The canal, which was now the supplying medium of Hooker's army, soon received our attention. A lock-gate was broken, and steps taken to intercept boats. At least a dozen were intercepted, and the next morning several loaded with troops, negroes, and stores were captured by Colonel Wickham, Forth Virginia Cavalry, commanding rear guard. I ascertained that Hooker was on the day previous at Poolesville, and his army in motion for Frederick. I realized the importance of joining our army in Pennsylvania, and resumed the march northward early on the 28th. General Hampton was sent by Darnestown to Rockville, and the other brigades took the direct route to the same place. General Hamtpon encountered small paarties of the enemy, which, with a number of wagons and teams, he captured, and reached Rockville in advance of the main body. The advance guard of W. H. F. Lee's brigade had a running fight with the Second New York Cavalry, but the speed of their horses deprived us of the usual results in capture. At Rockville, General Hamtpon encountered what he believed to be a large force of the enemy, and moving up W. H. F. Lee's brigade quickly to his assistance, I found that the enemy had already disappeared, having retreated toward the Great Falls. Rockville was speedily taken possession of. This place is situated on the direct wagon road from Washington City to Hooker's army, and, consequently on his route of communication with Washington after crossing the Potomac. The telegraph line along it was torn down for miles. Soon after taking possession, along train of wagons approached from the direction of Washington, apparently but slightly guarded. As soon as our presence was known to those in charge, they attempted to turn the wagons, and at full speed to escape, but the leading brigade (W. H. F. Lee's)m was sent in pursuit. The farthest wagon was within only 3 or 4 miles of Washington City, the train being about 8 miles long. Not one escaped, though many were upset and broken, so as to require their being burned. More than one hundred and twenty-five best United States model wagons and splendid teams with gay caparisons were secured and driven off. The mules and harness of the broken wagons were also secured. The capture and securing of this train had for the time scattered the leading brigade. I calculated that before the next brigade could march this distance and reach the defense of Washington, it would be after dark; the troops there would have had time to march to position to meet attack on this road. To attack at night with cavalry, particularly unless certain of surprise, would have been extremely hazardous; to wait till morning, would have lost much time from my march to join General Lee, without the probability of compensating results. I therefore determined, after getting the wagons under way, to proceed directly north, so as to cut the Baltimore and Ohio Railroad (now becoming the enemy's main war artery) that night. I found myself now encumbered by about 400 prisoners, many of whom were officers. I paroled nearly all at Brookeville that night, and the remainder next day at Cooksville. Among the number, were Major [James C.] Duane and Captain [Nathaniel] Michelr, Engineers, U. S. Army. At Cooksville, our advance encountered and put to flight a small party of the enemy, and among the prisoners taken there were some who said they belonged to the "Seven Hundred Loyal Eastern Shoremen. "