guard. On Saturday night Lieutenant Edwards, Third Artillery, reported to me with a section of two heavy rifled guns. On Sunday morning, the 21st, Lieutenant Thompson's section was placed in position on the right of the main road, overlooking the ford, and commanding the road by which the enemy's advance was expected. A few shells were, by direction of Colonel richardson, dropped into the woods and amongst the buildings which were supposed to contain the enemy, but no answer was returned, and the firing ceased. Soon after this an infantry column was seen pushing into the wood skirting Bull Run. Lieutenant Thompson moved forward a piece, and after a few rounds they disappeared.

At about 10 a.m. Colonel Miles ordered both sections of my battery to the extreme left, occupied by Davies' brigade. Edwards' section had been sent early in the morning to that position, from which he had opened his fire upon the woods and houses in front. I transmit herewith his report of the operations of his section, in which he describes the nature of the ground.

The firing was continued at intervals by the whole battery "as a demonstration, " but produced little or no effect, as there was no definite object, except when the enemy's moving columns came from time to time within our range. We were supported by two infantry battalions, drawn up in line behind the battery. On inquiry, made immediately after my arrival on the ground, I was informed that a brigade of infantry was posted in the wood to our left and rear, commanding a deep and wide ravine on our left flank, and watching the road beyond it, which leads from below the ford to Centreville; and as we had skirmishers pushed forward into the ravine, I felt no apprehension of danger from that quarter, but still requested, as a precaution, that the battalion on the left should be formed on the brink of the ravine and in column, so that it might be readily deployed to front in any direction. No attention was paid to this request, and the regiment remained in line.

About 4.30 or 5 p.m., after the battle was apparently gained on the right, and whilst large re-enforcements of infantry and cavalry were observed hurrying up from the direction of Manassas, a strong force of infantry and some cavalry, variously estimated at from 2,500 to 5,000 men in all, appeared on our left, approaching parallel to our front by the lateral openings into the great ravine on our flank. The infantry only was first seen, and as they approached without any apparent attempt at concealment, preceded by our skirmishers, they were supposed to be our own troops. As the number increased, I rode down the ravine with my first sergeant to reconnoiter them. Some of our skirmishers stated that they had seen no troops; others said they were the Thirty-first [?] New Yorkers coming in. They carried no colors, and their numbers increasing to an alarming extent, I hurried back and changed the front of the battery, so as to command all the openings into the ravine and the approaches to our position. Colonel Davies at the same time detached a couple of companies into the ravine as skirmishers. The latter had scarcely deployed, when a sharp rattle of musketry removed all doubts as to the character of the advancing troops. We had been surprised, and the enemy was close upon us in large force. Our infantry regiments had changed front with the battery, but unfortunately closed their intervals behind it. Precious time was now lost in getting them on our flanks. Had they remained in our rear they would have been unnecessarily exposed to the fire directed on the battery, and in case of a determined charge for our capture, which I confidently expected, they would have been apt to fire through us, destroying men and horses and crippling the guns. At length they were moved