The Navy is administered ashore by a bureau system, consisting of a number of bureaus and offices having charge of the various activities required for the building and upkeep of the fleets at sea, and all directed by the Secretary of the Navy through the Office of Naval Operations, the Chief of Naval Operations with the rank of Admiral being the senior or ranking officer of the Navy. The bureaus are the Bureau of Navigation, whose Chief has the rank of Rear Admiral, and which has charge of the issuing and enforcing of orders to officers and enlisted men and the keeping of the records; the Bureau of Ordnance, whose Chief has the rank of Rear Admiral, and which has charge of the design, manufacture and repair of guns, torpedoes and ammunition; the Bureau of Construction and Repair, whose head is the Chief Constructor of the Navy and has the rank of Rear Admiral, and which has charge of the designing, construction and repair of all of the vessels of the Navy; the Bureau of Steam Engineering, whose head is the Engineer in Chief of the Navy, with the rank of Rear Admiral, and which has charge of the designing, construction and repair of the engines and boilers in the ships of the Navy; a Bureau of Supplies and Accounts, whose head is the Paymaster General of the Navy, with the rank of Rear Admiral, and which has charge of the purchase and issue of supplies and provisions for the Navy and the paying of the officers and enlisted men; the Bureau of Medicine and Surgery, whose head is the Surgeon General of the Navy, with the rank of Rear Admiral, and which has charge of the hospitals ashore, the hospital ships, and the health and sanitation of the Navy both afloat and ashore; the Bureau of Yards and Docks, whose Chief has the rank of Rear Admiral, and which has charge of the designing and construction and repair of the buildings and docks at the shore establishments of the Navy; and the Office of the Judge Advocate General, whose head is the Judge Advocate General of the Navy with the rank of Captain, and which has charge of the courts-martial and legal affairs of the Navy. For purposes of command and organization afloat and ashore the officers of the Navy are divided into the “Line,” composed of the officers holding the military command in the various ranks, and of a number of “Staff Corps,” composed of officers who have charge of the various coordinate duties. These “Staff Corps” are the Medical Corps, the Pay Corps, the Chaplains, the Corps of Naval Constructors, the Corps of Civil Engineers and the Professors of Mathematics. Prior to 1899 there was also a separate Corps of Engineers, but in that year this corps was consolidated with the Line and since that time the only officers holding the ranks of Chief Engineer, Passed Assistant Engineer and Assistant Engineer in the Navy are officers of the old Engineer Corps who are now carried on the Retired List of Officers.