HARPER'S FERRY, September 10, 1862.

Major-General HALLECK, General-in-Chief:

Enemy reported advancing from Boonsborough. He may intend to pass on the Maryland Heights or the Potomac, at Antietam Creek. Troops in position and ready.

D. S. MILES,

Colonel Second Infantry.

HARPER'S FERRY, September 11, 1862.

Major-General HALLECK, General-in-Chief:

No sign of the enemy this morning. Yesterday Colonel Downey made a dash on force of 15,000 at Boonsborough with 19 cavalry; threw their line into confusion, killed 6, and safely retreated. Downey slightly wounded.

D. S. MILES,

Colonel Second Infantry.

ROCKVILLE, September 11, 1862.

Major-General HALLECK, General-in-Chief:

Colonel Miles is at or near Harper's Ferry, I understand, with 9,000 troops. He can do nothing where he is, and could be of great service if ordered to join me. I suggest that he be ordered at once to join me by the most practicable route.

GEO. B. MCCLELLAN,

Major-General, Commanding.

HEADQUARTERS OF THE ARMY,
Washington, D. C., September 11, 1862.

General GEORGE B. MCCLELLAN, Rockville:

There is no way for Colonel Miles to join you at present. His only chance is to defend his works till you can open communication with him. When you do so he will be subject to your orders.

H. W. HALLECK,

General-in-Chief.

HEADQUARTERS OF THE ARMY,
Washington, D. C., September 12, 1862.

Major-General MCCLELLAN, Middleburg:

Is it not possible to open communication with Harper's Ferry, so that Colonel Miles can co-operate with you?

H. W. HALLECK,

General-in-Chief.

HEADQUARTERS OF THE ARMY,
Washington, D. C., September 12, 1862.

Colonel DIXON S. MILES, Harper's Ferry:

You will obey such orders as General McClellan may give you. You will endeavor to open communication with him and unite your forces to his at the earliest possible moment. His army is now near the line of the Monocacy.

H. W. HALLECK,

General-in-Chief.

FREDERICK, September 14, 1862.

Major-General HALLECK, General-in-Chief:

A courier from Colonel Miles, who left in the night, has just arrived, and says Colonel Miles is surrounded by a large force of the enemy, but thinks he can hold out two days. General White has joined him with his command from Martinsburg. Miles is in possession of Harper's Ferry and Loudoun Heights. If he holds out to-day I can probably save him. The whole army is moving as rapidly as possible. The enemy is in possession of Maryland Heights.

GEO. B. MCCLELLAN,

Major-General, Commanding.

BALTIMORE, September 15, 1862.

Major-General HALLECK, General-in-Chief:

The following dispatch has been received from Colonel A. Voss, Twelfth Illinois Cavalry, dated Greencastle, Pa., September 15:

Harper's Ferry is from all sides invested by a force estimated at 30,000. By order of Colonel Miles, I left it last evening at 8 o'clock with the cavalry, about 1,500 strong, to cut my way through the