cavalry went into rear at North Mountain and on the Williams-port road. Colonel Mulligan, with his small force, fought the enemy stubbornly the whole day. In order to enable me to concentrate our forces, I ordered Colonel Mulligan to retire, if forced, as slowly as possible to Kearneysville and Shepherdstown. All stores were sent off on cars, and the remainder loaded on wagons. The train was sent to Shepherdstown to cross the river, and subsequently I withdrew the troops from Martinsburg, when Colonel Mulligan was compelled to retire toward Kearneysville all my troops, consisting of two old and two regiments Ohio National Guard, infantry, 1,000 dismounted cavalry, 2 pieces of artillery, and 1, 5000 cavalry. Colonel Mulligan fought Major-General Ransom and Early, unaided, on to Martinsburg.

The exact strength of the enemy I have not been able to ascertain. His cavalry is 2,600 strong. If our troops can cross the Potomac to-night I will march to Harper's Ferry to join General Weber's forces, and to operate from that place. The railroad being interrupted by the enemy, I could not communicate with General Hunter and General Kelley since about 10 a. m. to-day.

F. SIGEL,

Major-General.

ADJUTANT-GENERAL U. S. ARMY.

HEADQUARTERS RESERVE DIVISION,
Maryland Heights, July 5, 1864-6 a. m.

(Via Frederick, Md. Received 3.25 p. m.)

Before my troops arrived at Harper's Ferry, general Weber at 6.30 p. m. yesterday evacuated Harper's Ferry to occupy Maryland heights. My troops arrived at Sandy Hook at 8 p. m., and took position on Maryland Heights, the cavalry regiment at or near Weverton. It was ordered toward Point of Rocks to operate against the enemy that crossed there. The enemy that attacked Harper's Ferry was of Ewell's corps, so reported by General Weber; the strength not developed. About 7,000 of the enemy occupied Martinsburg after our evacuation, and of rebel cavalry crossed at Williamsport yesterday. I have sent the train from Martinsburg to Frederick, as it could be of no use to us nearer to Harper's Ferry after its evacuation. No stores of any kind were lost at Harper's ferry. We have sufficient subsistence stores and ammunition-the former for twenty days. Further information will be promptly forwarded.

F. SIGEL,

Major-General.

ADJUTANT-GENERAL U. S. ARMY.

HEADQUARTERS RESERVE DIVISION,
Maryland Heights, July 5, 1864-11 p. m.

(Received 10.15 a. m. July 6.)

A part of the enemy's cavalry is this evening at Boonsborough and on this side of Antietam Creek, on the Sharpsburg road. I expect an attack of the enemy in front and rear to-morrow.

F. SIGEL,

Major-General.

ADJUTANT-GENERAL U. S. ARMY.