"Nigh on the plain, in many cells prepared,
That underneath had veins of liquid fire
Sluiced from the lake, a second multitude
With wondrous art founded the massy ore;
Severing each kind, and scumm'd the bullion dross;
A third as soon had formed within the ground
A various mould, and from the boiling cells
By strange conveyance fill'd each hollow nook;
As in an organ, from one blast of wind,
To many a row of pipes the sound board breathes."

—Paradise Lost.

Ever since those perished races of men who left no other record but that engraven in rude emblems on the rocks, or no other signs of their existence but in the broken tools found buried deep among the solid leaves of the crusted earth, ever since Tubal Cain became "an instructor of every artificer in brass and iron," the art of smelting has been known. The stone age flourished with implements furnished ready-made by nature, or needing little shaping for their use, but the ages of metal which followed required the aid of fire directed by the hand of man to provide the tool of iron or bronze.

The Greeks claimed that the discovery of iron was theirs, and was made at the burning of a forest on the mountains of Ida in Crete, about 1500 B. C., when the ore contained in the rocks or soil on which the forest stood was melted, cleansed of its impurities, and then collected and hammered. Archeologists have deprived the Greeks of this gift, and carried back its origin to remoter ages and localities.

Man first discovered by observation or accident that certain stones were melted or softened by fire, and that the product could be hammered and shaped. They learned by experience that the melting could be done more effectually when the fuel and the ore were mixed and enclosed by a wall of stone; that the fire and heat could be alone started and maintained by blowing air into the fuel—and they constructed a rude bellows for this purpose. Finding that the melted metal sank through the mass of consumed fuel, they constructed a stone hearth on which to receive it. Thus were the first crude furnace and hearth invented.

As to gold, silver and lead, they doubtless were found first in their native state and mixed with other ores and were hammered into the desired shapes with the hardest stone implements.

That copper and tin combined would make bronze was a more complex proceeding and probably followed instead of preceding, as has sometimes been alleged, the making of iron tools. That bronze relics were found apparently of anterior manufacture to any made of iron, was doubtless due to the destruction of the iron by that great consumer—oxygen.

What was very anciently called "brass" was no doubt gold-coloured copper; for what is modernly known as brass was not made until after the discovery of zinc in the 16th century and its combination with copper.

Among the "lost arts" re-discovered in later ages are those which supplied the earliest cities with ornamented vessels of gold and copper, swords of steel that bent and sprung like whalebones, castings that had known no tool to shape their contour and embellishments, and monuments and tablets of steel and brass which excite the wonder and admiration of the best "artificers in brass and iron" of the present day.

To understand and appreciate the advancements that have been made in metallurgy in the nineteenth century, it is necessary to know, in outline at least, what before had been developed.

The earliest form of a smelting furnace of historic days, such as used by the ancient Egyptians, Hebrews, and probably by the Hindoos and other ancient peoples, and still used in Asia, is thus described by Dr Ure:

"The furnace or bloomary in which the ore is smelted is from 4 to 5 feet high; it is somewhat pear-shaped, being about 5 feet wide at bottom and 1 at top. It is built entirely of clay. There is an opening in front about a foot or more in height which is filled with clay at the commencement, and broken down at the end of each smelting operation. The bellows are usually made of two goatskins with bamboo nozzles, which are inserted into tubes of clay that pass into the furnace. The furnace is filled with charcoal, and a lighted coal being introduced before the nozzle, the mass in the interior is soon kindled. As soon as this is accomplished, a small portion of the ore previously moistened with water to prevent it from running through the charcoal, but without any flux whatever, is laid on top of the coals, and covered with charcoal to fill up the furnace. In this manner ore and fuel are supplied and the bellows urged for three or four hours. When the process is stopped and the temporary wall in front broken down the bloom is removed with a pair of tongs from the bottom of the furnace."

This smelting was then followed by hammering to further separate the slag, and probably after a reheating to increase the malleability.

It will be noticed that in this earliest process pure carbon was used as a fuel, and a blast of air to keep the fire at a great heat was employed. To what extent this carbon and air blast, and the mixing and remixing with other ingredients, and reheating and rehammering, may have been employed in various instances to modify the conditions and render the metal malleable and more or less like modern steel, is not known, but that an excellent quality of iron resembling modern steel was often produced by this simple mode of manufacture by different peoples, is undoubtedly the fact. Steel after all is iron with a little more carbon in it than in the usual iron in the smelting furnace, to render it harder, and a little less carbon than in cast or moulded iron to render it malleable, and in both conditions was produced from time immemorial, either by accident or design.

It was with such a furnace probably that India produced her keen-edged weapons that would cut a web of gossamer, and Damascus its flashing blades—the synonym of elastic strength.

Africa, when its most barbarous tribes were first discovered, was making various useful articles of iron. Its earliest modes of manufacture were doubtless still followed when Dr Livingstone explored the interior, as they now also are. He thus describes their furnaces and iron: "At every third or fourth village (in the regions near Lake Nyassa) we saw a kiln-looking structure, about 6 feet high and 2½ feet in diameter. It is a clay fire-hardened furnace for smelting iron. No flux is used, whether with specular iron, the yellow hematite, or magnetic ore, and yet capital metal is produced. Native manufactured iron is so good that the natives declare English iron "rotten" in comparison, and specimens of African hoes were pronounced at Birmingham nearly equal to the best Swedish iron." The natives of India, the Hottentots, the early Britons, the Chinese, the savages of North and South America, as discovery or research brought their labours to light, or uncovered the monuments of their earliest life, were shown to be acquainted with similar simple forms of smelting furnaces.

Early Spain produced a furnace which was adopted by the whole of Europe as fast as it became known. It was the Catalan furnace, so named from the province of Catalonia, where it probably first originated, and it is still so known and extensively used. "It consists of a four-sided cavity or hearth, which is always placed within a building and separated from the main wall thereof by a thinner interior wall, which in part constitutes one side of the furnace. The blast pipe comes through the wall, and enters the fire through a flue which slants downward. The bottom is formed of a refractory stone, which is renewable. The furnace has no chimneys. The blast is produced by means of a fall of water usually from 22 to 27 feet high, through a rectangular tube, into a rectangular cistern below, to whose upper part the blast pipe is connected, the water escaping through a pipe below. This apparatus is exterior to the building, and is said to afford a continuous blast of great regularity; the air, when it passes into the furnace, is, however, saturated with moisture."—Knight.

No doubt in such a heat was formed the metal from which was shaped the armour of Don Quixote and his prototypes.

Bell in his history of Metallurgy tells us that the manufacture of malleable iron must have fallen into decadence in England, especially before the reign of Elizabeth and Charles I., as no furnaces equal even to the Catalan had for a long time been in use; and the architectural iron column found in ancient Delhi, 16 inches in diameter, about 48 feet long and calculated to weigh about 17 tons, could not have been formed by any means known in England in the sixteenth century. This decadence was in part due to the severe laws enacted against the destruction of forests, and most of the iron was then brought to England from Germany and other countries.

From time immemorial the manufacture of iron and steel has been followed in Germany, and that country yet retains pre-eminence in this art both as to mechanical and chemical processes. It was in the eighteenth century that the celebrated Freiberg Mining Academy was founded, the oldest of all existing mining schools; and based on developing mining and metallurgy on scientific lines, it has stood always on the battle line in the fight of progress.

The early smelting furnaces of Germany resembled the Catalan, and were called the "StÜckofen," and in Sweden were known as the "Osmund." In these very pure iron was made.

The art of making cast iron, which differs from the ordinary smelted iron in the fact that it is melted and then run into moulds, although known among the ancients more than forty centuries ago, as shown by the castings of bronze and brass described by their writers and recovered from their ruins, appears to have been forgotten long before the darkness of the middle ages gathered. There is no record of its practice from the time the elder Pliny described its former use (40-79 A. D.), to the sixteenth century. It is stated that then the lost art was re-invented by Ralph Page and Peter Baude of England in 1543—who in that year made cast-iron in Sussex.

The "StÜckofen" furnace above referred to was succeeded in Germany by higher ones called the "Flossofen," and these were followed by still higher and larger ones called "Blauofen," so that by the middle of the eighteenth century the furnaces were very capacious, the blast was good, and it had been learned how to supply the furnaces with ore, coal and lime-stone broken into small fragments. The lime was added as a flux, and acted to unite with itself the sand, clay and other impurities to form a slag or scoria. The melted purified iron falling to the bottom was drawn off through a hole tapped in the furnace, and the molten metal ran into channels in a bed of sand called the "Sow and pigs." Hence the name, "pig iron."

The smelting of ore by charcoal in those places where carried on extensively required the use of a vast amount of wood, and denuded the surrounding lands of forests. So great was this loss felt that it gave rise to the prohibitory laws and the decadence in England of the manufacture of iron, already alluded to. This turned the attention of iron smelters to coal as a substitute. Patents were granted in England for its use to several unsuccessful inventors. Finally in 1619 Dud Dudley, a graduate of Oxford University, and to whom succeeded his father's iron furnaces in Worcestershire, obtained a patent and succeeded in producing several tons of iron per week by the use of the pitcoal in a small blast furnace.

This success inflamed the wood owners and the charcoal burners and they destroyed Dudley's works. He met with other disasters common to worthy inventors and discontinued his efforts to improve the art.

It is said that in 1664 Sir John Winter of England made coke by burning sea coal in closed pots. But this was not followed up, and the use of charcoal and the destruction of the forests went on until 1735, when Abraham Darby of the Coalbrookdale Iron Works at Shropshire, England, commenced to treat the soft pit coal in the same way as wood is treated in producing charcoal. He proposed to burn the coal in a smouldering fire, to expel the sulphur and other impurities existing in the form of phosphorus, hydrogen and oxygen, etc. while saving the carbon. The attempt was successful, and thus coke was made. It was found cheaper and superior to either coal or charcoal, and produced a quicker fire and a greater heat. This was a wonderful discovery, and was preserved as a trade secret for a long time. It was referred to as a curiosity in the Philosophical Transactions in 1747. In fact it was not introduced in America until a century later, when in 1841 the soft coal abounding around Pittsburgh in Pennsylvania and in the neighbouring regions of Ohio was thus treated. Even its use then was experimental, and did not become a practical art in the United States until about 1860.

With the invention of coke came also the revival of cast iron.

The process of making cast steel was reinvented in England by Benjamin Huntsman of Attercliff, near Sheffield, about 1740. Between that time and 1770 he practised melting small pieces of "blistered" steel (iron bars which had been carbonised by smelting in charcoal) in closed clay crucibles.

In 1784 Henry Cort of England introduced the puddling process and grooved rolls. Puddling had been invented, but not successfully used before. The term "puddling" originated in the covering of the hearth of stones at the bottom of the furnace with clay, which was made plastic by mixing the clay in a puddle of water; and on which hearth the ore when melted is received. When in this melted condition Cort and others found that the metal was greatly improved by stirring it with a long iron bar called a "rabble," and which was introduced through an opening in the furnace. This stirring admitted air to the mass and the oxygen consumed and expelled the carbon, silicon, and other impurities. The process was subsequently aided by the introduction of pig iron broken into pieces and mixed with hammer-slag, cinder, and ore. The mass is stirred from side to side of the furnace until it comes to a boiling point, when the stirring is increased in quickness and violence until a pasty round mass is collected by the puddler. As showing the value of Cort's discovery and the hard experience inventors sometimes have, Fairbairn states that Cort "expended a fortune of upward of £20,000 in perfecting his invention for puddling iron and rolling it into bars and plates; that he was robbed of the fruits of his discoveries by the villainy of officials in a high department of the government; and that he was ultimately left to starve by the apathy and selfishness of an ungrateful country. His inventions conferred an amount of wealth on the country equivalent to £600,000,000, and have given employment to 600,000 of the working population of our land for the last three or four generations." This process of puddling lasted for about an hour and a half and entailed extremely severe labour on the workman.

The invention of mechanical puddlers, hereinafter referred to, consisting chiefly of rotating furnaces, were among the beneficent developments of the nineteenth century.

Prior to Cort's time the plastic lump or ball of metal taken from the furnace was generally beaten by hammers, but Cort's grooved rollers pressed out the mass into sheets.

The improvements of the steam engine by Watt greatly extended the manufacture of iron toward the close of the 18th century, as powerful air blasts were obtained by the use of such engines in place of the blowers worked by man, the horse, or the ox.

So far as the art of refining the precious metals is concerned, as well as copper, tin and iron, it had not, previous to this century, proceeded much beyond the methods described in the most ancient writings; and these included the refining in furnaces, pots, and covered crucibles, and alloying, or the mixture and fusion with other metals. Furnaces to hold the crucibles, and made of iron cylinders lined with fire brick, whereby the crucibles were subjected to greater heat, were also known.

The amalgamating process was also known to the ancients, and Vitruvius (B. C. 27) and Pliny (A. D. 79), describe how mercury was used for separating gold from its impurities. Its use at gold and silver mines was renewed extensively in the sixteenth century.

Thus we find that the eighteenth century closed with the knowledge of the smelting furnaces of various kinds, of coke as a fuel in place of charcoal, of furious air blasts driven by steam and other power, of cast iron and cast steel, and of refining, amalgamating, and compounding processes.

Looking back, now, from the threshold of the nineteenth century over the path we have thus traced, it will be seen that what had been accomplished in metallurgy was the result of the use of ready means tested by prolonged trials, of experiments more or less lucky in fields in which men were groping, of inventions without the knowledge of the real properties of the materials with which inventors were working or of the unvarying laws which govern their operations. They had accomplished much, but it was the work mainly of empirics. The art preceding the nineteenth century compared with what followed is the difference between experience simply, and experience when combined with hard thinking, which is thus stated by Herschel: "Art is the application of knowledge to a practical end. If the knowledge be merely accumulated experience the art is empirical; but if it is experience reasoned upon and brought under general principles it assumes a higher character and becomes a scientific art."

With the developments, discoveries and inventions in the lines of steam, chemistry and electricity, as elsewhere told, the impetus they gave to the exercise of brain force in every field of nature at the outset of the century, and with their practical aid, the art of metallurgy soon began to expand to greater usefulness, and finally to its present wonderful domain.

The subject of metallurgy in this century soon became scientifically treated and its operations classified.

Thus the physical character and metallic constituents of ores received the first consideration; then the proper treatment to which the ores were to be subjected for the purpose of extracting the metal—which are either mechanical or chemical. The mechanical processes designed to separate the ore from its enclosing rock or other superfluous earthy matter called gangue became known as ore dressing and ore concentrating. These included mills with rollers, and stamps operated by gravity, or steam, for breaking up the ore rocks; abrasion apparatus for comminuting the ore by rubbing the pieces of ore under pressure; and smelting, or an equivalent process, for melting the ore and driving off the impurities by heat, etc. The chemical processes are those by which the metal, whatever it may be, is either dissolved or separated from other constituents by either the application to the ore of certain metallic solutions of certain acids, or by the fusion of different ores or metals in substantially the old styles of furnaces; or its precipitation by amalgamating, or by electrolysis—the art of decomposing metals by electricity.

In the early decades of the century, by the help of chemistry and physics, the nature of heat, carbon, and oxygen, and the great affinity iron has for oxygen, became better known; and particularly how in the making of iron its behaviour is influenced by the presence of carbon and other foreign constituents; also how necessary to its perfect separation was the proper elimination of the oxygen and carbon. The use of manganese and other highly oxidisable metals for this purpose was discovered.

Among the earliest most notable inventions in the century, in the manufacture of iron, was that of Samuel B. Rogers of Glamorganshire, Wales, who invented the iron floor for furnaces with a refractory lining—a great improvement on Cort's sand floor, which gave too much silicon to the iron; and the hot air blast by Neilson of Glasgow, Scotland, patented in 1828. The latter consisted in the use of heated air as the blast instead of cold air—whereby ignition of the fuel was quickened, intensity of the heat and the expulsion of oxygen and carbon from the iron increased, and the operation shortened and improved in every way. The patent was infringed and assailed, but finally sustained by the highest courts of England. It produced an immense forward stride in the amount and quality of iron manufactured.

By the introduction of the hot air blast it became practicable to use the hard anthracite coal as a fuel where such coal abounded; and to use pig iron, scrap iron, and refractory ore and metals with the fuel to produce particular results. Furnaces were enlarged to colossal dimensions, some being a hundred feet high and capable of yielding 80 or 100 tons of metal per day.

The forms of furnaces and means for lining and cooling the hearth and adjacent parts have received great attention.

The discovery that the flame escaping from the throat of the blast furnace was nothing else than burning carbon led Faber du Faur at Wasseralfugen in 1837 to invent the successful and highly valuable method of utilising the unburnt gas from the blast furnace for heating purposes, and to heat the blast itself, and drive the steam engine that blew the blast into the furnace, without the consumption of additional fuel. This also led to the invention of separate gas producers. Bunsen in 1838 made his first experiments at Hesse in collecting the gases from various parts of the furnace, revealing their composition and showing their adaptability for various purposes. Thus, from a scientific knowledge of the constituents of ores and of furnace gases, calculations could be made in advance as to the materials required to make pig iron, cast iron, and steel of particular qualities.

In the process of puddling difficulty had been experienced in handling the bloom or ball after it was formed in the furnace. A sort of squeezing apparatus, or tongs, called the alligator, had been employed.

In 1840 Henry Burden of America invented and patented a method and means for treating these balls, whereby the same were taken directly from the furnace and passed between two plain converging metal surfaces, by which the balls were gradually but quickly pressed and squeezed into a cylindrical form, while a large portion of the cinders and other foreign impurities were pressed out.

We have described how by Cort's puddling process tremendous labour was imposed on the workmen in stirring the molten metal by hand with "rabbles." A number of mechanical puddlers were invented to take the place of these hand means, but the most important invention in this direction was the revolving puddlers of Beadlestone, patented in 1857 in England, and of Heaton, Allen and Yates, in 1867-68. The most successful, however, was that of Danks of the United States in 1868-69. The Danks rotary puddler is a barrel-shaped, refractory lined vessel, having a chamber and fire grate and rotated by steam, into which pig iron formed by the ordinary blast furnaces, and then pulverised, is placed, with the fuel. Molten metal from the furnace is then run in, which together with the fuel is then subjected to a strong blast. Successive charges may be made, and at the proper time the puddler is rotated, slowly at some stages and faster at others, until the operation is completed. A much more thorough and satisfactory result in the production of a pure malleable iron is thus obtained than is possible by hand puddling.

But the greatest improvements in puddling, and in the production of steel from iron, and which have produced greater commercial results than any other inventions of the century relating to metallurgy, were the inventions of Henry Bessemer of Hertfordshire, England, from 1855 to 1860. In place of the puddling "rabbles" to stir the molten metal, or matte, as it is called, while the air blast enters to oxidise it, he first introduced the molten metal from the furnace into an immense egg-shaped vessel lined with quartzose, and hung in an inclined position on trunnions, or melted the metal in such vessel, and then dividing the air blast into streams forced with great pressure each separate stream through an opening in the bottom of the vessel into the molten mass, thus making each stream of driven air a rabble; and they together blew and lifted the white mass into a huge, surging, sun-bright fountain. The effect of this was to burn out the impurities, silicon, carbon, sulphur, and phosphorus, leaving the mass a pure soft iron. If steel was wanted a small amount of carbon, usually in the form of spiegeleisen, was introduced into the converter before the process was complete.

A. L. Holley of the United States improved the Bessemer apparatus by enabling a greater number of charges to be converted into steel within a given time.

Sir Henry Bessemer has lived to gain great fortunes by his inventions, to see them afford new fields of labour for armies of men, and to increase the riches of nations, from whom he has received deserved honours.

The Bessemer process led to renewed investigations and discoveries as to heat and its utilisation, the constituents of different metals and their decomposition, and as to the parts played by carbon, silicon, and phosphorus. The carbon introduced by the charge of pig iron in the Bessemer process was at first supposed to be necessary to produce the greatest heat, but this was found to be a mistake; and phosphorus, which had been regarded as a great enemy of iron, to be eliminated in every way, was found to be a valuable constituent, and was retained or added to make phosphorus steel.

The Bessemer process has been modified in various ways: by changing the mode of introducing the blast from the bottom of the converter to the sides thereof, and admitting the blast more slowly at certain stages; by changing the character of the pig iron and fuel to be treated; and by changing the shape and operation of the converters, making them cylindrical and rotary, for instance.

The Bessemer process is now largely used in treating copper. By this method the blowing through the molten metal of a blast of air largely removes sulphur and other impurities.

The principles of reduction by the old style furnaces and methods we have described have been revived and combined with improvements. For instance, the old Catalan style of furnace has been retained to smelt the iron, but in one method the iron is withdrawn before it is reduced completely and introduced into another furnace, where, mixed with further reducing ingredients, a better result by far is produced with less labour.

It would be a long list that would name the modern discoverers and inventors of the century in the manufacture of iron and steel. But eminent in the list, in addition to Davy and Bessemer, and others already mentioned, are Mushet, Sir L. Bell, Percy, Blomfield, Beasley, Giers and Snellus of England; Martin, Chennot, Du Motay, Pernot and Gruner of France; Lohage, Dr. C. L. Siemens and HÖpfer of Germany; Prof Sarnstrom and Akerman of Sweden; Turner of Austria; and Holley, Slade, Blair, Jones, Sellers, Clapp, Griffiths and Eames of the United States.

Some of the new metals discovered in the last century have in this century been combined with iron to make harder steel. Thus we have nickel, chromium, and tungsten steel. Processes for hardening steel, as the "Harveyized" steel, have given rise to a contest between "irresistible" projectiles and "impenetrable" armour plate.

If there are some who regard modern discoveries and inventions in iron and steel as lessening the number of workmen and cheapening the product too much, thus causing trouble due to labour-saving machinery, let them glance, among other great works in the world, at Krupp's at Essen, where on January 1st, 1899, 41,750 persons were employed, and at which works during the previous year 1,199,610 tons of coal and coke were consumed, or about 4000 tons daily. Workers in iron will not be out of employment in the United States, where 16,000,000 tons of coke are produced annually, 196,405,953 tons of coal mined, 11,000,000 tons of pig iron and about 9,000,000 tons of steel made. The increase of population within the last hundred years bears no comparison with this enormous increase in iron and fuel. It shows that as inventions multiply, so does the demand for their better and cheaper products increase.

As the other metals, gold, silver, copper and lead often occur together, and in the same deposits with iron, the same general modes of treatment to extract them are often applied. These are known as the dry and the wet methods, and electro-reduction.

Ever since Mammon bowed his head in search for gold, every means that the mind of man could suggest to obtain it have been tried, but the devices of this century have been more numerous and more successful than any before. The ancient methods of simply melting and "skimming the bullion dross" have been superseded. Modern methods may be divided into two general classes, the mechanical and the chemical. Of the former methods, when gold was found loose in sand or gravel, washing was the earliest and most universally practised, and was called panning. In this method mercury is often used to take up and secure the fine gold. Rockers like a child's cradle, into which the dirt is shovelled and washed over retaining riffles, were used; coarse-haired blankets and hides; sluices and separators, with or without quicksilver linings to catch the gold; and powerful streams of water worked by compressed air to tear down the banks. Where water could not be obtained the ore and soil were pulverised and dried, and then thrown against the wind or a blast of air, and the heavier gold, falling before the lighter dust, was caught on hides or blankets. For the crushing of the quartz in which gold was found, innumerable inventions in stamp mills, rollers, crushers, abraders, pulverisers and amalgamators have been invented; and so with roasters, and furnaces, and crucibles to melt the precious metal, separate the remaining impurities and convert it to use.

As to chemical methods for the precious metals, the process of lixiviation, or leaching, by which the ore is washed out by a solution of potash, or with dilute sulphuric acid, or boiling with concentrated sulphuric acid, is quite modern. About 1889 came out the great cyanide process, also known as the MacArthur-Forrest process (they being the first to obtain patents and introduce the invention), consisting of the use of cyanide potassium in solution, which dissolves the gold, and which is then precipitated by the employment of zinc. This process is best adapted to what are known as free milling or porous ores, where the gold is free and very fine and is attracted readily by mercury.

In 1807, Sir Humphry Davy discovered the metal potassium by subjecting moistened potash to the action of a powerful voltaic battery; the positive pole gave off oxygen and the metallic globules of pure potassium appeared at the negative pole. It is never found uncombined in nature. Now if potassium is heated in cyanogen gas (a gas procured by heating mercury) or obtained on a large scale by the decomposition of yellow prussiate of potash, a white crystalline body very soluble in water, and exceedingly poisonous, is obtained. When gold, for instance, obtained by pulverising the ore, or found free in sand, is treated to such a solution it is dissolved from its surrounding constituents and precipitated by the zinc, as before stated.

Chlorine is another metal discovered by Scheele in 1774, but not known as an elementary element until so established by Davy's investigations in 1810, when he gave it the name it now bears, from the Greek chloras, yellowish green. It is found abundantly in the mineral world in combination with common salt. Now it was found that chlorine is one of the most energetic of bodies, surpassing even oxygen under some circumstances, and that a chlorine solution will readily dissolve gold.

These, the cyanide and chlorination processes, have almost entirely superseded the old washing and amalgamating methods of treating free gold—and the cyanide seems to be now taking the lead.

Alloys.—The art of fusing different metals to make new compounds, although always practised, has been greatly advanced by the discoverers and inventors of the century. As we have seen, amalgamating to extract gold and silver, and the making of bronze from tin and copper were very early followed. One of the most notable and useful of modern inventions or improvements of the kind was that of Isaac Babbitt of Boston in 1839, who in that year obtained patents for what ever since has been known as "babbitting." The great and undesirable friction produced by the rubbing of the ends of journals and shafts in their bearings of the same metal, cast or wrought iron, amounting to one-fifth of the amount of power exerted to turn them, had long been experienced. Lubricants of all kinds had been and are used; but Babbitt's invention was an anti-friction metal. It is composed of tin, antimony, and copper, and although the proportions and ingredients have since been varied, the whole art is still known as babbitting.

Other successful alloys have been made for gun metal, sheathing of ships, horseshoes, organ pipes, plough shares, roofing, eyelets, projectiles, faucets, and many and various articles of hardware, ornamental ware, and jewelry.

Valuable metals, such as were not always rare or scarce, but very hard to reduce, have been rendered far less in cost of production and more extensive in use by modern processes. Thus, aluminium, an abundant element in rocks and clay, discovered by the German chemist WÖhler, in 1827, a precious metal, so light, bright, and tough, non-oxidizing, harder than zinc, more sonorous than silver, malleable and ductile as iron, and more tenacious, has been brought to the front from an expensive and mere laboratory production to common and useful purposes in all the arts by the processes commencing in 1854 with that of St. Clair Deoville, of France, followed by those of H. Rose, Morin, Castner, Tissier, Hall, and others.

Electro-metallurgy, so far, has chiefly to do with the decomposition of metals by the electric current, and the production of very high temperatures for furnaces, by which the most refractory ores, metals, and other substances may be melted, and results produced not obtainable in any other way. By placing certain mixtures of carbon and sand, or of carbon and clay, between the terminals of a powerful current, a material resembling diamonds, but harder, has been produced. It has been named carbonundrum. The production of diamonds themselves is looked for. Steel wire is now tempered and annealed by electricity, as well as welding done, of which mention further on will be made.

Thus we have seen how the birth of ideas of former generations has given rise in the present age to children of a larger growth. Arts have grown only as machinery for the accomplishment of their objects has developed, and machinery has waited on the development of the metals composing it. The civilisation of to-day would not have been possible if the successors of Tubal Cain had not been like him, instructors "of every artificer in brass and iron."