... of letters addressed to preeminent personages in Richmond, was captured at Leonardtown, Md., last week. In Baton Rouge a regiment of 1,000 negroes were treated with ill will and detestation. General Graves threatened to resign, and would not permit them to draw clothing, blankets, or pay. The Colonial of the 133d New York says he will not suffer the self-respect or manliness of his regiment to be lower...