This area is surrounded by casemated walls, which are in fact huge bomb-proof buildings, structures of stone with heavy arches of brick to support the great mass of earth which is required to protect them from shells thrown from mortars. In these casemates are quarters for the officers and men of the garrison, magazines for ammunition, storehouses for all manner of supplies, a hospital of generous dimensions, a huge cistern for water, an ice-house, cook, and mess-room, besides space for a large battery of heavy guns facing towards the sea. Some of these vaulted chambers are lighted through the outer walls by means of embrasures calculated for howitzers, or by loop-holes intended for defence by musketry. Others look out upon the parade ground, and have upon that face the appearance of stone dwellings of one storey, entered by ordinary doorways, and lighted through spacious windows. Those which occupy the northwest side of the parade are of two stories, one being below the level of the interior grade. These are for use as officers’ quarters, and during the war, those which are entered from the doors nearest to, and on either side of the entrance arch, were occupied by the civilians and officers among the prisoners confined in the fort. The interior depth of the casemates, from the inner to the outer wall, does not vary much from sixty feet, giving ample space, equal indeed to the depth of a large city residence. The barracks for the soldiers are divided into rooms, generally about sixty by twenty feet, and during a part of the war many of them were assigned to the enlisted men who were prisoners. A full garrison for Fort Warren would be not far from twenty-five hundred men, and that number could be quartered in the casemates. Above these buildings are the ramparts, on which the chief part of the armament is placed, and these ramparts are walled in by a parapet of about five feet in height, of very thick masonry, intended to protect the men while working the guns, from the fire of an enemy. These ramparts are now provided with a full armament of ten inch and fifteen inch guns, placed as near together as convenience in working would permit, but in our day the greater part of the guns were four inch and thirty-two pounders, the casemate battery alone, consisting of eight inch columbiads. The entire equipment of the Fort comprises over three hundred of these heavy guns, of which some seventy may always be concentrated upon any one point of the channel which they defend. Outside, and immediately surrounding the walls of the casemated fort is a fosse, or ditch, some fifty feet in width, and outside of this are other defences, (which outwardly, are earthworks,) including an exterior curtain on the north, a ravelin on the south, and a water battery on the northwest, the whole composing in fact a fortress of great strength, even in these days of iron-clads and great guns.