noon, notwithstanding the success wrested from the enemy by the stub born bravery of the troops, was at this time unpromising. Sumner's, Hooker's, and Mansfield's corps had lost heavily, several general officers having been carried from the field. I was at one time compelled to draw two brigades from Porter's corps (the reserve) to strengthen the right. This left for the reserve the small division of Regulars, who had been engaged in supporting during the day the batteries in the center, and a single brigade of Morell's division. Before I left the right to return to the center, I became satisfied that the line would be held without these two brigades, and countermanded the order, which was in course of execution. The effect of Burnside's movement on the enemy's right was to prevent the further massing of their troops on their left, and we held what we had gained.
Burnside's corps, consisting of Willcox's, Sturgis', and Rodman's divisions, and Cox's Kanawha division, was intrusted with the difficult task of carrying the bridge across the Antietam near Rohrback's farm, and assaulting the enemy's right, the order having been communicated to him at 10 o'clock a. m.
The valley of the Antietam at and near this bridge is narrow, with high banks. On the right of the stream the bank is wooded, and commands the approaches both to the bridge and the ford. The steep slopes of the bank were lined with rifle pits and breastworks of rails and stones. These, together with the woods, were filled with the enemy's infantry, while their batteries completely commanded and enfiladed the bridge and ford and their approaches.
The advance of the troops on an obstinate and sanguinary contest, and, form the great natural advantages of the position, it was nearly 1 o'clock before the heights on the right bank were carried. At about 3 o'clock p. m. the corps again advanced, and with success, the right driving the enemy before it and pushing on nearly to Sharpsburg, while the left, after a hard encounter, also compelled the enemy to retire before it. The enemy here, however, were speedily re-enforced, and with overwhelming masses. New batteries of their artillery also were brought up and opened. It became evident that our force was not sufficient to enable the advance to reach the town, and the order was given to retire to the cover of the hill which was taken from the enemy earlier in the afternoon. This movement was effected without confusion and the position maintained until the enemy retreated. General Burnside had sent to me for re-enforcements late in the afternoon, but the condition of things on the right was not such as to enable me to afford them.
During the whole day our artillery was everywhere bravely and ably handled. Indeed, I cannot speak too highly of the efficiency of our batteries and of the great service they rendered. On more than one occasion when our infantry was broken they covered its reformation and drove back the enemy.
The cavalry had little field for operations during the engagement, but was employed in supporting the horse-artillery batteries in the center, and in driving up stragglers, while awaiting opportunity for other service.
The Signal Corps, under Major Myer, rendered, during the operations at Antietam as well as at South Mountain and during the whole movements of the army, efficient and valuable service. Indeed, by its service here, as on other fields elsewhere, this corps has gallantly earned its title to an independent and permanent organization.