1825.] obtained by the Decomposition of Oil. 161 



vapour over heated oxide of copper: 0*776 grain of the sub- 

 stance produced 5*6 cubic inches of carbonic acid gas, at a 

 temperature of 60, and pressure 29*98 inches; and 0*58 grain 

 of water was collected. The 5*6 cubic inches of gas are 

 equivalent to 0*711704 grain of carbon by calculation, and the 

 0*58 grain of water to 0*064444 of hydrogen. 



Carbon 0*711704 or 11*44 



Hydrogen 0*064444 or ! 



These quantities nearly equal in weight the weight of the sub- 

 stance used ; and making the hydrogen 1, the carbon is not 

 far removed from 12, or two proportionals. 



Four other experiments gave results all approximating to 

 the above. The mean result was 1 hydrogen, 1 I '576 carbon. 



Now considering that the substance must, according to the 

 manner in which it was prepared, still retain a portion of the 

 body boiling at 186, but remaining fluid at 0, and which 

 substance I find, as will be seen hereafter, to contain less car- 

 bon than the crystalline compound (only about 8*25 to 1 of 

 hydrogen), it may be admitted, I think, that the constant 

 though small deficit of carbon found in the experiments is due 

 to the portion so retained ; and that the crystalline compound 

 would, if pure, yield 12 of carbon for each 1 of hydrogen, or 

 two proportionals of the former element and one of the latter. 



2 proportionals Carbon 12\ 10 , . , , , 



1 Hydrogen j |> 3 b.carburet of hydrogen. 



This result is confirmed by such data as I have been able to 

 obtain by detonating the vapour of the substance with oxygen. 

 Thus in one experiment 8092 mercury grain measures of oxy- 

 gen at 62 had such quantity of the substance introduced 

 into it as would entirely rise in vapour ; the volume increased 

 to 8505: hence the vapour amounted to 413 parts, or ^^of 

 the mixture nearly. Seven volumes of this mixture were 

 detonated in a eudiometer tube by an electric spark, and 

 diminished in consequence nearly to 6'1 : these, acted upon by 

 potash, were further diminished to 4, which were pure oxygen. 

 Hence 3 volumes of mixture had been detonated, of which 

 nearly 0*34 was vapour of the substance, and 2*65 oxygen. 

 The carbonic acid amounted to 2'1 volumes, and must have 

 consumed an equal bulk of oxygen gas ; so that 0*55 remain 



M 



