CARBURETTER is a device to form an explosive mixture of air and a hydrocarbon liquid fuel of a volatile nature such as petrol or gasolene. The function of a carburetter may be divided into three steps : to discharge into the air stream the desired amount of fuel; to atomize the fuel; and to make a homogeneous air-fuel mixture. (See MOTOR CARS.) Carburetters have to he multiplied in large-power engine outfits for aeroplanes, four being employed for a 12-cylinder engine, and they require an altitude control to compensate for the rarer atmosphere at high altitudes. Carburation is a process also required in the manufacture of air gas and carburetted water-gas (see WATER GAS).