...main in front, while the army should cross the Potomac, under partial cover of night, either at Edwards's Ferry, or, by means of a pontoon train, at a point nearly north of Fairfax Court-House, which General Beauregard was having reconnoitred for that purpose. This army was then to march rapidly upon Washington, and seize the Federal supplies in that city. It seemed almost certain that, even should McClellan re...