Inventions in the Century Part 16

Thus the physical character and metallic const.i.tuents 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 const.i.tuents 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 const.i.tuents; 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 a.s.sailed, 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, sc.r.a.p 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 Wa.s.seralfugen 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 const.i.tuents 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 b.a.l.l.s, whereby the same were taken directly from the furnace and pa.s.sed between two plain converging metal surfaces, by which the b.a.l.l.s 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 ma.s.s, thus making each stream of driven air a rabble; and they together blew and lifted the white ma.s.s into a huge, surging, sun-bright fountain. The effect of this was to burn out the impurities, silicon, carbon, sulphur, and phosphorus, leaving the ma.s.s 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 const.i.tuents 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 const.i.tuent, 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 Hopfer 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 c.o.ke 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 c.o.ke 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 cla.s.ses, 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; coa.r.s.e-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 pota.s.sium 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 pota.s.sium by subjecting moistened potash to the action of a powerful voltaic battery; the positive pole gave off oxygen and the metallic globules of pure pota.s.sium appeared at the negative pole. It is never found uncombined in nature. Now if pota.s.sium 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 const.i.tuents 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, surpa.s.sing even oxygen under some circ.u.mstances, 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 Wohler, 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 bra.s.s and iron."

CHAPTER XV.

METAL WORKING.

We referred in the last chapter to the fact that metal when it came from the melting and puddling furnace was formerly rolled into sheets; but, when the manufacturers and consumers got these sheets then came the severe, laborious work by hand of cutting, hammering, boring, shaping and fitting the parts for use and securing them in place.

It is one of the glories of this century that metal-working tools and machinery have been invented that take the metal from its inception, mould and adapt it to man's will in every situation with an infinite saving of time and labour, and with a perfection and uniformity of operation entirely impossible by hand.

Although the tools for boring holes in wood, such as the gimlet, auger, and the lathe to hold, turn and guide the article to be operated on by the tool, are common in some respects with those for drilling and turning metal, yet, the adaptation to use with metal const.i.tutes a cla.s.s of metal-working appliances distinct in themselves, and with some exceptions not interchangeable with wood-working utensils. The metal-working tools and machines forming the subject of this chapter are not those which from time immemorial have been used to pierce, hammer, cut, and shape metals, directed by the eye and hand of man, but rather those invented to take the place of the hand and eye and be operated by other powers.

It needs other than manual power to subdue the metals to the present wants of man, and until those modern motor powers, such as steam, compressed air, gas and electricity, and modern hydraulic machinery, were developed, automatic machine tools to any extent were not invented.

So, too, the tools that are designed to operate on hard metal should themselves be of the best metal, and until modern inventors rediscovered the art of making cast steel such tools were not obtainable. The monuments and records of ancient and departed races show that it was known by them how to bore holes in wood, stone and gla.s.s by some sharp instruments turned by hand, or it may be by leather cords, as a top is turned.

_The lathe_, a machine to hold an object, and at the same time revolve it while it is formed by the hand, or cut by a tool, is as old as the art of pottery, and is ill.u.s.trated in the oldest Egyptian monuments, in which the G.o.d Ptah is shown in the act of moulding man upon the throwing wheel. It is a device as necessary to the industrial growth of man as the axe or the spade. Its use by the Egyptians appears to have been confined to pottery, but the ancient Greeks, Chinese, Africans, and Hindoos used lathes, for wood working in which the work was suspended on horizontal supports, and adapted to be rotated by means of a rope and treadle and a spring bar, impelled by the operator as he held the cutting tool on the object. Joseph Holtzapffel in his learned work on _Turning and Mechanical Manipulation_, gives a list of old publications describing lathes for turning both wood and metal. Among these is Hartman Schapper's book published at Frankfort, in 1548. A lathe on which was formed wood screws is described in a work of Jacques Besson, published at Lyons, France, in 1582.

It is stated that there is on exhibition in the Abbott museum of the Historical Society, New York, a bronze drinking vessel, five inches in diameter, that was exhumed from an ancient tomb in Thebes, and which bears evidence of having been turned on a lathe. It is thought by those skilled in the art that it was not possible to have constructed the works of metal in Solomon's Temple without a turning lathe. One of the earliest published descriptions of a metal turning lathe in its leading features is that found in a book published in London, in 1677-83, by Joseph Moxon, "hydographer" to King Charles II., ent.i.tled, _Mechanical Exercises, or the Doctrine of Handy Works_. He therein also described a machine for planing metal. Although there is some evidence that these inventions of the learned gentleman were made and put to some use, yet they were soon forgotten and were not revived until a century later, when, as before intimated, the steam engine had been invented and furnished the power for working them.

Wood-working implements in which the cutting tool was carried by a sliding block were described in the English patents of General Sir Samuel Bentham and Joseph Bramah, in 1793-94. But until this century, and fairly within its borders, man was content generally to use the metal lathe simply as a holding and turning support, while he with such skill and strength as he could command, and with an expenditure of time, labour and patience truly marvellous, held and guided with his hands the cutting tool with which the required form was made upon or from the slowly turning object before him. The contrivance which was to take the place of the hand and eye of man in holding, applying, directing and impelling a cutting tool to the surface of the metal work was the _slide-rest_. In its modern successful automatic form Henry Maudsley, an engineer in London, is claimed to be the first inventor, in the early part of the century. The leading feature of his form of this device consists of an iron block which const.i.tutes the rest, cut with grooves so as to adapt it to slide upon its iron supports, means to secure the cutting tool solidly to this block, and two screw handles, one to adjust the tool towards and against the object to be cut in the lathe, and the other to slide the rest and tool lengthwise as the work progresses, which latter motion may be given by the hand, or effected automatically by a connection of the screw handle of the slide and the rotating object on the lathe.

A vast variety of inventions and operations have been effected by changes in these main features. Of the value of this invention, Nasmyth, a devoted pupil of Maudsley and himself an eminent engineer and inventor, thus writes:--"It was this holding of a tool by means of an iron hand, and constraining it to move along the surface of the work in so certain a manner, and with such definite and precise motion, which formed the great era in the history of mechanics, inasmuch as we thenceforward became possessed, by its means, of the power of operating alike on the most ponderous or delicate pieces of machinery with a degree of minute precision, of which language cannot convey an adequate idea; and in many cases we have, through its agency, equal facility in carrying on the most perfect workmanship in the interior parts of certain machines where neither the hand nor the eye can reach, and nevertheless we can give to these parts their required form with a degree of accuracy as if we had the power of transforming our-selves into pigmy workmen, and so apply our labour to the innermost holes and corners of our machinery."

The scope of the lathe, slide-rest and operating tool, by its adaptation to cut out from a vast roll of steel a ponderous gun, or by a change in the size of parts to operate in cutting or drilling the most delicate portions of that most delicate of all mechanisms, a watch, reminds one of that other marvel of mechanical adaptation, the steam hammer, which makes the earth tremble with its mighty blows upon a heated ma.s.s of iron, or lightly taps and cracks the soft-sh.e.l.led nut without the slightest touch of violence upon its enclosed and fragile fruit.

The adaptation of the lathe and slide to wood-working tools will be referred to in the chapter relating to wood-working.

Following the invention of the lathe and the slide-rest, came the _metal-planing_ machines. It is stated in Buchanan's _Practical Essays_, published in 1841, that a French engineer in 1751, in constructing the Marly Water Works on the Seine in France, employed a machine for planing out the wrought iron pump-barrels used in that work, and this is thought to be the first instance in which iron was reduced to a plane surface without chipping or filing. But it needed the invention of the slide-rest and its application to metal-turning lathes to suggest and render successful metal-planing machines. These were supplied in England from 1811 to 1840 by the genius of Bramah, Clement, Fox, Roberts, Rennie, Whitworth, Fletcher, and a few others. When it is considered how many different forms are essential to the completion of metal machines of every description, the usefulness of machinery that will produce them with the greatest accuracy and despatch can be imagined. The many modifications of the planing machine have names that indicate to the workman the purpose for which they are adapted--as the _jack_, a small portable machine, quick and handy; the _jim crow_, a machine for planing both ways by reversal of the movement of the bed, and it gets its name because it can "wheel about and turn about and do just so"; the key groove machine, the milling machine with a serrated-faced cutter bar, shaping machine and shaping bar, slotting machine, crank planer, screw cutting, car-wheel turning, bolt and nut s.c.r.e.w.i.n.g, etc.

As to the mutual evolution and important results of these combined inventions, the slide-rest and the planer, we again quote Nasmyth:--

"The first planing machine enabled us to produce the second still better, and that a better still, and then slide rests of the most perfect kind came streaming forth from them, and they again a.s.sisted in making better still, so that in a very short time a most important branch of engineering business, namely, tool-making, arose, which had its existence not merely owing to the pre-existing demand for such tools, but in fact raised a demand of its own creating. One has only to go into any of these vast establishments which have sprung up in the last thirty years to find that nine-tenths of all the fine mechanisms in use and in process of production are through the agency, more or less direct, of the _slide rest and planing machine_."