The officers of the Mint at Philadelphia are now closely engaged in coining the new silver pieces ot the denomination of three, five, ten, and twenty-five cents. In order to meet the want of small silver change, the work at the Mint now goes on both at night and by day. The new quarter of a dollar weighs precisely four pennyweights, and is 7 grains less than the former piece. As compared with the current Spanish quarters, the new COIN IS DECIDEDLY HEAVIER AND somewhat finer. None OF the new dimes or half-dimes have yet been struck. The moulds for the gold bars are intended to make bars of the value of $200, $1,000, and $4,000 each.