186 EXPANSION OF CARBONATED HIDROGEN. 



produced by hi- increafe of combuftible matter. He alfo found, that the ex- 



confotaTattr" P anfion C0llId not be carried beyond a certain point, about 

 twice the original bulk of the gas. Upon burning feparately 

 by means of oxigen, two equal portions of carbonated hidro- 

 gen gas, one of which had been expended by electricity to 

 twice its original bulk, the other not, he found that each of 

 them produced precifely the fame quantity of carbonic acid 

 gas ; a proof, that the carbon in both remained the fame, and 

 that the hidrogen could not have been produced from it. He 

 concluded therefore, that the evolution of the hidrogen is pro- 

 duced from the decompofition of the water with which hidro- 

 gen is always more or lefs impregnated ; to prove which, he 

 took hidrogen gas, from which he expelled as much water as 

 poflible, and found that the eleclric fpark produced a very 

 fmall dilatation ; but on admitting a drop or two of water, the 

 expanfion went on as ufual. It is eafily feen how this de- 

 compofition is effected. Carbon at a high temperature has a 

 greater affinity for oxigen than hidrogen gas ; when the tem- 

 perature is raifed, therefore, by the electric fpark, the carbon 

 unites with the oxigen of the water, forming carbonic acid gas, 

 and the hidrogen is evolved. As to the azote, it mud have 

 been produced from the admifiion of atmofpheric air into the 

 procefs. 

 But tliis difco- Although this theory of Mr. Henry feems to prove the pro- 

 very does not duclion of hidrogen from the decompofition of the water con- 

 greater quantity tained m tne g as J ftflt however, it is no more able to ac- 

 of oxigen re- count for the increafe of combuftible matter than that of Dr. 

 thcx 'anded™ Auftin. When the gas is dilated, hidrogen and oxigen are 

 gas. evolved from the water. The hidrogen goes to increafe the 



bulk of the gas, and the oxigen unites with the carbon. Ex- 

 panded carbonated hidrogen gas, then, contains hidrogen, 

 carbon, and carbonic acid gas. In combuftion, the evolved 

 hidrogen, in order to form water, requires a quantity of ad- 

 ditional oxigen, precifely the fame as that with which it was 

 combined before decompofition of the water : and on the other 

 hand, the carbon requires precifely the fame quantity lefs, as 

 part of it is already rendered incombufiible, by being com- 

 bined with the oxigen of the water. Therefore, according 

 to Mr. Henry's theory, a quantity of expanded carbonated 

 hidrogen gas requires the fame quantity of oxigen for its com- 

 buiiion, as an equal quantity that has not been expanded : 



and 



