HDQRS. SECOND DIVISION, NINTH ARMY CORPS, Lyon's Mills, Tenn., January 31, 1864.

CAPTAIN: On the 21st ultimo the Ninth Corps was at Strawberry Plains. The army was moving toward Knoxville, whit heavy trains over bad roads, and the Ninth Corps was left to bring up the rear. The bridge being dismantled and set on fire, our pickets were withdrawn, as directed by the major-general commanding, from the south side of the river in a flat-boat. The enemy soon appeared, lined the banks of the river commanding the plains, and from Seminary Hill opened fire whit a field battery. lieutenant Gittings, with Batteries L and M, third U. S. Artillery, was posted near a block-house covering the depot, but place his four guns in a better position on the ridge next in rear of the block-house, and replied with such effect as to silence the enemy, notwithstanding a cross-fire brought to bear upon him from a point to our left and front.

We remained in position all day at Strawberry Plains annoyed, after the artillery ceased, only by the enemy's sharpshooters. They showed a considerable force of cavalry and mounted infantry, some squadrons, and one long column which we were able to reach whit our shells with considerable apparent effect. They seemed to be moving down from the New Market od out upon the Sevierville road, from which there were roads leading to a ford 2 miles below us, and other fords still lower down, crossing at either of which would have enabled them to cut our train stretched between Strawberry Plains and Knoxville. The picket at the ford was strengthened,a nd a regiment sent to Flat Creek by the general's order. In the evening a train of cars was expected to take off some public property remaining at the depot, consisting mainly of two guns, said to belong to Godspeed's battery (not of the Ninth Corps), and some caissons. There was no transportation to take this property away,a nd a telegram was received stating that the cars had run off the track just out of Knoxville. The troops were ordered by General Parke to be at Flat Creek by daylight. The batteries were started at 12, the troops at 3. I was directed to bring off the guns and caissons, before mentioned, if possible; if not, to destroy them. The men of the Ninth Corps volunteered to drag the guns, which they did with much labor, and the caissons were destroyed, as it was impossible to bring them away. The troops reached Flat Creek by daylight, and were ordered to move on toward Knoxville in rear of the Twenty-third Corps.

At about 1 o'clock on the 22nd, the enemy's cavalry appeared in our rear, 1 mile above the Armstrong house, just as we came up with Manson's division, Twenty-third Corps, which had been halted. The lines were formed and we marched in company with General Manson, without annoyance from the enemy, to a position a mile above the intersection of the Armstrong's Ferry road with the Knoxville road, where I ordered a halt of all the troops, threw out skirmishers toward the enemy, encountered their skirmish line,d rove them back, and carried two wooded knolls which they had seized in our rear and right. The rebel force driven off, we went into bivouac. They made a demonstration on General Manson's pickets early in the evening, which was repulsed. Their whole force returned toward Strawberry Plains about midnight,a nd we saw no more of them. They were said to be Armstrong's division of cavalry and mounted infantry.