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METALLURGY. · Inventions of the Century

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Section fifteen of Inventions in the Century. This is a LibriVox recording. All
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LibriVox recordings are in the public domain. For more information or to volunteer,
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please visit LibriVox dot org. Inventions in the Century by William Henry Doolittle.
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Metallurgy nigh on the plain, in many cells prepared that underneath had veins of
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liquid fire sluiced from the lake. A second multitude, with wondrous art,
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founded the massy ore, severing each kind, and scummed the bullion dross.
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A third, as soon had formed within the ground a various mold, and
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from the boiling cells, by strange conveyance, filled each hollow nuke, as
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in an organ, from one blast of wind to many a row of pipes.
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The sound board breeds paradise lost ever since those perished races of men who
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left no other record but that engraven in rude emblems on the rocks, or
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no other signs of their existence, but in the broken tools found buried deep
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among the solid leaves of the crusted earth. Ever since, tubulcane became an
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instructor of every artificer in brass and iron, the art of smelting has been
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known the Stone Age, flourished with implements furnished, ready made by nature,
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or needing little shaping for their use. But the ages of metal which followed
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required the aid of fire directed by the hand of man to provide the tool
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of iron or bronze. The Greeks claimed that the discovery of iron was theirs,
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and was made at the burning of a forest on the mountains of Ida
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and Crete about fifteen hundred b C. When the ore contained in the rocks
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or soil on which the forest stood was melted, cleansed of its impurities,
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and then collected and hammered. Archaeologists have deprived the Greeks of this gift and
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carried back its origin to remoter ages and localities. Man first discovered by observation
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or accident that certain stones were melted or softened by fire, and that the
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product could be hammered and shaped. They learned by experience that the melting could
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be done more effectually when the fuel and the ore were mixed and enclosed by
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a wall of stone, that the fire and heat could be alone started and
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maintained by blowing air into the fuel, and they constructed a rude bellows for
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this purpose. Finding that the melted metal sank through the mass of consumed fuel,
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they constructed a stone hearth on which to receive it. Thus were the
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first crude furnace and hearth invented. As to gold, silver, and lead,
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they doubtless were found first in their native state and mixed with other oars,
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and were hammered into the desired shapes with the hardest stone implements that copper
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and tin combined would make. Bronze was a more complex proceeding, and probably
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followed instead of proceeding, as has sometimes been alleged, the making of iron
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tools. That bronze relics were found currently of anterior manufacture to any made of
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iron was doubtless due to the destruction of the iron by that great consumer oxygen.
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What was very anciently called brass was no doubt gold colored copper, for
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what is modernly known as brass was not made until after the discovery of zinc
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in the sixteenth century and its combination with copper. Among the lost arts rediscovered
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in later ages are those which supplied the earliest cities with ornamented vessels of gold
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and copper, swords of steel that bent and sprung like wellbones, castings that
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had known no tool to shape their contour, and embellishments, and monuments and
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tablets of steel and brass which excite the wonder and admiration of the best artificers
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in brass and iron of the present day. To understand and appreciate the advancements
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that had been made in metallurgy in the nineteenth century, it is necessary to
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know in outline at least what before had been developed. The earliest form of
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a smelting furnace of historic day, such as used by the ancient Egyptians,
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Hebrews, and probably by the Hindus and other ancient peoples, and still used
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in Asia, is thus described by doctor Yuri. The furnace or bloomery in
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which the ore is smelted is from four to five feet high. It is
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somewhat pear shaped, being about five feet wide at bottom and one at top.
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It is built entirely of clay. There is an opening in front,
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about a foot or more in height, which is filled with clay at the
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commencement and broken down at the end of each smelting operation. The bellows are
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usually made of two goat skins with bamboo nozzles, which are inserted into tubes
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of clay that pass into the furnace. The furnace is filled with charcoal and
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a lighted coal being introduced before the nozzle. The mass in the interior is
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soon kindled. As soon as this is accomplished, a small portion of the
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ore, previously moistened with water to prevent it from running through the charcoal,
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but without any flux whatsoever, is laid on top of the coals and covered
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with to fill up the furnace. In this manner, ore and fuel are
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supplied and the bellows urged for three or four hours. When the process is
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stopped and the temporary wall in front broken down, the bloom is removed with
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a pair of tongs from the bottom of the furnace. This smelting was then
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followed by hammering to further separate the slag, and probably after a reheating to
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increase the malleability. It will be noticed that in this earliest process pure carbon
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was used as a fuel, and a blast of air to keep the fire
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at a great heat was employed. To what extent This carbon and air blast
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and the mixing and remixing with other ingredients and reheating and rehammering may have been
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employed in various instances to modify the conditions and render the metal malleable and more
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or less like modern steel. Is not known, but that an excellent quality
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of iron resembling modern steel was often produced by this simple mode of manufacture by
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different peoples is undoubtedly the fact. Steel, after all, is iron with
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a little more carbon in it than in the usual iron in the smelting furnace
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to render it harder, and a little less carbon than in cast or molded
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iron to render it malleable, and in both conditions was produced from time immemorial,
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either by accident or design. It was with such a furnace probably that
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India produced her keen edged weapons that would cut a web of gossamer, and
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Damascus its flashing blades, the synonym of elastic strength. Africa, when its
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most barbarous tribes were first discovered, was making various useful articles of iron.
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Its earliest modes of manufacture were doubtless still followed when doctor Livingstone explored the interior,
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as they now also are. He thus describes their furnaces in iron.
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At every third or fourth village in the regions near Lake Nyassa, we saw
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a kiln looking structure, about six feet high and two and a half feet
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in diameter. It is a clay fire hardened furnace for smelting iron. No
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flux is used, whether with speculaar I iron, the yellow hematite or magnetic
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ore, and yet capital metal is produced. Native manufactured iron is so good
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that the natives declare English iron rotten in comparison, and specimens of African hose
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were pronounced at Birmingham nearly equal to the best Swedish iron. The natives of
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India, the Hottentots, the early Britons, the Chinese, the savages of
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North and South America, as discovery or research brought their labors to light or
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uncovered the monuments of their earliest life were shown to be acquainted with similar simple
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forms of smelting furnaces. Early Spain produced a furnace which was adopted by the
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whole of Europe as fast as it became known. It was the Catalan furnace,
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so named from the province of Catalonia, where it probably first originated,
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and it is still so known and extensively used. It consists of a four
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sided cavity or hearth, which is always placed within a building and separated from
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the main wall thereof by a thinner interior way, which in part constitutes one
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side of the furnace. The blast pipe comes through the wall and enters the
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fire through a flu which slants downward. The bottom is formed of a refractory
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stone, which is renewable. The furnace has no chimneys. The blast is
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produced by means of a fall of water, usually from twenty two to twenty
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seven feet high, through a rectangular tube into a rectangular cistern below, to
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whose upper part the blast pipe is connected, the water escaping through a pipe
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below. This apparatus is exterior to the building, and is said to afford
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a continuous blast of regularity. The air when it passes into the furnace is,
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however, saturated with moisture night no doubt in such a heat was formed
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the metal from which was shaped the armour of Don Quixote in his prototypes.
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Bell in its History of Metallurgy, tells us that the manufacture of malleable iron
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must have fallen into decadence in England, especially before the Rain of Elizabeth and
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Charles the First, as no furnaces equal even to the Catalan had for a
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long time been in use, and the architectural iron column found in ancient Delhi
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sixteen inches in diameter, about forty eight feet long and calculated to weigh about
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seventeen tons, could not have been formed by any means known in England in
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the sixteenth century. This decadence was in part due to the severe laws enacted
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against the destruction of forests, and most of the iron was then brought to
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England from Germany and other countries. From time immemorial, the manufacture of iron
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and steel has been followed in Germany, and that country yet retains pre eminence
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in this art, both as to mechanical and chemical processes. It was in
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the eighteenth century that the celebrated Freburg Mining Academy was founded, the oldest of
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all existing mining schools, and based on developing mining and metallurgy on scientific lines.
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It has stood always on the battle line in the fight of progress.
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The early smelting furnaces of Germany resembled the Catalan and were called the Stucophen and
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in Sweden were known as the Osmond. In these very pure iron was made.
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The art of making cast iron, which differs from the ordinary smelted iron
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in the fact that it is melted and then run into molds. Although known
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among the ancients more than forty centuries ago, as shown by the castings of
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bronze and brass described by their writers and recover from their ruins, appears to
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have been forgotten long before the darkness of the Middle Ages gathered. There is
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no record of its practice from the time the elder Pliny described its former use
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forty through seventy nine a d. To the sixteenth century. It is stated
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that then the lost art was reinvented by Ralph Page and Peter Bowt of England
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in fifteen forty three, who in that year made cast iron in Sussex.
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The stucophen furnace above referred to was succeeded in Germany by higher ones called the
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Phlosophen, and these were followed by still higher and larger ones called Blauephen,
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so that by the middle of the eighteenth century the furnaces were very capacious.
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The blast was good, and it had been learned how to supply the furnaces
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with ore, coal and limestone broken into small fragments. The lime was added
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as a flux and acted to unite with itself the sand clay and other impurities
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to form a slag or scoria. The melted purified iron falling to the bottom
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was drawn off through a hole tapped in the furnace, and the molten metal
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ran into channels in a bed of sand called the sow and pigs, hence
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the name pig iron. The smelting of ore by charcoal in those places where
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carried on extensively required the use of a vast amount of wood and denuded the
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surrounding lands of forests. So great was this loss felt that it gave rise
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to the prohibitory laws, and the decadence in England of the manufacture of iron
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already alluded to. This turned the attention of iron smelters to coal as a
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substitute. Patents were granted in England for its use to several unsuccessful inventors.
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Finally, in sixteen nineteen, dud Duddy, a graduate of Oxford University and
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to whom succeeded his father's iron furnaces in Worcestershire, obtained a patent and succeeded
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in producing several tons of iron per week by the use of the pit coal
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in a small blast furnace. This success inflamed the wood owners and the charcoal
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burners, and they destroyed Dudley's works. He met with other disasters common to
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worthy inventors and discontinued his efforts to improve the art. It is said that
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in sixteen sixty four Sir John Winter of England made coke by burning sea coal
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in clothes pots, but this was not followed up, and the use of
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charcoal in the destruction of the forest went on until seventeen thirty five, when
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Abraham Darby of the Colbrokdale Iron Works at Shropshire, England, commenced to treat
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the soft pit coal in the same way as wood is treated in producing charcoal.
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He proposed to burn the coal in a smoldering fire to expel the sulfur
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and other impurities existing in the form of phosphorus, hydrogen and oxygen, et
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cetera, while saving the carbon. The attempt was successful, and thus coke
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was made. It was found cheaper and superior to either coal or charcoal,
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and produced a quicker fire in a greater heat. This was a wonderful discovery
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and was preserved as a trade secret for a long time. It was referred
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to as a curiosity in the Philosophical Transactions in seventeen forty seven. In fact,
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it was not introduced in America until a century later, when in eighteen
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forty one the soft coal abounding around Pittsburgh and Pennsylvania and in the neighboring regions
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of Ohio, was thus treated. Even its use then was experimental and did
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not become a practical art in the United States until about eighteen sixty. With
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the invention of coke, also came the revival of cast iron. The process
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of making cast steel was reinvented in England by Benjamin Huntsman of Attercliffe, near
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Sheffield about seventeen forty. Between that time and seventeen seventy he practiced melting small
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pieces of blistered steel iron bars which had been carbone by smelting and charcoal in
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closed clay crucibles. In seventeen eighty four, Henry Court of England introduced the
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puddling process and grooved rolls. Puddling had been invented but not successfully used before.
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The term puddling originated in the covering of the hearth of stones at the
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bottom of the furnace with clay, which was made plastic by mixing the clay
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in a puddle of water and on which hearth. The ore when melted,
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is received when in this melted condition, Court and others found that the metal
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was greatly improved by stirring it with a long iron bar called a rabble,
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and which was introduced through an opening in the furnace. This stirring admitted air
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to the mass, and the oxygen consumed and expelled the carbon, silicon and
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other impurities. The process was subsequently aided by the introduction of pig iron broken
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into pieces and mixed with hammer, slag, cinder, and ore. The
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mass is stirred from side to side of the furnace until it comes to a
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boiling point, when the stirring is in increased in quickness and violence, until
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a pasty round mass is collected by the puddler. As showing the value of
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Court's discovery and the hard experience inventors sometimes have Fairbarn states that Court expended a
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fortune of upward of twenty thousand pounds in perfecting his invention for puddling iron and
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rolling it into bars and plates, that he was robbed of the fruits of
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his discoveries by the villainy of officials in a high department of the government,
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and that he was ultimately left to starve by the apathy and selfishness of an
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ungrateful country. His inventions conferred an amount of wealth on the country equivalent to
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six hundred million pounds, and have given employment to six hundred thousand of the
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working population of our land for the last three or four generations. This process
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of puddling lasted for about an hour and a half and entailed extremely severe labour
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on the workmen. The invention of mechanical puddlers hereinafter referred to, consisting chiefly
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of rotating furnaces, where among the beneficent developments of the nineteenth century. Prior
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to Quart's time, the plastic lump or ball of metal taken from the furnace
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was generally beaten by hammers, but quartz grooved rollers pressed out the mass into
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sheets. The improvements of the steam engine by Watt greatly extended the manufacture of
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iron toward the close of the eighteenth century, as powerful air blasts were obtained
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by the use of such engines in place of the blowers worked by man,
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the horse, or the ox. So far as the art of refining the
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precious metals is concerned as well as copper, tin, and iron it had
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not previous to this century proceeded much beyond the methods described in the most ancient
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writings, and these included the refining in furnaces, pots and covered crucibles,
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and alloying, or the mixture and fusion with other metals. Furnaces to hold
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the crucibles and made of iron cylinders lined with fire brick, whereby the crucibles
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were subjected to greater heat, were also known. The amalgamating process was also
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known to the ancients, and Churuvius BC. Twenty seven and Pliny eighty seventy
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nine describe how mercury was used for separating gold from its impurities. Its use
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at gold and silver mines was renewed extensively in the sixteenth century. Thus we
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find that the eighteenth century closed with the knowledge of the smelting furnaces of various
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kinds, of coke as a fuel in place of charcoal, of furious air
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blasts driven by steam and other power, of cast iron and cast steel,
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and of refining, amalgamating and compounding processes. Looking back now from the threshold
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of the nineteenth century, over the path we have thus traced, it will
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be seen that what had been accomplished in metallurgy was the result of the use
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of ready means, tested by prolonged trials of experiments more or less lucky.
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In fields in which men were groping of inventions without the knowledge of the real
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properties of the materials with which inventors were working, or of the unvarying laws
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which govern their operations, they had accomplished much. But it was the work
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mainly of empirics. The art preceding the nineteenth century compared with what followed is
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the difference between experience simply an experience when combined with hard thinking, which is
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thus stated by Herschel. Art is the application of knowledge to a practical end.
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If the knowledge be merely accumulated experience, the art is empirical. But
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if it is experienced, reasoned upon, and brought under general principles, it
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assumes a higher character and becomes a scientific art. With the developments, discoveries
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and inventions in the lines of steam, chemistry, and electricity, as elsewhere
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told the impetus, they gave to the exercise of brain force in every field
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of nature at the outset of the century, and with their practical aid.
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The art of metallurgy soon began to expand to greater usefulness and finally to its
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present wonderful domain. The subject of metallurgy in this century soon became scientifically treated
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in its operations. Classified. Thus, the physical character and metallic constituents of
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ores received the first consideration, then the proper treatment to which the ores were
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to be subjected for the purpose of extracting the metal, which are either mechanical
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or chemical. The mechanical processes designed to separate the ore from its enclosing rock
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or other superfluous earthy matter called gang became known as ore dressing and ore concentrating.
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These included mills with rollers and stamps operated by gravity or steam for breaking
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up the ore rocks, abrasion apparatus for commanuting the ore by rubbing the pieces
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of ore under pressure and smelting, or an equivalent process for melting the ore
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and driving off the impurities by heat, et cetera. The chemical processes are
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those by which the metal, whatever it may be, is either dissolved or
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separated from other constituents, by either the application to the ore of certain metallic
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solutions of certain acids, or by the fusion of different ores or metals in
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substantially the old styles of furnaces, or its precipitation by amalgamating or by electrolysis,
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the art of decomposing metals by electricity. In the early decades of the
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century, by the help of chemistry and physics, the nature of heat,
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carbon and oxygen, and the great affinity iron hasper oxygen became better known,
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and particularly how in the making of iron its behavior is influenced by the presence
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of carbon and other foreign constituents. Also, how necessary to its perfect separation
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was the proper elimination of the oxygen and carbon. The use of manganese and
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other highly oxidizable metals for this purpose was discovered. Among the earliest most notable
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inventions in the century in the manufacture of iron was that of Samuel B.
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Rodgers of Glamorganshire Whales, who invented the iron floor for furnaces with a refractory
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lining, a great improvement on quartz sand floor which gave too much silicon to
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the iron, and the hot air blast by Nielsen of Glasgow, Scotland,
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fattened in eighteen twenty eight. The latter consisted in the use of heated air
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as the blast instead of cold, whereby ignition of the fuel was quickened,
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intensity of the heat and the expulsion of oxygen and carbon from the iron increased,
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and the operation shortened and improved in every way. The patent was infringed
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and assailed, but finally sustained by the highest courts of England. It produced
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an immense forward stride in the amount and quality of iron manufactured. By the
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introduction of the hot air blast. It became practicable to use the hard anthracite
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coal as a fuel where such coal abounded, and to use pig iron,
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scrap iron and refractory ore in metals with the fuel to produce particular results.
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Furnaces were enlarged to colossal dimensions, some being one hundred feet high and capable
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of yielding eighty or one hundred tons of metal per day. The forms of
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furnaces and means for lining and cooling the hearth and adjacent parts have received great
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attention. The discovery that the flame escaping from the throat of the blast furnace
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was nothing else than burning carbon that fabered to fore it. At Wasslerfugen in
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eighteen thirty seven to invent the successful and highly valuable method of utilizing the unburnt
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gas from the blast furnace for heating purposes and to heat the blast itself and
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drive the steam engine that blew the blast into the furnace without the consumption of
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additional fuel. This also led to the invention of separate gas producers. Bunsen
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in eighteen thirty eight made his first experiments at Hesse in collecting the gases from
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various parts of the furnace, revealing their composition and showing their adaptability for various
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purposes. Thus, from a scientific knowledge of the constituents of ores and in
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furnace gases, calculations could be made in advance as to the materials required to
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make pig iron, cast iron, and steel of particular qualities in the process
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of puddling. Difficulty had been experienced in handling the bloom or ball after it
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was formed in the furnace. A sort of squeezing apparatus or tongs called the
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alligator, had been employed. In eighteen fourty, Henry Burden of America invented
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and patented a method in means for treating these balls, whereby the same were
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taken directly from the furnace and passed between two plain converging metal surfaces, by
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which the balls were gradually but quickly pressed and squeezed into a cylindrical form,
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while a large portion of the cinders and other foreign impurities were pressed out.
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We had described how by quartz puddling process, tremendous labor was imposed on the
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workmen in stirring the molten metal by hand with rabbles. A number of mechanical
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puddlers were invented to take the place of these hand means, but the most
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important invention in this direction was the revolving puddlers of Beetlestone, patented in eighteen
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fifty seven in England, and of Heaton, Allen and Yates in eighteen sixty
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seven through eighteen sixty eight. The most successful, however, was that of
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Danks of the United States in eighteen sixty eight through eighteen sixty nine. The
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Dank's rotary puddler is a barrel shaped, refractory lined vessel having a chamber and
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fire grate and rotated by ste into which pig iron formed by the ordinary blast
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furnaces and then pulverized, is placed with the fuel molten metal from the furnace
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is then run, in which, together with the fuel, is then subjected
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to a strong blast. Successive charges may be made, and at the proper
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time the puddler is rotated slowly at some stages and faster at others, until
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the operation is completed. A much more thorough and satisfactory result in the production
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of a pure malleable iron is thus obtained than is possible by hand puddling.
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But the greatest improvements in puddling and in the production of steel from iron,
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and which have produced greater commercial results than any other inventions of the century relating
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to metallurgy, where the inventions of Henry Bessemer of Hertfordshire, England, from
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eighteen fifty five to eighteen sixty in place of the puddling rabbles to stir the
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molten metal or mat as it is called, while the air blast enters to
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oxidize it. He first introduced the molten metal from the furnace into an immense
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egg shaped vessel, lying with cortzos and hung in an inclined position on trunnions
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or melted the metal in such vessel, and then dividing the air blast into
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streams forced with great pressure each separate stream through an opening in the bottom of
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the vessel into the molten mass, thus making each stream of driven air or
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rabble, and they together blue and lifted the white mass into a huge,
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surging, sun bright fountain. The effect of this was to burn out the
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impurities silicon, carbon, sulfur, and phosphorus, leaving the mass a pure
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soft iron. If steel was wanted, a small amount of carbon, usually
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in the form of spiegeleisen, was introduced into the converter before the process was
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complete. A L. Hally of the United States improved the Bessemer apparatus by
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enabling a greater number of charges to be converted into steel within a given time.
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Sir Henry Bessemer has lived to gain great fortunes by his inventions, to
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see them afford new fields of labor for armies of men, and to increase
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the riches of nations from whom he has received deserved honours. The Bessemer process
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led to renewed investigations and discoveries as to heat in its utilization, the constituents
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of different metals in their decomposition, and as to the parts played by carbons,
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silicon and phosphorus. The carbon introduced by the charge of pig iron in
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the Bessemer process was at first supposed to be necessary to produce the greatest heat,
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but this was found to be a mistake, and phosphorus, which had
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been regarded as a great enemy of iron to be eliminated in every way,
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was found to be a valuable constituent and was retained or added to make phosphorus
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steel. The Bessemer process has been modified in various ways, by changing the
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mode of introducing the blast from the bottom of the converter to the sides thereof,
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and admitting the blast more slowly at certain stages, by changing the character
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of the pig iron and fuel to be treated, and by changing the shape
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and operation of the converters, making them cylindrical and rotary. For instance,
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the Bessemer process is now largely used in treating copper. By this method,
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the blowing through the molten metal of a blast of air largely removes sulfur and
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other impurities. The principles of reduction by the old style furnaces and methods we
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have described have been revived and combined with improvements. For instance, the old
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Catalan style of furnace has been retained to smelt the iron, but in one
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method the iron is withdrawn before it is reduced completely and introduced into another furnace,
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where mixed with further reducing ingredients a better result by far as produced with
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less labor. It would be a long list that would name the modern discoverers
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and inventors of the century in the manufacture of iron and steel. But eminent
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in the list in addition to Davy and Bessemer and others already mentioned are Muchet,
27:44
Sir L. Bell, Percy, Blomfield, Beasley, Gears and Snellis
27:48
of England, Martin Cheneault, du Motet Pernault and Gruner of France, Lohge,
27:55
Doctor C. L. Siemans and Hopfur of Germany, Professor Sarnstrom and
27:59
acts Men of Sweden, Turner of Austria, and Holly Slade, Blair,
28:03
Joones, Sellers, Clap, Griffiths and Emes of the United States. Some
28:08
of the new metals discovered in the last century have in this century been combined
28:12
with iron to make harder steel. Thus we have nickel, chromium and tungsten
28:18
steel. Processes for hardening steel as the harveazed steel have given rise to a
28:23
contest between irresistible projectiles and impenetrable armor plate. If there are some who regard
28:30
modern discoveries and inventions in iron and steel as lessening the number of workmen and
28:34
cheapening the product too much, thus causing trouble due to labor saving machinery,
28:40
let them glance among other great works in the world at krupps at Essen,
28:45
where on January first, eighteen ninety nine, forty one thousand, seven hundred
28:48
and fifty persons were employed, and at which works during the previous year one
28:53
million, one hundred ninety nine thousand, six hundred and ten tons of coal
28:56
and coke were consumed, or about four thousand tons daily. Workers in iron
29:02
will not be out of employment in the United States, where sixteen million tons
29:07
of coke are produced annually, one hundred and ninety six million, four hundred
29:11
five thousand, nine hundred and fifty three tons of coal mined, eleven million
29:15
tons of pig iron, and about nine million tons of steel made. The
29:19
increase of population within the last hundred years bears no comparison with this enormous increase
29:26
in iron and fuel. It shows that as inventions multiply, so does the
29:30
demand for their better and cheaper products increase as the other metals gold, silver,
29:36
copper, and lead often occur together, and in the same deposits.
29:38
With iron, the same general modes of treatment to extract them are often applied.
29:44
These are known as the dry and the wet methods and electra of reduction.
29:48
Ever since Mammon bowed his head and searched for gold, every means that
29:52
the mind of man could suggest to obtain it had been tried. But the
29:56
devices of this century have been more numerous and more successful than any before the
30:00
ancient methods of simply melting and skimming the bullion dross had been superseded. Modern
30:07
methods may be divided into two general classes, the mechanical and the chemical.
30:12
Of the former methods, When gold was found loose in sand or gravel,
30:17
washing was the earliest and most universally practiced, and was called panning. In
30:22
this method, mercury is often used to take up and secure the fine gold
30:26
rockers like a child's cradle, into which the dirt is shoveled and washed over.
30:32
Retaining riffles were used. Coarse haired blankets and hides, sluices and separators
30:37
with or without quicksilver linings to catch the gold, and powerful streams of water
30:41
worked by compressed air to tear down the banks where water could not be obtained.
30:47
The ore and soil were pulverized and dried and then thrown against the wind
30:52
or a blast of air, and the heavier gold falling before the lighter dust
30:56
was caught on pides or blankets for the crushing of the quartz in which gold
31:00
was found. Innumerable inventions in stamp mills, rollers, crushers, abraiders,
31:06
pulverizers, and amalgamators have been invented, and so with roasters and furnaces and
31:11
crucibles to melt the precious metal, separate the remaining impurities and convert it to
31:15
use. As to chemical methods for the precious metals, the process of luxeviation
31:22
or leeching, by which the ore is washed out by a solution of potash
31:26
or with dilute sulfuric acid or boiling with concentrated sulfuric acid, is quite modern.
31:33
About eighteen eighty nine came out the Great Cyanide process, also known as
31:37
the MacArthur Forest process. They being the first to obtain patents and introduce the
31:41
invention consisting of the use of cyanide potassium and solution which dissolves the gold and
31:47
which is then precipitated by the employment of zinc. This process is best adapted
31:52
to what are known as free milling or porous ores, where the gold is
31:56
free and very fine and is attracted readily by mercury. In eighteen o seven,
32:00
Sir Humphry Davy discovered the metal potassium by subjecting moisten potash to the action
32:07
of a powerful voltaic battery. The positive pole gave off oxygen, and the
32:10
metallic globules of pure potassium appeared at the negative pole. It is never found
32:16
uncombined in nature. Now, if potassium is heated in cyanogen gas, a
32:22
gas procured by heating mercury, or obtained on a large scale by the decomposition
32:27
of yellow prociate of potash, a white crystalline body, very soluble in water
32:31
and exceedingly poisonous is obtained. When gold, for instance, obtained by pulverising
32:37
the ore or found free in sand, is treated to such a solution,
32:42
it is dissolved from its surrounded constituents and precipitated by the zinc. As before
32:45
stated, chlorine is another metal discovered by shield in seventeen seventy four, but
32:51
not known as an elementary element until so established by Davy's investigations in eighteen ten,
32:57
when he gave it the name it now bears, from the Greek lorous
33:00
yellowish green. It is found abundantly in the mineral world in combination with common
33:05
salt. Now it was found that chlorine is one of the most energetic of
33:08
bodies, surpassing even oxygen under some circumstances, and that a chlorine solution will
33:14
readily dissolve gold. These the cyanide and chlorination processes have almost entirely superseded the
33:21
old washing and amalgamating methods of treating free gold, and the cyanide seems to
33:25
be now taking the lead alloys. The art of fusing different metals to make
33:30
new compounds, although always practiced, has been greatly advanced by the discoverers and
33:36
inventors of the century. As we have seen, amalgamating to extract gold and
33:40
silver, and the making of bronze from tin and copper were very early followed.
33:45
One of the most notable and useful of modern inventions or improvements of the
33:50
kind was that of Isaac Babbitt of Boston in eighteen thirty nine, who in
33:53
that year obtained patents for whatever since has been known as babbitting. The great
33:59
and undesired friction produced by the rubbing of the ends of journals and shafts in
34:02
their bearings of the same metal cast or wrought iron, amounting to one fifth
34:07
of the amount of power exerted to turn them, had long been experienced.
34:12
Lubricants of all kinds had been and are used, but Babbitt's invention was an
34:15
antifriction metal. It is composed of tin, antimony, and copper, and
34:22
although the proportions and ingredients have since been varied, the whole art is still
34:25
known as babbitting. Other successful alloys have been made for gun metal, sheathing
34:31
of ships, horseshoes, organ pipes, plowshares, roofing islets, projectiles,
34:37
faucets, and many in various articles of hardware, ornamental wear, and jewelry.
34:44
Valuable metals such as were not always rare or scarce but very hard to
34:47
reduce, have been rendered far less in cost of production and more extensive in
34:52
use by modern processes. Thus, aluminium, an abundant element in rocks and
34:57
clay, discovered by the German chemistry Boler in eighteen twenty seven, a precious
35:01
metal so light, bright and tough, non oxidizing, harder than zinc,
35:07
more sonorous and silver, malleable and ductil as iron, and more tenacious,
35:12
has been brought to the front from an expensive and mere laboratory production to common
35:16
and useful purposes in all the arts by the processes commencing in eighteen fifty four
35:22
with that of Saint Clair d'aville of France, followed by those of h.
35:25
Rose, Morin, Cassner, Tissier, Hall, and others. Electro Metallurgy
35:31
so far has chiefly to do with the decomposition of metals by the electric current
35:37
and the production of very high temperatures for furnaces, by which the most refractory
35:42
ores metals in other substances may be melted and results produced not obtainable in any
35:46
other way. By placing certain mixtures of carbon and sand, or of carbon
35:52
and clay between the terminals of a powerful current, a material resembling diamonds but
35:57
harder has been produced. It has been named carbon undrum. The production of
36:02
diamonds themselves is looked for. Steel wire is now tempered and annealed by electricity,
36:08
as well as welding done, of which mention further on will be made.
36:14
Thus we have seen how the birth of ideas of former generations has given
36:17
rise in the present age to children of a larger growth. Arts have grown
36:22
only as machinery for the accomplishment of their objects has developed, and machinery has
36:28
weighted on the development of the metals composing it. The civilization of to day
36:31
would not have been possible if the successors of tubal Cane had not been like
36:36
him, instructors of every artificer in brass and iron. End of Section fifteen.