thought to be concentrating at Smithfield to-night. Whether this is preparatory to a movement up the Valley or into Pennsylvania is uncertain, but indications are of the former. His cavalry is withdrawn from the fords. Sheridan's cavalry is watching the enemy closely. The infantry have not as yet broken camp, but will probably be put in motion to-morrow. Twelve hours will certainly disclose the purpose of the enemy.

N. P. CHIPMAN.

Colonel and Aide-de-Camp.

CIRCULAR.] HEADQUARTERS MIDDLE MILITARY DIVISION,

Halltown, Va., August 27, 1864-7.30 p.m.

Corps and other independent commanders will have their commands in readiness to move at daylight to-morrow. The following will be the allowance of transportation; one wagon and one spring-wagon for corps, division, and brigade headquarters; the ammunition trains and ambulances, and also medical supply wagons; necessary transportation for intrenching tools. All other wagons and vechicles will be parked inside the fortifications at Bolivar Heights to await further orders from these headquarters. The men will be supplied with three days' rations, which will be required to last four days.

By command of Major-General Sheridan:

JAS. W. FORSYTH.

Lieutenant-Colonel and Chief of Staff.

HEADQUARTERS CAVALRY BRIGADE,
Near Fort Buffalo, Va., August 27, 1864

Lieutenant Colonel J. H. TAYLOR,

Chief of Staff and Assistant Adjutant-General:

COLONEL: I have the honor to report that reports, well authenticated, were brought in at an early hour this morning to the effect that a force of the enemy numbering about 100 were occupying the country in our immediate vicinity, having been seen yesterday immediately east of Fairfax Court-House, and this morning between this point and Vienna. Mosby, with a few men was reported as having been seen to-day in Fairfax Court-House. Under these circumstances, and as the immediate neighborhood and the country from fifteen to twenty miles in our front is reported as overrun by small parties, I sent Major Horton, with including one company from Annandale, to make a thorough examination of the country between here and Goose Creek and beyond, as far as consistent with success. Mosby, in his attack on Annadale, had with him 350 men, as is reported by a daughter of Yankee Davis and the lady who went with her with a letter concerning Doctor Boyle to-day to your headquarters. One of them counted them, she reports, as he passed their house.

Very respectfully, your obedient servant,

H. M. LAZELLE,

Colonel Sixteenth New York Cavalry, Comdg. Cavalry Brigade.