On the night of his arrival he requested that Sherman should be placed in command of the army of the Tennessee, and his wish was granted. Hooker's command from the army of the Potomac had been sent down to act with the army of the Cumberland, and was now at Bridgeport. The question of supplies was the first which engaged Grant's attention. Except the town of Chattanooga, the rebels held all the country south of the Tennessee, and frequently invaded the northern shore in cavalry raids, cutting off the Union supplies. A pontoon bridge was stretched across the river at Brown's Ferry, the boats, each carrying thirty men, being silently floated down the river unobserved by the rebel pickets. The operation was conducted in the night, and, being a complete success, a footing was gained on the south bank of the river below the town. The Nashville and Chattanooga Railroad crossed the Tennessee at Bridgeport, where Hooker, with the Eleventh and Twelfth Corps, was located, and came up to Chattanooga through Lookout Valley, on the south side of the stream, which, being in the hands of the enemy, had cut off the supplies. Hooker was ordered to cross the river, and follow the railroad up to the valley. At Wauhatchie he encountered the rebels, but drove them before him, and reached a point within a mile of the new pontoon bridge on the night of the 28th of October. He was fiercely attacked by Longstreet, but successfully repelled the assault, and Lookout Valley was virtually captured. By this movement a direct road to Bridgeport, to which the railroad from Nashville was in working order, was opened in five days after the arrival of Grant. Only a week before, Jeff. Davis himself had stood upon the summit of Lookout Mountain, and gazed down upon the Union army shut up in Chattanooga, absolutely sure that in a brief period, without striking a blow, it must surrender to Bragg. The tables were suddenly turned by the matchless skill of Grant. The ammunition and stores poured in upon the desponding army, now reënforced by two corps, and hope and joy supplanted fear and despair. The hungry men were once more fed on full rations, horses were promptly brought up, and the army of the Cumberland was ready to become the assailants again. The rebels were confounded by the sudden change in the situation before them.