Intricate Gun Rooms

Most of Fort Jefferson's heavy guns were mounted in intricately built casemates with arched ceilings designed to transfer the massive weight of brick and cannon on the upper tiers to vertical piers. Carpenters made wooden frames for the arches, and skilled masons laid brick and mortar on them. An embrasure in the wall allowed the gun crew to fire cannonballs at ships, and between firings iron Totten shutters, named for the fort's chief architect, Gen. Joseph G. Totten, closed automatically to protect cannon and crew from enemy fire. The fort was designed to hold 420 guns on three levels but was never fully armed, and whitewashed walls and ceilings brightened the casemate interiors.