Numbers 52. HEADQUARTERS ARMY OF VIRGINIA, Warrenton Junction, August 26, 1862-8.20 p. m.

Major-General HEINTZELMAN,

Commanding, &c.:

The major-general commanding the Army of Virginia directs me to send you the inclosed communication, and to request that you put a regiment on a train of cars and send it down immediately to Manassas to ascertain what has occurred, repair the telegraph wires, and protect the railroad there, till further orders.

With great respect, general, your obedient servant,

T. C. H. SMITH,

Lieutenant-Colonel and Aide-de-Camp.

Numbers 53. HEADQUARTERS ARMY OF VIRGINIA, August 26, 1862-12 m.

General McDOWELL:

General Sigel reports the enemy's rear guard at Orleans to-night, with his main force encamped at White Plains. You will please ascertain very early in the morning whether this is so, and have the whole of your command in readiness to march. You had best ascertain it to-night if you possibly can. Our communications have been interrupted by the enemy's cavalry near Manassas. Whether his whole force, or the larger part of it, has gone around is a question which we must settle instantly, and no portion of his force must march opposite to us to-night without our knowing it. I telegraphed you and hour or two ago what dispositions I had made, supposing the advance through Thoroughfare to be a column of not more than 10,000 men. If his whole force, or the larger part of it, has gone, we must know it ar once.

The troops here have no artillery, and if the main forces of the enemy are still opposite to you you must send forward to Greenwich, to be there to-morrow evening, two batteries of artillery, or three if you can get them, to meet Kearny.

We must know at a very early hour in the morning, so as to determine our plans.

JOHN POPE,

Major-General.

Numbers 54. GENERAL ORDERS,
HEADQUARTERS ARMY OF VIRGINIA, Numbers -.
Warrenton Junction, August 27, 1862.

The following movement of troops will be made, viz:

Major-General McDowell, with his own and Sigel's corps and the division of Brigadier-General Reynolds, will pursue the turnpike from Warrenton to Gainesville, so as to reach Gainesville, if possible, to-night.

The army corps of General Heintzelman, with the detachment of the Ninth Corps, under Major-General Reno (General Reno leading), will take the road from Catlett's Station to Greenwich, so as to reach there to-night or early in the morning. Major-General Reno will immediately communicate with Major-General McDowell, and his command, as well as that of Major-General Heintzelman, will support Major-General McDowell in any operations against the enemy.