Cyclopædia of Political Science, Political Economy, and the Political History of the United States
GOLD, a dense, ductile, malleable metal, of a brilliant yellow color, used in ornamentation and for money. Its especial adaptation for these purposes arises from its power to resist oxidation or corrosion upon exposure to air or moisture, and its insolubility in ordinary acids. In the form of coin it is readily distinguished from base metals by its characteristic lustre, its great specific gravity and its metallic ring. Alloyed with other metals its color changes: the yellow tint is successively lowered by increased additions of small quantities of silver, and, on the contrary, heightened by copper. In the ordinary state its hardness is about that of tin but not quite as soft as lead, varying, however, with the composition.
—Pure gold is the most malleable of all metals, and has been beaten into leaves of 1/282000 of an inch in thickness, and is then capable of transmitting light, the yellow hue being changed to green.
—Gold is exceedingly ductile, and can be finely divided without heating. The specific gravity of gold varies with its previous treatment, being, when cast in bars, from 18/100 and 29/100 to 19/100 and 37/100, and raised by pressure or heating to 19/100 and 40/100. Its atomic weight has been given by modern chemists at from 196 to 196.67.
—Pure gold can not be volatilized at any ordinary temperature when melted and kept in a state of fusion, but when alloyed with volatile metals and heated in contact with air, will rise in fumes. It is also dispersed by the electric battery, the concentrated heat of the sun's rays, or by the oxyhydrogen blow-pipe.
—Gold is dissolved by bromine, chlorine and selenic acid, and, when heated, in a solution of strong sulphuric with a little nitric acid.
—Gold is found diffused in many of the solid rocks, sometimes in a metallic state as native gold, and often in combination with silver, lead, tellurium and sulphides. Valuable and working deposits of gold are found in stratified rocks and in veins containing quartz traversing rocks of other geological periods; also in metallic sulphides and bitter spar, in which it is disseminated in grains, crystalline threads or masses, and in invisible particles.
—Besides these places of original deposit, gold is excavated in so-called dry diggings at the bottoms of now buried rivers, or nearer the surface in alluvial deposits adjacent to dry water crevices, and in wet diggings in the beds of streams by whose currents it has been brought down from higher altitudes, separated from the lighter earthy matter and deposited in auriferous gravels and sands, in masses called lumps and nuggets, or in smaller particles in the form of grains, dust or thin scales.
—Native gold is never found absolutely pure, but always contains a small quantity of silver and frequently copper or iron, the proportion of gold in the alloy being 60.49 in Transylvania to 99.25 in Australia. Gold is also found alloyed with bismuth, palladium, rhodium, and associated with minerals and ores containing arsenic, antimony, tellurium and metallic sulphides of lead, iron, copper, zinc, etc.
—The methods of obtaining and extracting gold vary with the character of the deposit in which it is found, but may be classified either as placer or vein mining. In the first, the gold is separated from an alluvial deposit by a purely mechanical process. After removing the overlying gravel or earthy material, the ground in contact with the bed rock is subjected to the action of water, where that is accessible, which, while removing the waste material, permits the gold to sink and be collected at the bottom. The separation of the gold in placer mining is effected in various ways: in some cases with a pan—a circular dish of sheet iron with sloping sides, a foot or more in diameter, held in a stream or hole filled with water. By skillful shaking and twisting the lighter materials are washed out, the heavier gold settling to the bottom. For treating larger quantities sometimes an appliance called a cradle, from its resemblance to that household article, is used. It is a box from three to six feet in length resting upon rockers and having an opening at one end and pieces of wood about an inch square, called riffle bars, nailed across its bottom. The dirt, upon which water from time to time is poured, is shaken by the rocking motion through a perforated riddle-box, into which it is shoveled by an assistant, and drops upon an apron sloping toward the upper end of the cradle, from which it falls to the bottom, running out at the lower end. The gold, mixed with the heavier sand and gravel, is detained by the riffle bars. A modified form of the cradle, called a tom, with an extended inclined sluice, is sometimes constructed. Currents of water are also made to run through long sluices or shallow troughs, upon the bottom of which riffles made of strips of wood are placed. Whatever the mechanical contrivance employed, from the simple washing on the prospector's shovel to the largest hydraulic operations, the principle involved is the same, namely, the greater specific gravity of the gold carries it to the bottom of the pan, rocker or sluice, while the lighter and worthless portions are washed away. Where the gold is very finely divided, being in small grains or thin scales, it is liable to float away with the dirt, and is secured by using blankets of wool or copper plates covered with quicksilver to form an amalgam, which is removed by working and scraping the plates.
—In California a large amount of gold is obtained by hydraulic mining, water being brought in many cases from great distances in ditches, flumes and iron pipes, from higher altitudes. Jets of water issuing under the pressure of a column, sometimes hundreds of feet in height, through nozzles skillfully arranged and directed, strike with tremendous force against the banks and beds of earth containing gold. Hills are undermined and washed away, their material being moved by the current into sluices where the gold is separated and collected. The earthy matter is carried to the lower levels and valleys or held in solution until it settles in the bays and more sluggish currents of the large rivers near the coast. The operations in mining gold-bearing quartz or other vein material are conducted in the manner usually employed in mining other metals or minerals. At a convenient point, either a tunnel, where practicable, is run horizontally from the surface to the vein, or a shaft is sunk perpendicularly to a sufficient depth, and from it a drift or level run until the vein is reached. Gold in quartz or free milling ores is usually disseminated in small particles, to obtain which, before undergoing the usual treatment, the gold-bearing rock must be finely pulverized. Various methods and devices are employed, among the simplest of which is the arrastra, which has a circular bed of stone of from eight to twenty feet in diameter with a post in the middle, through which extends a horizontal bar reaching to the circumference on either side. From each arm revolving around the post hangs a heavy stone weighing from three to five hundred pounds, the former end slightly raised above and the hinder resting upon the bed of rock to be crushed. Some what similar to this is the Chilian mill, with the same central upright and revolving arms, but having the grinding stones with a beveled face and roll, instead of being dragged upon the floor.
—These earlier and ruder methods have been succeeded in large mining operations by rock crushers and stamp mills. By the former the rock is broken and crushed between powerful iron jaws, and by the latter pulverized by successive blows of heavy iron stamps or hammers upon the rock or ore resting upon a hardened iron bed. The pulverized rock is washed away, and the gold, set free, is collected by mercury, as in placer mining, but with greater care, as the particles of gold being smaller are more liable to be carried away by the current.
—To separate the gold from the mercury, the amalgam, after first pressing out all the fluid mercury, is placed in an iron retort and heated to a low red heat, when the mercury volatilizes, passes over into a condenser connected with the retort, and is thus recovered for use in future operations. The gold is obtained nearly free from mercury (it being difficult to drive off the last portion of that metal) in a porous, sponge-like form, which can readily be melted and cast into bars.
—Ores in which the matrix is an oxide of the metals are generally free milling. Those other than free milling are chiefly the sulphides of iron and copper, and to some extent lead, antimony and zinc, though in the latter silver is usually the more valuable constituent.
—Ores in which gold is combined with the sulphides of the base metals are refractory in proportion to the extent of the base metal, and the treatment is as varied as are the proportions in which the combinations exist. With some ores a simple roasting to eliminate the sulphur is found to be sufficient, and the most economical treatment which the value of the ore will permit, preparatory to crushing and amalgamating. Other ores of iron are better treated by the chlorinating process, while those in which copper or lead are valuable constituents are best treated by a smelting process which results in forming base bars of lead containing the precious metals or copper matte. The gold is removed from lead in a reverberating furnace, and copper matte is usually sold to copper works.
—Gold as received at the mints, unless it is from a refinery, invariably contains silver. The methods of separating these two metals are known as the nitric acid process and the sulphuric acid process, in both of which the same principle is involved, that of dissolving the silver, decanting it from the gold, and subsequently recovering it by precipitation.
—In the nitric acid process, to accomplish the solution of the silver, the gold is melted with twice its weight of silver, and while in a fused condition poured in a thin stream from a height of two or three feet into a tank of cold water for the purpose of subdividing it into granulations and giving a large surface for the action of the acid. The granulations are transferred to porcelain pots and treated with nitric acid; the pots are placed in a water bath to accelerate chemical action, the nitrous fumes of which are abundantly emitted, being carried away by a high flue. After the silver has been dissolved, the solution is drawn off into wooden vats containing a solution of sodium chloride, which precipitates the silver from a nitrate into a chloride. The gold is placed on a filter, washed, dried, pressed into cakes and melted. The precipitated chloride is removed to lead-lined vats, and zinc in a granulated condition is introduced, when a reaction attended by evolution of heat sets in, a soluble chloride of zinc is formed, and the silver liberated in a metallic state. It is subsequently washed, dried, pressed and melted into bars as in the case of the gold.
—In the sulphuric acid process the same preliminary steps are observed in granulating the bullion. The granulations are treated in iron pots, with concentrated sulphuric acid, which in part breaks up, giving oxygen to the silver, while the undecomposed acid combines with the oxide of silver thus formed and forms sulphate of silver. The fumes from the operation are carried into a lead-lined chamber and reconverted into sulphuric acid by the aid of air and hyponitric acid. The gold is taken from the pots after the silver has been dissolved and drawn off, and treated as the residual gold from the nitric acid process. The sulphate of silver is decomposed in lead-lined vats by metallic copper, which in the process is converted into sulphate of copper, and the silver is precipitated in a metallic form. The solution of sulphate of copper, after being decanted, is concentrated by heat to the crystallizing point and recovered as commercial blue vitriol, and the silver is washed, died, etc., and cast into bars.
—The fineness of bullion and coin is estimated in thousandths, pure metal being considered 1000 fine. The process of ascertaining the fineness of gold, or assaying, may be briefly described as follows: One thousand parts of the alloy is accurately weighed; the weight used, for convenience' sake, is the French gramme divided into 1000 parts or millegrammes. Pure silver, to the amount of twice the weight of pure gold estimated to be contained in the alloy, is added, and the whole, enveloped in a piece of lead foil, is placed in a cupel in a muffle furnace heated to a high temperature. The cupel is made of compressed bone ash, and possesses the property of absorbing the oxides of base metals. The lead foil is oxidized, and as it is absorbed by the cupel carries with it the oxides of the base metals which may be contained in the alloy. This part of the process eliminates the base metal from the 1000 parts of alloy being operated upon. The button of gold and silver taken from the cupel is laminated by hammer and rolls into a thin slip and digested in nitric acid, which dissolves the silver and leaves the pure gold, which, after washing, drying and annealing, is returned to the balance and weighed. Its weight in millegrammes expresses in thousandths the fineness of the alloy.
—Gold is one of the metals earliest mentioned in history, and has been found in all parts of the world. Almost every country contains workable mines or deposits of gold, but nearly all the fields in which supplies prior to the Christian era were obtained are at present abandoned. The most productive appear to have been situated cast of Persia, probably in Tartary or southern Siberia, from which large stores were derived; also in India, Egypt, Nubia, Ethiopia and other regions on the cast coast of Africa; and in Asia Minor, Thrace, Greece, and some of the neighboring islands, Italy, Spain and Gaul.
—From the historical accounts of the large quantities of gold used in the ornamentation of ancient temples and public buildings, held in the treasuries and owned by monarchs and private citizens, in the form of plate, or money, and of the sums collected at various times for tribute, it is supposed that ancient mining was prosecuted with its greatest success during the first few centuries preceding the Christian era, but, either because mining for gold became less profitable or the mines were gradually exhausted, the production of gold after the reign of Augustus Cæsar rapidly diminished, and in the fifth century of our era had almost ceased. Many of the countries conquered by the Romans contained mines of gold which continued to furnish supplies during the continuance of the empire. But the Roman method of leasing and operating the mines soon ruined the mining industry. The operations were carried on by the labor of unwilling slaves, and being leased to favorites, whose only care was to secure the greatest profit during the term for which they were to have possession, the richest deposits were worked out and no care taken to keep open the drifts and tunnels for the use of future occupants.
—The principal deposits of gold worked during the present century are in the United States, in Australia, and in portions of Africa. Gold is mined to a limited extent in some of the mountainous regions of central and southwestern Europe in which the large rivers take their rise—notably the Rhine, the Danube and the Rhone. Small quantities have been annually produced in Italy. Hungary, Germany, Spain, and, in former years, in Turkey, Japan, China, in many other regions of Asia and Africa, and even in Great Britain. The largest gold production of the eastern hemisphere is found in Siberia on the eastern slope of the Ural mountains, and still further cast on the head waters of the Yenessei and Amoor rivers. These mines have been worked for many years with an increasing annual yield, amounting in 1880 to $28,000,000. A still larger quantity has been annually furnished to the world, since 1852, from Australia, embracing Victoria, New South Wales. Queensland and New Zealand, which together, in 1880, added $30,000,000 to the world's stock of the precious metals. A less productive but still important gold field is found in South America, principally in Colombia, Venezuela, Bolivia and Brazil, which promises to increase its present yield of $6,000,000 per annum. Gold is also found in North America on the Atlantic slope, in Nova Scotia, also near Quebec and on the eastern watershed of the Alleghany mountains, in the Carolinas and Georgia, and in the western mountain regions, in various localities, from Alaska to Central America. But the richest and most extensive deposits thus far discovered have been found in the states on the Pacific slope or in the basins or parallel ranges west of the Rocky mountains.
—The gold mines of the United States, according to the mint reports, produced, in the fiscal year 1881, $36,500,000, and for thirty-four years, from 1848 to 1881 inclusive, $1,557,000,000. The yield of the several states and territories for 1880-81 was reported by the director of the mint as follows:
—The production of the precious metals in the early centuries prior to and immediately succeeding the commencement of the Christian era, is somewhat conjectural. No reports are extant of the amount yearly obtained from the mines. As far as any authentic information has been received, the deposits of gold known to the ancients were little worked after the fall of the Roman empire, and from that date to the close of the fifteenth century, although in some regions gold was still obtained, the total amount was not large. If Mr. Jacob's conclusions are reliable, the total production of gold in Europe and western Asia from A. D. 800 to A. D. 1500 could not have exceeded $35,000,000, for he states that during that period the production of the precious metals was one-seventh or one-eighth of what it was from 1700 to 1800 in Europe and east of the Ural mountains, which for the last twenty years, the most productive period, he reports to have been $1,000,000 gold and $3,000,000 silver. According to his estimates, the mines of America sent to the old world, between A. D. 1492 and 1600, gold and silver of the value of $690,000,000, and from A. D. 1600 to 1700, $1,687,000,000; the mines of Europe and America furnished from A. D. 1700 to 1810, $4,000,000,000, and from A. D. 1810 to 1830, $500,000,000. The official statements published by him show that from the Russian mines, which commenced to produce in 1704, up to 1810, gold had been extracted to the value of 1,726 puds ($1,500,000) of which $500,000 was obtained within the last twenty years of the period. The average annual production of Asia and Africa he made $6,000,000.
—Dr. Adolph Soetbeer's summary of the production in all the gold-producing countries of the world, from the discovery of America, to 1880, gives the following amounts and values:
The countries from which supplies of gold were obtained and the yield of each in 1830 has been estimated by the director of the mint as follows.
—That the gold obtained from the mines for many centuries before the discovery of America was insignificant compared with their present production, is to some extent evidenced by contrasting the yearly coinages of the periods. The mint records of Great Britain show that gold coinage from the eighteenth year of Edward III. to the death of Henry VII., was only £464,908, from the accession of James I. to George I., £18,244,868; from that date to 1829. £132,056,241; and from 1830 to 1880, £201,897,275. The average annual gold coinage was—
—The gold coinage of the United States has in like manner increased. From A. D. 1793 up to and including the year 1848, when gold began to arrive at the mint from California, a period of fifty-six years, $76,341,440 of gold was coined—an annual average of $1,363,400. But in the succeeding thirty three years, 1849-81, the gold coinage increased to $1,135,495,746, and averaged yearly $34,408,962, and for the last eight years nearly $50,000,000. The same fact is seen in looking at the total gold coinage, etc., of a number of countries for the preceding five years, as stated in the reports of the director of the mint as follows:
The total yearly coinage at the mints of the various countries of the world, however, always far exceeds the production, as those institutions are employed in manufacturing into coins of their own country, the coins imported from foreign countries as well as the bullion received from the mines.
—Upon a careful review of the metallic circulation in all the commercial countries of the world, both Dr. Soetbeer and the director of the United States mint find that the total amount of the gold coin in those countries is less than half the amount of gold received from the mines since the discovery of America, and not even half of their yield during the twenty-nine years from 1851 to 1879. It is evident, therefore, that the greater portion of the annual production is appropriated for other purposes than coinage into money.
—Efforts have been made by several statisticians, notably by Jacob and by Soetbeer, to ascertain the amount of gold and silver lost by abrasion and used in ornamentation and the arts. In the years 1879, 1880 and 1881 the director of the mint caused circular inquiries to be issued, the replies to which reported as used in manufactures and the arts in the United States in 1881, of coin and bullion other than old jewelry, plate, etc., over ten millions of gold and over three millions of silver, and the director estimated in 1881, that over eleven millions of gold was thus used in the United States and at least seventy five millions in the world. The character of the gold was reported to him as follows:
—Mr. William Jacob, in 1831, made a very exhaustive inquiry as to the amount of money in the world at various periods up to that date. He placed the accumulated stock of gold and silver, in the year A. D. 14, at 1,790 millions of dollars, which he estimated, however, to have been reduced by the year 482 to 435 millions of dollars, and in A. D. 806 to 168 millions, and that it remained at about 170 millions up to the discovery of America in 1492. By the year 1600, accessions from the mines of America had increased the amount of gold and silver to 1,650 millions of dollars, by 1700 to 1,130 millions, by 1809 to 1,900 millions, and twenty years later, 1829, to 1,566 millions.
—Some authorities have questioned the allowance made by Jacob for abrasion and appropriation in the arts, and place the stock in the world upon the discovery of America at a higher rate. Seyd's estimate makes it 900 millions of dollars. He estimates the amount of money in the world in 1848 to be, of gold, 2,000 millions; in 1872, 3,650 millions; and in 1878, 4,150 millions.
—Soetbeer, assuming that the amount of gold available for coinage in civilized countries in 1830 was 800,000 kilograms ($531,216,000), estimated that, after deducting for consumption in the arts and export to the Orient, there remained 4,690,000 kilograms ($3,116,974,000). This nearly coincides with the estimate of the director of the mint for 1880, who makes the gold circulation of the world $3,221,223,971.
—During the three centuries preceding our own, general prices seem to have advanced in Europe, as the same nominal sum of money would buy much less in the eighteenth than in the fifteenth century. This is accounted for in some measure by the debasement of the coins then frequently practiced in every country, but it is more generally attributed to the effect of the large amount of gold and silver received during that period from the western world. It might therefore have been expected, and has been asserted, that the increased production of gold in the world after 1848, and the large addition to the stock of money in commercial countries, would depress its purchasing power, or, what is the same thing, inflate prices. A comparison, however, of the market prices of staple articles in several commercial countries, does not show any large advance in the average prices of the years 1878 to 1881, over the prices of 1850. In some instances they appear to be lower. According to statistical tables in the "London Economist," the prices, in 1878, of a large number of selected articles, being the principal commodities entering into consumption in England, were 101 per cent. of the mean of their prices for the years 1845-50, and their mean prices for the years 1878-81 were 114 per cent., and in 1881 were about 116 per cent. A comparative table of the prices of French imports and exports at different periods shows that in 1878 the prices of French imports were 96 per cent. and of French exports 74 per cent—a mean of 85 per cent. of their prices in 1850. A like comparison of the prices of leading commodities in the New York market for the same years shows in 1878 no advance, although prices were somewhat higher in 1880. It may therefore be said that the enormous addition to the metallic circulation witnessed in the last thirty years appears to have been required by the increased wealth, greater commercial enterprise and enlarged production of the present period, and to have been received and absorbed without thus far materially affecting general prices.
HORATIO C. BURCHARD.
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