Up to this period our forces at Chattanooga were practicably invested, the enemy's line extending from the Tennessee River above Chattanooga to the river and below the point of Lookout Mountain below Chattanooga, with the south bank of the river picketed to near Bridgeport, his main force being fortified in Chattanooga Valley, at the foot of and on Missionary Ridge, and Lookout Mountain, and a brigade in Lookout Valley. True, we held possession of the country north of the river, but it was from 60 or 70 miles over the most impracticable of roads to any supplies. The artillery horses and mules had become so reduced by starvation that they could not have been relied on for moving anything. An attempt at retreat must have been with men alone, and with only such supplies as they could carry. A retreat would have been almost certain annihilation, for the enemy, occupying positions within gunshot of and overlooking our very fortifications, would unquestionably have pursued our retreating forces. Already more than 10,000 animals had perished in supplying half rations to the troops by the long and tedious route from Stevenson and Bridgeport to Chattanooga over Walden's Ridge. They could not have been supplied another week. The enemy was evidently fully apprised of our condition in Chattanooga, and of the necessity of our establishing a new and shorter line by which to obtain supplies, if we could no maintain our position; and so fully was he impressed of the importance of keeping from us these lines-lost to him by surprise and in manner he little dreamed of-that in order to regain possession of them a night attack was made by a portion of Longstreet's forces on a portion of Hooker's troops (Geary's division, of the Twelfth Corps) the first night after Hooker's arrival in the valley. This attack failed, however, and Howard's corps, which was moving to the assistance of Geary, finding that it was not required by him carried the remaining heights held by the enemy west of Lookout Creek. This gave us quiet possession of the lines of communication heretofore described south of the Tennessee River. Of these operations I cannot speak more particularly, the sub-reports having been sent to Washington without passing through hands. By the use of two steam-boats, one of which had been left at Chattanooga by the enemy and fell into our hands, and one that been built by at Bridgeport, plying between Bridgeport and Kelley's Ferry, we were enabled to obtain supplies with but 8 miles of wagoning. The capacity of the railroad and steam-boats was not sufficient, however, to supply all the wants of the army, but actual suffering was prevented. Ascertaining from scouts and deserters that Bragg was detaching Longstreet from the front and moving him in the direction of Knoxville, Tennessee, evidently to attack Burnside, and feeling strongly the necessity of some moved that would compel him to retain all his forces and recall those he had detached, directions were given for a movement against Missionary Ridge, with a view to carrying it, and threatening the enemy's communication with Longstreet, of which I informed Burnside by telegraph on the 7th of November. After a through reconnaissance of the ground, it was deemed utterly impracticable to make the move until Sherman could get up, because of the inadequacy of our forces and the condition of the animals then at Chattanooga, and I was forced to leave Burnside for the present to contend against superior forces of the enemy until the arrival of Sherman with his men and means of transportation. In the meantime reconnaissance were made and plans matured for operations.