John G. Nicolay, The Outbreak of Rebellion

The three hours of unopposed bombardment from the rebel batteries had by this time already determined one important phase of the fight. Carefully watching the effect of the enemy's cannonade, it was apparent, without further question, that under the concentrated missiles of their guns, and particularly because of the precision of their vertical fire, it would be folly to expose the gunners on the rampart or the open parade of the fort. Had Sumter contained a full war garrison, new men could have replaced those killed or disabled; but, with his slender force, Anderson decided that he could not afford this risk, and therefore at once ordered an abandonment of all the barbette guns and a few mounted on the parade to throw shells, restricting the men rigidly to the casemates. Thus at one swoop his fighting armament was reduced more than one-half. This, however, was not the worst; it practically annihilated the offensive strength of the fort. Of the twenty-one casemate guns but four were fortytwo pounders, the rest only thirty-twos, a weight of metal of little avail against the enemy's strong earthworks and iron roofs.

In this way the cannonade went actively on during the forenoon of April 12th, without much damage or effect, except upon the buildings in both Sumter and Moultrie, ordinarily occupied as barracks and quarters. Sumter suffered most in this respect: the balls striking the face of its walls merely buried themselves in the brick-work, without passing through; but those which nearly or quite grazed the parapet, in their fall took the buildings or wall in reverse, coming as they did from three sides. The men, however, while sheltered in casemates, were beyond the reach of these missiles. So too of the bombs. Falling on the parapet and the