ness was in a state of comparative ruin, and viz: ores, fuel to reduce them, and a suitnot over 20,000 tons were produced. There was a protective duty on iron from 1825 to 1837, but none from 1837 to 1813. From 1843 to 1848 there was protection, but none from 1848 to 1863. The high protective duty was modified in 1866, and since that time the protection has been more and more moderate as the premium on gold declined. The tariff of 1870 reduced the duty from nine to seven dollars per ton on pig iron, and from eight to six dollars per ton on scrap iron. Until the year 1840, charcoal had been the only fuel used in the manufacture of iron; and while it produced a metal far superior in quality to that made with coke, the great demands of the trade were for cheap irons, and the market was chiefly supplied with these from Great Britain. The introduction of anthracite for smelting iron ores in 1840 marked a new era in the manufacture, though its influence was not sensibly felt for several years. MATERIALS EMPLOYED IN THE MANUFACTURE. Before attempting to exhibit the resources of the United States for making iron, and the methods of conducting the manufacture, it is well to give some account of the materials employed, and explain the conditions which this manufacture depends. Three elements are essential in the great branch of the business-that of producing pig iron, upon able flux to aid the process by melting with and removing the earthy impurities of the ore in a freely flowing, glassy cinder. The flux is usually limestone, and by a wise provision, evidently in view of the uses to which this would be applied, limestone is almost universally found conveniently near to iron ores; so also are stores of fuel commensurate with the abundance of the ores. The principal ores are hematites, magnetic and specular ores, the red oxides of the secondary rocks, and the carbonates. Probably more than three-quarters of the iron made in the United States is from the first three varieties named, and a much larger propor tion of the English iron is from the lastfrom the magnetic and specular ores none. Hematites, wherever known, are favorite ores. They are met with in great irregular-shaped deposits (apparently derived from other forms in which the iron was distributed), intermixed with ochres, clays, and sands, sometimes in scattered lumps and blocks, and sometimes in massive ledges; they also occur in beds interstratified among the mica slates. Although the deposits are regarded as of limited capacity, they are often worked to the depth of more than 100 feet; in one instance in Berks county, Penn., to 165 feet; and when abandoned, as they sometimes are, it is questionable whether this is not rather owing to the increased expenses incurred in continuing the enormous excavations at such depths, than from failure of the ore. Mines of hematite have proved the most valuable mines in the United States. At Salisbury, in Connecticut, they have been worked almost uninterruptedly for more than 100 years, supplying the means for supporting an active industry in the country around, and enriching generation after generation of proprietors. The great group of mines at Chestnut Hill, in Columbia county, Penn., and others in Berks and Lehigh counties in the same state, are of similar character. The ore is a hydrated peroxide of iron, consisting of from 72 to 85 per cent. of peroxide of iron (which corresponds to about 50 to 60 per cent. of iron), and from 10 to 14 per cent. of water. Silica and alumina, phosphoric acid, and peroxide of manganese are one or more present in very small quantities; but the impurities are rarely such as to interfere with the production of very excellent iron, either for foundry or forge purposes—that is, for castings or bar iron. It is easily and cheaply mined, and works easily of iron to that from the hematite and magin the blast furnace. On account of its de- netic ores, and better adapted for castings ficiency in silica it is necessary to use a lime- than for converting into malleable iron. The stone containing this ingredient, that the pure, rich ores, however, are many of them elements of a glassy cinder may be provided, unsurpassed. It is found in beds of all diwhich is the first requisite in smelting iron; mensions, and though in the castern part of or the same end may be more advantageously the United States they prove of limited exattained by adding a portion of magnetic tent, those of Missouri and Lake Superior ore, which is almost always mixed with are inexhaustible. Magnetic and specular silica in the form of quartz; and these two ores are associated together in the same disores are consequently very generally worked trict, and sometimes are accompanied by together the hematites making two-thirds hematite beds; and it is also the case, that or three-quarters of the charge, and the mag- iron districts are characterized by the prevanetic ores the remainder. lence of one kind only of these ores, to the exclusion of the others. Magnetic ore is the richest possible combination of iron, the proportion of which cannot exceed 72.4 per cent., combined with 27.6 per cent of oxygen. It is a heavy, black ore, compact or in coarse crystalline grains, and commonly mixed with quartz and other minerals. It affects the magnetic needle, and pieces of it often support small bits of iron, as nails. Such ore is the loadstone. It is obtained of various qualities; some sorts work with great difficulty in the blast furnace, and others are more easily managed and make excellent iron for any use; but all do better mixed with hematite. The magnetic ores have been largely employed in the ancient processes of making malleable iron direct from the ore in the open forge, the Catalan forge, etc., and at the present time they are so used in the bloomary fires. They are found in inexhaustible beds of all dimensions lying among the micaceous slates and gneiss rocks. These beds are sometimes so extensive that they appear to make up the greater part of the mountains in which they lie, and in common language the mountains are said to be all ore. Specular ore, or specular iron, is so named from the shining, mirror-like plates in which it is often found. The common ore is sometimes red, steel gray, or iron black, and all these varieties are distinguished by the bright red color of the powder of the ore, which is that of peroxide of iron. Magnetic ore gives a black powder, which is that of a less oxidized combination. The specular ore thus contains less iron and more oxygen than the magnetic; the proportions of its ingredients are 70 parts in 100 of iron, and 30 of oxygen. Though the difference seems slight, the qualities of the two ores are quite distinct. The peroxide makes iron fast, but some sorts of it produce an inferior quality The red oxides of the secondary rocks consist, for the most part, of the red fossiliferous and oolitic ores that accompany the so-called Clinton group of calcareous shales, sandstones, and argillaceous limestones of the upper silurian along their lines of outcrop in Pennsylvania, Maryland, and eastern Tennessee, and from Oneida county, N. Y., westward past Niagara Falls, and through Canada even to Wisconsin. The ore is found in one or two bands, rarely more than one or two feet thick, and the sandstone strata with which they are associated are sometimes so ferruginous as to be themselves workable ores. The true ores are sometimes entirely made up of the forms of fossil marine shells, the original material of which has been gradually replaced by peroxide of iron. The oolitic variety is composed of fine globular particles, united together like the roe of a fish. The ore is also found in compact forms, and in Wisconsin it is in the condition of fine sand or seed. Its composition is very variable, and its per-centage of iron ranges from 40 to 60. By reason of the carbonate of lime diffused through some of the varieties, these work in the blast furnace very freely, and serve extremely well to mix with the silicious ores. Of the varieties of carbonate of iron, the only ones of practical importance in the United States are the silicious and argillaceous carbonates of the coal formation, and the similar ores of purer character found among the tertiary clays on the western shores of Chesapeake Bay. The former varieties are the chief dependence of the iron furnaces of Great Britain, where they abundantly occur in layers among the shales of the coal formation, interstratified with the beds of coal-the shafts that are sunk for the exploration of one also penetrating beds of the other. The layers of ore are in flat- inferior, brittle quality of cast iron. They tened blocks, balls, and kidney-shaped lumps, are chiefly found near the coast, and being which are picked out from the shales as the casily dug, and also reduced to metal with beds of these are excavated. The ore is great facility, they proved very convenient lean, affording from 30 to 40 per cent. of for temporary use before the great bodies of iron; but it is of easy reduction, and makes, ore in the interior were reached. Some furwhen properly treated, iron of fair quality. naces are still running on these ores in the In Pennsylvania, Ohio, western Virginia, south-west part of New Jersey, and at SnowKentucky, and Tennessee, the ores occur hill, on the eastern shore of Maryland, and with the same associations as in England; the iron they make is used to advantage in but the supply is, for the most part, very pre-mixing at the great stove foundries in Albany carious, and many furnaces that have de- and Troy with other varieties of cast iron. pended upon them are now kept in opera- It increases the fluidity of these, and protion only by drawing a considerable portion duces with them a mixture that will flow of their supplies from the mines of Lake into and take the forms of the minutest Superior, more than one thousand miles off. markings of the mould. Among the horizontally stratified rocks west of the Alleghanies, the same bands of ore are traced over extensive districts, and are even recognized in several of the different states named. One of the most important of these bands is the buhrstone ore, so called from a cellular, flinty accompaniment which usually underlies it, the whole contained in a bed of peculiar fossiliferous limestonc. So much carbonate of lime is sometimes present in the ore, that it requires no other flux in the blast furnace. Its per-centage of iron is from 25 to 35. Along the line of outcrop of some of the carbonates are found deposits of hematite ores, the result of superficial changes in the former, due to atmospheric agencies long continued. In southern Ohio, at Hanging Rock particularly, numerous furnaces have been supported by these ores, and have furnished much of the best iron produced at the west. Charcoal has been the only fuel employed in the manufacture of iron until anthracite was applied to this purpose, about the year 1840, and still later-in the United Statescoke and bituminous coal. So long as wood continued abundant in the iron districts, it was preferred to the mineral fuel, as in the early experience of the use of the latter the quality of the iron it produced was inferior to that made from the same ores with charcoal, and even at the present time, most of the highest-priced irons are made with charcoal. The hard woods make the best coal, and after these, the yellow pine. Hemlock and chestnut are largely used, because of their abundance and cheapness. The charcoal furnaces are of small size compared with those using the denser mineral coal, and their capacity rarely exceeds a production of ten or twelve tons of pig iron in twenty-four hours. In 1840 they seldom The carbonates of the tertiary are found made more than four tons a day; the differin blocks and lumps among the clays along ence is owing to larger furnaces, the use of the shores of the Chesapeake at Baltimore, hot blast, and much more efficient blowing and its vicinity. The ores are of excellent machinery. The consumption of charcoal character, work easily in the furnace, make a to the ton of iron is one hundred bushels of kind of iron highly esteemed-particularly hard-wood coal at a minimum, and from this for the manufacture of nails-and are so running up to one hundred and fifty bushels abundant that they have long sustained a or more, according to the quality of the coal considerable number of furnaces. They lie and the skill of the manager. The economy near the surface, and are collected by exca- of the business depends, in great part, upon vating the clay beds and sorting out the the convenience of the supplies of fuel and balls of ore. The excavations have been of ores, of each of which rather more than carried out in some places on the shore be- two tons weight are consumed to every ton low the level of tide, the water being kept of pig iron. As the woods are cut off in back by coffer dams and steam pumps. the vicinity of the furnaces, the supplies are gradually drawn from greater distances, till at last they are sometimes hauled from ten to fourteen miles. The furnaces near Baltimore have been supplied with pine wood discharged from vessels at the coaling kilns Bog ores, with which the earliest furnaces in the country were supplied, are now little used. They are rarely found in quantities sufficient for running the large furnaces of the present day, and, moreover, make but an |