Throughout the preceding day, while occupied about Harper's Ferry, we heard heavy cannonading across the Maryland border, apparently eight or ten miles from us. This had increased in volume, and by sunset had evidently advanced toward us, as the sound of musketry was distinctly heard. It proved to be an attack on Gen. D. H. Hill's division and other commands occupying the South Mountain passes. After stubborn resistance the Confederates had been forced to yield. So on reaching camp toward midnight, after our visit to Charlestown, we were not surprised to find the battery preparing to move. With scarcely an hour's delay we were again on the march, heading for Maryland. We arrived at Shepherdstown before dawn, and while halting in the road for half an hour Henry Lewis, driver at my gun, overcome with sleep, fell sprawling from his horse, rousing those about him from a similar condition.
INTO MARYLAND AGAIN--BATTLE OF SHARPSBURG--WOUNDED--RETURN TO WINCHESTER--HOME
Half a mile below the town we forded the Potomac for the third time, and by the middle of the afternoon were on the outskirts of Sharpsburg, four miles from the river. On the opposite, or east, side of this village are Antietam creek and valley; a mile from the creek and parallel to it was a heavily wooded mountain. It is not my design to attempt a description of the battle which was fought on this ground on the following day, generally conceded to have been the fiercest of the war, but only to mention what came under my observation or was especially associated therewith.
The unusual activity and aggressiveness on the part of General McClellan, as evidenced by the fierce attacks made on our forces in the South Mountain passes for the two preceding days, were explained by his being in possession of General Lee's order to his subordinates. This order, or a copy of it, which contained directions for the movements of the various portions of the Confederate army, including the investment of Harper's Ferry, had been lost or disposed of by some one in Frederick City, and when this place was occupied, on September 13, by the Federals, was delivered to General McClellan. Thus acquainted with the location and movements of each division of the Confederate army, which was scattered over a wide territory and separated by a river and rugged mountains, it seems surprising that with his army of 90,000 men he should not have practically destroyed General Lee's army of 40,000. General Lee, however, was informed early on the morning of the fourteenth that a copy of his order had fallen into the hands of General McClellan.