The lieutenant of marines has the command of the marines, or soldiers, on board the ship, of whom there were twenty in the Harrisburg. These men are employed as sentinels in various parts of the ship. One is always stationed at the wardroom door, one at the “brig,” and one at the scuttle-butt, or pump. At anchor, one is on duty at the gangway, or place where the ship is entered; and one on the forecastle. Between sailors and marines there is a mortal antipathy, which the officers do not seek to abate; for the soldiers are depended upon in case of mutiny and insubordination. The chief engineer has the sole charge of the engines and boilers, and the subordinate engineers are under his command. On board our ship there were one first, two second, and four third assistant-engineers; these officers having the actual charge of the engines, keeping watch like the other officers: but their chief does not keep a watch. Master’s mates and midshipmen, who occupy the steerage, are aids to the various officers, and have miscellaneous duties. The forward officers are, the boatswain, who has charge of the rigging and cordage; the gunner, who has charge of the guns and ammunition; the carpenter, who does the joinery-work; and the sailmaker, who makes and mends sails. The boatswain has four mates, one of whom is called chief. The gunner has one mate, and one quarter-gunner for each division of three guns on a side. The carpenter and sailmaker have each one mate, and each his gang, selected from the crew. All ranking below the forward officers are called petty-officers, of whom there is a host: such as captain of the fore, main, or mizzen top; captain of the hold, of the forecastle, of the after-guard; quartermaster, master-at-arms, ship’s corporal, yeoman, armorer, etc. Quartermasters have charge of the wheel, or steering-apparatus, of the signals, and of the lead. The master-at-arms is the chief of police, assisted by the ship’s corporals. The yeoman has charge of the ordnance and stores. Each of the boats is in charge of a petty-officer called a cockswain. The duties of the other petty-officers will be understood from their names. CHAPTER VIII. “ALL HANDS, UP ANCHOR!” Jack Somers had a very correct idea of the interior of a man-of-war, and of the various officers and their duties, when he went on board the Harrisburg; but he was not a little confused by the many numbers he had to remember, which were used to indicate his various stations at the guns and the mess, on deck, in the top, in the boat, and in his hammock.