Colonel E. D. KEYES,

Commanding First Brigade, First Division.

No. 19. Report of Brigadier General Robert C. Schenck, U. S. Army, commanding Second Brigade, First Division.

2nd Brigadier, 1ST DIV., DEP'T NORTHEASTERN VIRGINIA, July 23, 1861.

GENERAL: I have the honor to submit this report of the movements and service of my brigade in the battle of Bull Run, on the Gainsville road, on the 21st instant:

Leaving my camp, one mile south of Centreville, at 2.30 a.m. of that day, I marched at the head of your division, as ordered, with my command in column, in the following order: The First Regiment of Ohio Volunteers, Colonel McCook; the Second Ohio, Lieutenant Colonel Mason; the Second New York State Militia, Colonel Tompkins, and Captain Carlisle's battery of light artillery, six brass guns. To Captain Carlisle's command was also attached the large Parrott gun [30-pounder], under direction of Lieutenant Hains, of the Artillery Corps.

Proceeding slowly and carefully, preceded by five companies of skirmishers of the First and Second Ohio, which I threw out on either side of the road, we approached the bridge over Bull Run, beyond which the rebels were understood to be posted and intrenched, and to within a distance, perhaps, of three fourths of a mile of their batteries on the other side of the stream. In obedience to your command, on first discovery of the presence of the enemy's infantry forming into line on the hill-side beyond the Run, I deployed my three regiments of infantry to the left of the road, and formed them in line of battle in front of his right. Thus my command was constituted-the left wing of our division, Colonel Sherman's brigade, coming up and taking position to the right of the road.