reverberatory or air furnace is used for melting the metal. The furnace consists of two principal parts, separated from each other, viz., the fire-chamber and the bed or hearth. In the first, the fuel is burned, and in the latter, which is round or oval and slightly depressed, the metal, spread out in not too high a layer, is melted. Opposite to the fire-chamber in the front wall of the furnace is the tapping-hole, closed from the inside by a plug, which is pushed in when the metal is melted.

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In casting bells it is a rule to melt the metai as rapidly as possible and keep its surface covered with powdered coal or coke. First melt the copper, and when that is perfectly liquid add the other metals. When adding the tin, endeavor to push it down to the bottom of the melted copper, otherwise a considerable portion of it will volatilize and burn before combining with the copper. When the metal is melted, a sample is taken out with a ladle, cast in sand, and examined as to grain and fracture. If the . mixture proves successful, the melted metal is freed from impurities and casting may be proceeded with. If instead of new metal old bell-metal is to be used, a sufficient quantity of new bronze (copper and tin) to make up the loss in the old bronze has to be added. For melting 4 to 8 hours are required, ac

cording to the mass of metal. Before casting, the casting gutter must be thoroughly heated and then cleansed. The plug closing the tapping-hole is then pushed in, and the liquid mass commences to flow over the casting-gutter into the mould of the bell. The air enclosed in the mould escapes through the

vent-holes.

The accompanying illustrations show the groundplan and side-view of a reverberatory furnace. The line a b represents the sole-plate or bed of the furnace ; e e are two vaulted passages which can be closed by doors at c. They serve for the entrance of air under the fire-chamber. Underneath the hearth is a vault u; h is the fire-chamber with the grate. The fuel is thrown upon the grate through the stokehole g, while f represents the slide for closing the stoke-hole g. To the right and left, d and k represent steps leading to the stoke-hole; p is the hearth; o o, at the right and left sides, are apertures for charging, stirring, cleansing and observing the metal; s, m and n are levers for raising the doors of the working apertures; qq air-holes of the hearth; t t the slides for closing the air-holes; v the tapping-hole with the plug; and r the casting-gutter. Several modifications of this construction are employed, the working doors, for instance, being opened on the side

instead with levers over the furnace.

Many bellfounders have also furnaces with simple flues in the vault without chimney, but they are not suitable for large castings.

The principle of the reverberatory furnace is so to deflect, or direct, the currents of flame and heated air that they may exert their most intense power upon the metal lying on the bed of the furnace, in which respect the air-furnace somewhat resembles the action of the blow-pipe, with which the greatest concentration of heat on a certain body can be effected in the least time.

The casting being completed, it is allowed to cool 12 to 24 hours. The pit is then emptied, the cope removed, and the bell lifted from the pit with the assistance of a crane or tackle. It is then trans ported to the work-room, where the feeding-head and vent-hole pieces are sawed off, the letters ground an·l the ornamentations chased, or, with ordinary bells, simply rubbed with sand-paper.

Repairing cracked bells. Cracked bells, if it is not preferred to recast them, may be repaired by filling up the crack, or if it does not extend beyond the sound-bow, by cutting it out. However, bells repaired in this manner never possess their original pure and beautiful tone, and are not very durable.

The operation of filling up the crack is as follows: Saw or file the edges of the crack so as to form an empty triangular space. Into this space accurately fit a piece of wood, which serves for the preparation of a mould, in which the piece of bell-metal to be set in is cast. Then fill and surround the bell with glowing coals so that as uniform a heat as possible is maintained, care being, however, taken to prevent the melting of the bell. After 10 to 12 hours direct the blast only upon the crack, lay the piece to be set in, which has been previously cast, in the fire, and, when it and the edges of the crack are nearly at a white heat, remove the coals and ashes, scatter borax upon the edges, place the piece in the crack with the assistance of tongs, and drive it in by gentle blows of the hammer. By hammering, the heat of the edges. is sufficiently increased to cause them to fuse together with the new piece.

The bell is then allowed

to cool slowly, when the crack is filed smooth. Weight of a few peals of bells. The following scale gives the average weight of a few peals of bells, of such sizes and proportions as are recommended by Messrs. Warner and Sons in their "Notes on Bells:"