Against this force advanced General McDowell, who had succeeded Mansfield in command of operations south of the Potomac, with something less than twenty-nine thousand men and forty-nine guns. With his army under the commanders already named, he was ready and started from Washington on July 16th, within a week of the date he had planned, notwithstanding the slow operations of the Government's military machinery, rusted by long disuse and not as yet in smooth working order. The departure of his column was a strange spectacle. The novelty of warfare and the general impression that the war was to be ended with one grand, brilliant stroke--an impression largely derived from the confidence at headquarters that the expedition would be successful--turned the march into a sort of festive picnic. Citizens accompanied the column on foot; Congressmen, newspaper correspondents, sightseers, went along in carriages. There was a tremendous turnout of non-combatants, eager to see the finishing stroke to the rebellion. These were destined to share in the general rout that followed and to come pouring back into the security of Washington, all mixed in with the disorganized and flying troops. One member of Congress, John A. Logan, of Illinois, a veteran of the Mexican War, followed the army from the House of Representatives, armed with a musket, and began as a civilian a participation in the four years' fighting that brought him high rank, great honor, and a distinguished reputation. [Illustration: UNITED STATES MILITARY RAILROAD, BULL RUN.] [Illustration: GENERAL AMBROSE E. BURNSIDE.] [Illustration: GENERAL LOUIS BLENKER.]