It sometimes happens that houses are so planned that a stove-pipe passes through the floor to the room in second story before passing into the chimney, a drum being used for heating the up-stairs room. The illustration represents the upper end of a safe and register through which the pipe passes. The length of the safe is equal to the width of the joists plus the thickness of the floor and the lath and plastering. The space between the two walls (tin or Russia iron) of the safe is three inches; they are connected together below by a perforated cast-iron circle, and above by the circle shown in cut, which is fitted with a sliding circle which opens or closes the apertures. When open, the warm air from the room below rushes up to the upper room; when closed it is simply a perfect safe, the large air space between the walls being perfect protection. The slide of the register is operated from below by cords which drop to a convenient distance below the ceiling.