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286 bent round the opposite edges of the latter. The bent extremity of an iron rod passed under the loop thus formed over the middle of the bottom, serves to raise and remove any cover from place to place. When a crucible is in use, the cover should be arranged over it in such a manner as not to touch the vessel, but rest by its edge on the earthenware plate around.

The platinum stirrers in use with this furnace have been before described (28. 75), fig. 3. The platinum ladle consists of a small crucible of that metal riveted to a platinum wire, and that made fast by a screw to an iron rod (fig. 4).

The use and manner of working this furnace will be well understood from the above description, and what has before been said (26, &c.). The crucible should never be suddenly heated or cooled. The coke may be fed and arranged at such of the crucible holes as are out of use at the time. Because of the very valuable effects of a trough of water under the fire-bars (45) experienced in the larger furnace, one is constantly used with that just described.

Finishing furnace.—This furnace on the outside is a parallelepiped, principally of brickwork, built against a wall; it is 64 inches in length, from the fire front to the beginning of the flue, against which it is built, 45 inches wide, and 28 inches high (figs. 5, 6 & 7). It is the only one that has yet been built, and, for the reasons before given, shall be described exactly as it is. The fire-place is at one end, and the course of the flame and smoke is directly from that to the other end, and then immediately into the upright Hue. The fire-place is 15 inches from back to front, 13 inches wide, and 11½ inches from the arched roof to the bars. Its outward side, or that from the wall, is 18½ inches in thickness of brickwork, which is intended to give stability to the structure. The mouth of the fire-place is an aperture 8 inches by 6 inches, made in a piece of tire-stone 7 inches inwards from the front of the brickwork: its lower edge is level with a fire-stone sill, which, extending forwards from the fire-place to the outer surface of the brickwork, forms a shelf, on which two bricks stand, that serve in place of a door to close the mouth of the furnace. The ash-pit is 25 inches long, 12 inches wide under the fire, and 10 inches high to the bars. A trough made of rolled iron, riveted together, and 5½ inches high on the sides, occupies its lower part. This being