The Army Of The Potomac

New York, Jan. 2G, The IleraWs Army of the Potomac's special says : üur pieket's near Kaccoon Ford were driven in a few days sinee by about sixty rebel cavalry, wtio crossed the river aud had a brief sk.rraish, but were aftcrwards rcpulsed aud compelled to retire iu confusión. A considerablo farce of cavalry aud infautry is visible on the otlier sido of the Rapidan. Deserten say Lee's army is widely scattered, but do uot believe any partion of t has been out oiT. They are certain no troops have beon sent from thoir imnaediaio camraand. They represent foraga as being diflicult to obtain, and the horses are reduoed in pumber and ciBoienoy ; alao, that no supplies are reoeived by Lee's army in advanoe of ts actual neqessitics. Araong the deserters are guards wha were assigned tho duty of watching rebel pickets. A battalion of the Sixteenth New York Cavalry made a reconuoissance to Wolfe lliver Shoala aud Occoquan, but discoered only fivo or six rebels, wbere they expected to meet a eomparatively large forue. The roads were bad and the mud deep. On Saturday the rebels n front of Kilpatriek's cavalry undoubtedly had a flght among themselves, heavy artillery and ufantry iighting being heard there.