138 Dr Bischof s Examination of Three Inflammable Gases 



oxide gas, however insufficient it may be for eudiometrical 

 purposes, seemed available in the present case, where the de- 

 termination of a small quantity of oxygen gas was alone con- 

 cerned. This gas added to the pit-gas from the balloon, 

 afforded, in three experiments, an absorption of 0.03. 0.03, 

 and 0.034 vol., while the absorption in pure pit gas amounted 

 to 0.004 vol., being the mean of three experiments. Conse- 

 quently, the oxygen in the gas from the balloon amounted to 

 about 0.009 vol. 



How much nitrogen was indicated by this quantity, it is 

 difficult to determine, because, as is well known, water ex- 

 posed to the atmospheric air absorbs oxygen in a larger 

 proportion than that contained in atmospheric air. If we 

 should assume that the air which has passed from the wa- 

 ter to the pit gas was constituted like the atmospheric air, 

 then we should have 0.0433 \ ol. of atmospheric air ; and, ac- 

 cording to this assumption, the specific gravity of the pure pit- 

 gas, according to the second experiment, would be reduced to 

 0.552281. There is, however, no question that the quantity 

 of oxygen and nitrogen is made much too great in this way. 



If we calculate the specific gravity of the pit-gas according 

 to the results of the analysis in the detonation-tube (§ ix.) r 

 and reckon the specific gravity of carburetted hydrogen gas 

 = 0.5589, that of olefiant gas = 0.9804, and that of nitrogen 

 = 0976, then we obtain 0.5952. But if, according to the 

 analysis with chlorine, the pit-gas be composed of : — 



Carburetted hydrogen, . . . 0.9388 



Olefiant gas, ..... 0.0380 



Nitrogen, ..... 0.0232 



1.0000 

 then the specific gravity would be 0.5846. 



More confidence is plainly to be put in the analysis by the 

 detonation- tube that in that by means of chlorine, although 

 the specific gravity, calculated according to the latter, corres- 

 ponds better with that found by direct experiment, than does 

 the specific gravity calculated from the former. 



The specific gravity of marsh-gas, according to Henry, is 

 0.582 to 0.586. After subtracting ^ nitrogen, we obtain 

 0.556. which corresponds pretty accurately with the specific 



