...an's army are to the 7th. A dispatch from Cumberland, Md., on that day, states that Col. Imboden's entire wagon train, two pieces of artillery, and fifty prisoners, had been captured by the Federal Colonel McReynolds , on the Cacapon river. An explosion occurred in a powder magazine at Harper's Ferry, on the 6th, wounding several soldiers. The following dispatches are all from the Army of the Potomac that are ...