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.

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.

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.

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.

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.

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.

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.

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.

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?