...-Cincinnati Gazette. The Thirty-seventh, Twenty-second, and Eleventh regiments of New York militia, left New York for the scene of operations in Penn sylvania.--the Mechanic Light Infantry left Salem, Mass. , for the seat of war.--the steamer Platte Valley was fired into at Bradford's Landing on the Mississippi, and two persons were killed and a number wounded.--the English schooner Harriet was captured ...