 They were sent to reconnoitre, and if assailed were ordered to signal, when they would have been reinforced by a corps of regular infantry and a battery...

At twelve o'clock the infantry regiment, artillery and cavalry corps began to muster and assume marching order.As fast as the several regiments were ready they proceeded to the Long Bridge, those in Washington being directed to take that route.The troops quartered at Georgetown, the Sixty-ninth, Fifth, Eighth and Twenty-eighth New York regiments, proceeded across what is known as the chain bridge, above the mouth of the Potomac Aqueduct, under the command of General McDowell.