Tennessee Tragedies.—A special tothe American-; from Knoxyille, Tenn^ 9ays: Two tragedies are reported fromthe line of the new railroad to Cumberland Gap. An unknown negro gambler was driven from Donovan’s works by the laborers* He returned shortly with a dozen desperadoes at his heels, all armed with Winchester rifles. They fired several shots at Capt.D. Dunovant, a prominent contractor, none of which took effect. The crowd was then dispersed. A posse arrested the leader of the mob at Cnmberland Gap, andstarted toward Tazewell with him. On the road they were surrounded by a mob of 100 who took the negro and bung him totheneaKest tree.Near the same place two negroes, half brothers, Fred and Henry Satteriee, quarreled over a woman. Henry stabbed Fred through the bowels, killing him instantly.WEDNESDAY llEf! 10