actions of Hooker, King, and Ricketts on the 27th and 28th, and the furious battle on the 29th - were estimated by me and others as follows: McDowell's corps, including Reynolds' division, 12,000 men; Sigel's corps, 7,000 men; Reno's corps, 7,000; Heintzelman's corps, 7,000 men; Porter's corps, which had been in no engagement, and was, or ought to have been, perfectly fresh, I estimated at about 12,000 men, including the brigade of Piatt, which formed a part of Sturgis' division, and the only portion that ever joined me; but of this force the brigades of Piatt and of Griffin, numbering, as I understood, about 5,000 men, had been suffered to march off at daylight on the 30th to Centreville, and were not available for operations on that day. This reduced Porter's effective force on the field to about 7,000 men, which gave me a total force of 40,000 men. Banks' corps, about 5,000 strong, was at Bristoe Station, in charge of the railroad trains and of a portion of the wagon trains of the army still at that place.
Between 12 and 2 o'clock in the day I advanced the corps of Porter, supported by King's division, of McDowell's corps, to attack the enemy along the Warrenton turnpike. At the same time I directed Heintzelman and Reno, on our right, to push forward to the left and front toward Warrenton turnpike and attack the enemy's left in flank, if possible. For a short time Rickett's division, of McDowell's corps, was placed in support of this movement on our right. It was necessary for me to act thus promptly and make an attack, as I had not the time, for want of provisions and forage, to await an attack from the enemy, nor did I think it good policy to do so under the circumstances. During the whole night of the 29th and the morning of the 30th the advance of the main army under Lee was arriving on the field to re-enforce Jackson, so that by 12 or 1 o'clock in the day we were confronted by forces greatly superior to our own, and these forces were being every moment largely increased by fresh arrivals of the enemy from the direction of Thoroughfare Gap. Every moment of delay increased the odds against us, and I therefore advanced to the attack as rapidly as I was able to bring my forces into action. Shortly after General Porter moved forward to the attack along the Warrenton turnpike and the assault on the enemy was made by Heintzelman and Reno on the right it became apparent that the enemy was massing his troops as fast as they arrived on the field on his right and was moving forward from that direction to turn our left, at which point it was plain he intended to make his main attack. I accordingly directed General McDowell to recall Ricketts' division immediately from our right and post it on the left of our line with its left refused. The attack of Porter was neither vigorous nor persistent, and his troops soon retired in considerable confusion. As soon as they commenced to fall back the enemy advanced to the assault, and our whole line from right to left was soon furiously engaged. The main attack of the enemy was made upon our left, but was met with stubborn resistance by the divisions of General Schenck, General Milroy, and General Reynolds, who, shortly after the action began, were re-enforced on their left and rear by the division of Ricketts. The action raged furiously for several hours, the enemy bringing up his heavy reserves and pouring mass after mass of his troops upon our left. So greatly superior in number were his forces that, whilst overpowering us on our left, he was able to assault us also with very superior forces on our right. Porter's forces were rallied and brought to a halt as they were retiring to the rear. As soon as they could be used I pushed them forward to support our left, and they there rendered most distinguished service, especially the brigade of regulars under Colonel Buchanan.