Propeller

—That which transmits the power of the engine to the water; generally speaking, the screw propeller, which | is a spirally vaned wheel whose rotation displaces the water, consequently driving the ve el along. In automobiles, a fan resembling a screw propeller in appearance, which induces a draught through the radiator which cools the circulating water; in air cooled engines the fan drives air over the cylinders to maintain them at a moderate temperature, instead of using water circulation for that purpose.