Petty Officers in the Navy correspond to the noncommissioned officers of the Army, and they are divided into three general Branches, the Seaman Branch consisting of the deck force which mans the guns of the battery and performs the strictly “sailor” duties; the Artificer Branch composed of the engineering force, the electricians, the carpenters and the painters; and the Special Branch made up of yeomen, or clerical force, the commissary stewards, cooks and bakers, the hospital nurses and the bandsmen. As a rule the special duties of each of the Petty Officers are indicated by their titles, or “ratings,” as it is styled in the Navy, as given in the list on pages 37-40, but a few words of explanation may not be amiss. Masters-at-Arms are the policemen of the ship; boatswain’s mates are the petty officers who assist the boatswain and see that the orders of the officer of the deck are carried out in the different parts of the ship; turret captains are the petty officers who have charge of the turret guns crews under the Division Officer; gunner’s mates are the petty officers who assist the gunner and see to the repairs of the guns of the battery and have charge of the issue of powder and shell from the magazines to the guns; gun captains are the petty officers in charge of the individual gun crews; quartermasters are the petty officers who stand the watch at the wheel and steer the ship under the orders of the Officer of the Deck; machinist’s mates are the petty officers on duty at the engines and machinery; water tenders see that the proper amount of water is kept in the boilers, and the duties of the other petty officers are as indicated by their “ratings.” The ordinary enlisted men are apportioned to the three branches in the same manner as the petty officers, the Seaman Branch having seamen gunners especially trained for duty at the guns, seamen, ordinary seamen and apprentice seamen under training; the Artificer Branch having firemen who tend the fires under the boilers, coal passers who transfer the coal from the bunkers to the firerooms and landsmen or untrained men; and the Special Branch having the musicians of the band and buglers, and the lower ratings of cooks, bakers and hospital men. In the Marine Corps the commands considered appropriate for the officers of the different grades are as follows: COMMISSIONED OFFICERS