ACIDIFIABLE COMBUSTIBLES. 



be 0*5590 : this nearly agrees with the specific 

 gravity of the first specimen of gas collected by 

 me near Glasgow. 



It has been established by accurate experi- 

 ments, that a volume of this gas requires, for 

 complete combustion, two volumes of oxygen 

 gas, and that the residual gas is one volume of 

 carbonic acid. From this fact, it is easy to de- 

 duce the true specific gravity, the composition, 

 and the atomic weight of this gas. 



(I.) One volume of the oxygen gas must have 

 gone to the formation of carbonic acid gas, and 

 must have united with 1 volume of carbon va- 

 pour 5 the other volume of oxygen gas must 

 have gone to the formation of water, and must 

 have united with two volumes of hydrogen gas. 

 Thus it appears, that the constituents of car- 

 buretted hydrogen gas, are one volume carbon 

 vapour, and 2 volumes hydrogen gas, condensed 

 into 1 volume. Hence, its specific gravity will 

 be obtained by adding together the specific gra- 

 vity of carbon vapour, and twice the specific 

 gravity of hydrogen gas. 



Sp. gr. of carbon vapour = 0-4166' 

 2 sp. gr. of hydrogen gas = 0-1388 



0-5555 = sp. gr. 

 of carburetted hydrogen gas. 



Or its specific gravity is exactly half that of oxy- 

 gen gas. 



