facture of steel; and none but very skilful and industrious men will make good hands at the tilt. In fig. 24, as will be seen at a glance, a tilt-house is

represented. The faces of the hammer-head, as well as the anvil, are of the best cast-steel, well hardened and polished. Each hammer has a blast-pipe conducted to it, which ends in a nozzle, from which a stream of air is constantly blowing upon the anvil, to keep it free from dust and scales. This cleanliness is necessary to impart a good polish to the steel bars.

CAST-STEEL

Is made by melting blistered steel in crucibles. The converted steel is broken into convenient pieces for charging it in the narrowest space possible. A portion of carbon is always dissipated in this process; therefore, the most highly carbonized bars of the blis

tered steel are selected to be transformed into caststeel. The highly converted steel is known by its larger crystals and brighter lustre, in a newly-made fracture, than in the other bars. These broken pieces of blistered steel are charged in crucibles made of the best Stourbridge fire-clay.

THE MAKING OF CRUCIBLES,

Or melting-pots, is an important branch in this department of the art. They are from eighteen to twenty inches high, and of a sugar-loaf shape. The clay is, as we have said, of the best Stourbridge, worked to a high degree of uniformity and smoothness. To give it this uniformity, the clay is first moistened with water, and well puddled; it is then spread on a smooth floor underneath the castinghouse, and worked by bare feet; this requires the uninterrupted work of two men for six hours. In some establishments, the clay is mixed with finelypulverized coke, or finely-ground cement of old crucibles, or a portion of black lead; and sometimes it is mixed with the whole of these ingredients. Up to the present time, every attempt has failed to substitute machinery for manual labour in mixing the clay; it would seem that there is an efficacy in the

human hand, or, in this case, in the foot, which no machinery has been found or can be expected to possess.

The crucibles are moulded in a cast-iron mould, as in fig. 25. A is a solid block of wood, in which the outer part of the iron mould, B, closely fits, but still so loose as to be easily lifted out of its place. This iron mould is well bored out on the turning lathe, and polished. The

core of the mould, C, is also of cast-iron, well turned. It has two guide-pins, one above and one below. In the space between the core of the mould and the case, a lump of clay is laid on the bottom, just sufficient to fill the space and make a crucible. When

the

proper size of a lump has been found by experiment, it is weighed, and its weight made the standard for future operations, thus securing uniformity in the A dried and baked Sheffield crucible weighs from twenty-five to thirty pounds, and will contain forty pounds of broken steel.

crucibles.

Crucible-making is the most tedious and expensive branch in the manufacture of cast-steel. The best

Sheffield crucibles do not last longer than three heats, or one day.

The core, C, is pressed down upon the lumps of clay in the mould, by which they are forced upwards and fill the upper part of the mould. In this way, the lower portion of the crucible receives the necessary degree of compactness. The hole in the bottom of the crucible, caused by the guide-pin, is stopped up with clay before the vessel is taken out of the mould. When the core is removed, and the bottom hole stopped, the mould, B, is lifted out of the wooden block, and reversed upon a board. If the clay is of the right texture and well worked, the withdrawal of the core and the crucible is easy enough; but if the clay is a little too damp, it will adhere to the iron, and is with difficulty loosened. If the clay should be too dry, on the other hand, the crucibles are very apt to crack, or to become porous. With the proper degree of moisture, the crucibles are easily removed from the mould. The adhesion of imperfectly prepared clay to the mould may be prevented, to some extent, by rubbing the mould with coke-dust, or laying sheets of paper or muslin in it; but these expedients are troublesome, and the necessity for them should be avoided.

The crucibles, after being moulded, are placed in

drying-stoves, where they are slowly dried by a liberal access of atmospheric air, gently heated. They are here dried hard, but not baked. The day before they are intended to be used, the crucibles are set upon an annealing grate, made of fire-clay, where they are covered with the refuse coke from the airfurnaces; they are here baked, if it can be called baking, for one day.

THE CAST-HOUSE

Has a great resemblance to a brass foundry. There are a dozen or more air-furnaces in one or two ranges, their tops being on a level with the undermined floor of the building, as shown in fig. 26. It is very convenient to have the top of the furnaces level with the floor, as it gives the workman a better chance of lifting the crucible with the melted metal. The ash-pits are below the floor, in a subterranean vaulted passage, from which the grates derive a supply of cool air, which favours the rapid combustion of the fuel. The crucibles are made and dried in these vaults. The pit of the air-furnace is a square cavity; if intended but for one crucible, it is twelve inches square-if for two, it is twelve by eighteen inches. The crucibles being six inches wide at the