AUGUST 21, 1864-Skirmish in Loudoun County, Va.

Reports of Lieutenant Colonel Roger E. Cook, First Maryland Potomac Home Brigade Infantry, commanding U. S. forces at Sandy Hook, Md.

HEADQUARTERS, Sandy Hook Md., August 22, 1864.

CAPTAIN: I have the honor to report that agreeable to instructions from headquarters, a scouting party of the Loudoun (Virginia) Rangers crossed the river early in the morning of August 21, under command of Lieutenant Atwell, and proceeded in the direction of Leesburg, where they encountered a detachment of White's battalion; routed them, with a loss of three men mortally wounded. thence proceeded to Dry Holow and Grove Meeting-House, where they found five of Mosby's command; captured one, supposed to belong to the quartermaster's department; the other four made their escape. they had just murdered a sick, paroled Federal soldier. they ten returned to camp by the way of Goose Creek Meeting-House, Harmony, and Waterford. Heard of no enemy in force north of Rectortown. Longstreet's command reported at Sperryville Gap and Front Royal. Four companies of white's and Mosby's command are the only troops supposed to be in Loudoun county.

I am, captain, most respectfully, &c.,
R. E. COOK,

Lieutenant-Colonel, Commanding.

Captain H. M. BURLEIGH,

Assistant Adjutant-General, Harper's Ferry, Va.

HEADQUARTERS, Sandy Hook, August 22, 1864.

CAPTAIN: I have the honor to state that the report of a scout into Loudoun County, Va., by a detachment of the Loudoun Rangers on the 21st instant, forwarded to headquarters this date, embraces the operations and is the report of the scout ordered to Aldie. The reason of their failure to fully execute the order is not stated in their written report to these headquarters, bat have since learned from the lieutenant commanding the scout that it was in consequence of detachment of White's or Mosby's command, 100 strong, lying at or near that place, and he, having only about twenty men, did not feel safe in attacking them.

I am, captain, very respectfully, your obedient servant,
R. E. COOK,

Lieutenant-Colonel, Commanding, &c.

Captain H. M. BURLEIGH,

Assistant Adjutant-General, Harper's Ferry, Va.