...ofitless population. Gen. Lee mentions, in his recent correspondence, an instance of the barbarity of some of the Yankee soldiers in the Abolition Army of the Potomac. They thrust into the Rappahannock River a poor old negro man, whom they had taken from his master, because he had the small-pox; and he would have been drowned had he not been rescued by our pickets. It is surmised that this dreadful dis...