Page:Brinkley - Japan - Volume 7.djvu/153

RV 129 the furnace, and sprinkling it while hot with sulphate of copper and nitric acid.

With regard to the method of casting, Mr. Gowland's description of a typical operation witnessed by himself is this:—

The bronze was melted in a cupola furnace. Charcoal was used as fuel, and the blast was produced by a "tatara" (kind of bellows) worked by eight persons.

From an early hour in the morning, and whilst the melting was proceeding, the foundry staff was engaged in preparing the moulds for the reception of the metal by heating them to redness. This was effected in the following manner: The mould was placed on five or six bricks, to raise it above the earthen floor of the melting-room. Its ingates were closed with stoppers of clay, and conical tubes were fitted over its air outlets to prevent any fuel from falling into them. A wall of fireclay slabs was now built up around it, the slabs being kept in position by hoops and bands of iron and an external luting of clay, a space about three inches wide at its narrowest part being left between the inside of the wall and the outside of the mould. A charcoal fire was then made on the floor below the mould, and the space between the wall and the mould was completely filled with burning charcoal which was mixed with fragments of bricks and crucibles to prevent the heat from becoming too intense. The interior of the core was also partly filled with the same mixture, and two clay tubes were fitted above it to serve the purpose of chimneys. The temperature of the interior was regulated by partially or entirely closing the upper openings of these tubes with tiles. The mould was kept at a red heat for more than two hours, by which time the metal was nearly ready. The wall of clay slabs and the draught tubes were now rapidly taken down and the fire was raked away. The bricks supporting the mould were carefully removed and the holes through which the wax had run out stopped up with fireclay. During their removal the floor below was sprinkled with water and softened by shovelling, and on this the mould was allowed to rest. Large stones were now piled