246 INFLAMMABLE GAS. 



Experiments by keeping, ii was left a month standing over an open trough' 



aRd observa- of water. Its specific eravity was now fou-d to be 0.8354, or 

 ^jons on the in- , , V , , . . . . ^ . , • 



flammable gas about 1 -2000th less than when newly deprived of its carbonic 



from peat. acid. Though these experiments were made with as much 



care as possible, I think it not unlikely that at least a ptirt of 



this small difference may be owing to errors committed in 



weighing the air. 



As the gas was not pure, but contained 12 per cent, of com- 

 mon air, it is obvious that it would have been lighter, if the 

 air had been altogether absent. Il is now perfectly estab- 

 lished, that two gases, when mixed, do not sensibly change- 

 their bulk, unless they have the property of combining inti- 

 mately, and of forming a new gas, which is not the case with 

 the gas from peat and common air. We may therefore, from 

 the preceding experiment, deduce the specific gravity of ab- 

 solutely pure inflammable gas, from peat, by calculation.*' 

 This method gives us the specific gravity of the pure gas, 0.8 128*. 

 Hence, 100 cubic inches of it, at the temperature of 60S 

 would weigh 25.18 grs. under a mean barometer. 



When thi« gas is made to issue from a narrow aperture into 

 the open air, and alighted taper brought in contact with it, it 

 catches fire, and burns with a beautiful bluish red flame. 

 When mixed with common air in any proportion whatever 

 that "will burn, and kindled in a close vessel by an electric 

 spark, the flame is always pale blue. If it be mixed with a 

 small proportion of oxygen, it burns with a reddish blue flame; 

 but with its own bulk of that gas, the flame is a fine white. 

 After the combustion, a portion of carbonic acid may always 

 be detected in the detonating vessel. The bulk of the mixture 

 is always diminished after combustion. 



6. To form precise notions of the changes produced upon 

 this gas, by burning it with common air and with oxygen, a 

 considerable number of experiments were essential; for as 

 these experiments are necessarily made upon very small quan- 

 tities of gas, we can hope for correct results only by taking the 



mean 



% * Let A be the bulk, of common air in the mixture; a, its specific 

 gravity; B, the bulk,-of inflammable gas; x, its specifig gravity, and c 

 the specific gravity of the mixture. We have A c + B c=A a + B x ; . 

 Ac + Bc — A a 



and — =x. In the present case, A=12, a=\"; B=»68i 



B 

 uai 6=0'3354; from which we deduce x=0.S128. 



