In 1600 Sheffield became celebrated for its tobacco-boxes and Jew"s-harps. The town was as yet of small size and population; for when a survey of it was made in 1615 it was found to contain not more than 2207 householders, of whom one-third, or 725, were "not able to live without the charity of their neighbours: these are all Begging poor." [2] It must, however, have continued its manufacture of knives; for we find that the knife with which Felton stabbed the Duke of Buckingham at Portsmouth in 1628 was traced to Sheffield. The knife was left sticking in the duke"s body, and when examined was found to bear the Sheffield corporation mark. It was ultimately ascertained to have been made by one Wild, a cutler, who had sold the knife for tenpence to Felton when recruiting in the town. At a still later period, the manufacture of clasp or spring knives was introduced into Sheffield by Flemish workmen. Harrison says this trade was begun in 1650. The clasp-knife was commonly known in the North as a jocteleg.
Hence Burns, describing the famous article treasured by Captain Grose the antiquarian, says that--
"It was a faulding jocteleq, Or lang-kail gully;"
the word being merely a corruption of Jacques de Liege, a famous foreign cutler, whose knives were as well known throughout Europe as those of Rogers or Mappin are now. Scythes and sickles formed other branches of manufacture introduced by the Flemish artisans, the makers of the former princ.i.p.ally living in the parish of Norton, those of the latter in Eckington.
Many improvements were introduced from time to time in the material of which these articles were made. Instead of importing the German steel, as it was called, the Sheffield manufacturers began to make it themselves, princ.i.p.ally from Dannemora iron imported from Sweden. The first English manufacturer of the article was one Crowley, a Newcastle man; and the Sheffield makers shortly followed his example. We may here briefly state that the ordinary method of preparing this valuable material of manufactures is by exposing iron bars, placed in contact with roughly-granulated charcoal, to an intense heat,--the process lasting for about a week, more or less, according to the degree of carbonization required. By this means, what is called BLISTERED STEEL is produced, and it furnishes the material out of which razors, files, knives, swords, and various articles of hardware are manufactured. A further process is the manufacture of the metal thus treated into SHEAR STEEL, by exposing a fasciculus of the blistered steel rods, with sand scattered over them for the purposes of a flux, to the heat of a wind-furnace until the whole ma.s.s becomes of a welding heat, when it is taken from the fire and drawn out under a forge-hammer,--the process of welding being repeated, after which the steel is reduced to the required sizes. The article called f.a.gGOT steel is made after a somewhat similar process.
But the most valuable form in which steel is now used in the manufactures of Sheffield is that of cast-steel, in which iron is presented in perhaps its very highest state of perfection. Cast-steel consists of iron united to carbon in an elastic state together with a small portion of oxygen; whereas crude or pig iron consists of iron combined with carbon in a material state.[3] Chief merits of cast-steel consist in its possessing great cohesion and closeness of grain, with an astonishing degree of tenacity and flexibility,--qualities which render it of the highest value in all kinds of tools and instruments where durability, polish, and fineness of edge are essential requisites. It is to this material that we are mainly indebted for the exquisite cutting instrument of the surgeon, the chisel of the sculptor, the steel plate on which the engraver practises his art, the cutting tools employed in the various processes of skilled handicraft, down to the common saw or the axe used by the backwoodsman in levelling the primeval forest.
The invention of cast-steel is due to Benjamin Huntsman, of Attercliffe, near Sheffield. M. Le Play, Professor of Metallurgy in the Royal School of Mines of France, after making careful inquiry and weighing all the evidence on the subject, arrived at the conclusion that the invention fairly belongs to Huntsman. The French professor speaks of it as a "memorable discovery," made and applied with admirable perseverance; and he claims for its inventor the distinguished merit of advancing the steel manufactures of Yorkshire to the first rank, and powerfully contributing to the establishment on a firm foundation of the industrial and commercial supremacy of Great Britain. It is remarkable that a French writer should have been among the first to direct public attention to the merits of this inventor, and to have first published the few facts known as to his history in a French Government Report,--showing the neglect which men of this cla.s.s have heretofore received at home, and the much greater esteem in which they are held by scientific foreigners.[4] Le Play, in his enthusiastic admiration of the discoverer of so potent a metal as cast-steel, paid a visit to Huntsman"s grave in Atterclifle Churchyard, near Sheffield, and from the inscription on his tombstone recites the facts of his birth, his death, and his brief history. With the a.s.sistance of his descendants, we are now enabled to add the following record of the life and labours of this remarkable but almost forgotten man.
Benjamin Huntsman was born in Lincolnshire in the year 1704. His parents were of German extraction, and had settled in this country only a few years previous to his birth. The boy being of an ingenious turn, was bred to a mechanical calling; and becoming celebrated for his expertness in repairing clocks, he eventually set up in business as a clock maker and mender in the town of Doncaster. He also undertook various other kinds of metal work, such as the making and repairing of locks, smoke-jacks, roasting-jacks, and other articles requiring mechanical skill. He was remarkably shrewd, observant, thoughtful, and practical; so much so that he came to be regarded as the "wise man" of his neighbourhood, and was not only consulted as to the repairs of machinery, but also of the human frame. He practised surgery with dexterity, though after an empirical fashion, and was held in especial esteem as an oculist. His success was such that his advice was sought in many surgical diseases, and he was always ready to give it, but declined receiving any payment in return.
In the exercise of his mechanical calling, he introduced several improved tools, but was much hindered by the inferior quality of the metal supplied to him, which was common German steel. He also experienced considerable difficulty in finding a material suitable for the springs and pendulums of his clocks. These circ.u.mstances induced him to turn his attention to the making of a better kind of steel than was then procurable, for the purposes of his trade. His first experiments were conducted at Doncaster;[5] but as fuel was difficult to be had at that place, he determined, for greater convenience, to remove to the neighbourhood of Sheffield, which he did in 1740. He first settled at Handsworth, a few miles to the south of that town, and there pursued his investigations in secret. Unfortunately, no records have been preserved of the methods which he adopted in overcoming the difficulties he had necessarily to encounter. That they must have been great is certain, for the process of manufacturing cast-steel of a first-rate quality even at this day is of a most elaborate and delicate character, requiring to be carefully watched in its various stages. He had not only to discover the fuel and flux suitable for his purpose, but to build such a furnace and make such a crucible as should sustain a heat more intense than any then known in metallurgy. Ingot-moulds had not yet been cast, nor were there hoops and wedges made that would hold them together, nor, in short, were any of those materials at his disposal which are now so familiar at every melting-furnace.
Huntsman"s experiments extended over many years before the desired result was achieved. Long after his death, the memorials of the numerous failures through which he toilsomely worked his way to success, were brought to light in the shape of many hundredweights of steel, found buried in the earth in different places about his manufactory. From the number of these wrecks of early experiments, it is clear that he had worked continuously upon his grand idea of purifying the raw steel then in use, by melting it with fluxes at an intense heat in closed earthen crucibles. The buried ma.s.ses were found in various stages of failure, arising from imperfect melting, breaking of crucibles, and bad fluxes; and had been hid away as so much spoiled steel of which nothing could be made. At last his perseverance was rewarded, and his invention perfected; and though a hundred years have pa.s.sed since Huntsman"s discovery, the description of fuel (c.o.ke) which he first applied for the purpose of melting the steel, and the crucibles and furnaces which he used, are for the most part similar to those in use at the present day. Although the making of cast-steel is conducted with greater economy and dexterity, owing to increased experience, it is questionable whether any maker has since been able to surpa.s.s the quality of Huntsman"s manufacture.
The process of making cast-steel, as invented by Benjamin Huntsman, may be thus summarily described. The melting is conducted in clay pots or crucibles manufactured for the purpose, capable of holding about 34 lbs. each. Ten or twelve of such crucibles are placed in a melting-furnace similar to that used by bra.s.s founders; and when the furnace and pots are at a white heat, to which they are raised by a c.o.ke fire, they are charged with bar steel reduced to a certain degree of hardness, and broken into pieces of about a pound each. When the pots are all thus charged with steel, lids are placed over them, the furnace is filled with c.o.ke, and the cover put down. Under the intense heat to which the metal is exposed, it undergoes an apparent ebullition. When the furnace requires feeding, the workmen take the opportunity of lifting the lid of each crucible and judging how far the process has advanced. After about three hours" exposure to the heat, the metal is ready for "teeming." The completion of the melting process is known by the subsidence of all ebullition, and by the clear surface of the melted metal, which is of a dazzling brilliancy like the sun when looked at with the naked eye on a clear day. The pots are then lifted out of their place, and the liquid steel is poured into ingots of the shape and size required. The pots are replaced, filled again, and the process is repeated; the red-hot pots thus serving for three successive charges, after which they are rejected as useless.
When Huntsman had perfected his invention, it would naturally occur to him that the new metal might be employed for other purposes besides clock-springs and pendulums. The business of clock-making was then of a very limited character, and it could scarcely have been worth his while to pursue so extensive and costly a series of experiments merely to supply the requirements of that trade. It is more probable that at an early stage of his investigations he shrewdly foresaw the extensive uses to which cast-steel might be applied in the manufacture of tools and cutlery of a superior kind; and we accordingly find him early endeavouring to persuade the manufacturers of Sheffield to employ it in the manufacture of knives and razors. But the cutlers obstinately refused to work a material so much harder than that which they had been accustomed to use; and for a time he gave up all hopes of creating a demand in that quarter. Foiled in his endeavours to sell his steel at home, Huntsman turned his attention to foreign markets; and he soon found he could readily sell abroad all that he could make. The merit of employing cast-steel for general purposes belongs to the French, always so quick to appreciate the advantages of any new discovery, and for a time the whole of the cast-steel that Huntsman could manufacture was exported to France. When he had fairly established his business with that country, the Sheffield cutlers became alarmed at the reputation which cast-steel was acquiring abroad; and when they heard of the preference displayed by English as well as French consumers for the cutlery manufactured of that metal, they readily apprehended the serious consequences that must necessarily result to their own trade if cast-steel came into general use. They then appointed a deputation to wait upon Sir George Savile, one of the members for the county of York, and requested him to use his influence with the government to obtain an order to prohibit the exportation of cast-steel. But on learning from the deputation that the Sheffield manufacturers themselves would not make use of the new steel, he positively declined to comply with their request. It was indeed fortunate for the interests of the town that the object of the deputation was defeated, for at that time Mr.
Huntsman had very pressing and favourable offers from some spirited manufacturers in Birmingham to remove his furnaces to that place; and it is extremely probable that had the business of cast-steel making become established there, one of the most important and lucrative branches of its trade would have been lost to the town of Sheffield.
The Sheffield makers were therefore under the necessity of using the cast-steel, if they would retain their trade in cutlery against France; and Huntsman"s home trade rapidly increased. And then began the efforts of the Sheffield men to wrest his secret from him. For Huntsman had not taken out any patent for his invention, his only protection being in preserving his process as much a mystery as possible. All the workmen employed by him were pledged to inviolable secrecy; strangers were carefully excluded from the works; and the whole of the steel made was melted during the night. There were many speculations abroad as to Huntsman"s process. It was generally believed that his secret consisted in the flux which he employed to make the metal melt more readily; and it leaked out amongst the workmen that he used broken bottles for the purpose. Some of the manufacturers, who by prying and bribing got an inkling of the process, followed Huntsman implicitly in this respect; and they would not allow their own workmen to flux the pots lest they also should obtain possession of the secret. But it turned out eventually that no such flux was necessary, and the practice has long since been discontinued.
A Frenchman named Jars, frequently quoted by Le Play in his account of the manufacture of steel in Yorkshire,[6] paid a visit to Sheffield towards the end of last century, and described the process so far as he was permitted to examine it. According to his statement all kinds of fragments of broken steel were used; but this is corrected by Le Play, who states that only the best bar steel manufactured of Dannemora iron was employed. Jars adds that "the steel is put into the crucible with A FLUX, the composition of which is kept secret;" and he states that the time then occupied in the conversion was five hours.
It is said that the person who first succeeded in copying Huntsman"s process was an ironfounder named Walker, who carried on his business at Greenside near Sheffield, and it was certainly there that the making of cast-steel was next begun. Walker adopted the "ruse" of disguising himself as a tramp, and, feigning great distress and abject poverty, he appeared shivering at the door of Huntsman"s foundry late one night when the workmen were about to begin their labours at steel-casting, and asked for admission to warm himself by the furnace fire. The workmen"s hearts were moved, and they permitted him to enter. We have the above facts from the descendants of the Huntsman family; but we add the traditional story preserved in the neighbourhood, as given in a well-known book on metallurgy:--
"One cold winter"s night, while the snow was falling in heavy flakes, and the manufactory threw its red glared light over the neighbourhood, a person of the most abject appearance presented himself at the entrance, praying for permission to share the warmth and shelter which it afforded. The humane workmen found the appeal irresistible, and the apparent beggar was permitted to take up his quarters in a warm corner of the building. A careful scrutiny would have discovered little real sleep in the drowsiness which seemed to overtake the stranger; for he eagerly watched every movement of the workmen while they went through the operations of the newly discovered process. He observed, first of all, that bars of blistered steel were broken into small pieces, two or three inches in length, and placed in crucibles of fire clay. When nearly full, a little green gla.s.s broken into small fragments was spread over the top, and the whole covered over with a closely-fitting cover. The crucibles were then placed in a furnace previously prepared for them, and after a lapse of from three to four hours, during which the crucibles were examined from time to time to see that the metal was thoroughly melted and incorporated, the workmen proceeded to lift the crucible from its place on the furnace by means of tongs, and its molten contents, blazing, sparkling, and spurting, were poured into a mould of cast-iron previously prepared: here it was suffered to cool, while the crucibles were again filled, and the process repeated. When cool, the mould was unscrewed, and a bar of cast-steel presented itself, which only required the aid of the hammerman to form a finished bar of cast-steel. How the unauthorized spectator of these operations effected his escape without detection tradition does not say; but it tells us that, before many months had pa.s.sed, the Huntsman manufactory was not the only one where cast-steel was produced." [7]
However the facts may be, the discovery of the elder Huntsman proved of the greatest advantage to Sheffield; for there is scarcely a civilized country where Sheffield steel is not largely used, either in its most highly finished forms of cutlery, or as the raw material for some home manufacture. In the mean time the demand for Huntsman"s steel steadily increased, and in 1770, for the purpose of obtaining greater scope for his operations, he removed to a large new manufactory which he erected at Attercliffe, a little to the north of Sheffield, more conveniently situated for business purposes. There he continued to flourish for six years more, making steel and practising benevolence; for, like the Darbys and Reynoldses of Coalbrookdale, he was a worthy and highly respected member of the Society of Friends. He was well versed in the science of his day, and skilled in chemistry, which doubtless proved of great advantage to him in pursuing his experiments in metallurgy.[8]
That he was possessed of great perseverance will be obvious from the difficulties he encountered and overcame in perfecting his valuable invention. He was, however, like many persons of strong original character, eccentric in his habits and reserved in his manner. The Royal Society wished to enrol him as a member in acknowledgment of the high merit of his discovery of cast-steel, as well as because of his skill in practical chemistry; but as this would have drawn him in some measure from his seclusion, and was also, as he imagined, opposed to the principles of the Society to which he belonged, he declined the honour. Mr. Huntsman died in 1776, in his seventy-second year, and was buried in the churchyard at Attercliffe, where a gravestone with an inscription marks his resting-place.
His son continued to carry on the business, and largely extended its operations. The Huntsman mark became known throughout the civilised world. Le Play the French Professor of Metallurgy, in his Memoire of 1846, still speaks of the cast-steel bearing the mark of "Huntsman and Marshall" as the best that is made, and he adds, "the buyer of this article, who pays a higher price for it than for other sorts, is not acting merely in the blind spirit of routine, but pays a logical and well-deserved homage to all the material and moral qualities of which the true Huntsman mark has been the guarantee for a century." [9]
Many other large firms now compete for their share of the trade; and the extent to which it has grown, the number of furnaces constantly at work, and the quant.i.ty of steel cast into ingots, to be tilted or rolled for the various purposes to which it is applied, have rendered Sheffield the greatest laboratory in the world of this valuable material. Of the total quant.i.ty of cast-steel manufactured in England, not less than five-sixths are produced there; and the facilities for experiment and adaptation on the spot have enabled the Sheffield steel-makers to keep the lead in the manufacture, and surpa.s.s all others in the perfection to which they have carried this important branch of our national industry. It is indeed a remarkable fact that this very town, which was formerly indebted to Styria for the steel used in its manufactures, now exports a material of its own conversion to the Austrian forges and other places on the Continent from which it was before accustomed to draw its own supplies.
Among the improved processes invented of late years for the manufacture of steel are those of Heath, Mushet, and Bessemer. The last promises to effect before long an entire revolution in the iron and steel trade.
By it the crude metal is converted by one simple process, directly as it comes from the blast-furnace. This is effected by driving through it, while still in a molten state, several streams of atmospheric air, on which the carbon of the crude iron unites with the oxygen of the atmosphere, the temperature is greatly raised, and a violent ebullition takes place, during which, if the process be continued, that part of the carbon which appears to be mechanically mixed and diffused through the crude iron is entirely consumed. The metal becomes thoroughly cleansed, the slag is ejected and removed, while the sulphur and other volatile matters are driven off; the result being an ingot of malleable iron of the quality of charcoal iron. An important feature in the process is, that by stopping it at a particular stage, immediately following the boil, before the whole of the carbon has been abstracted by the oxygen, the crude iron will be found to have pa.s.sed into the condition of cast-steel of ordinary quality. By continuing the process, the metal losing its carbon, it pa.s.ses from hard to soft steel, thence to steely iron, and last of all to very soft iron; so that by interrupting the process at any stage, or continuing it to the end, almost any quality of iron and steel may be obtained. One of the most valuable forms of the metal is described by Mr. Bessemer as "semi-steel," being in hardness about midway between ordinary cast-steel and soft malleable iron. The Bessemer processes are now in full operation in England as well as abroad, both for converting crude into malleable iron, and for producing steel; and the results are expected to prove of the greatest practical utility in all cases where iron and steel are extensively employed.
Yet, like every other invention, this of Mr. Bessemer had long been dreamt of, if not really made. We are informed in Warner"s Tour through the Northern. Counties of England, published at Bath in 1801, that a Mr. Reed of Whitehaven had succeeded at that early period in making steel direct from the ore; and Mr. Mushet clearly alludes to the process in his "Papers on Iron and Steel." Nevertheless, Mr. Bessemer is ent.i.tled to the merit of working out the idea, and bringing the process to perfection, by his great skill and indomitable perseverance.
In the Heath process, carburet of manganese is employed to aid the conversion of iron into steel, while it also confers on the metal the property of welding and working more soundly under the hammer--a fact discovered by Mr. Heath while residing in India. Mr. Mushet"s process is of a similar character. Another inventor, Major Uchatius, an Austrian engineer, granulates crude iron while in a molten state by pouring it into water, and then subjecting it to the process of conversion. Some of the manufacturers still affect secrecy in their operations; but as one of the Sanderson firm--famous for the excellence of their steel--remarked to a visitor when showing him over their works, "the great secret is to have the courage to be honest--a spirit to purchase the best material, and the means and disposition to do justice to it in the manufacture."
It remains to be added, that much of the success of the Sheffield manufactures is attributable to the practical skill of the workmen, who have profited by the acc.u.mulated experience treasured up by their cla.s.s through many generations. The results of the innumerable experiments conducted before their eyes have issued in a most valuable though unwritten code of practice, the details of which are known only to themselves. They are also a most laborious cla.s.s; and Le Play says of them, when alluding to the fact of a single workman superintending the operations of three steel-casting furnaces--"I have found nowhere in Europe, except in England, workmen able for an entire day, without any interval of rest, to undergo such toilsome and exhausting labour as that performed by these Sheffield workmen."
[1] AGRICOLA, De Re Metallica. Basle, 1621.
[2] The Rev. JOSEPH HUNTER, History of Hallamshire.
[3] MUSHET, Papers On Iron and Steel.
[4] M. Le Play"s two elaborate and admirable reports on the manufacture of steel, published in the Annales des Mines, vols. iii. and ix., 4th series, are unique of their kind, and have as yet no counterpart in English literature. They are respectively ent.i.tled "Memoire sur la Fabrication de l"Acier en Yorkshire," and "Memoire sur le Fabrication et le Commerce des Fers a Acier dans le Nord de l"Europe."
[5] There are several clocks still in existence in the neighbourhood of Doncaster made by Benjamin Huntsman; and there is one in the possession of his grandson, with a pendulum made of cast-steel. The manufacture of a pendulum of such a material at that early date is certainly curious; its still perfect spring and elasticity showing the scrupulous care with which it had been made.
[6] Annales des Mines, vols. iii. and ix., 4th Series.
[7] The Useful Metals and their Alloys (p. 348), an excellent little work, in which the process of cast-steel making will be found fully described.
[8] We are informed that a mirror is still preserved at Attercliffe, made by Huntsman in the days of his early experiments.
[9] Annales des Mines, vol. ix., 4th Series, 266.
CHAPTER VII.
THE INVENTIONS OF HENRY CORT.
"I have always found it in mine own experience an easier matter to devise manie and profitable inventions, than to dispose of one of them to the good of the author himself."--Sir Hugh Platt, 1589.
Henry Cort was born in 1740 at Lancaster, where his father carried on the trade of a builder and brickmaker. Nothing is known as to Henry"s early history; but he seems to have raised himself by his own efforts to a respectable position. In 1765 we find him established in Surrey Street, Strand, carrying on the business of a navy agent, in which he is said to have realized considerable profits. It was while conducting this business that he became aware of the inferiority of British iron compared with that obtained from foreign countries. The English wrought iron was considered so bad that it was prohibited from all government supplies, while the cast iron was considered of too brittle a nature to be suited for general use.[1] Indeed the Russian government became so persuaded that the English nation could not carry on their manufactures without Russian iron, that in 1770 they ordered the price to be raised from 70 and 80 copecs per pood to 200 and 220 copecs per pood.[2]
Such being the case, Cort"s attention became directed to the subject in connection with the supply of iron to the Navy, and he entered on a series of experiments with the object of improving the manufacture of English iron. What the particular experiments were, and by what steps he arrived at results of so much importance to the British iron trade, no one can now tell. All that is known is, that about the year 1775 he relinquished his business as a navy agent, and took a lease of certain premises at Fontley, near Fareham, at the north-western corner of Portsmouth Harbour, where he erected a forge and an iron mill. He was afterwards joined in partnership by Samuel Jellicoe (son of Adam Jellicoe, then Deputy-Paymaster of Seamen"s Wages), which turned out, as will shortly appear, a most unfortunate connection for Cort.
As in the case of other inventions, Cort took up the manufacture of iron at the point to which his predecessors had brought it, carrying it still further, and improving upon their processes. We may here briefly recite the steps by which the manufacture of bar-iron by means of pit-coal had up to this time been advanced. In 1747, Mr. Ford succeeded at Coalbrookdale in smelting iron ore with pit-coal, after which it was refined in the usual way by means of c.o.ke and charcoal.
In 1762, Dr. Roebuck (hereafter to be referred to) took out a patent for melting the cast or pig iron in a hearth heated with pit-coal by the blast of bellows, and then working the iron until it was reduced to nature, or metallized, as it was termed; after which it was exposed to the action of a hollow pit-coal fire urged by a blast, until it was reduced to a loop and drawn out into bar-iron under a common forge-hammer. Then the brothers Cranege, in 1766, adopted the reverberatory or air furnace, in which they placed the pig or cast iron, and without blast or the addition of anything more than common raw pit-coal, converted the same into good malleable iron, which being taken red hot from the reverberatory furnace to the forge hammer, was drawn into bars according to the will of the workman. Peter Onions of Merthyr Tydvil, in 1783, carried the manufacture a stage further, as described by him in his patent of that year. Having charged his furnace ("bound with iron work and well annealed") with pig or fused cast iron from the smelting furnace, it was closed up and the doors were luted with sand. The fire was urged by a blast admitted underneath, apparently for the purpose of keeping up the combustion of the fuel on the grate. Thus Onions" furnace was of the nature of a puddling furnace, the fire of which was urged by a blast. The fire was to be kept up until the metal became less fluid, and "thickened into a kind of froth, which the workman, by opening the door, must turn and stir with a bar or other iron instrument, and then close the aperture again, applying the blast and fire until there was a ferment in the metal." The patent further describes that "as the workman stirs the metal," the scoriae will separate, "and the particles of iron will adhere, which particles the workman must collect or gather into a ma.s.s or lump." This ma.s.s or lump was then to be raised to a white heat, and forged into malleable iron at the forge-hammer.
Such was the stage of advance reached in the manufacture of bar-iron, when Henry Cort published his patents in 1783 and 1784. In dispensing with a blast, he had been antic.i.p.ated by the Craneges, and in the process of puddling by Onions; but he introduced so many improvements of an original character, with which he combined the inventions of his predecessors, as to establish quite a new era in the history of the iron manufacture, and, in the course of a few years, to raise it to the highest state of prosperity. As early as 1786, Lord Sheffield recognised the great national importance of Cort"s improvements in the following words:--"If Mr. Cort"s very ingenious and meritorious improvements in the art of making and working iron, the steam-engine of Boulton and Watt, and Lord Dundonald"s discovery of making c.o.ke at half the present price, should all succeed, it is not a.s.serting too much to say that the result will be more advantageous to Great Britain than the possession of the thirteen colonies (of America); for it will give the complete command of the iron trade to this country, with its vast advantages to navigation." It is scarcely necessary here to point out how completely the antic.i.p.ations of Lord Sheffield have been fulfilled, sanguine though they might appear to be when uttered some seventy-six years ago.[3]
We will endeavour as briefly as possible to point out the important character of Mr. Cort"s improvements, as embodied in his two patents of 1783 and 1784. In the first he states that, after "great study, labour, and expense, in trying a variety of experiments, and making many discoveries, he had invented and brought to perfection a peculiar method and process of preparing, welding, and working various sorts of iron, and of reducing the same into uses by machinery: a furnace, and other apparatus, adapted and applied to the said process." He first describes his method of making iron for "large uses," such as shanks, arms, rings, and palms of anchors, by the method of piling and f.a.ggoting, since become generally practised, by laying bars of iron of suitable lengths, forged on purpose, and tapering so as to be thinner at one end than the other, laid over one another in the manner of bricks in buildings, so that the ends should everywhere overlay each other. The f.a.ggots so prepared, to the amount of half a ton more or less, were then to be put into a common air or balling furnace, and brought to a welding heat, which was accomplished by his method in a much shorter time than in any hollow fire; and when the heat was perfect, the f.a.ggots were then brought under a forge-hammer of great size and weight, and welded into a solid ma.s.s. Mr. Cort alleges in the specification that iron for "larger uses" thus finished, is in all respect"s possessed of the highest degree of perfection; and that the fire in the balling furnace is better suited, from its regularity and penetrating quality, to give the iron a perfect welding heat throughout its whole ma.s.s, without fusing in any part, than any fire blown by a blast. Another process employed by Mr. Cort for the purpose of cleansing the iron and producing a metal of purer grain, was that of working the f.a.ggots by pa.s.sing them through rollers. "By this simple process," said he, "all the earthy particles are pressed out and the iron becomes at once free from dross, and what is usually called cinder, and is compressed into a fibrous and tough state." The objection has indeed been taken to the process of pa.s.sing the iron through rollers, that the cinder is not so effectually got rid of as by pa.s.sing it under a tilt hammer, and that much of it is squeezed into the bar and remains there, interrupting its fibre and impairing its strength.
It does not appear that there was any novelty in the use of rollers by Cort; for in his first specification he speaks of them as already well known.[4] His great merit consisted in apprehending the value of certain processes, as tested by his own and others" experience, and combining and applying them in a more effective practical form than had ever been done before. This power of apprehending the best methods, and embodying the details in one complete whole, marks the practical, clear-sighted man, and in certain cases amounts almost to a genius.
The merit of combining the inventions of others in such forms as that they shall work to advantage, is as great in its way as that of the man who strikes out the inventions themselves, but who, for want of tact and experience, cannot carry them into practical effect.
It was the same with Cort"s second patent, in which he described his method of manufacturing bar-iron from the ore or from cast-iron. All the several processes therein described had been practised before his time; his merit chiefly consisting in the skilful manner in which he combined and applied them. Thus, like the Craneges, he employed the reverberatory or air furnace, without blast, and, like Onions, he worked the fused metal with iron bars until it was brought into lumps, when it was removed and forged into malleable iron. Cort, however, carried the process further, and made it more effectual in all respects. His method may be thus briefly described: the bottom of the reverberatory furnace was hollow, so as to contain the fluid metal, introduced into it by ladles; the heat being kept up by pit-coal or other fuel. When the furnace was charged, the doors were closed until the metal was sufficiently fused, when the workman opened an aperture and worked or stirred about the metal with iron bars, when an ebullition took place, during the continuance of which a bluish flame was emitted, the carbon of the cast-iron was burned off, the metal separated from the slag, and the iron, becoming reduced to nature, was then collected into lumps or loops of sizes suited to their intended uses, when they were drawn out of the doors of the furnace. They were then stamped into plates, and piled or worked in an air furnace, heated to a white or welding heat, shingled under a forge hammer, and pa.s.sed through the grooved rollers after the method described in the first patent.
The processes described by Cort in his two patents have been followed by iron manufacturers, with various modifications, the results of enlarged experience, down to the present time. After the lapse of seventy-eight years, the language employed by Cort continues on the whole a faithful description of the processes still practised: the same methods of manufacturing bar from cast-iron, and of puddling, piling, welding, and working the bar-iron through grooved rollers--all are nearly identical with the methods of manufacture perfected by Henry Cort in 1784. It may be mentioned that the development of the powers of the steam-engine by Watt had an extraordinary effect upon the production of iron. It created a largely increased demand for the article for the purposes of the shafting and machinery which it was employed to drive; while at the same time it cleared pits of water which before were unworkable, and by being extensively applied to the blowing of iron-furnaces and the working of the rolling-mills, it thus gave a still further impetus to the manufacture of the metal. It would be beside our purpose to enter into any statistical detail on the subject; but it will be sufficient to state that the production of iron, which in the early part of last century amounted to little more than 12,000 tons, about the middle of the century to about 18,000 tons, and at the time of Cort"s inventions to about 90,000 tons, was found, in 1820, to have increased to 400,000 tons; and now the total quant.i.ty produced is upwards of four millions of tons of pig-iron every year, or more than the entire production of all other European countries. There is little reason to doubt that this extraordinary development of the iron manufacture has been in a great measure due to the inventions of Henry Cort. It is said that at the present time there are not fewer than 8200 of Cort"s furnaces in operation in Great Britain alone.[5]
Practical men have regarded Cort"s improvement of the process of rolling the iron as the most valuable of his inventions. A competent authority has spoken of Cort"s grooved rollers as of "high philosophical interest, being scarcely less than the discovery of a new mechanical Power, in reversing the action of the wedge, by the application of force to four surfaces, so as to elongate a ma.s.s, instead of applying force to a ma.s.s to divide the four surfaces." One of the best authorities in the iron trade of last century, Mr.
Alexander Raby of Llanelly, like many others, was at first entirely sceptical as to the value of Cort"s invention; but he had no sooner witnessed the process than with manly candour he avowed his entire conversion to his views.