428 Dr. Henry on the Action of [June, 



From the facts which have been stated, I derived a method of 

 obtaining carburetted hydrogen gas perfectly free from oleHant 

 gas, hydrogen, and carbonic oxide, and mixed only with a little 

 oxygen, which, had it been necessary to my purpose, might also 

 have been separated. The early product of the distillation of 

 pit-coal was washed with a watery solution of chlorine, and 

 afterwards with liquid potash, to remove a little chlorine that 

 arose into the gas from the solution. The residuary gas was 

 next heated with one-fourth its volume of oxygen, at the tem- 

 perature of 350° Fahrenheit, in contact with the sponge ; which 

 converted the carbonic oxide into carbonic acid, and the hydro- 

 gen into water. The carbonic acid being removed by liquid 

 potash, there remained only the carburetted hydrogen, the 

 redundant oxygen, and a very minute quantity of nitrogen intro- 

 duced by the latter gas. Hitherto, 1 have prepared this gas 

 only in a small quantity, but it would be easy to extend the scale 

 of the operation, and to remove the excess of oxygen by obvious 

 methods. 



Sect. III. — Application of the Facts to the Analysis of Mixtures 

 of the Combustible Gases in unknoivn Proportions. 



At an early period of the investigation described in the first 

 section, I proceeded to apply the facts of which I was then pos- 

 sessed, to the analysis of a mixture of gases in unknown propor- 

 tions. For this purpose, I caused a quantity of gas to be 

 collected from coal, by continuing the application of heat to the 

 retorts two hours beyond the usual period, and receiving the gas 

 into a separate vessel. Gas of this quality was purposely 

 chosen, because, from former experience, I expected it to con- 

 tain free hydrogen, carbonic oxide, and carburetted hydrogen, 

 but no defiant gas, the production of which is confined to the 

 early stages of the process. After washing it, therefore, with 

 liquid potash, to remove a little carbonic acid, and ascertaining 

 its specific gravity when thus washed to be 308, I proceeded at 

 once to subject it to the new method of analysis. 



Having ascertained, by a previous experiment with Volta's 

 eudiometer, that 10 volumes of the gas required for saturation 

 9 volumes of oxygen, I mixed 43 measures with 43 of oxygen 

 (=41 pure) and passed a platinum ball, which had been recently 

 heated, into the mixture. An immediate diminution of volume 

 took place, attended with a production of heat, and formation of 

 moisture. The residuary gas, cooled to the temperature of the 

 atmosphere, measured 43'5 volumes. Of these 4*5 were absorbed 

 by liquid potash, indicating 4*5 carbonic acid, equivalent to 4*5 

 carbonic oxide; the rest, being fired in a Volta's eudiometer 

 with an additional quantity of oxygen, gave 1 1 volumes of car- 

 bonic acid ; the diminution being 22 volumes, and the oxygen 

 consumed 22 also, circumstances which prove that 1 1 volumes 



