in Gunnery, the train of powder that is laid, from the opening of the vent, along the gutter or channel on the upper part of the breech of the gun: which, when fired, conveys the flame to the vent, by which it is further communicated to the charge, in order to fire the piece. This operation is only used on ship-board at the proof, and sometimes in garrison; for, on all other occasions, tubes are used for that purpose.

PRIMING-WIRE, in Gunnery, a sort of iron needle employed to penetrate the vent or touch-hole of a piece of ordnance, when it is loaded: in order to discover whether the powder contained therein is thoroughly dry and fit for immediate service; as likewise to search the vent and penetrate the cartridge, when the guns are not loaded with the loose powder.

among painters, signifies the laying on of the first colour.