Major G. W. Cullum, United States Engineers, and Major Schuyler Hamilton, as aides de-camp. The general had an office up stairs on Seventeenth Street, opposite the War Department, and resided in a house close by, on Pennsylvania Avenue. All fears for the immediate safety of the capital had ceased, and quite a large force of regulars and volunteers had been collected in and about Washington. Brigadier-General J. K. Mansfield commanded in the city, and Brigadier-General Irvin McDowell on the other side of the Potomac, with his headquarters at Arlington House. His troops extended in a semicircle from Alexandria to above Georgetown.