became satisfied that nearly the whole force of the enemy from Richmond was assembling in my front, along the south side of the Rapidan, and extending from Raccoon Ford to Liberty Mills.
The cavalry expeditions sent out on the 16th in the direction of Louisa Court-House captured the adjutant-general of General Stuart, and was very near capturing that officer himself. Among the papers taken was an autograph letter of General Robert E. Lee to General Stuart, dated Gordonsville, August 13, which made manifest to me the position and force of the enemy and their determination to overwhelm the army under my command before it could be re-enforced by any portion of the Army of the Potomac. I held on to my position thus far to the front for the purpose of affording all time possible for the arrival of the Army of the Potomac at Aquia Creek and Alexandria and to embarrass and delay the movements of the enemy as far as practicable. On the 18th of August it became apparent to me that this advanced position, with the small force under my command, was no longer tenable in the face of the overwhelming forces of the enemy. I determined, accordingly, to withdraw behind the Rappahannock with all speed, and, as I had been instructed, to defend, as far as practicable, the line of that river, I directed Major-General Reno to send back his trains on the morning of the 18th, by the way of Stevensburg, to Kelly's or Barnett's Ford, and, as soon as the trains had gotten several hours in advance, to follow them with his whole corps, and take post behind the Rappahannock, leaving all his cavalry in the neighborhood of Raccoon Ford to cover this movement. General Banks' corps, which had been ordered on the 12th to take position at Culpeper Court-House, I directed, with its trains preceding it to cross the Rappahannock at the point where the Orange and Alexandria Railroad crosses that river. General McDowell's train was ordered to pursue the same route, while the train of General Sigel was directed through Jefferson, to cross the Rappahannock at Warrenton Sulphur Springs. So soon as these trains had been sufficiently advanced McDowell's corps was directed to take the route from Culpeper to Rappahannock Ford, whilst General Sigel, who was on the right and front, was instructed to follow the movements of his train to Sulphur Springs. These movements were executed during the day and night of the 18th and the day of the 19th, by which time the whole army, with its trains, had safely recrossed the Rappahannock, and was posted behind that stream, with its left at Kelly's Ford and its right about 3 miles above Rappahannock Station, General Sigel having been directed immediately upon crossing at Sulphur Springs to march down the left bank of the Rappahannock until he connected closely with General McDowell's right.
Early on the morning of the 20th the enemy drove in our pickets in front of Kelly's Ford and at Rappahannock Station, but finding we had covered those fords, and that it would be impracticable to force the passage of the river without heavy loss, his advance halted, and the main body of his army was brought forward from the Rapidan. By the night of the 20th the bulk of his forces confronted us from Kelly's Ford to a point above our extreme right. During the whole of the days of the 21st and 22nd effort were made by the enemy at various points to cross the river, but they were repulsed in all cases. The artillery fire was rapid and continuous during the whole of those days, and extended along the line of the river for 7 or 8 miles. Finding that it was not practicable to force the passage of the river in my front, the enemy began slowly to move up the river for the purpose of turning our right. My orders required me to keep myself closely in communi