The owners of the Trenton Locomotive Works have been awarded the contract for building a marine hospital for the United States government at New Orleans, the material to be of iron. Its length is to be three hundred and forty-eight feet, with wings each of two hundred and four feet. The main building will be three stories high and the wings two stories ; both the main building and the wings will be surmounted with domes. A verandah, two stories high, will extend around the entire structure. The exterior walls, roof and vcrandahs, are tobe entirely of iron. That the walls may be rendered nonconductors of heat, unburnt preparcd clay will be used for the filling. The work is done at Trenton.Philadelpl!ia Ledger.