The spring that would drive the Yankees’ trap shut was coiling itself tight as Burnside’s men slowly readied themselves for the advance, but General McClellan could not shake the northern part of the battlefield from his fears. It was from that northern sector, which had been harrowed by death all morning, that he expected the great rebel counterattack that would jeopardize his army’s existence. One of his generals reported imminent disaster in those northern fields, while another claimed that with one more effort the North could sweep the rebels out of the West Woods and back through Sharpsburg altogether, and so fierce was their argument that once his lunch was taken McClellan crossed the creek for the first and only time that day. He met his generals, he listened to their arguments, and then he pronounced his verdict. Caution, he declared, was best. The generals must hold their ground against the worst the rebels could throw against them, but they were to make no more attacks. The enemy, he said, must not be provoked and then, with that decided, McClellan went back to his armchair, from where he sought reassurance that his heavy reserve of men was still in place to meet the rebel attack he knew must be coming. After all, as he explained to Pinkerton, the rebels did outnumber him.

“That they do, chief, that they do,” Pinkerton agreed enthusiastically. “Hordes of the scoundrels, just hordes!” The Scotsman blew his nose vigorously, then unfolded the handkerchief to inspect the result. “It’s a miracle we’ve done as well as we have, chief,” he opined, still staring at the handkerchief. “Nothing short of a miracle.”

McClellan, who rather thought it was his superior generalship that had staved off disaster all day, grunted, then stooped to the telescope to watch as the troops in the center of the field at last began their advance from the sunken lane. Their job was to hold Lee’s men in Sharpsburg while Burnside cut behind them. It was a grand sight, McClellan thought. Thousands of men marched beneath their flags. Wisps of smoke drifted across the telescope’s lens, giving the great attack a fine romantic flavor.

It was less romantic in the ranks. There, advancing across open fields toward the massive gun line assembled on the hill above the village, the North suffered as the smoldering battle burst again into livid flame. The cannons’ long range meant the infantry had no chance of replying, but could only trudge through the smoke of the explosions and across the blood of their comrades until it was their turn to be hit. Ahead of them was the skyline above the village, but that skyline was rimmed by guns that pumped tongues of flames and billows of smoke. The shells screamed and wailed and cracked and killed, while from beyond the creek the heavy Federal guns returned the fire with big shells that rumbled in the sky to flower in bloody gouts on the rebel artillery line.

Burnside’s men started forward at last. There, and only there on all the battlefield, a band played as the flags were carried up the hill to begin the grand attack that would cut the retreat of the rebel army.