But this flattering reception was not the best fortune that befell the Union army in Frederick. On his arrival in the town, General McClellan came into possession of a copy of General Lee's order, dated three days before, in which the whole campaign was laid out. By this order, Jackson was directed to march through Sharpsburg, cross the Potomac, capture the force at Martinsburg, and assist in the capture of that at Harper's Ferry; Longstreet was directed to halt at Boonsborough with the trains; McLaws was to march to Harper's Ferry, take possession of the heights commanding it, and capture the force there as speedily as possible; Walker was {176} to invest that place from the other side and assist McLaws; D. H. Hill's division was to form the rear guard. All the forces were to be united again at Boonsborough or Hagerstown. General Lee had taken it for granted that Martinsburg and Harper's Ferry would be evacuated at his approach (as they should have been); and when he found they were not, he had so far changed or suspended the plan with which he set out as to send back a large part of his army to capture those places and not leave a hostile force in his rear. On the approach of Jackson's corps General White evacuated Martinsburg, and with his garrison of two thousand men joined Miles at Harper's Ferry. That town, in the fork of the Potomac and Shenandoah rivers, can be bombarded with the greatest ease from the heights on the opposite sides of those streams. Miles, instead of taking possession of the heights with all his men, sent a feeble detachment to those on the north side of the Potomac, and stupidly remained in the trap with the rest. McLaws sent a heavy force to climb the mountain at a point three or four miles north, whence it marched along the crest through the woods, and attacked three or four regiments that Miles had posted there. This force was soon driven away, while Jackson was approaching the town from the other side, and a bombardment the next day compelled a surrender when Jackson was about to attack. General Miles was mortally wounded by one of the last shots. About eleven thousand men were included in the capitulation, with seventy-three guns and a considerable amount of camp equipage. A body of two thousand cavalry, commanded by Colonel Davis, had been with Miles, but had escaped the night before, crossed the Potomac, and by morning reached Greencastle, Pa. On the way they captured Longstreet's ammunition train of fifty wagons. Jackson, leaving the arrangements for the surrender to A. P. Hill, hurried with the greater part of his force to rejoin Lee, and reached Sharpsburg on the morning of the 16th. [Illustration: THE TWENTY-SECOND NEW YORK NEAR HARPER'S FERRY.] [Illustration: BREVET BRIGADIER-GENERAL J. C. KELTON. (Adjutant-General to General Halleck.)]