SEMINARY, September 17, 1862.

Captain IRWIN, Aide-de-Camp:

Scouts just in report no signs of enemy's pickets at Fairfax or Centreville; that they have their line from Warrenton, through White Plains, to Leesburg, and all their sick are going toward Winchester, which seems to be the rendezvous. The flag of truce met a scouting party on Bull Run battle-field. There is also a small force beyond Manassas Gap and near Bristoe Station; but all their forces on this flank seem to be moving toward Winchester and Leesburg.

D. B. BIRNEY,

Brigadier-General, Commanding.

(Copy to Secretary of War and General McClellan.)

UPTON'S HILL, VA.,

September 17, 1862 - 9.40 a. m.

Lieutenant-Colonel MCKEEVER,

Chief of Staff, Arlington:

I have a report from Lieutenant-Colonel Kilpatrick that 30,000 men left Winchester for Harper's Ferry yesterday noon. He does not send his source of information. He also gives his opinion that a portion is coming through Snicker's Gap. This is not so, I think. Certainly not on their way to Harper's Ferry. He sends me a scout of the enemy, who left Shepherdstown yesterday morning, and a citizen. From them I learn that a column from direction of Leesburg, apparently, crossed the Shenandoah yesterday on their way to Harper's Ferry. It had thirty pieces of artillery and fifty wagons, and I think at least two brigades of infantry. Met no other force between Harper's Ferry and Leesburg. One of the men says he saw the enemy's officers reconnoitering for entrenchments between Boonsborough and Shepherdstown. The scout says their main body had fallen back to Sharpsburg. There is a small force watching Edwards Ferry.

J. M. DAVIES,

Colonel, Commanding Cavalry Brigade.

(Telegraphed by Banks to McClellan, 12.20 p. m.)

HEADQUARTERS CAVALRY BRIGADE,
Upton's Hill, September 17, 1862.

Lieutenant-Colonel MCKEEVER,

Chief of Staff, Army of Virginia:

I send, under guard, two men, captured last evening at Dranesville by Lieutenant-Colonel Kilpatrick. One is a rebel scout, though not, I understand, a soldier. He is not communicative. The other will tell his own story, to the effect that he had thought of joining the Virginia cavalry in Maryland; went over the river with them, and left at Shepherdstown. He will tell all he knows, and I got most of the information I telegraphed from him. I send a copy of Lieutenant-Colonel Kilpatrick's report. He evidently mistakes the column from Leesburg for another one from Winchester. The road from Winchester to Harper's