M., a demand for the surrender of Fort Sumter was sent to General Beauregard, with a threat that, if the demand was not complied with, the city of Charleston should be shelled within four hours. The demand was refused, although the fort was a ruin; and the paper containing the demand was returned at seven o’clock on the morning of the 22d to General Gilmore. The flag of truce which had been hoisted during the sending of and return of the demand, was now lowered, and the firing recommenced in all its fury, passing from end to end of the Union line, and continuing with unabated fierceness for the remainder of the day. General Gilmore, (after allowing time for the removal of the women and children,) gave orders to Lieutenant Sellmer, commanding the “Swamp Angel,” to open with his heavy rifled gun upon the city of Charleston; and accordingly, fifteen shells (of Birney’s invention), were thrown across the James Island batteries into the town. The arrival of these projectiles caused the utmost terror and dismay to the inhabitants, who rushed blindly to and fro in indescribable confusion, while the light of burning buildings and the ringing of alarm bells, gave proof to the Unionists of the consternation caused by the unexpected arrival of the messengers from the “Swamp Angel.” Fort Wagner now gathered up her whole strength to throw against the Union forces, and her firing, directed exclusively against the right, became really terrific. The Ironsides and two other monitors came up, and for four hours poured a torrent of shells into the Confederate fort, which finally silenced her. Another flag of truce was hoisted during the day to receive a message from General Beauregard, which turned out to be an indignant protest against what he was pleased to call General Gilmore’s “unchristian and uncivilized mode of warfare” in shelling the city of Charleston. The dispatches were instantly replied to, and in a manner not calculated to quiet Beauregard’s indignation. Again there was a suspension of hostilities while the message was being carried, but the firing recommenced as soon as the dispatch had been delivered. During the night only a few shots were exchanged by the combatants; and on the next morning such a dense fog hung over the bay that operations were temporarily suspended. The “Swamp Angel” was again trained on Charleston; and the shelling of the city continued with great violence for a good part of the night, while the rebel batteries on James island continued playing away on the “Swamp Angel,” but without doing it any great damage.