It was shown by this paper that the gases dissolved in American petroleum, and which gave to it such a high degree of inflammability, were composed of the lower members of the marsh gas series, having the general formula,

and to which the liquid products have already been referred.

The gases evolved from the Pennsylvanian oil were collected at a temperature of −1° Cent., as they floated, mixed with air, over the surface of the liquid in the casks in which it is imported into this country and the hydrocarbons were shown by eudiometrical analysis to have the composition of a mixture in nearly equal proportions of the hydrides of ethyl and propyl.