“The masses of his troops were still concealed behind the opposite heights. Their left and centre were upon and in front of the Sharpsburgh and Hagerstown turnpike, hidden by woods and irregularities of the ground; their extreme left resting upon a wooded eminence near the cross roads to the north of J. Miller’s farm: their left resting upon the Potomac. Their line extended south, the right resting upon the hills to the south of Sharpsburgh, near Shaveley’s farm. “The bridge over the Antietam, described as No. 3, near this point, was strongly covered by riflemen protected by rifle-pits, stone fences, etc., and enfiladed by artillery. The ground in front of this line consisted of undulating hills, their crests in turn commanded by others in the rear. On all favorable points the enemy’s artillery was posted, and their reserves, hidden from view by the hills, on which their line of battle was formed, could manœuvre unobserved by our army, and from the shortness of their line could rapidly reinforce any point threatened by our attack. Their position, stretching across the angle formed by the Potomac and Antietam, their flanks and rear protected by these streams, was one of the strongest to be found in this region of country, which is well adapted to defensive warfare.” At dawn of the 17th, skirmishing by the Pennsylvania reserves opened the battle for the day. General Hooker’s entire corps was soon engaged. The right of General Pickett’s line, and the left of General Meade’s reserve, opened fire at about the same moment. A battery was pushed forward into the middle of an open field, where some of the deadliest struggles of the bloody battle subsequently took place. For half an hour, the line did not swerve a hair’s-breadth from the right to the left. At the close of the half hour, the enemy began to fall slowly back. Their first receding movement inspired the brave patriots before them. Forward! was the cry; and the whole line moved forward, with a cheer and a rush; while the rebels in full retreat, running over corn-fields, crossing roads and leaping fences, fled before them.