(21) Benzol.
Benzol has been used to some extent in Europe as a fuel, its use being due to the rapidly increasing cost of gasoline.
Benzol is a distillate of coal tar, and is a by-product of the coke industry. In England benzol brings approximately the same price as gasoline (called petrol), but benzol proves economical for the reason that it develops more power per gallon.
Benzol is not as volatile as gasoline, but is sufficiently volatile to allow of easy motor starting.
Benzol is also used for denaturing alcohol.
(22) Alcohol.
Alcohol is of vegetable origin, being the result of the destructive distillation of various kinds of starchy plants or vegetables. Starch is the base of alcohol.
As a fuel, alcohol has much in its favor, as it causes no carbon deposit, has smokeless and odorless exhaust, can stand high compression, and requires less cooling water than gasoline, as the heat loss is less through the cylinder walls, and for this reason it is more efficient fuel than gasoline.
At the present time the price of alcohol prohibits its general use. In order that alcohol equal gasoline in price per horse-power hour, it should sell for 10c. per gallon, the price of gasoline being 15c. per gallon.
Alcohol can be used in any ordinary gasoline engine with readjustment of carburetor and the compression.