Edward Porter Alexander, Military memoirs of a Confederate: a critical narrative

‘ [264] had gathered up about 200 men, and I sent them to the right to attack the Yankees in flank. They drove them back a short distance, but were in turn repulsed. These two attacks, however, had a most happy effect. The Yankees were completely deceived by their boldness, and induced to believe that there was a large force in our centre. They made no further attempt to pierce our centre.’

These details give an instructive lesson in the value of pertinacity; Longstreet with his staff helped man two guns of the Washington Artillery and materially aided in the result.

While Richardson's advance was still being pushed, Pleasanton advanced about three brigades of cavalry and four batteries across the Antietam, by the Boonsboro bridge. The batteries crowned the hills upon our side and opened fire, supported by the cavalry, and by a regiment of regulars deployed as skirmishers. Presently the line was reenforced by three more batteries of the 5th corps and Buchanan's brigade of regulars. These troops felt of our line quite heavily, the pressure coming upon Evans's brigade and parts of the brigades of Wilcox, Featherstone, and Pryor of R. H. Anderson's division, and G. T. Anderson of D. R. Jones's division. D. H. Hill, himself on foot (having had three horses killed under him during the morning) and carrying a musket, led some of these troops which he had rallied. S. D. Lee's battalion of artillery was also now back upon the field with ammunition replenished, and this demonstration was presently driven back under cover of the hills bordering the Antietam.

Pleasanton, who appreciated the opportunity, called for reenforcements, but McClellan had started on a visit to his right flank, and had ordered two brigades of regulars of the 5th corps to follow him. The absence of these brigades prevented Porter from complying with Pleasanton's request. So his demonstration was abandoned, and his troops and artillery were withdrawn, having suffered something over 100 casualties.

When McClellan reached the field on his right, he conferred with Sumner and Franklin. The latter urged a renewal of the attack, but Sumner advised against it, and McClellan took his advice. Franklin was ordered simply to stand on the defensive. The two brigades of regulars brought over from the centre were marched back. Thus, McClellan's expedition to the right at a critical time saved the shattered Confederate lines from two assaults by fresh troops, on their left and on their centre, just