Among the innumerable contraband articles seized by the Louisville inspectors, during the smuggling season, were two or three breast-plates of cast iron, about one-eighth of an inch in thickness, covered with bunches of cotton cord half an inch thick, with which some valiant Secessionists expected, I presume, to protect their carcasses from Minie balls. The other day one of them was put to the test, without a man to stand behind it. It withstood the balls of Colt’s navy pistol, receiving only a deep indentation, and cracking very slightly; but when tried with the Minie musket, at fifty paces, it fractured like a gourd. Mr. Durett, now of Fort Lafayette, made some efforts to get them released from seizure, and it may be one was intended for his protection.