The Federal loss in the three-days fight was twenty-three thousand; the Confederate was not officially reported, but probably much exceeded that number. Meade slowly followed Lee, who re-crossed the Potomac, and took position back of the Rapidan. _The Effect_ of this battle was to put an end to the idea of a Northern invasion. Lee's veterans who went down in the awful charges of Gettysburg could never be replaced. THE WAR ON THE SEA AND THE COAST. ATTACK ON CHARLESTON (April 7).--Such was the confidence felt in the ability of the iron-clads to resist cannonballs, that Admiral Dupont determined to run the fortifications at the entrance to Charleston, and force his way up to the city. The attempt was a disastrous failure. [Footnote: The Keokuk was sunk and nearly all the vessels were seriously injured. The officers declared that the strokes of the shots against the iron sides of their ships were as rapid as the ticks of a watch.] General Gillmore now took charge of the Union troops, and, landing on Morris Island, by regular siege approaches and a terrible bombardment captured Fort Wagner and reduced Fort Sumter to a shapeless mass of rubbish (map, p. 280). A short time after, a party of sailors from the Union fleet essayed to capture it by night, but its garrison, upstarting from the ruins, drove them back with great loss. [Footnote: In a marsh west of Morris Island, piles were driven in the mud twenty feet deep, and a platform made on which was placed an eight-inch rifled Parrot gun, which was nicknamed the "Swamp Angel." It threw shells five miles into Charleston, but burst on the thirty-sixth round. The bombardment of the city was afterward continued from the other batteries.] [Footnote: Two unsuccessful charges were made on this fort. In one, the 54th regiment, Colonel Shaw, bore a prominent part. It was the first colored regiment organized in the free States. In order to be in season for the assault it had marched two days through heavy sands and drenching storms. With only five minutes rest it took its place at the front of the attacking column. The men fought with unflinching gallantry, and planted their flag on the works; but their colonel, and so many of the officers were shot, that what was left of the regiment was led off by a boy--Lt. Higginson. No measure of the war was more bitterly opposed than the project of arming the slaves. It was denounced at the North, and the Confederate Congress passed a law which threatened with death any white officer captured while in command of negro troops, leaving the men to be dealt with according to the laws of the State in which they were taken. Yet, so willing were the negroes to enlist, and so faithful did they prove themselves in service, that in December, 1863, over fifty thousand had been enrolled, and before the close of the war that number was quadrupled.]