John G. Nicolay, The Outbreak of Rebellion

[64] but the existing conditions created an immense disparity. Anderson's fire was diffused; the rebel fire was concentrated. Anderson's barbette guns, more than half his pieces, were exposed; most of the rebel guns were sheltered in bombproofs of palmetto logs and sand; some protected with sloping roofs of railroad iron. Anderson had only a garrison of 128 souls all told; while a volunteer force of from four to six thousand supported the rebel batteries. The greatest difference, however, was in the quality of the ordnance. Anderson's guns could only deliver a horizontal fire against the besiegers' earth-walls and bomb-proofs. But seventeen of the rebel pieces were mortars, delivering what is termed a vertical fire; that is, throwing their bursting shells by means of a high curve through the air, so as to drop down upon the parapet and inside the walls of the besieged fort.

The garrison of Sumter, notwithstanding its tedious confinement, was in excellent spirit, and, since the long apprehended contest had finally come, was quite ready to make a manful resistance. Even the forty-three non-combatant workmen caught the impulse of fight and freely volunteered their help. The needful preparations had been already made, and since the 10th every one had by order changed his quarters into the gun casemates. Here they were securely housed when at 4.30 A. M. the rebel cannonade began. It was not yet daylight, and for some hours the fort made no reply, but lay in the morning twilight as silent and apparently as unconcerned as if it were tenantless. The rations had already become uncomfortably short; the last barrel of flour was issued two or three days before, and now there was little left to subsist upon except pork and water. On this mainly the command made a breakfast, and at about seven o'clock Captain Abner Doubleday fired the first gun from the fort at an iron-clad battery on Cumming's Point.