as a cold, pasty mass, which the hottest blast will not soften into a fluid slag.

ee. If we wish to revive most, or all of the iron, in cases where titanium is the enemy against which we have to contend, our most successful plan of operation is to increase the foreign matter, and to form a large quantity of a more or less fusible cinder, according to the quality of metal to be made. In this case, as in other cases, it is not advisable to employ pure silex, or pure clay or lime; but to select ferruginous clay, ferruginous slate, or lime containing iron. Pure lime and pure clay are injurious in every instance. Titanium is subject to the general law of the solubility of the oxides of metals in silicates; and the more fusible such silicates are, or the lower the temperature at which they melt, the greater is their dissolving power. Hence, where the amount of titanium is large, the amount of cinder should be uncommonly large, to produce gray iron; but if we are indifferent about the loss of a little ore, and smelt white forge metal at a low temperature, the fluxing of the furnace requires but little foreign matter. Ores containing titanium may be considered very favorable for the manufacture of steel metal; in many respects, they are preferable to the spathic ores; for, with very little attention, they will produce white iron with a large amount of carbon, the very material from which German steel is manufactured. For this purpose, a high stack, and a low hearth, or none at all, like the Styrian furnaces, are required: as well as the addition of a flux which shall carry off the titanium. A sandstone hearth would not answer so well as a hearth of granite and gneiss.

ff. Cinders No. 4 and No. 5 possess but little interest; but Nos. 6 and 7 are taken from a furnace of which we have personal knowledge. This furnace is known to produce a first rate article, from which German steel for the Solingen market is manufactured. No. 6 was taken while the furnace labored under too heavy a burden; the metal produced was white, serviceable for the manufacture of bar iron. No. 7 was derived from the furnace when in good order, and while smelting gray iron, a kind of foundry metal. But for this purpose the furnace is seldom employed; because the region in which it is situated abounds in rich spathic ore, and supplies no ore of inferior quality. This rich spathic ore is scarcely at all adapted to produce soft gray iron. From the same furnace we have a third specimen of cinder from a different source; this cinder was made when the furnace was smelting steel metal, that is, a white, crystallized metal, containing a great deal of carbon.

As the manufacture of steel metal is carried on, in this country, only to a very limited extent, notwithstanding we possess ore and fuel in abundance sufficient to relieve us from the tribute we at present pay to Europe for steel, we shall make some remarks which may be useful to those who design to engage in its manufacture. We shall call the following specimen of cinder No. 12:

The ore employed in cinders Nos. 6, 7, and 12 was of the same composition. Nothing but its burden was changed. In No. 6 it was heaviest; in No. 7 lightest. It will be observed that there is a considerable increase of silex from No. 6 to Nos. 12 and 7. No. 7 contains the largest amount of silex, but scarcely any iron. The iron contained in No. 6 is replaced by magnesia, alumina, and manganese. Scientific investigation shows us that the cinder from gray iron contains fifty per cent. more oxygen in its silex, in proportion to the oxygen of the alkali, than the cinder from white iron, No. 6, contains; the latter is almost a single silicate, in which the oxygen in the acid is equal to the oxygen in the alkali.

The characteristic feature of cinder No. 12 is that it contains no lime. This is an important circumstance. The lime is replaced by manganese; but we cannot expect, in every instance, to find manganese in quantities sufficiently large to flux the cinder. This remark applies especially to the magnetic ores of this country. Therefore, if we wait until we find an ore which can be fluxed by the manganese it contains, before we succeed in manufacturing steel, we shall be under the necessity of waiting a long time. An addition of black manganese will be highly serviceable; but this can be only partially applied; partly on account of its expense, and partly because of the limited quantity in which it is found. Neither lime, magnesia, nor any of the alkaline earths, are of any use. Protoxide of iron is inefficient, because, in spite of all our efforts, it will be dissolved by the temperature of the furnace, and the amount of carbon present. The only resource which remains is the alkalies proper, that is, potash or soda. Soda is preferable to potash, as we shall, in the following chapter, more fully show.

Lime, in this instance, does not answer the purpose of a flux, for the following reasons: Metal adapted for the manufacture of German steel should contain a large amount of carbon, and be as free as possible from foreign matter; these are objects accomplished with great difficulty in the blast furnace. We are enabled to combine a large amount of carbon with iron, in the blast furnace; as in the case of gray anthracite iron, or the charcoal iron of Hanging Rock. But this object is always effected by means of a strong, silicious cinder; and such iron contains a large amount of silex. But this iron, though an excellent forge metal, is not adapted for the manufacture of steel.

The combination of the revived metal with carbon may be effected with comparative facility, as we have before demonstrated. But in the present case, we need a metal free from foreign matter; therefore it is requisite that we employ an ore as free as possible from foreign matter. We have an abundance of such ores in this country from Maine to Alabama, and from Iowa to Texas; but the usual method of conducting blast furnace operations will not enable us to produce the required metal. Silex and clay, if they are present in the ore, do no harm to the metal; but lime is injurious. Lime facilitates the reviving of iron in a higher degree than any. other alkali. While it protects the bright surface of the metal, it will prevent, and sometimes even dissolve, the combination of iron and carbon. For these reasons, lime is inapplicable to our purpose. Still another reason is, that the affinity of lime for silex is not sufficiently strong to prevent the combination of silex and iron; and in the presence of a surplus of carbon, silex will be reduced to silicon, and, combining with the iron, will make it brittle, and useless for the manufacture of steel.

The application of soda or potash in furnace operations, as a means of fluxing, has been recommended by various writers; but we are not aware that a successful experiment has ever been made. While the application of these fluxes will improve the metal for the forge, it will impair its malleability as a foundry metal.

gg. The hearth and in-wall of a furnace suitable for the manufacture of steel require a thoroughly different construction from those of ordinary furnaces. The material employed at common furnaces cannot resist the action of strong alkalies; but of the material of which a hearth should be constructed, we shall speak in the next chapter. A different internal form from that of common furnaces

is required. The interior should be high; there should be no hearth, or a very low one. The blast should not be too strong, but in abundance. Very rich ores are desirable, in case artificial flux is to be employed, for expenses will augment in proportion to the amount of foreign matter contained in the ore. It is worthy of remark, that steel metal can be manufactured, so far as charcoal is concerned, at a very small cost; for, in Styria, where a large number of furnaces produce this metal, less fuel is consumed than in any other blast furnaces in the world.

The analyses of cinders Nos. 6, 7, and 12 show conclusively that cinders from the same furnace, from the same ore, and produced, with the exception of burden, under the same conditions, differ greatly in composition. Therefore we should be cautious in drawing conclusions from analyses of cinder, and avoid hasty imitations. We do not always know to what kind of work the cinder belongs. The theory of the artificial composition of cinder, which has of late been so highly developed, may, while it is useful to the utilitarian, seriously mislead the speculator, who, in his eagerness to secure profitable results, fails to examine whether his conclusions are drawn. from sound or insufficient premises. The application of theories is accompanied with difficulty, because the science of the manufacture of iron is far in advance of the practice. The rules with which science has furnished us in relation to the rudiments of the business have, thus far, been applied only to a very limited degree; therefore, we cannot expect that improvements, based upon conditions thus incompletely fulfilled, will be altogether successful. Speculative minds are too little disposed to notice slight imperfections; but these imperfections constitute the greatest obstacle to the progress of the business. Were they properly estimated, and due pains taken to correct them, the United States would be enabled, in a few years, to compete against the world in the manufacture of iron.

hh. We conclude that cinder No. 10, on account of the large amount of lime it contains, produced red-short iron and white metal. No. 9 is decidedly of better quality; and close investigation will show that this cinder produced gray metal. To enter into details upon this subject would probably be less acceptable to the reader than to present the subject in as brief and significant a manner as possible. We infer that No. 10 produced white iron, because the amount of oxygen in the alkali is greater than that in the silex; whence it follows that the cinder is a basic or subsilicate. To make

gray metal, at least a single silicate, that is, the presence of an equal amount of oxygen in the alkali and acid, is required. The process will be more effectual if the amount of oxygen in the silex is greater than that in the alkali. This is the case with respect to No. 9; and, in spite of the large amount of protoxide of iron present, the cinder is the result of a good quality of metal. If not excessively gray, it is at least good foundry metal, made by cold blast. No. 10 is a peculiar cinder, and is from the same furnace as No. 9. The furnace is said to have been in bad order; but this cannot be true, because the amount of sulphur in this cinder is 1.4 per cent. Nearly three tons of cinder, at a coke furnace, are produced per one ton of metal; therefore, should a good cinder have been made, the iron of No. 9 ought to contain three times 1.4 per cent. of sulphur. But this amount would render the iron entirely useless, even though the largest proportion of sulphur present was expelled. Be this as it may, the coal or the ore of the furnace at the Dowlais Works, in South Wales, contained a large amount of sulphur, which is visible in No. 10. We allude to this cinder especially, because it was produced under conditions which resemble very closely those which exist at the Great Western Iron Works, in Pennsylvania.

The presence of sulphur in the furnace occasions great annoyance. In the case before us, the furnace required a large charge of limestone to produce, even at a high temperature, a surplus of lime; for this is the best means of carrying off a certain amount of sulphur. A high temperature will produce a white cinder, streaked with various shades. This cinder contains, besides a silicate of lime, a sulphuret of lime, and is characterized by soon losing its lustre on being exposed to the atmosphere. If, under such circumstances, the temperature of the furnace falls below a given point, the cinder changes rapidly into a pitch black, heavy mass, containing a large amount of sulphuret of iron. The same circumstance happens where too small a quantity of limestone is used. In this case, the sulphur, having no free alkali with which to combine, follows the iron into the pig bed, where its presence is indicated by the odor of sulphurous acid. If the furnace is cooled below the temperature at which gray iron is usually made, the cinder, by absorbing sulphuret of iron is soon blackened. In such cases, the smelting of gray metal is accompanied with difficulties which absorb more attention than can well be spared. In addition to the difficulty of continuing a furnace on gray iron, the metal produced is of inferior quality, and unsuitable for the market. To get rid of the sul