but he was uncertain whether Lee intended to recross the Potomac or to move northwards into Pennsylvania.  On the morning of the 13th, although General Hooker, commanding the First Army Corps, took the liberty of reporting that, in his opinion, “the rebels had no more intention of going to Pennsylvania than they had of going to heaven,” the Federal Commander-in-Chief was still undecided, and on the Boonsboro’ road only his cavalry was pushed forward.  In four days McClellan had marched no more than five-and-twenty miles; he had been unable to open communication with Harper’s Ferry, and he had moved with even more than his usual caution.  But at noon on the 13th he was suddenly put into possession of the most ample information.  A copy of Lee’s order for the investment of Harper’s Ferry, in which the exact position of each separate division of the Confederate army was laid down, was picked up in the streets of Frederick, and chance had presented McClellan with an opportunity unique in history.* (* General Longstreet, in his From Manassas to Appomattox, declares that the lost order was sent by General Jackson to General D.H.  Hill, “but was not delivered.  The order,” he adds, “that was sent to General Hill from general headquarters was carefully preserved.”  General Hill, however, in Battles and Leaders volume 2 page 570 (note), says:  “It was proper that I should receive that order through Jackson, and not through me.  I have now before me (1888) the order received from Jackson.  My adjutant-general swore affidavit, twenty years ago, that no order was received at our office from General Lee.”  Jackson was so careful that no one should learn the contents of the order that the copy he furnished to Hill was written by his own hand.  The copy found by the Federals was wrapped round three cigars, and was signed by Lee’s adjutant-general.) He was within twenty miles of Harper’s Ferry.  The Confederates were more than that distance apart.  The intrenched camp still held out, for the sound of McLaws’ battle on the Maryland Heights was distinctly heard during the afternoon, and a resolute advance would have either compelled the Confederates to raise the siege, or have placed the Federal army between their widely separated wings.

But, happily for the South, McClellan was not the man for the opportunity.  He still hesitated, and during the afternoon of the 13th only one division was pushed forward.  In front of him was the South Mountain, the name given to the continuation of the Blue Ridge north of the Potomac, and the two passes, Turner’s and Crampton’s Gaps, were held by Stuart.  No Confederate infantry, as Lee’s order indicated, with the exception, perhaps, of a rear-guard, were nearer the passes than the Maryland Heights and Boonsboro’.* (* For the lost order, see Note at end of chapter.) The roads were good and the weather fine, and a night march of twelve miles would have placed the Federal advanced guards at the foot of the mountains, ready to force the Gaps at earliest dawn.  McClellan, however, although his men had made no unusual exertions during the past few days, preferred to wait till daylight.