Grant, however, held a different opinion. On the night of the 23d the enemy's picket lines were forced back and an improved position secured. The following morning, Hooker, having already crossed the river, was ordered to attack the position on Lookout Mountain. His movements were hidden for a time by a dense fog, and it was his intention to stop as soon as the enemy's rifle-pits at the base were captured; but, when this was accomplished, the men were carried away by their enthusiasm, noting which Hooker ordered them to charge the Confederate position. Up the mountain the cheering, eager fellows swept with irresistible valor. The Stars and Stripes was planted on the crest and 2,000 of the fleeing Confederates were made prisoners. The fog still lay heavy in the valley below, a fact which has led to the battle being called the "Battle above the Clouds." DEFEAT OF THE CONFEDERATES. The following morning was also foggy, but, when it lifted, Sherman's corps was seen advancing against the Confederate right, close to Chickamauga station. In the face of a heavy artillery fire the Federals pressed on, but at the end of an hour they were compelled to retreat. By order of Grant the attack was renewed, but another severe repulse followed. Next a general movement against the left centre was ordered, and this was successful. The enemy was driven in confusion toward Ringgold, to the southeast, while a large number of prisoners and a vast amount of supplies were captured. General Hooker pursued and drove the Confederates out of Ringgold, but they assumed so strong a position at Taylor's Ridge that Grant ordered him not to attack, but to remain and hold Ringgold, Sherman, in the meantime, marching against Longstreet. Bragg had blundered so much in conducting this disastrous campaign that President Davis was forced to replace him with Hardee. RAISING OF THE SIEGE OF KNOXVILLE. Meanwhile, Longstreet was besieging Burnside at Knoxville, where the 15,000 Union troops were threatened with starvation. The town was invested November 17th, and the next day some of the outworks were carried. Well aware that Grant, after his defeat of Bragg, would hurry to the relief of Knoxville, Longstreet attacked on the 29th, but suffered a bloody repulse. He stubbornly held his ground until he learned that Sherman was close upon him, when he withdrew and started on his march to Virginia. The campaign soon ended in Tennessee, which was virtually recovered to the Union. The reader will note that we have described the leading events in the West and Southwest from the opening of the year to its close. Once more it is necessary to return to January, 1863, in order to give a history of the most important campaign of all--that against Richmond, which was defended by the formidable Army of Northern Virginia, under the command of General Robert E. Lee. BURNSIDE SUPERSEDED BY HOOKER.