CORPORAL of a Ship of War, an officer under the master at arms, employed to teach the officers the exercise of small arms, or of musketry; to attend at the gangway, on entering ports, and observe that no spirituous liquors are brought into the ship, unless by express leave from the officers. He is also to extinguish the fire and candles at eight o'clock in winter, and nine in summer, when the evening gun is fired; and to walk frequently down in the lower decks in his watch, to see that there are no lights but such as are under the charge of proper sentinels.