The position of the batteries under General Pleasonton being one of great exposure, the battalion of the Second and Tenth U. S. Infantry, under Captain Poland, Second Infantry, was sent to his support. Subsequently four battalions of regular infantry, under Captain Dryer, Fourth Infantry, were sent across to assist in driving off the sharpshooters of the enemy.

The battalion of the Second and Tenth Infantry, advancing far beyond the batteries, compelled the cannoneers of a battery of the enemy to abandon their guns. Few in numbers and unsupported, they were unable to bring them off. The heavy loss of this small body of men attests their gallantry.

The troops of General Burnside held the left of the line opposite Bridge No. 3. The attack on the right was to have been supported by an attack on the left. Preparatory to this attack, on the evening of the 16th General Burnside's corps was moved forward and to the left, and took up a position nearer the bridge.

I visited General Burnside's position on the 16th, and after pointing out to him the proper dispositions to be made of his troops during the day and night, informed him that he would probably be required to attack the enemy's right on the following morning, and directed him to make careful reconnaissances.

General Burnside's corps, consisting of the divisions of Generals Cox, Willcox, Rodman, and Sturgis, was posted as follows: Colonel Crook's brigade, Cox's division, on the right; General Sturgis' division immediately in rear; on the left was General Rodman's division, with General Scammon's brigade, Cox's division, in support;General Willcox's division was held in reserve.

The corps bivouacked in position on the night of the 16th.

Early on the morning of the 17th, I ordered General Burnside to form his troops and hold them in readiness to assault the bridge in his front, and to await further orders. At 8 o'clock an order was sent to him by Lieutenant Wilson, Topographical Engineers, to carry the bridge, then to gain possession of the heights beyond, and to advance along their creat upon Sharpsburg and its rear. After some time had elapsed, not hearing from him, I dispatched an aide to ascertain what had been done. The aide returned with the information that but little progress had been made. I then sent him back with an order to General Burnside to assault the bridge at once, and carry it at all hazards. The aide returned to me a second time with the report that the bridge was still in the possession of the enemy; whereupon I directed Colonel Sacket, Inspector-General, to deliver to General Burnside my positive order to push forward his troops without a moment's delay, and, if necessary, to carry the bridge at the point of the bayonet, and I ordered Colonel Sacket to remain with General Burnside and see that the order was executed promptly.

After these three hours' delay, the bridge was carried at 1 o'clock by a brilliant charge of the Fifty-first New York and Fifty-first Pennsylvania Volunteers. Other troops were then thrown over and the opposite bank occupied, the enemy retreating to the heights beyond. A halt was then made by General Burnside's advance until 3 p. m., upon hearing which I directed one of my aides, Colonel Key, to inform General Burnside that I desired him to push forward his troops with the utmost vigor, and carry the enemy's position on the heights; that the movement was vital to our success; that this was a time when we must not stop for loss of life if a great object could thereby be accomplished; that if, in his judgment, his attack would fail, to inform me so at once,