Popular Science Monthly/Volume 22/February 1883/The Decrease of Gold
By F. von BRIESEN.
WHEN, in the beginning of 1850, California and Australia sent annually about one hundred and eighty million dollars of gold into the world, national economists became frightened, and Michel Chevalier and Cobden expressed the fear that the world would be completely inundated with a flood of gold. But when, after the year 1867, this production decreased with alarming rapidity, the opposite fears were expressed. As early as 1869, the London "Economist," when reviewing the year past, said that it would be a great blessing if new sources of gold could be discovered, since the production of thirty thousand pounds sterling per year was barely sufficient to cover the necessities of a flourishing commerce, more especially since America consumed a great part of the gold for itself, thus withdrawing it from the European market. Notable statesmen saw in it the cause of the periodically recurring commercial crises; and Professor Süss, of Vienna, demonstrated in his pamphlet, "The Future of Gold," that the present sources of gold are being exhausted, and that the territory in which new deposits might be found is gradually diminishing in extent.
It is not our purpose, however, tothe national, economical side of the question, but merely to consider it in its scientific bearing.
Gold and silver are the so-called precious metals, for the simple reason that they are rare. But, if we ask why gold is so scarce, Dr. Süss answers that its scarcity is caused by its specific gravity. We possess three metals distinguished for their great density—iridium, platinum, and gold. If we assume the weight of water as unity, the gravity of these metals—is iridium, 22·23; platinum, 21·50; gold, 19·25. With the exception of iridium, rare as well as remarkable, gold and platinum weigh more than any other metal: for instance, lead has a specific gravity of 11·35; silver, 10·47; copper, 8·80; and iron, only 7·84. The question occurs next, whether the scarcity of gold stands in any connection with its gravity.
Since the earth originally passed from a gaseous into a fluid state, the heaviest components must, in its fluid condition, have tended toward the center. If it he true that our entire planetary system developed from an immense nebula, it follows that the planets nearest to the center must be the heaviest.
"Their great specific gravity," says Professor Petzholt, speaking of metals, "is the reason that they can so rarely be seen on the surface of the earth; the largest masses are to be found within the interior, in a molten condition, and are there protected against the cupidity of man."
Further observations have confirmed the truth of this view. Because spectral analysis reveals no gold in the sun, we must accept the fact that it lies hidden in its interior, and that it is covered by lighter bodies, which, in a gaseous state, form the photosphere of the sun. Hydrogen, the lightest of all gases, constitutes the chief component of this photosphere. Now, the planets are divided into two groups, according to their weight: the heavy, which lie within, and the light, which lie beyond, the circle of the asteroids. Mercury, the nearest to the sun, is seven times as heavy as water; Venus, the Earth, and Mars are five times as heavy; while Jupiter barely attains the weight of water. The specific weight of Saturn is 0·73; of Uranus, 0·84; consequently, they are lighter than water. The density of Neptune, not yet exactly determined, is at any rate very small. We therefore find in our planetary system that the densest bodies are nearest to the center, and this leads us to the presumption that the same law governs on each individual planet, and that, therefore, the heavy gold must be found nearest to the center.
This leads to the question, Whence the gold and platinum to be found upon the surface of the earth? These two heavy metals are only found in places where volcanic rocks have penetrated through earlier formations, and the granite has split up. Platinum, only found in excess in the Ural Mountains, is obtained from rocks that have come up from below; gold is found only in quartz-veins. These veins have been formed in the following manner: As a natural consequence of the contraction of the earth's crust, internal revolutions, and volcanic eruptions, crevices opened, which were partly filled by hot springs, partly by eruptions with quartz. Rich deposits are often found in these crevices, called by the American miners "pockets," or "bonanzas"; but, besides these bonanzas, crevices contain no gold, and only the hope of encountering them leads to their being worked.
The places in which gold is found may be divided into the following three classes—auriferous ore, auriferous veins, and auriferous alluvium:
The first group contains ore, rich in magnesium, interspersed with gold. It is frequently found in the Ural Mountains. As a transition to the second class may be regarded the auriferous minerals, in rock of volcanic origin, as it occurs on the west coast of South America and in many parts of Brazil. The granite of the Erz Gebirge, in Bohemia, which contains tin, is a similar formation. Interesting as this class is, considered from a geological stand-point, it is of little practical value to the gold miner.
The next class consists of the auriferous veins, which are fissures filled by hot springs, geysers, or volcanic eruptions. The gold is found here together with silver, as in the case of the Comstock lode, in Nevada, the gold deposits in Queensland and New Zealand, as well as the mines near Kremnitz, in the Carpathian range, in Hungary. The gold is sometimes found in them pure, sometimes mixed with silver, copper, or sulphur. In the older volcanic veins the gold is not mixed with silver, and bonanzas are never found in them. In many of these veins, also, granite veins are encountered, and, although remote from volcanic regions, it is presumed that the gold was carried up by the granite. The celebrated "Mother lode" of California is a sample of this kind.
The third class is the gold-bearing alluvium. This alluvium (earth washed down by rivers upon lower lands) has been produced by the decomposition of auriferous rock, and the gold is found in grains and lumps to the size of a hen's egg. It is a peculiar fact that the gold found in these deposits is purer than that contained in the veins from which it originated, nor is the formation of lumps and grains satisfactorily explained. The deposits of California, Australia, and Siberia pertain to this group, which may again be subdivided into—a. Deposits on the earth's surface, from which the gold is obtained by simple washing; b. Deposits which have been covered by subsequent inundations, and from which the gold has to be mined only by difficult work and great expense. These old deposits in California are frequently covered with basalt or lava, and are called "deep leads." They are worked by the hydraulic system: the water is conducted through pipes, and directed with full force against the soil, which is hereby converted into a fluid mud, and passes in this condition through a long line of sluices, set in zigzag, in which the particles of gold are deposited.
The most remarkable deposits of this kind are to be found at Ballarat, Australia, where they are covered with four hundred feet of ground and four layers of lava, which have come from a neighboring volcano. These deposits are the banks and bars of former streams, which have subsequently been filled up. The greatest part of the gold comes from these sources. Dr. Süss estimates that, of all the gold which has been mined between the years 1848 and 1875, the working of the ore has yielded 12·02, while that of the former deposits furnished 87·98 per cent.
Since these deposits are exhausted, attention has for the past few years been directed to the working of the ore. As soon as gold-mines are exhausted, new ones must be found. While the mining of silver is sometimes continued in the same regions for centuries, that of gold is always of short duration, wherefore gold-mines are only to be found in the extreme limits of civilization. Herodotus remarked, when speaking of the quantity of gold-dust paid as a tribute to Darius by the inhabitants of India, that the greatest treasures always come from the most remote places of the earth. The old countries have entirely ceased to be productive, and search must be instituted in the yet unexplored regions in order to discover new fields.
Gold was in excess in ancient times, and mostly taken from the rivers in Asia. The fables of Pactolus, of the golden fleece of the Argonauts, of the gold from Ophir, the history of King Midas, etc., all point to an Eastern origin of this metal. According to Pliny, Cyrus returned with 34,000 Roman pounds of gold (about $10,000,000). The treasures exacted from Persia by Alexander the Great amounted to 351,000 talents, or $400,000,000. Gold also came from Arabia, and upon the Nile from the interior of Africa. Pliny calls Asturias the country in which the most gold is found. A tablet bearing the following inscription was found in Idanha Velha, Portugal: "Claudius Rufus returns his thanks to Jupiter for having permitted him to find one hundred and thirty pounds of gold."
These sources of wealth have ceased to flow, and the endeavor of several Englishmen to reopen them have been unsuccessful. Bohemia, Mähren, Silesia, and Tyrol, all have produced gold, and the receding of the glaciers has caused old mines to be uncovered, while upon the Italian side, at Monte Rosa, Yal Sesina, and Val Ansaca, goldmine's are still worked to-day, although with indifferent success. The only works of any note are those of Kremnitz, Hungary. It may, therefore, be safely asserted that Europe is completely exhausted in this respect.
After America was discovered, the Antilles, especially Hispaniola, and the western coast of Mexico, furnished incredible quantities of gold. That used by Alexander VI to gild Saint Mary Maggiore came from Hispaniola, as is seen by the following inscription: "Quod primo Catholici reges ex India receperant." But the production of these mines did not last long.
We find several peculiar statements, with regard to the mining of gold, in an old Dutch book, printed in Amsterdam in the year 1590. It says: "Gold comes from different countries, from the mountains in Bohemia, and the rivers in Sweden. More than twenty thousand pounds came formerly from Spain, but these mines are exhausted. It came next from the Spanish Indies, first from San Domingo, then from other parts, but that also has stopped. It comes at present from Peru, formerly three millions annually, at present five, six, and eight millions, but it will not be long until these mines also will be exhausted and abandoned." The prophecy of the old book has been fulfilled.
Humboldt entertained great hopes of New Granada and Colombia, where precious metals are found, but, in spite of English capital and highly-improved machinery, the mines do not produce beyond two millions annually.
The Indians of Chili, Peru, and the entire western coast of South America, formerly dug much gold from the alluvium; they obtained plenty of silver afterward, but little gold, while at the present time they produce ten or twelve times less than at the time of Humboldt's visit. The total production of South America, except Brazil, from 1500 to 1875, was about thirteen hundred million dollars. We can nowhere follow the history of mining better than in Brazil. Toward the end of the sixteenth century the inhabitants of São Paulo were struck with the gold trinkets worn by the savages, and they began washing. In the year 1697 Bartholomeo Bueno found rich gold deposits in the province of Minas Geraes, in consequence of which many adventurers went there, and a war broke out between the Paulists and the Portuguese. The governor finally succeeded in restoring peace, and gold-washing was prosecuted according to a fixed system, whereby the mines became very productive. Towns were built—for instance, Villa Rica—and people flocked from all regions. The province of Matto Grosso, after the year 1720, ceased to produce gold, and in the eighteenth century Brazil occupied the place of California in the nineteenth. Minas Geraes alone, in the middle of the eighteenth century, produced seven, and Brazil ten, million dollars per year, but the deposits were soon exhausted, and toward 1820 the entire production of Brazil had dwindled to five hundred thousand dollars. The leads were next commenced to be worked, but without success, in spite of the vast sums expended upon them by large capitalists. Brazil, which a hundred years ago excelled any other country in the production of gold, has in this respect become fully impoverished within the last fifty years. Its total production, from the end of the sixteenth century up to to-day, amounts to one hundred and sixty million dollars.
In ancient times, and in the beginning of the middle ages, Africa was known as the gold country. Herodotus speaks of the Carthaginians, who gathered gold on the other side of the Pillars of Hercules; the Arabian geographer El Edrisi (1154) speaks of gold in Wangara, the source of the Niger, and the same mention is made by the Moor, Leo Africanus, who was baptized by Pope Leo X; he had explored Africa and the countries of Wangara and Timbuctoo. The Moors of Spain and Northern Africa obtained their precious metals from these countries. The French of Senegal lately took possession of them. They still found gold, but no longer in paying quantities, and the once famous Gold Coast at present furnishes not half a million dollars per year. The auriferous sand is washed by the negroes during leisure hours, and they are content with a yield which would ruin a European enterprise.
The Egyptians obtained their gold from the upper Nile and Ethiopia, attested by inscriptions dating from the year 1600 before Christ. Herodotus mentions a king of Ethiopia who was attacked by Cambyses, but not conquered, who shackled his prisoners with golden chains, since gold was more common than bronze. According to Edrisi, there was so much gold in Sofala that a copper trinket was worth more than one of gold. The celebrated explorer Mauch, in 1867, found the remains of ancient gold-mines, but the gold of Africa belongs to the past. The celebrated necklace of the Queen Aalie Topeh, said to be three thousand six hundred years old, and still to be seen in Boolak; the gold chains worn by the Afghan prisoners at the time of Cambyses; the treasures brought by the Queen of Sheba to Solomon's Temple; the masses of gold with which the throne of the King of Ghana was adorned—all these, no matter whether they be fables or not, indubitably point to the former immense gold wealth of Africa, while to-day it produces barely a million dollars. Entire Northern Africa, as far as the Sahara and the Falls of the Nile, consists of sedimentary ground, which never can have furnished metals; but in the interior we find old rock—granite, gneiss, and hornblende—and there the auriferous alluvial soil had been formed; but it appears that it has been thoroughly exhausted in antiquity and the middle ages. According to Ab. Jevones, the natives have been the first to discover auriferous sand. It is, therefore, possible that the interior country still contains deposits, and even bonanzas, but large ones may no longer be expected, since its gold would long ago have reached the coast.
Neither China nor Japan produces sufficient gold for home consumption.
The three chief sources are at present Siberia, the United States, and Australia, while the last two are becoming exhausted. An immense alluvial territory exists in Siberia, covering the entire space from the Ural to the river Amoor, but the climate prevents washing during the greater part of the year. Here, similar to California, gold is found wherever granite fills the fissures. Although the yield of the washings is gradually decreasing, it is really increased by daily discoveries of new fields, and amounts at present to about $28,000,000 annually. The greatest quantity of gold has of late years been mined in America, partly due to its natural wealth, partly to the energy brought to bear for obtaining it. Volcanic forces have brought gold as well as silver to the surface in the Rocky Mountains, but its exhaustion is approaching rapidly. Montana, in 1860, produced $18,000,000, while to-day its yield is $2,500,000; Idaho, from 1864 to 1871, yielded from $5,000,000 to $7,000,000, which in the year 1880 has decreased to $1,510,546; Oregon and Washington yielded, in the year 1868, $4,000,000; in 1879, not more than $1,275,000; Dakota has increased a little, and produced $2,420,000 in 1879; Colorado has an average yield of $3,000,000; California has passed through the several stages of a gold-producing country; the washing of the river-sands, after 1848, produced immense wealth, while at present only the Chinese are engaged in it, and earn a bare living. The gold on the surface is exhausted, and only the deep deposits and the veins remain to be worked.
It has been estimated that $1,200,000,000 of gold and silver have been mined in the West of the United States within the last thirty years; and that, in spite of the recklessness and extravagance which characterized the two decades from 1849 to 1869, a net profit of $30,000,000 per year was realized. Since 1850, the money invested and the labor expended in mining in the West for precious metals are estimated at $710,000,000. What may fairly be called the mining territory of the United States embraces an area of 1,190,000 square miles, with a population of barely 1,500,000.
The entire ridge of the Sierra Nevada consists of granite; but on the western slope limestone is found mixed with it. Where these two rocks come together, a belt from eight to nine miles wide, and running from north to south, is found, which contains all the gold leads of the district. The "Mother lode" commences at Mariposa, passes through the northern boundary of the State, and is covered by the lava of the large (not yet extinguished) volcanoes Pilot Peak and Lossan Peak farther north. This lava also covers an old alluvial bottom with overlying layers of basalt from fifty to two hundred feet thick, and these form the so-called "Table Mountains." We find the same formation south of the Sierra Nevada, near the "Big Trees," where the sedimentary deposits, lying upon granite, are covered with basalt. From here the auriferous sand was washed away by mountain-streams, and appeared on the surface. These deep deposits, in connection with the offshoots of the Mother lode, still sustain the gold production of California at from fifteen to seventeen million dollars.
In Nevada was discovered the Comstock lode, for a long time held to be inexhaustible, and this is also covered with later volcanic formation. The largest of these bonanzas is the Gold Hill mine, which lies 700 feet deep, and several companies have commenced to work this rich vein. The most important, the Virginia Consolidated, has sunk a shaft 1,600 feet deep, and driven a tunnel of 20,000 feet in length through the side of the mountain, projected by Engineer Sutro, so as to work the lead from underneath. But it is, perhaps, too late, because results have not kept pace with expectations; besides this, the heat below in the shaft is so great that work is almost impossible. This bonanza has in ten years furnished $200,000,000, $90,000,000 of which were in gold. The discoverer, Henry Comstock, after having sold his share, committed suicide. The lode, in 1877, furnished $37,911,000, of which $17,771,000 was in gold; in 1878, $10,404,000 silver, and $9,825,000 gold—a total of $20,230,000; 1879, $5,190,000 silver, and $9,725,000 gold—total, $14,915,000; 1880, $2,634,000 silver, and $8,830,000 gold—total, $11,484,000. The total yield of the twenty-eight mines of the Comstock lode has, from $271,000,000 in 1875, sunk to $14,000,000 in 1881. This decrease had a due influence upon the total production of the United States, which was in 1878, $47,266,107; 1879, $38,900,600; 1880, $36,000,030.
The traveler who visits the gold-regions of the United States will everywhere meet with decayed buildings and abandoned localities, which, in former years, were in a flourishing condition.
The gold production of Australia has followed about the same course: first, the washing of the auriferous sand; next, the working of the deep deposits, and, finally, the lodes; after that, again decrease of production. The chain of mountains passing in Australia from north to south consists of sedimentary rock, in places mixed with volcanic. Auriferous veins come up to the surface. The mountains of New South Wales contain veins and sand mixed with gold, which placers were worked for a distance of 180 miles. But the working of the leads was not remunerative, and the gold in the sand was soon exhausted. Production fell from 126,780 ounces in 1876 to 75,492 ounces in 1879.
Where the chain of the Australian mountains passes through Queensland, it attains in places to a breadth of 25 miles, and also here the volcanic rock has carried the gold up to the surface. Large mining establishments, with shafts sunk 600 feet in depth, and producing 70,852 ounces annually, are to be found here.
The German consul in Sydney, Mr. Soetbeer, has arranged the following table, exhibiting the decrease of the Australian gold production:
Thus we will find a uniform decrease in all parts of the world, and this at a time when the expansion of commerce makes the metal indispensable. If we consider in this connection that America consumes at present a great part of the gold with which it formerly inundated the European markets, we are led to believe that the national economists, Dr. Süss, Robert Giffen, P. Rogers, Patterson Williamson (Liverpool), and others, are not altogether wrong in ascribing the great periodically occurring commercial crises to the want of gold, the sole legal circulating medium. Commercial crises are like fever; after convalescence a certain equilibrium is re-established, soon to be destroyed again, however, and new elements gather, finally producing another crisis. Since America at present spends alone ten million dollars annually for gold and art productions, and, besides this, has reserved a large capital for speculating purposes, while its gold production is decreasing, it may be logically established that the gold for commercial purposes must constantly diminish, and financial crises will recur in ever-shortening intervals.—Fortschritt der Zeit.