From the Potomac.movements of our army — successful Withdrawal from Fairfax — citizens leaving — Camps quiet — fighting at Evansport and Harper's Ferry.
We are enabled to lay before our readers a full confirmation of the report that our army has fallen back from Fairfax Court-House, with the object, doubtless, of obtaining a better position. The following dispatch, received last night from our special correspondent, is approved by the highest authority in the army: Army of the Potomac, October 17, 1861. Our army fell back from Fairfax on Tuesday night, between twelve o'clock and daylight. The movement was well regulated, expeditious, and orderly. It the object was to obtain a better position, the movement has been decidedly successful. It would certainly be impolitic to fight, should the enemy offer battle immediately under their fortifications. Our pickets still hold Fairfax, from whence a majority of the residents have retired. The camps are quiet, and seem settled as before. A fight has been going on all day at Evansport also at Harper's Ferry. B. The report circulated on Wednesday of the burning of Fairfax Court-House, was an exaggeration. We learn that some sheds, used by the commissarial were destroyed, to present their occupation by the enemy, in the event of an advance upon the place.