GASOLINE, GASOLENE, or PETROL, a mixture of hydrocarbons chiefly derived from petroleum (q.v.) by direct (straight) distillation or by "cracking" and other synthetic and catalytic processes; it is also obtained from refinery gases (lique fied) and from natural gas (q.v.). Its principal use is as a fuel for the internal combustion engines (q.v.) of motor vehicles, and it is in expanding use in aviation for which special aviation gasoline has been developed by significant new refinery processes (see