... of Sharpsburg, and the day that McClellan had lost on his right seemed about to be won by Burnside on his left. It was at this critical moment that A. P. Hill, who had marched seventeen miles from Harper's Ferry that morning, and had waded the Potomac, reached the field upon the flank of Burnside's victorious column. With a skill, vigor and promptness, which cannot be too highly praised, A. P. Hill formed ...