Part 22

Several theories as to the origin of coal have been put forth from time to time. The one now generally accepted is that the rank and luxuriant vegetation which prevailed during the carboniferous age grew and decayed upon land but slightly raised above the sea; that by slow subsidence this thick layer of vegetable matter sank below the water, and became gradually covered with sand, mud, and other mineral sediment; that then, by some slight upheaval or gradual silting up of the sea bottom, a land surface was once more formed, and covered with a dense mass of plants, which in course of time decayed, sank, and became overlaid with silt and sand as before. At length, thick masses of stratified matter would accumulate, producing great pressure, and this, acting along with chemical changes, would gradually mineralize the vegetable layers into coal.

In passing from wood or peat to coal, the proportion of carbon increases, while that of oxygen and hydrogen decreases, these substances being given off in the form of marsh-gas and carbonic acid gas in the process of decay.

Deposits occur in almost all parts of the world, but many are almost entirely undeveloped; as, for example, the coal fields of China. The largest production is in the United States, Wales, England, Germany, Austria, Russia and Australia. Mines are worked in India, Japan, Mexico, South America, South Africa, China and the Philippines. Pennsylvania, Ohio, West Virginia, Alabama, Indiana, Iowa and many other states mine coal in great amount. Pennsylvania produces nearly all of the anthracite and a large quantity of bituminous coal.

_Bituminous coal_, coking coal, non-coking coal, cannel coal, cherry coal, splint coal, gas coal, steam coal, etc., are all varieties of soft coal and contain a considerable percentage of volatile matter.

Bituminous coal is the fuel which runs the factories, railways and steamships of the world. The distillation of coal tar and the utilization of its numerous by-products, is one of the best examples of modern economy which turns waste material into useful products and large profits. Much coke is made without saving the by-products.

By distillation, bituminous coal yields gas, ammonia, coal tar and coke. Coal tar products are numbered by the thousand. Among them are naphtha, benzine, oil of mirbane, perfumes, flavors, drugs, saccharine, aniline and other dyes, phenol, carbolic acid, salicylic acid, naphthaline, photographic developers, creosote, oils, tar and pitch.

_Anthracite coal_ is almost pure carbon.

=Cobalt= is a metal the ores of which are sparingly distributed. It generally occurs as Speiss-cobalt, cobalt-glance (or cobaltite), wad, cobalt-bloom, linnæite and skutterudite. Its minerals are found chiefly in the Erzgebirge Mountains, Sweden, Norway, Chile, in silver ores near Coleman township, Ontario, in Oregon (as garnierite), and in New Caledonia. The metal itself is of a gray color with a reddish tinge, brittle, hard, and very magnetic.

Many of its compounds are valued on account of the brilliance and permanence of their colors. The protoxide of cobalt, is employed in the form of smalt in the production of the blue colors in porcelain, pottery, glass, encaustic tiles, fresco-painting, etc., and forms the principal ingredient in Old Sevres Blue, Thenard’s Blue, etc. The chlorid of cobalt, dissolved in much water, may be employed as a sympathetic ink. In dilute solutions, it is of a faint pink color, which is not observable upon paper; but when heated before the fire, it loses water, and becomes blue, and the writing is then capable of being read.

=Copper= is, next to iron, the most important metal in use. Its greatest production is in the United States, in Arizona, Montana, Michigan, and Utah. Spain, Japan, Chili, Australia and Germany produce smaller amounts. The metal is purified by smelting, and refined, often by electrolytic methods. There are many ores.

_Chalcopyrite_ and _bornite_ (sulphides of copper and iron) are widely distributed.

_Chalcocite_ (copper sulphide) is mined in Montana, _malachite_ and _azurite_ (carbonates of copper) in Arizona and metallic copper in Michigan.

_Copper matte_ is the crude metal as it comes from the smelter.

_Brass_ and _bronze_ are alloys of copper with zinc, tin, aluminum, etc.

_Copper sulphate_ (blue vitriol) is the most important chemical compound of copper.

The value of copper has increased within recent years, due to its enormous use in electrical work. Aside from this, copper is employed in large amount in the various alloys into which it enters, and in coins, utensils, printing plates, etc. Copper sulphate is extensively used in electrical apparatus dyes, chemical work and as an antiseptic. Large amounts of manufactured copper are exported to Europe. Smaller quantities of ores, matte and regulus are imported from Mexico, South America and other countries. Copper wire is extensively used by telephone and telegraph companies.

=Diamond.= See gems.

=Gems, or Precious Stones= are those which, because of their beauty, hardness, and rarity, are prized for use in ornamentation, especially in jewelry. The diamond, ruby, sapphire, and emerald are the only stones which are, strictly speaking, entitled to be called “precious” in this sense; but the opal, on account of its beauty, is often classed with the precious stones; as is also the pearl, which is really not a stone, but a secretion of a shellfish.

_Alexandrite._--A variety of chrysoberyl found in the mica slate of the Ural mountains. It is of a rich garnet color by artificial light, by daylight of a dark moss green. It is the only stone that so changes. The finest specimens of alexandrite are nearly as valuable as diamonds.

_Amethyst._--A variety of crystallized quartz of a purple or bluish-violet color, of different shades. It is much used as a jeweler’s stone. The lighter colored ones come from Brazil, the deep purple ones from Siberia. In value they are about the same as the garnet.

_Beryl._--A very hard mineral of much beauty when transparent. It occurs in hexagonal prisms, commonly of a green or bluish-green color, but also yellow, pink and white. It is a silicate of aluminum and glucinum. Beryls are very rich in colors.

_Bloodstone._--A green siliceous stone sprinkled with red jasper, whence the name.

_Cameo._--A figure cut in stone or shell that is composed of different colored layers. The value depends on the artistic merit of the engraved figure.

_Carbuncle._--A beautiful gem of a deep red color (with a mixture of scarlet), found in the East Indies. When held up to the sun it loses its deep tinge, and becomes of the color of a burning coal.

_Carnelian._--A variety of chalcedony, of a clear, deep red, flesh-red, or reddish-white color. It is moderately hard, capable of a good polish, and often used for seals. It is now used but little.

_Cat’s-eye._--A variety of quartz or chalcedony exhibiting opalescent reflections from within, like the eye of a cat. The name is given to other gems affording like effects, especially the chrysoberyl.

_Chalcedony._--A translucent variety of quartz, having usually a whitish color, and a luster nearly like wax.

_Dendrite._--A stone or mineral in which are branching figures, resembling shrubs or trees, produced by a foreign mineral, usually by an oxide of manganese, and the moss agate.

_Diamond._--A precious stone or gem excelling in brilliancy, beauty of prismatic colors, and remarkable for extreme hardness. It is found in many hues--green, rose, straw, yellow, etc.--but the straw-colored ones are the most common. The diamond is a native carbon, occurring in isometric crystals, often octahedrons, with rounded edges. It is the hardest substance known. Diamonds are said to be of the first water when very transparent, and of the second and third water as the transparency decreases.

_Diopside._--A crystallized variety of pyroxene (a silicate of lime and magnesia), of a clear, grayish-green color; also called mussite.

_Emerald._--A precious stone of a rich green color; it is the most valuable variety of beryl. (See beryl.)

_Epidote._--A mineral, commonly of a yellowish-green color, occurring granular, massive, columnar, and in crystals. It is a silicate of alumina, lime, and oxide of iron, or manganese.

_Fluorite._--Calcium fluoride, a mineral of many different colors, white, yellow, purple, red, etc., often very beautiful. When crystallized it is commonly in cubes with perfect octahedral cleavage. Some varieties are used for ornamental vessels. Also called fluor spar, or simply fluor. The colored varieties are often called false ruby, false emerald, false topaz, false sapphire, and false amethyst.

_Flint._--A massive, somewhat impure variety of quartz, in color usually of a gray to brown or nearly black. (See quartz.)

_Garnet._--A mineral having many varieties, differing in color and in their constituents, but with the same general chemical formula. The commonest color is red; the luster is vitreous, or glassy; and the hardness is greater than that of quartz, about half as hard as the diamond. Besides the red varieties there are also white, green, yellow, brown and black ones.

The garnet is a silicate with various bases. The transparent red varieties are used as gems. The garnet was the carbuncle of the ancients. Garnet is a very common mineral in gneiss and mica slate.

The finest specimens of red garnets come from Arizona and a single carat stone is worth about two dollars. A green variety that comes from Russia is worth about half as much as the diamond.

_Heliotrope_ or _bloodstone_.--A green siliceous stone sprinkled with jasper, as if with blood, whence the name.

_Hyacinth._--A red variety of zircon, sometimes used as a gem. It resembles closely a dark Spanish topaz, and is worth a little more than the garnet.

_Indicolite._--A variety of tourmaline of an indigo-blue color.

_Iolite._--A silicate of alumina, iron, and magnesia, having a bright blue color and a vitreous or glassy luster. It is remarkable for its dichroism, and is also called dichroite.

_Jacinth._--Same as hyacinth.

_Jade._--A stone commonly of a pale to dark green color, but sometimes whitish. It is hard and very tough, capable of a fine polish, and is used for ornamental purposes and for implements, especially in eastern countries and among many primitive peoples.

_Jasper._--An opaque, impure variety of quartz, of red, yellow, and other dull colors, breaking with a smooth surface. (See quartz.)

_Labradorite._--A kind of feldspar, commonly showing a beautiful play of bluish-gray colors, and, hence, much used for ornamental purposes. The finest specimens come from Labrador.

_Lapis-lazuli_ or _lazuli_.--A mineral of a fine azure-blue color, usually occurring in small rounded masses. It is essentially a silicate of alumina, lime, and soda, with some sodium sulphide. It is often marked by yellow spots or veins of sulphide of iron, and is much valued for ornamental work.

_Moonstone._--A nearly pellucid variety of feldspar, showing pearly or opaline reflections from within.

The best specimens come from Ceylon. Their value is not much more than the expense of cutting.

_Obsidian._--A kind of glass produced by volcanoes. It is usually of a black color and opaque, except in thin splinters.

_Onyx._--Chalcedony in parallel layers of different shades of color. It is used for making cameos, the figure being cut in one layer with the next layer as a background (see cameo). It is stained black and used to make mourning jewelry.

_Opal._--A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity. The precious opal shows a peculiar play of colors of delicate tints and it is highly esteemed as a gem. One kind, with a varied play of colors in a reddish ground, is called harlequin opal. The fire opal (which comes from Mexico) has colors like the red and yellow of flame. This is not the cheap variety commonly called Mexican opal.

+-------------------------------------+----------+--------+----------+ | =Name and Possessor= | =Carats |=Carats | =Dis- | | | (Cut=) |(Uncut=)| covered= | +-------------------------------------+----------+--------+----------+ | 1. Great Mogul Indian Moguls| 280 | ... |17th Cent.| |2-11. Pitt or Regent King of| 136-7/8 | 410 | 1702 | | Prussia| | | | | 3-5. Florentine Emperor of| 139-1/2 | ... | ... | | Austria| | | | |4-12. Star of the Brazilian| 127 | 254 | 1853 | | South Government| | | | | 6. Sancy Czar of| 53-1/2 | 83 |15th Cent.| | Russia| | | | | 7. Green Diamond Dresden Museum | 40 | ... | ... | |8-10. Koh-i-noor Crown of England |{280 (Old)| ... | B. C. 56 | | |{106-9/16 | | | | | (New) | | | | 9. Hope Mrs. E. B. McLean,| 44-1/2 | ... | ... | | Washington, D. C.| | | | +-------------------------------------+----------+--------+----------+

=OTHER NOTED DIAMONDS=

+-------------------------------------+----------+--------+----------+ |Cullinan I } King Edward VII|{ 561-1/2 |}3,025- | 1905 | |Cullinan II } |{ 309-3/4 |} 3/4 | | |Braganza King of Portugal|Never Cut | 1,680 | 1741 | |Rajah of Mattan Rajah of Mattan| 367.9 |787-1/2 | 1756 | | (Borneo)| | | | |Orloff Czar of Russia (scepter)| 194-3/4 | ... | ... | |Tavernier Stolen in 1792| ... |242-1/2 | 1668 | |King of Portugal | 138-1/2 | 150 | 1775 | |Light Yellow Stewart (diamond)| ... |288-5/8 | ... | |Shah Czar of Russia| 86 | ... | ... | |Nassac Lord (Marquis of)| 78-5/8 | 89-5/8 | ... | | Westminster| | | | |Porter Rhodes Found in South America| ... | 150 | 1872 | |Blue | 67-1/2 | 112 | ... | |Pigott Bought by Messrs. Rundell| 49 | ... | ... | | and Bridge| | | | |Dudley Earl of Dudley| 49-1/2 | 88-1/2 | ... | |Star of South Africa | 46-1/2 | 83-1/2 | 1867 | |Pasha of Egypt Khedive of Egypt| 40 | ... | ... | |Charles the Bold | 28 | ... | ... | +-------------------------------------+----------+--------+----------+

_Pearl._--A shelly concretion, usually rounded, having a brilliant luster, with varying tints, formed in the mantle, or between the mantle and shell, of certain bivalve mollusks (especially in the pearl oysters and river mussels) and sometimes in certain univalves. Its substance is the same as nacre or mother-of-pearl. Pearls which are round, or nearly round, and of fine luster, are highly prized as jewels. They are sold by carat grains instead of carats.

_Rhodonite._--Manganese spar, or silicate of manganese, a mineral occurring crystallized and in rose-red masses. It is almost entirely used for ornamental purposes, in slabs, blocks, etc.

_Rock crystal_ or _mountain crystal_.--Any transparent crystal of quartz, particularly of limpid or colorless quartz. A sphere of rock crystal of absolutely perfect clearness, about five inches in diameter, is worth at least twenty thousand dollars.

_Rose quartz._--A variety of quartz which is pinkish red.

_Rubellite._--A variety of tourmaline varying in color from a pale rose-red to a deep ruby, and containing lithium. It is a little more valuable than the garnet.

_Ruby._--A precious stone of a carmine-red color, sometimes verging to violet, or intermediate between carmine and hyacinth red. It is a crystallized variety of corundum. The ruby from Siam is of a dark color and is called oxblood ruby. It has about the same value as the diamond. The ruby from Burmah, called the pigeon-blood ruby, is of a lighter color and several times more valuable than the oxblood ruby.

_Sapphire._--A variety of native corundum or aluminium sesquioxide. As the name of a gem the term is restricted to the transparent varieties of blue, pink, yellow, and other colors. The best specimens of the blue variety are nearly as valuable as the diamond. The sapphire is next to the diamond in hardness.

_Sard._--A variety of carnelian, of a reddish-yellow or brownish color.

_Sardonyx._--A variety of onyx consisting of sard and white chalcedony in alternate layers. (See onyx.)

_Spinel._--A mineral occurring in octahedrons of great hardness and various colors, as red, green, blue, brown, and black, the red variety being the gem spinel ruby. It consists essentially of aluminum magnesium, but commonly contains iron and sometimes also chromium. The fine specimens of spinel ruby are worth rather more than half as much as the diamond.

_Topaz._--A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenish, bluish, or brownish shades. It sometimes occurs massive and opaque.

_Tourmaline._--A mineral occurring in three-sided prisms. Black tourmaline is the most common variety, but there are also other varieties, as the blue (indicolite), red (rubellite); also green, brown, and white. The red and green varieties, when transparent, are valued as jewels. The finest ones come from Maine, and are worth four or five times as much as garnets.

_Turquoise._--A hydrous phosphate of alumina containing a little copper. It has a blue, or bluish-green color, and usually occurs in kidney-shaped masses with a nodular surface like that of a bunch of grapes. The finest specimens are worth nearly half as much as diamonds.

_Verd antique._--A mottled-green, serpentine marble, also a green porphyry, which is called oriental verd antique.

_Zircon._--A mineral usually of a brown or gray color. It consists of silicon and zirconium, and is harder than the garnet. The transparent varieties are used as gems. The red variety is called Hyacinth; a colorless, pale yellow, or smoky-brown variety from Ceylon is called jargon.

=Gold=, a metal valued on account of its scarcity, color, luster, and power of resisting oxidation. It is found in nearly all parts of the world. South Africa and the United States are the leading producers. Australia, South America and parts of Europe possess important gold fields.

Gold is separated from gravel (placer mines) by washing with water. The particles of metal, being heavy, sink and can be collected. Rock containing gold is crushed to fine powder and the gold combined with mercury (amalgamation). Low-grade ores are treated with a solution of cyanide of potassium which dissolves the gold and the metal is later separated.

_Chloride of gold_, used in photographic work, is its only important compound. Pure gold is called twenty-four carats fine. A smaller figure indicates that the metal is alloyed to harden it.

Gold is used for money, jewelry, gold leaf (gilding) and in dentistry. It is almost always alloyed with copper and silver. Gold is the world’s accepted standard of value. Shipments of gold go from one country to another chiefly to balance international business dealings. Government treasuries and bank vaults are the chief storehouses for gold, either as bullion or coin.

=Graphite= is almost pure carbon. It is produced in Bohemia, Ceylon, Italy, Germany, Mexico and the United States. The deposits in Ceylon are the largest in the world. Much of that mined in New York and Alabama is of very high grade.

_Plumbago_ or _black lead_ is used in making crucibles, lead pencils, lubricants for heavy machinery, stove polish, foundry facings, paint, etc.

_Artificial graphite_ is made from coal or coke by an electric process.

Powdered graphite is mixed with fine clay in greater or less proportion and then molded and baked to form such articles as crucibles and lead for pencils. Graphite is imported from Ceylon to the United States, and lead pencils from Europe.

=Iron= is the most useful of all metals. The United States, Germany, Great Britain, Spain and France are the greatest producers of iron. Its ores occur in almost all parts of the world. Hematite is mined in Minnesota, Michigan, Alabama and other parts of the United States and in Germany, England, France, Spain, Russia, etc. Limonite is also widely distributed. Pig iron is made by smelting iron ore in a blast furnace. The ore, mixed with limestone, is melted by burning coke, coal or charcoal.

_Pyrite_ (iron pyrites, or fool’s gold) is found in Spain and many other parts of the world and is valuable in the preparation of sulphuric acid (oil of vitriol), but useless as an iron ore.

_Hematite_ (sesquioxide of iron) is the ore which supplies three-fourths of the iron of commerce.

_Limonite_ brown (hematite) is a hydrous oxide and furnishes nearly one-fourth of the world’s supply of the metal. Magnetite and siderite are less common ores.

_Pig iron_ is the crude form of the refined metal and is transformed into cast iron, wrought iron and steel in their multitudinous forms.

These three forms of iron differ in hardness, strength, elasticity, malleability, etc., according to the amounts of carbon, sulphur, phosphorus, manganese and other elements.

_Ochers_ and metallic paints are iron oxides. _Prussian blue_ and _copperas_ are iron compounds.

The United States manufactures more iron and steel than any other country. Almost half of the production is in Pennsylvania. _Cast iron_ appears in many articles but is weaker than other forms of iron. _Wrought iron_ contains less impurity and is used for bars, plates, wire, structural material and parts of machinery. _Steel_ (Bessemer, Siemens-Martin, open hearth, etc.) contains more carbon than wrought iron, possesses both strength and hardness, and is used for rails, structural material, machinery, tools, wire rope, sheet steel, etc. Its hardness may be increased by tempering. The United States imports iron ore from Cuba and Spain, pig iron from Great Britain and a little manufactured iron and steel from Europe. We export large quantities of manufactured iron and steel.

=Lanthanum.= See rare metals.

=Lead= is the softest, heaviest, most malleable and most easily melted of the common metals. Its ores are found in many countries but the main supply is from the United States, Spain, Germany and Mexico. The chief lead mines of the United States are in Missouri, Idaho, Utah, Colorado and Kansas. Much lead bullion is from smelters where silver ores are reduced.

_Galena_ (lead sulphide) is the only important ore; it often carries a considerable percentage of silver. Carbonates and sulphates of lead are less common. _Solder_ and _type metal_ are alloys of lead with tin and antimony. _White lead_ is a carbonate, _red lead_ and _litharge_ are oxides. _Chrome yellow_ and _orange mineral_ are lead compounds used as pigments.

The chief use of metallic lead is in piping, sheet lead, shot and alloys. Large amounts of ore are transformed not into metallic lead but into white lead for use in paints. Lead ores and lead bullion are imported from Mexico. England is the greatest importer of lead and lead ores.