ART. V.-1." Ironmaking" and "Smelting," in the Encyclopædia Britannica. 7th Edition. 2. Report of Trial in causa, James Beaumont Neilson and Others against the Househill Coal and Iron Company. Edinburgh, 1842. 3. Report of Trial in causa, James Beaumont Neilson and Others against William Baird and Company. Edinburgh, 1843. 4. First Report of the Childrens' Employment Commission (Mines), and Appendixes thereto. London, 1842. 5. Report of Special Commissioner on the State of the Population in the Mining Districts. London, 1844.-Report of do. do. London, 1845. "GEOLOGY, in the magnitude and sublimity of the objects of which it treats, undoubtedly ranks, in the scale of sciences, next to astronomy." This remark of Sir John Herschel is verified by the most cursory glance at the researches of geologists. Although the range of their actual penetration has been limited to 3000 feet beneath the surface, they present us with an analysis of the crust of our globe to a depth of ten miles. They tell us that, resting on a foundation of unstratified rocks, of igneous origin, there rise, in successive piles, a series of parallel stratified layers, deposited, from time to time, by the action of water; -they inform us that these strata, though, if left in their natural order, placed far beyond the reach of man, have been dragged up from their beds for his inspection and use, by the force of what may be termed volcanic levers;-they disclose to us the plants which flourished in luxuriant vegetation during each successive epoch of the earth's history; and they reveal to us the animals that roamed unrestrained amid the primeval forests and marshes of these far distant periods. So minute, indeed, are the discoveries of geologists, that they can even track the footsteps of the tortoise as it crawled over the long buried sands of another age;—thus warranting the following beautiful reflections by one of the most distinguished of their number. † "The historian, or the antiquary, may have traversed the fields of ancient or of modern battles, and may have pursued the line of march of triumphant conquerors, whose armies trampled down the most mighty kingdoms of the world. The winds and storms have utterly obliterated the ephemeral impressions of their course. Not a track The deepest mine in the world (Kitzpuhl, in the Tyrol) is only 2764 feet below the surface."_Phillips' Geology, i. 18. + Buckland's Br. Tr., i. 262. remains of a single foot, or a single hoof, of all the countless millions of men and beasts whose progress spread desolation over the earth. But the reptiles that crawled upon the half finished surface of our infant planet have left memorials of their passage, enduring and indelible. No history has recorded their creation or destruction,--their very bones are found no more among the fossil relics of a former world. Centuries and thousands of years may have rolled away between the time in which these footsteps were impressed by tortoises upon the sands of their native Scotland, and the hour when they are again laid bare and exposed to our curious and admiring eyes. Yet we behold them stamped upon the rock, distinct as the track of the passing animal upon the recent snow, as if to show that thousands of years are but as nothing amidst eternity, and, as it were, in mockery of the fleeting perishable course of the mightiest potentates among mankind." But the science of geology is not more remarkable for its magnitude and sublimity than it is for its utility. By ascertaining the relative positions of strata to each other, it directs our otherwise blindfold search into the bowels of the earth. The importance of such a guide in a country like ours, where the strata of the carboniferous group abound, cannot be over estimated; and strikingly appears from two illustrations that may here be quoted : "It is not many years since an attempt was made to establish a colliery at Bexhill, in Sussex. The appearance of thin seams and sheets of fossil-wood and wood-coal, with some other indications similar to what occur in the neighbourhood of the great coal-beds in the north of England, having led to the sinking of a shaft, and the erection of machinery on a scale of vast expense-not less than eighty thousand pounds are said to have been laid out on this project-which, it is almost needless to add, proved completely abortive, as every geologist would have at once declared it must, the whole assemblage of geological facts being adverse to the existence of a regular coal-bed in the Hastings' sand; while this, on which Bexhill is situated, is separated from the coal-strata by a series of interposed beds of such enormous thickness, as to render all idea of penetrating through them absurd. The history of mining operations is full of similar cases, where a very moderate acquaintance with the usual order of nature-to say nothing of theoretical views-would have saved many a sanguine adventurer from utter ruin.”* The next illustration is of an opposite kind :— "Only sixteen years ago (it is in our own memory), a valuable estate in Durham was pronounced to be devoid of coal, because it * HERSCHEL'S Int. to Nat. Phil., sec. 36, p. 45. was situated on the magnesian limestone;' and might have been sold under this opinion, but that a geologist of celebrity, Dr. William Smith, showed the falsity of the reasoning-reported favourably of the probability of finding good coal in abundance beneath the property-and advised the proprietor to work it. That estate is now the centre of a rich and well-explored mining tract, all situated beneath the magnesian limestone; and this result was the fruit of scientific geology, not practical' coal-viewing, though the professional mine-agents of the north of England are now employed in extending its benefits."* The carboniferous group, of which mention has been made, contains ironstone, coal, and limestone ; " and the occurrence of this most useful of metals (ironstone) in immediate connexion with the fuel requisite for its reduction, and the limestone which facilitates that reduction, is an instance of arrangement so happily suited to the purposes of human industry, that it can hardly be considered as recurring unnecessarily to final causes, if we conceive that this distribution of the rude materials of the earth, was determined with a view to the convenience of its inhabitants."† It is to the distribution here referred to, that we owe the iron manufacture of Great Britain, of which a brief account will now be given. Any one unacquainted with minerals, would be unable to discover the slightest affinity betwixt the rough ironstone, as brought up from the mines, and the iron of commerce. The two have apparently no properties in common. And it is only after subjecting the ironstone to severe processes of manufacture, that iron can be obtained from it. These processes include, 1st, the roasting or calcining it, so as to clear it from sulphur, carbonic acid, and other deleterious substances; and, 2d, the exposing the calcined iron ore, so obtained, to intense heat in a blast furnace, charged with fuel and flux. In early times, the furnace used for the latter purpose was of the rudest description-consisting of a low narrow conical structure, such as is still to be seen in Africa. It was called an airbloomery, and was dependent, for its blast, upon the varying currents of air that played around the hill on which it was placed. The air-bloomery was succeeded by the blast-bloomery, which, though not differing materially in construction, was blown by bellows, driven by water or wind power, whereby a more regular blast was obtained. This was its distinguishing feature; and the change formed an important improvement in the manufacture of iron. PHILLIPS' Geology, ii., p. 295. + CONYBEARE'S Geology of England and Wales, p. 333. The blast-bloomery, in its turn, gave way to the modern blastfurnace, now almost universally used in the smelting of iron. The blast-furnace costs about £1500 to erect. It is a huge building of brick or stone, bulging out near the base, and gradually narrowing towards the top. Its height may be from 40 to 50 feet-its width from 12 to 15. And its capacity and strength may be estimated from the fact that the largest of these furnaces will hold 150 tons. The materials are thrown in at an opening in the top, by which the gases also escape; and the molten metal flows out from an aperture at the bottom, and is run into moulds of sand made for the purpose of receiving it. Cotemporaneous with the improvements in size, strength, and capacity of the modern furnace, were the improvements in its blast. A gigantic steam-engine has been substituted for water or wind, as the propelling power; and, in order to equalize the blast, this steam-engine transmits the air into a capacious cylindrical iron reservoir or regulator, (placed in the vicinity of the furnaces) from which the blast is conveyed to the fire-not as previously in irregular gusts-but in regular and continuous currents. Another not less important change was the substitution of charred pit coal, or coke, for charred wood, as the fuel of the furnace. It was not until the end of last century that this change was completely effected. Coke had been tried in James the First's time, but had not succeeded; and the experiment was not repeated until the supply of wood had entirely failed, when the iron-masters were necessitated again to resort to coke, and finally to adopt it. During the period of transition from the one fuel to the other, the iron manufacture was in a most languid state. A short time prior to 1740, the number and produce of the furnaces in England appears to have been very considerable; but, by that year, the number of furnaces had decreased to fifty-nine, being only three-fourths of their previous number, and their produce had fallen to 17,350 tons. Such was the miserable state of the iron manufacture in England an hundred years ago. The following table shews its subsequent development down to the present time : 1740, Number of tons of pig iron produced, 17,350 61,300 108,793† 250,000† The main channel in the sand is called the sou, and the branches from it the litter of pigs-hence the name pig-iron. + We are indebted for our knowledge of the Iron trade in 1796 and 1806, to the attempts made (unsuccessfully) at these periods to tax coal and iron, which caused inquiry into the subject. VOL. IV. NO. VII. I On looking over the materials from which this Table has been obtained, it is remarkable to notice the altered distribution of the furnaces in point of locality. So long as charred wood was used as fuel, Gloucester, Sussex, and Kent, were the principal seats of the iron manufacture; but, after the substitution of coke, the manufacture was transferred to Wales, Staffordshire, Shropshire, and Yorkshire where coal abounded. Another remark that occurs is the gradual increase in quantity of the iron produced by each furnace in the year and week, as shown in the subjoined note : Thus, it appears that in England, during the last 100 years, the produce of iron has increased from seventeen thousand to a million and a quarter tons; and the yield of each furnace during the same period has multiplied nearly twenty fold-illustrating at once the extent of the demand, the capital expended, and the improvements introduced in the manufacture. Turning from England to Scotland, we find the progress of the iron manufacture still more striking. The carboniferous strata of Scotland form a broad belt which traverses the centre of the island from the Firth of Forth to the shores of Ayrshire; and alongst this belt will be found the principal coal and iron works of the country. In the east of Scotland, the coal is wrought almost exclusively for family consumption; but in the west of According to a statistical return made by M. Goldenberg of Berlin, the following is the annual production of iron in the different European States :England (including Scotland also,) France, Russia, Germany, 1,500,000 tons. 350,000 320,000 150,000 |