Thwarted in his plan to secure easy possession of Morris Island as a base for breaching operations against Fort Sumter, Gillmore now determined to batter the fort into submission from the ground he already possessed. Batteries Wagner and Gregg would be taken by protracted siege operations. Anticipating that Sumter was “liable to be silenced sooner or later” and fearing attack at other points about the harbor, Confederate authorities continued to remove the fort’s guns and ammunition for use elsewhere. By mid-August, Sumter’s armament was reduced to 38 cannon and two mortars.
At distances of 2 to 2½ miles from Fort Sumter—distances extraordinary for such operations—Gillmore set up eight batteries of heavy rifled cannon. In the marsh west of Morris Island, where the mud was like liquid, his engineers successfully placed a 200-pounder Parrott rifle—the notorious “Swamp Angel”—to fire on Charleston.
Gillmore’s batteries did some experimental firing in late July and early August, testing the range and the effects of their shots on Sumter. The real bombardment began on August 17, with nearly 1,000 shells being fired that first day alone. Almost 5,000 more were fired during the week that followed. Even at the end of the first day it was obvious that the fort was never intended to withstand the heavy Parrotts. Three days later, a monstrous 13-ton Parrott rifle hurling 250-pound shells was added to Gillmore’s armament, making 18 rifled cannon in action. The range kept Sumter from replying to the land batteries, and the monitors appeared only fleetingly.
On the 21st, with the “Swamp Angel” in position, Gillmore demanded the evacuation of Fort Sumter and Morris Island. Otherwise he would fire on Charleston. The ultimatum was unsigned, however, and before the Confederates could confirm its origin, Gillmore had opened fire. But little damage had been done when, on the 36th round, the “Swamp Angel” burst. Meanwhile, Beauregard had delivered an indignant reply. The bombardment of Sumter continued.
Early on the 23d, against Dahlgren’s ironclads, Fort Sumter fired what proved to be its last shots in action. Its brick masonry walls were shattered and undermined; a breach 8 by 10 feet yawned in the upper casemates of the left face; at points, the sloped debris of the walls already provided a practicable route for assault. Still, the Confederate garrison, supplemented by a force of 200 to 400 blacks, labored night and day, strengthening and repairing the defenses. The debris, accumulating above the sand- and cotton-filled rooms, itself bolstered the crumbling walls. By the 24th, Gillmore was able to report the “practical demolition” of the fort. On the 26th General Beauregard ordered the fort held “to the last extremity.”
The bombardment continued sporadically during the following week. On the night of September 1-2, the ironclads moved against the fort—the first major naval operation against Fort Sumter since the preceding April. For five hours, the frigate New Ironsides and five monitors bombarded the fort, now without a gun with which to answer the “sneaking sea-devils.” Two hundred and forty-five shot and shell were hurled against the ruins—twice as many as were thrown in the April attack. The tidal conditions, plus a “rapid and sustained” fire from Fort Moultrie, forced the monitors to withdraw.
Some desultory firing on the 2d brought to an end the first sustained bombardment of Fort Sumter. More than 7,300 rounds had been hurled against the fort since August 17. Now, with the fort reduced to a “shapeless and harmless mass of ruins,” the Federals could concentrate on Battery Wagner, only 100 yards from Gillmore’s forward trenches.
On the morning of September 5, Federal cannoneers began a devastating barrage against Battery Wagner. For 42 hours, night and day, in what General Gillmore called a spectacle “of surpassing sublimity and grandeur,” 17 mortars and nine rifled cannon, as well as the powerful guns of the ironclads, pounded the earthwork. Calcium lights turned night into day. On the night of September 6-7, the Confederates evacuated Wagner and Gregg. Morris Island was at last in Union hands.
Fort Sumter, however, remained defiant. When Dahlgren demanded the fort’s surrender, on the morning of the 7th, General Beauregard sent word that the admiral could have it when he could “take it and hold it.” On September 4 the garrison had been relieved by fresh troops, 320 strong. Maj. Stephen Elliott succeeded to the command.