HEADQUARTERS THIRD BRIGADE, July 24, 1863.

Captain Weir,
Assistant Adjutant-General:

SIR: The scout to Warrenton has not yet reported. Major [William H.] Fry, just in from scout, reports that he mistook the road and went to New Baltimore; that he saw the Eleventh Corps, and heard that we had troops at Warrenton, but did not learn what they were. Very respectfully,

J. IRVIN GREGG, Colonel,

Commanding Third Brigade.

HARPER'S FERRY, W. VA., July 24, 1863-3 a. m. (Received 10. 10 a. m.)

Major General H. W. HALLECK,

General-in-Chief:

The following has just been received from Colonel McReynolds, commanding at Sharpsburg, with request to forward it to you: This morning I sent Major Quinn, of the First New York Cavalry, with 200 men, across the river at Shepherdstown, with instructions to proceed to Martinsburg, if practicable, which, from information of my scouts, I had but little doubt they could do. They accomplished the mission without interruption, arriving at Martinsburg at 1 p. m., and remaining till 4. 30 p. m. Their arrival was heralded with every demonstration of joy on the part of the citizens. They have just returned to camp. On Monday, General Lee moved from Bunker Hill in the direction of Winchester. Ewell followed on Tuesday, and Longstreet on Wednesday. The immediate destination was known to be Millwood, which evidently points either to Ashby's Gap or Front Royal. This morning General Stuart left, moving toward Berryville, with 2, 000 cavalry. Berryville is in a direct line to Millwood; distance 6 miles. Lee is said to be re-enforced by D. H. Hill, from Richmond, with 15, 000, making his force some 65, 000 men. This comes from a direct source-Ewell's adjutant-general.

The dispatch is dated 11. 30 p. m., July 23. Respectfully, &c.,

HENRY H. LOCKWOOD,

Brigadier-General.

HEADQUARTERS ARMY OF THE POTOMAC, [Linden], July 24, 1863-6. 30 a. m.

Brigadier-General LOCKWOOD,
Commanding Harper's Ferry:

The major-general commanding directs me to acknowledge the receipt of your dispatch, and to inform you that he engaged the enemy yesterday at this point. The enemy appears to be withdrawing, and his whole army is undoubtedly en route to Culpeper and Orange Court-House, and probably his rear has passed the Shenandoah at this place and Strasburg. Very respectfully, &c., A. A. HUMPHREYS, Major-General, and Chief of Staff.