night, on the receipt of the information that the enemy was crossing at Sulphur Springs, by direction of Major-General French, I placed Clark's battery in position covering the reserve batteries, in order to guard against any raid or night attack from the direction of Fox's Ford.

On the 13th, two batteries were assigned to the Second two to the Third, and three to the First, and the corps marched to Three-Mile Station, where line of battle was formed six batteries being placed in very good positions, facing toward Warrenton and the direction of the Warrenton pike. One battery was held in reserve and two rifled batteries placed on the right of road leading to Auburn were intended to be used wherever on the field more artillery should become necessary.

At 3 p.m. the corps, First Division leading, resumed the march toward Greenwich. Near Auburn, the major-general commanding discovered the cavalry vedettes of the enemy on a high hill on the left of the road, and, sending his escort for the purpose, discovered in our immediate front a large force of the enemy's cavalry. Skirmishing having commenced on the part of the escort, General French ordered the leading section of Sleeper's battery into battery on the road, and deployed the infantry of First Division on the left of the road. The section opened fire with shell upon the woods in which the enemy were and soon after the remaining four pieces also opened fire with good effect. After the enemy had been driven, a section of Clark's and one of Sleeper's were placed by General French on the top of the hill on the left to reply should the enemy use artillery, but these guns had no occasion to fire. The march was resumed, and the corps encamped at Greenwich, the batteries attached to the Second Division reaching camp between 3 and 4 a.m. of the 14th.

At 5 o'clock of the 14th, I received your order to move at 6. The march was promptly made, trains doubling at every opportunity and every exertion made to shorten the column and hasten the march. The corps massed at Broad Run and then moved on through Manassas, across Mitchell's Ford, to Centreville. One battery remained at Manassas with two brigades of Third Division, retained by General Meade until night, and then rejoined the corps at Centreville.

On the morning of the 15th, three batteries marched with the First Division to Fairfax Station; the other four marched to Union Mills. A section of 12-pounders was sent to McLean's Ford with General Mott. This section was found to be of too short range, and when General Mott was attacked by the enemy's cavalry, I was sent by General French with a section of Robinson's rifled guns, with discretion to use a whole battery if I thought best. I moved the section which had preceded from the position assigned it by General Mott, near the ford, to the commanding hill upon which was a redoubt built by the enemy. This position commands the ford and the hills in front of Blackburn's Ford, as well as the road from Centreville to Manassas, via Blackburn's and McLean's Fords. The section engaged the enemy at once, firing upon his cavalry, and receiving the fire from his artillery. I ordered the remainder of the battery up, but before it arrived the enemy had nearly all retired. Captain Robinson did very good service. The section of 12-pounders was placed in reserve behind the hill, and at night returned to Union Mills.

On the 19th,the batteries one attached to each division and five in reserve, marched to Bristoe Station.