It was near six o’clock when this contest terminated—two hours after the main army were in full retreat. If ever delay and accident were providential on this earth, it was here; for brave as these men were, no sane leader would have felt justified in exposing them to such peril upon a deserted battle-field, and in the face of a whole victorious army, after all chance of protection had been withdrawn. When this band of victorious men reached Centreville, a stream of jaded, wounded and heavy-hearted men were pouring through the village, while General McDowell was making a desperate effort to collect all the troops that still kept a show of organization, under his own command. These troops were principally composed of the left wing, which came off the ground in good order. McDowell, about eight o’clock, left Centreville for Fairfax Court House. Before going Colonel Miles was relieved from his command of the left wing, and the following order, written on the back of a visiting card, was handed to Colonel Davies: Colonel Davies is consigned to the command of the left wing, as the troops are now formed. By command, J. B. FRY, A. A. G. _July 21._ Under this running order Colonel Davies assumed command of all that was left of the army in Centreville, and marched them in good order to Alexandria and Washington, Blenker’s division being the last to leave the field. This gallant officer had been among the bravest and most resolute in protecting the retreat, and had by his firmness held the enemy in check during the afternoon and evening. THE BATTLE-FIELD AT NIGHT. At night the calm air, the gently falling dew, visited that blasted earth sweetly as they had done the night before, when the valley was fresh with verdure and beautiful with thrifty crops. But the scene it presented was O, how different! In mercy the deep shadows cast by the woods concealed its worst features, and the smoke had risen so densely between earth and sky that the moon looked down upon it mournfully, through a veil. The battle-field was still, save when the solemn shiver of the leaves came like a painful and mighty sigh, or the troubled waves of the Run continued it in hoarser murmurs. If human moans broke the stillness, they were lost on that vast field, and only heard by the pitying angels. But solitary lights wandered over the field, like stars dropped by a merciful heaven to light the departing souls through the valley and shadow of death. They were indeed heavenly rays, for all that is divine in human mercy sent them forth. Kind men, and more than one heroic woman carried them from point to point over that dreary battle-field, searching among the dead for those who, breathing yet, might suffer for water or Christian comfort.