Needle Valve
- As colloquially used, refers to the shut-off valve in the carburettor, and is opened and shut, automatically, by the action of the float. (See illustration.) Neutral position of the gear lever is when the sliding gears, in the change-speed box, are disconnected or out of mesh. Out of Gear.- [See "NEUTRAL POSITION."] Overheating is caused by a variety of misdemeanours, such as bad lubrication, rich mixture, "racing" the engine, faulty water circulation, choked-up silencer, &c.
Petrol. Volatile distillates from petroleum of a specific gravity of from 610 to 750.
Piston. That portion of the engine mechanism which reciprocates inside the cylinder and transfers the effect of the explosions to the crank shaft (per the connecting rod).
Piston Ring.-Flat metal rings encircling the piston and making it gas-tight.
Planet Wheels. Of the differential; so called because of their motion (1) on their own axis, and (2) about the axis of the axle shaft, thus giving them a characteristic of the heavenly bodies.
Radiator. The reticulated structure, placed either before or behind, the engine, and constituting an efficient device for cooling off the heated water from the cylinder jackets.
Secondary Current.-A current "induced" by a primary current, and caused by the proximity of the secondary coil to the primary, at a time a change of effect is taking place in the latter. It is purely reactive or sympathetic, and, apart from this, is one of the puzzles of the universe.