly contain solid par- 

 ticles. Thus the flame of metallic arsenic burning in oxygen emits a 

 remarkably intense white light ; and as metallic arsenic volatilizes 

 at 180° C, and its product of combustion (arsenious anhydride) at 

 218° C, whilst the temperature of incandescence of solids is at least 

 500° C, it is obviously impossible here to assume the presence of 

 ignited solid particles in the flame. Again, if carbonic disulphide 

 vapour be made to burn in oxygen, or oxygen in carbonic disulphide 

 vapour, an almost insupportably brilliant light is the result. Now 

 fuliginous matter is never present in any part of this flame, and the 

 boiling-point of sulphur (440° C.) is below the temperature of incan- 

 descence, so that the assumption of solid particles in the flame is 

 here also inadmissible. If the last experiment be varied by the sub- 

 stitution of nitric oxide gas for oxygen, the result is still the same ; 

 and the dazzling light produced by the combustion of these com- 

 pounds is also so rich in the more refrangible rays, that it has been 

 employed in taking instantaneous photographs, and for exhibiting the 

 phenomena of fluorescence. 



Many other similar cases of the production of brilliant light from 

 incandescent, gaseous, or vaporous matter might be cited; but I will 



* Phil. Trans, vol. cli. p. 629 (1861). 



Lectures on Coal-gas, delivered at the Poyal Institution in March 1867. 

 Journal of Gas-lighting. % Phil. Trans, for 1817, p. 75. 



