I found it necessary to make considerable changes in the position of General Burnside's corps, and directed him to advance to a strong position in the immediate vicinity f the bridge and to reconnoiter the approaches to the bridge carefully. In front of Generals Sumner's and Hooker's corps, near Keedysville, and on the ridge of the first line of hills overlooking the Antietam, and between the turnpike and Pry's house on the right of the road, were placed Captains Taft's, Langner's, Von Kleiser's, and Lieutenant Wever's batteries of 20-pounder Parrott guns; on the crest of the hill, in the rear and right of Bridge Numbers 3, Captain Weed's 3-inch and Lieutenant Benjamin's 20-pounder batteries. General Franklin's corps and General Couch's division held a position in Pleasant Valley, in front of Brownsville, with a strong force of the enemy in their front. General Morell's division, of Porter's corps, was en route from Boonsborough, and General Humphreys' division of new troops en route from Frederick, Md. About daylight on the 16th the enemy opened a heavy fire of artillery on our guns in position, which was promptly returned. Their fire was silenced for the time, but was frequently renewed during the day. In the heavy fire of the morning, Major Arndt, commanding First Battalion First New York Artillery, was mortally wounded while directing the operations of his batteries.

It was afternoon before I could move the troops to their positions for attack, being compelled to spend the morning in reconnoitering the new position taken up by the enemy, examining the ground, finding fords, clearing the approaches, and hurrying up the ammunition and supply trains, which had been delayed by the rapid march of the troops over the few practicable approaches from Frederick. These had been crowded by the masses of infantry, cavalry, and artillery pressing on with the hope of overtaking the enemy before he could form to resist an attack. Many of the troops were out of rations on the previous day, and a good deal of their ammunition had been expended in the severe action of the 14th.

My plan for the impending general engagement was to attack the

enemy's left with the corps of Hooker and Mansfield, supported by Sumner's and, if necessary, by Franklin's, and, as soon as matters looked favorably there, to move the corps of Burnside against the enemy's extreme right, upon the ridge running a to the south and rear of Sharpsburg, and, having carried their position, to press along the crest toward our right, and, whenever either of these flank movements should be successful, to advance our center with all the forces then disposable.

About 2 p.m. General Hooker with his corps, consisting of Generals Ricketts', Meade's, and Doubleday's divisions, was ordered to cross the Antietam at a ford, and at Bridge Numbers 1, a short distance above, to attack and, if possible, turn the enemy's left. General Sumner was ordered to cross the corps of General Mansfield(the Twelfth) during the night and hold his own (the Second) Corps ready to cross early the next morning. On reaching the vicinity of the enemy's left, a sharp contest commenced with the Pennsylvania Reserves- the advance of General Hooker's corps-near the house of D. Miller. The enemy were driven from the strip of woods where he was first met. The firing lasted until after dark, when General Hooker's corps rested on their arms of ground won from the enemy.

During the night General Mansfield's corps, consisting of Generals Williams' and Greene's divisions, crossed the Antietam at the same ford and bridge that General Hooker's troops had passed, and bivouacked on the farm of J. Poffenberger, about a mile in rear of General Hooker's position. At daylight on the 17th the action was commenced by the