EXPLANATION OF THE FRONTISPIECE, IN VOLUME SECOND. The Frontispiece exhibits a portable universal furnace, which is made of strong wrought iron plates, and is lined with bricks bedded in fire-proof loom. The height of this furnace without its chimney a a is two feet. The inner diameter of the cylindrical fire place measures 12 inches. The body of the furnace is elliptical; in its upper part a circular hole is cut, for receiving an iron sand-pot b which may be occasionally removed, and exchanged for an iron plate. In the front of the furnace there are three openings over cach other, furnished with sliding doors, and fitted with stoppers made of crucible ware. The lower opening c is the ash-pit of the furnace; it is composed of two register plates sliding backwards and forwards in grooves, in order to diminish or enlarge the opening for regulating the heat, by admitting or excluding air at pleasure. In the side of the furnace a hole is cut furnished with a stopper and door, for passing a tube through the fire part of the furnace, an expedient very necessary for a variety of chemical processes. |