BROOKVILLE, MD.,

September 9, 1862-7 p. m.

Major General H. W. HALLECK,

General-in-Chief, and

General McCLELLAN:

The following dispatches were received while on the march to-day:

HEADQUARTERS ADVANCE RESERVE,
Lisbon Road Junction, six miles south of Cooksville, September 9-7 a. m.

Colonel T. C. DEVIN:

SIR: Left picket at Cooksville, with whom General Wool's cavalry communicated last night at 9.30 o'clock, to ascertain whether General Burnside's advance were at Cooksville. They consisted of a company of the First Pennsylvania. Twelve men were seen at Poplar Springs this morning. It is reported an advance of 200 will be made to Cooksville this morning. Communicated with Lieutenant Patterson this morning. So far all quiet. Please send rations and forage. Have thought it expedient to stop the passing of citizens to our rear and return this morning. Surrounded with rebels in disguise. We trust no one will endeavor to reconnoiter to Lisbon this p. m.

Respectfully,

W. E. BEARDSLEY,

Captain Troop E.

Respectfully forwarded.

THOS. C. DEVIN,

Colonel.

TRINITY, MD., September 9.

Colonel DEVIN:

SIR: I sent a patrol, under command of Sergeant Real, last evening about 6 o'clock. They patrolled the road between this place and Damascus, and arrived at said place at 11 o'clock. They learned that the rebels had a force at Kemptown, and their pickets were within 2 miles of Damascus. They have pickets on the railroad and pike to the right of Damascus. The rebels are in force at Woodbine, on the turnpike, at that place. General Wool's pickets killed 3 rebel pickets night before last. They are also at Clarksburg, on the Georgetown road, to the left of Trinity. There is said to be a large force at Harristown [Hyattstown], 6 miles to the left of Damascus. There is a man at Trinity who has been in the habit of visiting the rebels ever since they came into that section of country. I think he had better be sent to headquarters. I sent out a patrol party this a. m. at 3 o'clock to scout the roads to Damascus. They have not yet returned.

Very respectfully,

F. A. PATTERSON,

First Lieutenant, Commanding Troop.

A. E. BURNSIDE,

Major-General, Commanding.

HEADQUARTERS ARMY OF THE POTOMAC,
Camp near Rockville, September 9, 1862-10 p. m.

Major-General BURNSIDE, Brookville:

General Pleasonton telegraphs that Jackson's headquarters are to-day at New Market, and J. E. B. Stuart's at Urbana. This indicates that enemy intends moving on Baltimore, and it is now more necessary than ever that you should promptly execute the instructions of to-day, to drive in the enemy's pickets to Ridgeville, and beyond if possible, by cavalry and section of horse artillery. Push your reconnaissance north of railroad as far as possible toward Westminster; also by Ridgeville road from Damascus to Ridgeville. Should the enemy make any demonstration toward Baltimore, let his column get well in motion, and then attack him vigorously on the flank, sending immediate information to the major-general commanding, who will support you with all his avail-