"They rallied and repulsed us, but only to give us again the victory, which seemed complete. But our men, exhausted with fatigue and thirst, and confused by firing into each other, were attacked by the Enemy's reserves, and driven from the position we had gained, overlooking Manassas. After this, the men could not be rallied, but slowly left the field. In the meantime the Enemy outflanked Richardson at Blackburn's Ford, and we have now to hold Centreville till our men can get behind it. Miles's Division is holding the town. It is reported that Colonel Cameron is killed, Hunter and Heintzelman wounded, neither dangerously. "IRWIN MCDOWELL, "Brigadier-General, Commanding. "Lieutenant-Colonel TOWNSEND." "FAIRFAX COURT HOUSE, July 21, 1861. "The men having thrown away their haversacks in the battle, and left them behind, they are without food; have eaten nothing since breakfast. We are without artillery ammunition. The larger part of the men are a confused mob, entirely demoralized. It was the opinion of all the commanders that no stand could be made this side of the Potomac. We will, however, make the attempt at Fairfax Court House. From a prisoner we learn that 20,000 from Johnston joined last night, and they march on us to-night. "IRWIN MCDOWELL. "Colonel TOWNSEND" "FAIRFAX COURT HOUSE, [July] 22, 1861. "Many of the volunteers did not wait for authority to proceed to the Potomac, but left on their own decision. They are now pouring through this place in a state of utter disorganization. They could not be prepared for action by to-morrow morning even were they willing. I learn from prisoners that we are to be pressed here to-night and tomorrow morning, as the Enemy's force is very large, and they are elated. I think we heard cannon on our rear-guard. I think now, as all of my commanders thought at Centreville, there is no alternative but to fall back to the Potomac, and I shall proceed to do so with as much regularity as possible. "IRWIN MCDOWELL. "Colonel TOWNSEND." "ARLINGTON, July 22, 1861. "I avail myself of the re-establishing of telegraph to report my arrival. When I left the forks of the Little River turnpike and Columbia turnpike, where I had been for a couple of hours turning stragglers and parties of regiments upon this place and Alexandria, I received intelligence that the rear-guard, under Colonel Richardson, had left Fairfax Court House, and was getting along well. Had not been attacked. I am now trying to get matters a little organized over here. "IRWIN MCDOWELL. "Brigadier-General. "E. D. TOWNSEND."