about ten miles from us, to the north-northwest — the direction of the road from Harper's Ferry
This excited apprehensions of the near approach of General Patterson
had marched from the Potomac
with instructions from the general-in-chief
to turn the right of the Confederate army and seize its line of communication with Richmond
Before involving himself in such an enterprise, the Federal
general bestowed three days upon the examination of the ground before him. In this way he learned that the region into which he would have been led, by obedience to his instructions, was altogether unfavorable to the more numerous assailing army, and advantageous to the smaller force standing on the defensive; for it is rugged, and covered with thick woods, and the Occoquan
, a stream to be crossed, is large enough to be a serious obstacle; while to the west the country is open, the hills gentle, and Bull Run
almost everywhere fordable.
He therefore decided, judiciously, to attempt to turn the Confederate
line by moving through the open and favorable ground on his right, instead of involving his army in the thick woods and rugged hills on his left.
The best argument for this change of plan, however, was the object explained by General McDowell
-“to break up the communication between the two Confederate armies,” an object which might have been accomplished by prompt action.
For some unexplained purpose, one Federal division, Runyon
's, had been left between the Potomac
, near Vienna
Leaving another, Miles
's, at Centreville
, to divert attention from the