Middletown, five miles from Frederick. He has positive information, however, that Lieutenant-Colonel Brum [Burks?], of Stuart's cavalry, intends making a raid upon Hagerstown. Nothing from Martinsburg. Road in both directions unprotected. They expect to reopen telegraph office at Hagerstown this evening, and will send about 400 cavalry from Carlisle to Hagerstown to-night, and patrol all that region to secure information. Please communicate fully and frequently with these headquarters.

By command of Major-General McClellan:

R. B. MARCY,

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC.

September 9, 1862-1.45 p. M.

General J. G. PARKE

Chief of Staff, Leesborough, Va., [Md.]:

A telegraph dispatch was sent to General Burnside last night directing him to move his command this morning to Cracklintown and Goshen. The telegraph operator at Leesborough says he received the dispatch at 3 o'clock this morning. As no acknowledgment has been received of this dispatch, and as you say nothing of the movement in your telegrams, it is feared that the general did not get the order. The movement is an important one, taken in connection with the movements of other troops and it is desirable that your troops should occupy the positions named to-night. Please inform me at once whether the order was received and at what time.

R. B. MARCY

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC.

Camp near Rockville, September 9, 1862-3 p. M.

Major-General BURNSIDE:

Leesborough:

Drive in enemy's pickets on turnpike and railroad as far as possible in the direction of Ridgeville and beyond by cavalry and section of horse artillery. Ascertain strength of enemy if possible; endeavor to cut off Captain Beardsley: take steps that no one shall pass along the Baltimore and Ohio Railroad or the National road without your knowledge; push reconnaissances northof the railroad as far as possible toward Westminster.

By command of Major-General McClellan:

R. B. MARCY.

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC.

Camp near Rockville, September 9, 1862-10 a. M.

Brigadier-General PLEASONTON.

Poolesville:

Major Myer, Chief Signal Officer, thinks the possession of Sugar Loaf Mountain as a signal station will be of great importance to us,