METALS OF THE ARTS AND SCIENCES
The development of modern civilization is directly connected with the
mining and manufacture of the useful metals. Their effect on the affairs
of mankind can be rightly understood only when they are studied in their
relations to one another, as well as to the people who used them. Next
to the discovery of the use of fire, an appreciation of the use of
metals has been the chief thing to develop the intellect of mankind.
When human beings discarded natural caves for artificially constructed
dwellings--when they began to cook their food and clothe their bodies,
they required tools. These, in the main, consisted of the spears and
arrow-heads used as weapons of the chase, and the axes and knives used
as constructive tools.
Rough stone gave place to flint because the latter would take a better
edge. For the same reason the people of central Europe sent to the
deserts of central Asia for jade wherewith to make axes and knives.
Again, for the same reason, jade was discarded, because an alloy of
copper and tin produced a bronze that would not only take a sharper edge
than stone, but it was hard enough to cut and dress the latter. Egypt
rose to a commanding position because of her control of the copper mines
in the Sinaitic peninsula, and subsequently of the gold products coming
from the upper Nile.
A meridian drawn through Cairo, Egypt, practically divides the world
into two kinds of civilization. East of this meridian the population is
almost wholly agricultural and, excepting Japan and India, the
character of the civilization has changed but little in the past 2,000
years. West of the line the population is essentially characterized as
metal-workers. It controls the world--not especially by virtue of a high
degree of intellectual development, but because it has availed itself of
the properties and characteristics of metals and their applications to
commerce.
The four metals that have had the greatest influence on western
civilization are gold, silver, iron, and copper. The discovery of gold
and silver has always resulted in a rapid settlement of the regions in
which the discoveries were made, and usually in the building of great
industrial centres. Thus, the discovery of gold in California was the
first step in making the United States a world power. The acquisition of
so large an amount of gold caused an industrial expansion that hurried
the Civil War, and led to the manufacture of iron and steel both for
agricultural machinery and railroad transportation. This, in turn,
brought the country so closely in touch with the affairs of China and
Japan, that European and American diplomacy in eastern Asia are a common
concern. The commercial position of Great Britain is very largely due to
her iron mines.
The production of Bessemer steel at a price far less than that of iron
at the beginning of the nineteenth century lowered the cost of
transporting commodities to the extent that large areas, once of
necessity very moderately productive of food-stuffs, are now densely
peopled because food-stuffs can be transported to these regions more
economically than they can be grown there. Thus, owing to the
improvements in iron and steel manufacture, the farmer of Minnesota, the
planter of Louisiana, the miner of Colorado, and the factory operative
of Massachusetts have each the same comforts of living that are enjoyed
by all the others, and have them at scarcely more than half the cost of
fifty years ago.
[Illustration: STEEL MANUFACTURE--THE NATIONAL STEEL COMPANY'S SMELTERY
AND ROLLING-MILLS, MINGO JUNCTION, OHIO]
The gradual decrease in the production of the silver mines near the
present site of Ergasteria proved a beginning of the fall of Athens; and
when gold was discovered in the Perim Mountains of Macedonia, the seat
of Greek power moved thither. Philip of Macedon hoarded the treasure
from the mines of Pangæus, and with the capital thus acquired his son,
Alexander the Great, conquered the East, implanted Hellenic business
methods there, and drew the various trade routes between Europe and Asia
under one control.
In the fifteenth century copper from the mines near Budapest and silver
from the Schwarz Mountains of Germany were the resources that made
Germanic Europe pre-eminent. The wresting of the trade in these two
metals from Venice caused the rise of Antwerp and brought immense gains
to Lübeck, London, Brussels, Augsburg, and Nuremberg. In the latter part
of the nineteenth century copper again reached a high position of
importance from the fact that upon it largely depends electric motive
power and transportation.
=Iron.=--Iron is one of the most widely diffused of metals. It is abundant
in the sun; meteorites contain from more than ten to eighty or ninety
per cent. of it; all earths and rocks contain at least traces of it; and
in various places the deposits of ore in nearly pure form aggregate
cubic miles in extent.
In only a few localities is iron ore found in a metallic or "native"
form. Many meteorites consist of metallic iron mixed with nickel and
manganese, and in Greenland a volcanic dyke or ledge of metallic iron is
known to exist. The iron of commerce is derived from "ores," or chemical
compounds of iron and oxygen, or iron and carbon. The cheapness of the
product depends upon the ease with which the ore may be quarried,
transported to coal, and smelted. The following are the ores commonly
employed in the production of iron:
_Red hematite_ has a reddish metallic lustre and when pure contains
seventy per cent. of iron.[42] It is the most abundant of the workable
ores, and certainly the best for the manufacture of Bessemer steel. The
ores of the Lake Superior region are mainly red hematite, and the latter
constitutes more than four-fifths of the output of the United States.
[Illustration: THE COMPARATIVE PRODUCTION OF IRON AND STEEL]
_Brown hematite_, or limonite, has a chestnut brown color and contains
very nearly sixty per cent. of iron[43]; it includes the "bog" ores, and
is very abundant. Not far from one-quarter of the Appalachian ores are
brown hematite; it constitutes about one-eighth of the output of the
United States.
_Magnetic_ iron ore, or magnetite, of which loadstone, a natural magnet,
is an example, has a metallic, steel lustre and contains 72.4 per cent.
of iron.[44] Most of the ores obtained in Pennsylvania and New York are
magnetite. The magnetites furnish about one-sixteenth of the output of
the United States.
_Carbonate of Iron_, or siderite, occurs in a few localities, the ore
produced in Ohio being almost wholly of this kind. It contains when
pure about forty-eight per cent. of iron.[45] It constitutes less than
one per cent. of the output of the United States.
_Iron pyrites_, or sulphide of iron, sometimes called "fools' gold," is
a very common mineral. It is used in the manufacture of sulphuric acid,
but is worthless for the production of iron; indeed, the presence of a
very small percentage of sulphur in iron renders the latter worthless
for many purposes.
Extensive deposits of iron are known to exist in very nearly every
country in the world, but those which can be advantageously worked are
few in number. In order to be available, the deposits must be within
easy transporting distance of the people who use it, and likewise within
a short distance of the coal used to manufacture it.
For these reasons most of the workable deposits of ore are in or near
the great centres of population in western Europe and the eastern part
of the United States; as a matter of fact, practically all the iron and
steel of the latter country is produced in the populous centres of the
Atlantic slopes. In most great steel-making districts it is essential to
mix the native ores with special ores brought from a distance, the
latter being used to give strength and hardness to the resulting metal.
Ores from Sweden, and from Juragua, Cuba, are employed for this purpose
in the steel-making establishments of the United States.
In the past few years the United States has jumped from an insignificant
position in the production of iron and steel to the first rank among the
iron-producing countries. This great advance is due to the fortunate
geographic position of the iron ore and the coal, and also to the
discovery of the Bessemer process of making steel.
In general it is more economical to ship the ore to the coal than _vice
versa_. The position of the steel-making plant is largely determined by
the cost of moving the coke and ore, together with that of getting the
steel to the place of use. Formerly, iron manufacture in the United
States was not profitable unless the coal, ore, and limestone[46] were
very near to one another.
These conditions still obtain in the southern Appalachian mineral
fields; the ore and the coal are at no great distance apart, and a great
iron-making industry, in which Birmingham and Bessemer form the
principal centre, has grown into existence. For the greater part the
coal is coked; and in this form less than a ton[47] is sufficient to
make a ton of pig-iron. The smelteries and rolling-mills are built at
places where the materials are most conveniently hauled.
In the past few years the iron and steel industry which formerly centred
about the navigable waters at the head of the Ohio River, has undergone
a readjustment. Rolling-mills and smelteries exist at Pittsburg and
vicinity, and at Youngstown, New Castle, and other nearby localities,
but greater steel-making plants have been built along the south shores
of Lakes Michigan and Erie, all of which have come about because of
reasons that are purely geographic.
Immense deposits of excellent hematite ore in the old mountain-ranges
near Lake Superior have recently become available. For the greater part
the ore is very easily quarried. In many instances it is taken out of
the quarry or pit by steam-shovels which dump it into self-discharging
hopper-cars. Thence the ore is carried on a down grade to the nearest
shipping-port on the lake. There it is dumped into huge bunkers built at
the docks, and from these it slides down chutes into the holds of the
steam-barges. A 6,000-ton barge is loaded in less than two hours; a car
is unloaded in a few seconds.
[Illustration: MOVEMENT OF IRON ORE]
Water transportation is very cheap compared with railway transportation,
even when the road is built and equipped as an ore-hauling road. The ore
is therefore carried a distance varying from one thousand to one
thousand five hundred miles for less than it could be loaded, on cars
hauled one-tenth that distance by rail, and unloaded.
[Illustration: STEEL MANUFACTURE--ORE DOCKS]
At the south shore of Lake Erie, the ore meets the coke from western
Pennsylvania and coal from the Ohio coal-fields, and as a result new
centres of iron and steel manufacture have grown up along this line of
"least resistance." The ore is unloaded at the docks by means of
mechanical scoops and shovels. So cheaply and quickly is it mined and
transported that it is delivered to the smelteries at a cost varying
from $1.75 to $3.25 per ton.
[Illustration: LAKE SUPERIOR IRON ORE FIELDS]
There are three forms in which iron is used--cast iron, wrought iron,
and steel. Cast iron is crystalline and brittle. The product as it comes
from the blast furnace is called pig-iron. In making such commodities as
stoves, and articles that do not require great strength, the pig-iron is
again melted and cast into moulds which give them the required shape.
Cast iron contains from one to five per cent. of carbon.
Wrought iron is malleable, ductile, and very flexible; when pure it is
also very soft. It is prepared by melting pig-iron in furnaces having
such a shape that the molten metal can be stirred or "puddled" in
contact with the air. By this means the carbon is burnt out, and while
still at a white heat the pasty iron is kneaded or "wrought," in order
to expel other impurities.
Steel is a form of iron which is thought to contain a chemical compound
of iron with carbon. It is stronger than iron and finer in grain.
Formerly, steel was made by packing bars of pure iron in charcoal
powder, the whole being enclosed in clay retorts that were heated to
whiteness for about three days. The product obtained by this method is
known as cementation steel. It is still used in the manufacture of
cutlery, tools, and fine machinery; it is likewise very expensive. In
smelting certain ores it is easy to burn out the carbon in open
furnaces, and "open-hearth" steel is an important factor.
Just about the beginning of the Civil War, when the railways of the
United States were taxed beyond their capacity to carry the produce of
the country, it became apparent that something more durable than iron
must be used for rails. The locomotives, then weighing from twenty-five
to thirty-five tons each, were too light to haul the freight offered the
roads; they were also too heavy for the rails, which split at the ends
and frayed at the edges.
[Illustration: IRON AND STEEL]
The Bessemer process of making steel was the result of the demand for a
better and a cheaper method. By this process, the iron is put into a
"converter" along with certain Swedish or Cuban ores to give the product
hardness. A hot blast is then forced into the converter which not only
melts the mass but burns out the excess of carbon as well. The color of
the flame indicates the moment when the conversion to steel is
accomplished.
In 1860, before the establishment of the Bessemer process, steel
commanded a price of about one hundred and twenty-five dollars per ton;
at the beginning of the twentieth century steel billets were about
eighteen dollars per ton. In western Europe and the United States there
are used about three hundred pounds of iron and steel per capita; in
South America the rate of consumption is about fifteen pounds; in Asia
(Japan excepted) it is probably less than three pounds.
The economic results of low-priced steel are very far-reaching. Steam
boilers of steel carry a pressure of more than two hundred and fifty
pounds to each square inch of surface--about four times as great as in
the iron boilers formerly used. Locomotives of eighty tons draw the fast
passenger trains at a speed of sixty miles an hour. Ponderous
compounding engines weighing one hundred and twenty tons haul ninety or
more steel freight cars that carry each a load of 100,000 pounds. The
iron rails formerly in use weighed about forty pounds per yard; now
steel rails of one hundred pounds per yard are employed on most trunk
lines.
In the large commercial buildings steel girders have entirely supplanted
timber, while in nearly all modern buildings of more than six stories in
height, the frame is constructed of Bessemer steel. Indeed, a
steel-framed building of twenty-five stories has greater stability than
a brick or stone building of six. Such a structure as the "Flatiron
Building" in New York or the Masonic Temple in Chicago would have been
impossible without Bessemer steel.
In ocean commerce cheap steel has worked even a greater revolution. In
1860, a vessel of 4,000 tons displacement was thought to be almost up to
the limit. The Oceanic of the White Star Line has a displacement of
about twenty-eight thousand five hundred tons. This is nearly equalled
by the measurement of half a dozen other liners, and is exceeded by the
freighters built by Mr. J.J. Hill for the China trade.
[Illustration: _From a copyrighted photograph by C.L. Ritzmann, N.Y._
STEEL MANUFACTURE
THE FULLER (FLATIRON) BUILDING, NEW YORK CITY]
HISTORICAL
1619.--Iron works established on Falling Creek, Va.
1643.--First foundry in Massachusetts, at Lynn.
1658.--Blast furnace and forge at New Haven, Conn.
1679.--Father Hennepin discovers coal in Illinois.
1703.--Mordecai Lincoln, ancestor of Abraham Lincoln, establishes
iron works at Scituate, Mass.
1717.--First bar iron exported from American Colonies to West
Indies.
1728.--Steel made, Hebron, Ct.
1732.--Father of George Washington establishes furnace in Virginia.
1740.--First iron works in New York, near Hudson.
1750.--Bituminous coal mined in Virginia.
1766.--Anthracite coal discovered in Pennsylvania.
1770.--First rolling-mill in Colonies, Boonton, N.J.
1801-1803.--Lake Champlain iron district, New York, developed.
1812.--First rolling-mill at Pittsburg.
1828.--Baltimore & Ohio Railroad, first steam railway in the United
States, begun.
1829.--"Stourbridge Lion," first locomotive in America, used in
Delaware & Hudson Railway.
1830.--The T rail invented by Robert L. Stevens.
1830.--First American locomotive, "Tom Thumb," built by Peter
Cooper at Baltimore.
1830.--Twenty-three miles of railway in the United States.
1844.--Lake Superior iron ores discovered by William Burt.
1850.--First shipment of Lake Superior ore, ten tons.
1857.--Iron industry founded in Chicago.
1862.--Phoenix wrought iron column, or girder, first made.
1864.--Bessemer steel first made in the United States.
1865.--First Bessemer steel rails in the United States rolled at
Chicago.
1890.--First armor-plate made in the United States rolled at
Bethlehem, Pa.
1890.--The United States surpasses Great Britain in production of
pig-iron.
1900.--The United States leads in the production of open-hearth
steel.
=Gold.=--Gold is one of the metals earliest to be mined. It is mentioned
by the ancient profane as well as by sacred writers. Pictorial
representations of fusing and working the metal are sculptured on early
Egyptian tombs, and beautiful gold ornaments have been found that were
made by the prehistoric peoples who once occupied ancient Etruria, in
Italy. Columbus found gold ornaments in the possession of the aboriginal
Americans. The Incas of Peru and the Aztecs of Mexico possessed large
quantities of gold.
[Illustration: LEACHING (CYANIDE) TANKS DISSOLVING THE GOLD FROM THE
ROASTED ORE]
[Illustration: STOPING OUT A TUNNEL]
[Illustration: INTERIOR OF MILL]
[Illustration: GOLD MINING]
Gold is one of the most widely diffused of metals. Traces of it are
found in practically all igneous and most sedimentary rocks. It occurs
in sea-water, and quite frequently in beach-sands. Traces of it are also
usually to be found in alluvial deposits and in the soils of most
mountain-folds. In spite of its wide diffusion, however, all the gold
that has been mined could be stored readily in the vaults of any large
New York bank.
In all probability most of the gold now in use has been deposited by
solution in quartz veins, the latter usually filling seams and crevices
in granitic or volcanic rocks. Quartz veins seldom yield very great
returns, but they furnish a steady supply of the metal. The rock must be
mined, hoisted to the surface, and crushed. The gold is then dissolved
by quicksilver (forming an amalgam from which the quicksilver is removed
by heat), by potassium cyanide solution, or by chlorine solution.
In many instances the quartz veins have been broken and weathered by
natural forces. In such cases the gold is usually carried off by swiftly
running water and deposited in the channel lower down. In this way
"placer" deposits of gold occur. Placer deposits are sometimes very
rich, but they are quickly exhausted. The first gold discovered in
California was placer gold.
Nearly all the gold mined in the United States has come from the western
highlands. In 1900, Colorado, California, South Dakota (Black Hills),
Montana, and Alaska yielded about seven-eighths of the entire product.
The placer mines of Alaska are confined mainly to the beach-sands and
the tributaries of Yukon River. Since 1849 the average annual yield of
gold in the United States is about forty-three million dollars.
The Guinea coast of Africa, Australia, California, the Transvaal of
South Africa, and Venezuela have each stood at the front in the
production of gold. The aggregate annual production of the world has
increased from one hundred and sixty million dollars in 1853 to more
than three hundred million dollars in 1900.
A considerable part of the gold product is used in gilding
picture-frames, book-titles, sign-letters, porcelain, and ornamental
brass work. Practically, all of this is lost, and in the United States
alone the loss aggregates about fifteen million dollars yearly. The
abrasion and unavoidable wear of gold coin is another great source of
loss.
An enormous amount is used in the manufacture of jewelry, most of which
is used over and over again. By far the greater part, however, is used
as a commercial medium of exchange--that is, as coin. For this purpose
its employment is wellnigh universal; and indeed this has been its chief
use since the beginning of written history. Gold coin of the United
States is 900 fine, that is, 900 parts of every thousand is pure gold;
gold coin of Great Britain is 916-2/3 fine. In each case a small amount
of silver, or silver and copper, is added to give the coin the requisite
hardness. The coining of gold, and also other metals, is a government
monopoly in every civilized country.
The fiat value of gold throughout the commercial world is the equivalent
of $20.6718 per troy ounce of fine metal; an eagle weighs, therefore,
2580 grains. The real value, however, is reckoned by a different and a
more accurate standard, namely, the labor of man, and this, the
sporadic finds of placer gold excepted, has not changed much in two
thousand years or more. The increased production has scarcely equalled
the demand for the metal; moreover, the longer a mine is worked the
greater becomes the expense of its operation. Improved processes for the
extraction of gold have not created any surplus of gold; indeed, the
supply is not equal to the demand; and this fact keeps the metal
practically at a fixed value.
=Silver.=--Silver is about as widely diffused as is gold, but it is more
plentiful. It is found sparingly in most of the older rocks and also in
sea-water. It was used by the Greeks for coinage more than eight hundred
years before the Christian era, and was known to the Jewish people in
very early times. According to the writer of the Book of Kings (1 Kings
x. 21), "It was nothing accounted of in the days of Solomon," but
Tacitus declares that in ancient Germany silver was even more valuable
than gold. The mines of Laureion (Laurium) gave the Greek state of
Attica its chief power, and the failure of the mines marked the
beginning of Athenian decline.
Silver is rarely found in a metallic state. For the greater part it
occurs combined with chlorine ("horn silver"), or with sulphur ("silver
glance"), or in combination with antimony and sulphur ("ruby ore"). The
ranges of the western highland region of the American continent yield
most of the present supply. The mines of Colorado, Montana, Utah, and
Idaho produce about six-sevenths of the yield in the United States,
which in 1900 was 74,500,000 ounces. In Europe the Hartz Mountains have
been famous for silver for several centuries.
About four-fifths of the silver bullion is used in the arts, most of it
being manufactured into ornaments or into table-service called "plate."
A considerable amount is used in photography, certain silver salts,
especially the chloride and the bromide, changing color by exposure to
the light. The remaining part of the silver output is made into coin.
The ratio of silver and gold has fluctuated much in the history of
civilization. In the United States the value of an ounce of fine silver
is fixed at $1.2929, thereby making the ratio 16 to 1. The silver
dollars, 900 fine, were coined on this basis, weighing 412.5 grains.
With the tremendous output of the silver mines between 1870 and 1880 the
price of silver fell to such an extent that, in time, most countries
limited the amount of coinage or demonetized it altogether. In the
United States the purchase of silver bullion for coinage has been
practically suspended, and the silver purchased is bought at the bullion
value--about fifty cents per troy ounce in 1900. In Japan the ratio has
been officially fixed at 32 to 1.
=Copper.=--Copper is probably the oldest metal known that has been used in
making tools. An alloy of copper and tin, hard enough to cut and dress
stone, succeeded the use of flint and jade, and its employment became so
general as to give the name "bronze" to the age following that
characterized by the use of stone implements.
Copper is very widely distributed. It occurs in quantities that pay for
mining in pretty nearly every country in the world. The rise of Egypt as
a commercial power was due to the fact that the Egyptians controlled the
world's trade in that metal, and it is highly probable that the
conquests of Cyprus at various times were chiefly for the possession of
the copper mines of Mount Olympus.
At the present time there are several great centres of production which
yield most of the metal used. These are the Rocky Mountain region,
including Mexico; the Lake Superior region of the United States; the
Andean region, including Chile, Peru, Argentina, and Bolivia; the
Iberian region, consisting of Spain and Portugal; and the Hartz
Mountain region of Germany. In 1900 they produced about four hundred and
fifty thousand tons, of which two hundred and eighty thousand were mined
in the United States.
Montana, the Lake Superior mines, and Arizona are the most productive
regions of the United States, and the mines of these three localities
yield more than half the world's product. Of these mines the Calumet and
Hecla of the Lake Superior region is the most famous. It was discovered
by Jesuit explorers about 1660, but was not worked until 1845. It is one
of the most productive mines in the world, its yearly output averaging
fifty million tons.
The export trade in copper is very important, amounting at the close of
the past century to about one hundred and seventy thousand short tons.
Of this amount, half goes to Germany (most of it through ports of the
Netherlands), and one-fifth each to France and Great Britain. The market
price to the consumer during the ten years closing the century averaged
about sixteen cents per pound. Most of the product is exported from New
York and Baltimore. The head-quarters of the great copper-mining
companies of America are at Boston. The imports of raw ores and partly
reduced ores called "regulus," come mainly from Mexico to New York and
Baltimore, and from Mexico and Japan to Puget Sound ports. The most
important American refineries are at New York and Baltimore.
A part of the copper is mixed with zinc to form brass, an alloy much
used in light machinery. A considerable quantity is rolled into sheets
to sheath building fronts and the iron hulls of vessels. By far the
greater part, however, is drawn into wire for carrying electricity, and
for this purpose it is surpassed by silver alone. The decrease in the
price of copper in the past few years is due, not to a falling off in
the demand, but to methods of reducing the ores and transporting the
product more economically.
=Aluminium.=--Aluminium is the base of clay, this mineral being its oxide.
It occurs in the various feldspars and feldspathic rocks, and in mica.
The expense of extracting the metal from these minerals has been so
great as to prohibit its commercial use. In 1870 there were probably
less than twenty pounds of the metal in existence, and it was to be
found only as a curiosity in the chemical laboratories. The discovery
that the metal could be extracted cheaply from cryolite, a mineral with
an aluminium base, obtained from Ivigtut, Greenland, led to a sparing
use of the metal in the economic arts.
The chief step in the production of the metal dates from the time that
the mineral _bauxite_, a hydroxide of aluminium and iron, was decomposed
in the electric furnace. The process has been repeatedly improved, and
under the patents covered by the Hall process the crude metal is now
produced at a market price of about eighteen cents per pound. The entire
production of the United States is controlled by the Pittsburg Reduction
Company, which also manufactures much of the commercial product of
England. The competitor of the Pittsburg Reduction Company is an
establishment in Germany, near Bremen.
Aluminium does not corrode; it is easily rolled, drawn, or cast; and,
bulk for bulk, it is less than one-third as heavy as copper. Because of
these properties it has a great and constantly growing economic value.
Because of its greater size, a pound of aluminium wire will carry a
greater electric current than a pound of copper wire of the same length.
It therefore has an increasing use as a conductor of electricity.
Bauxite, the mineral from which the metal is now chiefly extracted, is
obtained in two localities. One extends through Georgia and Alabama;
the other is in Arkansas.
=Lead.=--Lead is neither so abundant nor so widely diffused as iron,
copper, and the precious metals, but the supply is fully equal to the
demand. Lead ores, mainly galena or lead sulphide, occur abundantly in
the Rocky Mountains, Colorado, Idaho, and Utah, producing more than half
the total output of the United States. In these localities, in Mexico,
and in the Andean states of South America it is used mainly in the
smelting of silver ores.
Metallic lead is used largely in the manufacture of water-pipes, and for
this purpose it must be very nearly pure. It is also rolled into sheets
to be used as lining for water-tanks. The fact that the edges of
sheet-lead and the ends of pipes may be readily joined with solder gives
to lead a great part of its economic value. Alloyed with arsenic it is
used in making shot; alloyed with antimony it forms type metal; alloyed
with tin it forms pewter and solder.
The greater part, however, is manufactured into the carbonate or "white"
lead that is used as a pigment, or paint. Red lead, an oxide, is a
pigment; litharge, also an oxide, is used for glazing the cheaper kinds
of pottery. About two hundred and thirty thousand tons of lead are
produced in the United States and one-half as much is imported--mainly
from Mexico and Canada. The linotype machines, now used in all large
printing establishments, have increased the demand for lead.
=Other Metals.=--Most of the remaining economic metals occur in small
quantities as compared with iron, copper, gold, and silver. Some of
them, however, are highly important from the fact that in various
industrial processes no substitutes for them are known.
_Quicksilver_, or _mercury_, is the only industrial metal that at
ordinary temperatures is a liquid. It is the base of the substance
calomel, a chloride, and corrosive sublimate, a dichloride, both of
which are employed as medicines. It is essential in the manufacture of
thermometers and barometers, but is used chiefly, however, as a solvent
of gold, which it separates from the finely powdered ore by solution or
amalgamation. Quicksilver occurs in the mineral cinnabar, a sulphide.
Nearly one-half the world's product comes from California. The New
Almaden mines of Santa Clara County produce over five thousand flasks
(each seventy-six and one-half pounds net); those of Napa County nearly
nine thousand flasks; the mines of the whole State yield about
twenty-six thousand flasks, valued at $1,200,000. Almaden, Spain, and
Idria, Austria, produce nearly all the rest of the output. An average of
about fifteen thousand flasks are exported from San Francisco, mainly to
the mines of Mexico, and Central and South America.
_Tin_ is about the only metal of industrial value whose ores are not
found in paying quantities in the United States. Small quantities occur
in San Bernardino County, Cal., and in the vicinity of Bering Strait,
Alaska, but it is doubtful if either will ever pay for development.
About three-fifths of the world's product comes from the Straits
Settlements on the Malay Peninsula; the nearby islands of Banca and
Billiton also yield a considerable quantity.
The mines of Cornwall, England, have been worked for two thousand years
and were probably the source of the tin that made the "bronze age." The
United States imports yearly about twenty million dollars worth of tin,
about half of which comes from the Straits Settlements. This is used
almost wholly for the manufacture of tin plate[48]--that is, sheet-iron
coated with tin. Much of the block tin imported from Great Britain is
returned there in the form of tin plate, being manufactured in the
United States much more economically than in Europe.
_Nickel_ occurs in New Caledonia, in Canada, and in the State of
Missouri. It is used in the manufacture of small coins and for plating
iron and steel. It is an essential in the metal known as "nickel steel"
which is now generally used in armor-plate and propeller-shafts, about
four per cent. of nickel being added to the steel. Most of the product
used in the United States is imported from Canada.
_Manganese_, a metal resembling iron, occurs in Russia, Brazil, and
Cuba, Russia producing about half the total output. It is used mainly to
give hardness to steel. The propeller-blades of large steamships are
usually made of manganese bronze. The building of war-ships in the
United States during the past few years has led to the extensive use of
manganese for armor-plate, and manganese ores to the amount of more than
two hundred and fifty thousand tons were imported in 1900. More than
one-half of this came from Russia; most of the remaining half from
Brazil.
_Zinc_ is abundant in nearly every part of the world. In the United
States the best known mines are in the Galena-Joplin District, in
Missouri and Kansas, which produce about two-thirds of the home
product--mainly from the ore _blende_, a sulphide. There are also
extensive zinc-mining operations in Illinois, New Jersey, and
Pennsylvania. The lower Rhine District, Great Britain, and Silesia are
the chief European sources. Sheet-zinc is found in nearly every dwelling
in the United States, and zinc-coated or "galvanized" iron has become a
domestic necessity. Zinc-white is extensively used as a pigment. About
two hundred and fifty million pounds of crude zinc, or "spelter," are
produced in the United States; forty-five million pounds were exported
in 1900, mainly to Great Britain.
QUESTIONS FOR DISCUSSION
What are the qualities that make iron the most valuable of metals?
In what ways does commerce depend on iron and steel?
What substances are used for food, clothing, or domestic purposes that
are not manufactured by the aid of iron?
Ingot or billet steel is rated at about one cent per pound; the
hair-springs of watches are worth several thousand dollars per pound;
what makes the difference in their value?
What are the qualities that give to gold its value?
Would all the gold mined in the United States pay the national debt at
the end of the Civil War?
What causes have led to the increasing price of copper during the past
few years?
What is the market price each of copper, silver, steel rails, and
aluminium to-day?
FOR STUDY AND REFERENCE
Obtain specimens of the following iron ores: Hematite, brown hematite,
magnetite, carbonate, and pyrites. Note the color and physical
appearance of each; scratch the first four with a very hard steel point
and note the color of the streak.
Obtain specimens of pig-iron, cast iron, wrought iron, and cast steel;
note carefully the fracture or "break" of each; how does cast iron
differ from wrought iron?
Obtain specimens of the following copper ores: Malachite, azurite,
chalcopyrite, and red oxide; wet a very small fragment with an acid and
note the color when it is held in the flame of an alcohol lamp or a
Bunsen burner; dissolve a crystal of blue vitriol (copper sulphate) in
water and note what occurs if the end of a bright iron wire be dipped in
the solution.
Name the various uses to which nickel, tin, lead, and aluminium are put.
Consult the chapters on these subjects in any cyclopædia.
[Illustration: TRANSPORTING SUGAR-CANE, CUBA]
[Illustration: SUGAR-CANE GROWING IN CUBA]
[Illustration: HAVEMEYER SUGAR-REFINERY, BROOKLYN, N.Y.]