No. 61. Report of Lieutenant Oliver D. Greene, Second U. S. Artillery.

ALEXANDRIA, VA., July 24, 1861.

SIR: In compliance with your circular order of this date, just received, I have the honor to report that, on the morning of the 21st instant, my battery was placed in position in reserve near Centreville by Colonel Miles, commanding division, in person. Shortly afterwards, I received an order to hasten to the front with it, at Bull Run, as the enemy were there in force, and supposed to be attempting to turn our left flank. I took it forward as rapidly as possible, and came into action on the crest of a hill about six hundred yards from the enemy's line of skirmishers. I opened fire immediately upon a fixed battery partially masked by the woods, at a distance of about fifteen hundred yards, and also upon a point where it was known another masked battery was placed. The enemy were congregated in considerable force inside of the first battery, but as soon as I got the range the spherical case shot dispersed them and they disappeared from that position for nearly three hours. I then ceased firing, while skirmishers were thrown to the front from Colonel Richardson's brigade to feel the strength of the enemy in the edge of the woods in front of us. They were found to be in overwhelming force, and as our skirmishers retired theirs advanced in very strong force, but incautiously presented their flank to my battery. I threw in canister and spherical case as rapidly as possible, killing and wounding several, the first shot knocking over three. I kept up this fire for about five minutes, when I supposed the enemy were driven from that immediate vicinity. I then turned the fire of the battery upon columns of dust seen rising above the woods and indicating the march of troops in mas. Whether any effect was produced or not by this fire I cannot say.

At this time Lieutenant Prime, of the Engineers, directed my attention to a group of thirty or forty horsemen, evidently officers, on the plateau opposite, who, with maps on their horses' necks, were apparently taking a view of our position and strength at a safe distance. By diggings a hole under the trail I got two pieces bearing upon them at an angle of twenty-five or thirty degrees. The distance must have been two and one-half or three miles, but the first shot sent the center figure of the group to the rear; the second scattered the remainder in all directions. Firing was then ordered to cease at all the guns, for some time nothing appearing worth attention, until finally a cloud of dust was seen approaching our position from the direction of Manassas upon a road that was entirely concealed by woods from our sight except at one here spot within our best range, and the range of this point we had got accurately before. The guns were all prepared with shell and spherical case, and pointed upon this spot. When the head of the column appeared it proved to be a battery of light artillery. I opened fire upon it instantly, and fired with the utmost rapidity. The smoke of the guns obscured my sight, so that I saw none of the effect produced, but Colonel Richardson, who was looking with a glass, informed me afterwards that I cut them up badly, and forced them to turn back. We saw them no more. Shortly after this one of my men called my attention to the battery we first fired upon. The enemy were endeavoring to plant a field piece, the horses of which were just passing to the rear as I looked with my glass. I opened upon them with spherical case, firing several rounds. When the smoke cleared away there was no gun to be seen, and the battery gave me no more trouble during the day.

About this time heavy re-enforcements commenced being sent into the