Upon learning that Fort Henry had fallen, Grant steamed up the Cumberland to attack Fort Donelson, which was reinforced until the garrison numbered some 20,000 men. It was a powerful fortification, with many rifle-pits and intrenchments on the land side, and powerful batteries commanding the river. The political General Floyd was in chief command, the right wing being under General Simon B. Buckner and the left in charge of General Gideon J. Pillow. On the afternoon of February 14th, Commodore Foote opened the attack with two wooden vessels and four ironclad gunboats. The garrison made no reply until the boats had worked their way to within a fourth of a mile of the fort, the elevation of which enabled it to send a plunging fire, which proved so destructive that two of the boats were disabled and drifted down current, the other following. Some fifty men were killed, and among the wounded was Commodore Foote. He withdrew to Cairo, intending to wait until a sufficient force could be brought up from that point. [Illustration: UNITED STATES 12-INCH BREECH-LOADING MORTAR, OR HOWITZER.] But General Grant, like the bull-dog to which he was often compared, having inserted his teeth in his adversary, did not mean to let go. Placing his troops in front of the works, it did not take him long to invest the whole Confederate left, with the exception of a swampy strip near the river. The weather, which had been unusually mild for the season, now became extremely cold, and some of the Union men were frozen to death in the trenches. The garrison also suffered greatly, but the siege was pressed with untiring vigor. Seeing the inextricable coils closing round them, the defenders made an attempt to cut their way out, but Grant with true military genius saw the crisis and ordered an advance along the whole line, the gunboats giving all the help they could. The situation of the garrison was so dangerous that a council of war was held that night. Floyd and Pillow were frightened nearly out of their wits. They rated themselves so high as prizes for the Federals that they determined to make their escape before the surrender, which was inevitable, was forced. Buckner was another sort of man. Disgusted with the cowardice of his associates, he quietly announced that he would stay by his men to the last. Floyd stole out of the fort with his brigade and crossed the river in boats, while Pillow followed in a scow, a large number of the cavalry galloping by the lower road to Nashville.