bj/ Means q/'Uoebere'mer's Eudiometer. 281 



rapid combustion by the electric spark, being never attended 

 with that precipitation of charcoal which is often observed 

 when the gases are exploded with oxygen. A regulated tem- 

 pei'ature also effects the analysis of such mixtures much more 

 correctly than the action of the sponge or balls, because in the 

 latter case the heat produced is uncertain; and though some- 

 times adequate to the effect, yet there is always a risk that it 

 may exceed or fall short of that degree which is required for 

 the successful result of the analytic process. 



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

 obtaining carburetted hydrogen gas perfectly free from ole- 

 fiant 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 watei'y solution of 

 chlorine, and afterwards with liquid potash, to remove a little 

 chlorine that arose into the gas from the solution. The re- 

 siduary gas was next heated with one-fourth of its volume of 

 oxygen at the temperature of 350° Fahrenheit, in contact with 

 the sponge, which converted the carbonic oxide into carbonic 

 acid, and the hydrogen 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 introduced by the latter gas. Hitherto I 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 oxj^gen by obvious methods. 



Section III. 



Application of the Facts to the Analj/sis of Mixtures of the com- 

 bustible Gases in unknown Proportions. 



At an early period of the investigation described in the 

 first section, I jiroceeded to apply the facts of which I was 

 then possessed, to the analysis of a mixture of gases in unknown 

 proportions. 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 pur- 

 posely chosen, because from former experience I expected it 

 to contain free hydrogen, carbonic oxide, and carburetted hy- 

 drogen, but no olefiant gas; the production of which is con- 

 fined to the early stages of the progress. After washing it 

 therefore with liquid potasli to remove a little carbonic acid, 

 and ascertaining its specific gravity, when thus washed, to be 



Vol. 05. No. 324. April 1825. N a 308, 



