... Longstreet with his whole force, estimated at 4,000, was at Hagerstown, while Jackson had disposed his own command, including Mc-Laws' and A. P. Hill's divisions, either with a view to an attack on Harper's Ferry or to cutting off the retreat of the force occupying it. Three days later McClellan, according to his own report, advanced to the attack at Sharpsburg with 87,000 men. Of this vast army probably 33,0...