General Burnside's task was the hardest of all. The banks of the river by the lower bridge are steep and high, and the land on both sides is broken. The road leading to the bridge winds down a narrow ravine. The bridge is of stone, with three arches. It is twelve feet wide, and one hundred and fifty feet long.
The western bank is so steep that one can hardly climb it. Oak-trees shade it. Half-way up the hill there is a limestone quarry,—excavations affording shelter to sharpshooters. At the top there is a stone wall, a hundred feet above the water of the winding stream, and yet so near that a stone may be thrown by a strong-armed man across the stream.
A brigade of Rebels, with four pieces of artillery, guarded the bridge. There were sharpshooters beneath the willows, and in the thick underbrush along the bank of the stream. There were riflemen in the excavations on the hillside and behind the trees. The four cannon were behind the wall, with the great body of infantry in support. The bridge, the hills and hollows on the eastern bank, are raked and searched in every part by the infantry.
South of Sharpsburg there are numerous batteries ready to throw solid shot and shells over the heads of the brigade by the bridge. If Burnside carries the bridge, there are the heights beyond, the ground in front all open, swept and enfiladed by batteries arranged in a semicircle, supported by A. P. Hill's and a portion of Longstreet's troops. A. P. Hill was not on the ground in the morning, but arrived while the battle was in progress on the right and center.
General Burnside formed his troops on the farm of Mr. Rohrbach, with Sturgis's division on the right, Wilcox in the center, Rodman on the left, and Cox's division, commanded by Crook, in reserve. Benjamin's battery of twenty-pounder Parrotts, Simmons's, McMullen's, Durrell's, Clark's, Muhlenburgh's, and Cook's batteries were stationed on the hills and knolls of Rohrbach's estate during the night of the 16th. The troops lay on their arms, prepared to move whenever General McClellan issued the order.
At daybreak the Rebel batteries on the Sharpsburg hills began a rapid fire. The shells fell among the troops. Here and there a man was struck down, but they maintained their ground with great endurance. It was a severe test to the new regiments, which never had been under fire. It requires strong nerves to lie passive, hour after hour, exposed to a cannonade. But the men soon learned to be indifferent to the screaming of the something unseen in the air. They ate their hard tack, and watched the distant flashes from the white cloud upon the Sharpsburg hills. They talked of the guns, and learned to distinguish them by the sound.
"That is a rifle shot."
"There comes a shell."
"I wonder where that will strike."
With such remarks they whiled away the moments.