Thomas was being reënforced from all sides; Hooker was already on the ground; Sherman was advancing rapidly from Memphis, while Burnside's forces at Knoxville offered protection for the left flank of the Federal army. General Bragg had his forces in a line extending a distance of twelve miles across to Missionary Ridge, and was strengthened by entrenchments throughout the lowlands. He determined to attack Burnside at Knoxville, and dispatched Longstreet over his protest with 20,000 men to do this, thus weakening his extended lines. This has been considered a very great mistake of Bragg, as his total force was much less than had opposed Rosecrans at Chickamauga. Grant had now arrived and had assumed command of the entire Federal forces, and had planned to attack Bragg on November 24th, but on receiving information, which proved to be unreliable, that Bragg was preparing to retreat, he decided to make the attack on the 23d, and ordered Thomas to advance upon Bragg's center. This attack took the Confederates by surprise. After some severe fighting, they fell back more than a mile and left the Federals in command of some advantageous positions, thus ending the first day's battle. Preparations were made during the night for a general engagement the next day. Sherman was in command of the left wing, while Thomas held the center, and Hooker the right, and they had planned to sever communications between Bragg and Longstreet, and thus keep the Confederate army divided. Early on the 24th Sherman moved against the Confederate right, and with little opposition occupied the northern end of Missionary Ridge. The Confederates, after discovering this advantageous position taken by Sherman, fought desperately in the afternoon to regain it, but were finally repulsed. While this was going on, General Hooker, with a division of Sherman's army, was making a desperate struggle for the capture of Lookout Mountain, whose rugged crests towered above the clouds. This mountain was ably defended by the Confederates, but they were finally pushed back by overwhelming numbers and made their final stand within the breastworks about the Craven house, but were finally dislodged from this place and retired within their entrenchments in the valley. This has been termed "The Battle in the Clouds." [Illustration: BATTLE OF GETTYSBURG]