its colour a bright silvery white, and the tables of the crystals are lustrous like brilliants. The central crystals are always smaller than those near the surface of the bar. TILTING. Blistered steel is hardly fit for any purpose, no matter how simple or coarse the article made of it may be. Its blisters and fissures make it unfit for the manufacture of tools, until it is re-heated and tilted. The first operation of this kind of refining makes common steel; the second makes shear-steel, and steel for cutlery. Very little steel is exposed to three welding-heats, as each heat adds to its tenacity and strength, but, if carried too far, will reduce some of it to iron. THE REFINING FIRES Are like a blacksmith's forge-hearth; the fire is, however, of a larger size. Soft or bituminous coal is used for welding the bundles of steel. This coal is converted into a coke, and forms an arch over the fire, giving the appearance of a bakeoven. Neither charcoal nor anthracite has this effect. The forge-fires are supplied with air by cylinder blast-machines, or by common bellows, placed above the head, and worked by a crank which is driven either by water or steam-power. The air is conveyed in copper or tin pipes to the tuyere. The blistered steel is cut or broken into lengths of twelve or eighteen inches, and four of such lengths are piled along with a fifth of double length. This longer bar is placed in the middle, between the others, and forms the handle to the pile. This pile, or fagot, is held together by being bound with a small steel rod. It is carried to the fire, and a good welding heat given to it. While in the fire, it is occasionally sprinkled with sand, to form a protecting slag against the impurities of the coal. The fagot, when of a cherryred heat, is carried from the fire to the tilt, and notched down-that is, hammered down in a rough so as to unite the bars together, and close up every internal flaw and fissure. manner In the first heat, the fagot is merely welded in a rough manner; after which the bindings are knocked off, and the pile is again re-heated. In the second heat, the welded bars are drawn out into a uniform rod of the thickness required, which is generally an inch or an inch and a half square, and twice or three times the length of the original fagot. The bars of the first heat, which are common steel, are piled again to form shear-steel. Five or six of such bars are piled and held together by a slender band of steel, as before, when they are once more exposed to a welding heat in the first forge-fire, and welded imperfectly, or soaked, to cement the bars together. This fagot, which also is supplied with a long bar for a handle, is then carried to a larger fire, in which it receives a thorough welding heat, and is then tilted at the heaviest hammer of the establishment, called the "shear-hammer." In this heat a bar of two or two and a half inches square is drawn out; and if steel of more than two heats, or "double shear," is required, it is cut in two, doubled, welded together, and drawn out again. Blistered steel, repeatedly re-heated and drawn out, assumes a very uniform, fine grain; it loses all its flaws, fissures and blisters, and is by far more tenacious than any other steel; it is also less affected by heat than cast-steel. When rendered compact by welding and hammering, this steel is also susceptible of a very fine polish, in which respect it is but little inferior to cast-steel. It is therefore a superior steel for cutlery, and unites a fine, close texture, with great tenacity. Shear-steel has not derived its name from being particularly useful in making scissors. In days gone by, there were a large kind of shears in use for dressing woollen cloth; they were formed like those in use for shearing sheep, being four or five feet long, with blades of twelve or eighteen inches in length, by eight to twelve inches wide. The refined blistered steel was particularly adapted to make the edge and spring of these shears. el THE TILTS, Or hammers, are very much the same as those described in the last chapter for tilting natural steel. The heaviest hammer-the shear-hammer-varies in weight from two hundred to four hundred pounds. In Sheffield, the principal and cheapest mart for the manufacture of steel, the hammers are driven by a small water-wheel, upon whose prolonged axis are one or more iron rings, which contain the wipers, or In the periphery of the cam-ring, or wiper wheel, there are from twelve to eighteen cams, which strike the tail of the hammer in rapid succession, by which the hammer-head is raised and suffered to fall on the steel. To increase the effect of the hammer, a spring is placed under its tail, so as to work the hammer partly by weight, and partly by recoil. cams. Large tilts make two hundred, smaller ones four hundred, strokes per minute. The majority of the hammer frames in Sheffield are of wood, which in fact is the most suitable material for tilts. In some establishments, more than one hammer is on one wheelshaft. The anvils are placed upon a stone foundation, and these stones upon a grate of wood-piles. The surface of the anvils is almost level with the floor of the tilt-house, and the workman sits down in a fosse, or pit, with his face towards the hammer. The smaller rods are tilted sitting, the larger ones standing. At the lighter tilts, the hammer-man or tilter sits on a swinging seat, suspended from the roof of the building. While thus suspended, he takes one end of the bundle of rods between his legs, and by the motion of his body gives to the rods a rapid backward and forward motion under the hammer. tilter has two boys in attendance, to furnish him with hot rods, and take away those which are sufficiently hammered. The rods are heated to a higher or lower degree, but, after the welding is done, not higher than a cherry-red. Small rods of good steel, which very soon cool after being brought upon the anvil, speedily become red again under the rapid blows of the hammer. Each Tilting is a very important process in the manu |