The captured despatch revealed to Pope the fact that Lee intended to fall upon him with his entire army and crush him before he could be reinforced from the Army of the Potomac. Pope says: "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 Acquia 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 Burnett'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, {166} leaving all his cavalry in the neighborhood of Raccoon Ford to cover this movement. General Banks's 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 three miles above Rappahannock Station." The Confederates followed rapidly, and on the 20th confronted Pope at Kelly's Ford, but with the river between. For two days they made strenuous efforts to cross, but a powerful artillery fire, which was kept up continuously for seven or eight miles along the river, made any crossing in force impossible. Lee therefore sent Jackson to make a flank march westward along that stream, cross it at Sulphur Springs, and come down upon Pope's right. But when Jackson arrived at the crossing, he found a heavy force occupying Sulphur Springs and ready to meet him. Meanwhile Gen. James E. B. Stuart, with fifteen hundred cavalrymen, in the dark and stormy night of August 22d, had ridden around to the rear of Pope's position, to cut the railroad. He struck Pope's headquarters at Catlett's Station, captured three hundred prisoners and all the