MINES.

MINES (in Greek Miraλλα, and in Latin Fodinae Metallicae or Metalli Fodincε) are pits dug deep in the earth, whence are drawn the metals, the demi-metals, and other mineral substances, such as coal, rock-salt, alum, and the like. The excavations from which stones are obtained, however deep these may be, are denominated quarries, and not mines.

I.—ANCIENT MINES.

Scripture ascribes the discovery of brass (or copper) and iron, at least that of the methods of working them, to Tubal Cain, who lived before the Flood. But ere these metals could have been subjected to the skill of the antediluvian artificer, the metalliferous ore must have been extracted from the earth, and subjected to some metallurgic process, however rude; in other words, the invention ascribed to Tubal Cain implies the previous existence of mines and mining. This, however, has occasioned some perplexity, and produced considerable speculation as to the causes, whether accidental or other, which led to the discovery of mines. The method of discovering these is still a matter of so much difficulty, that it cannot but appear surprising, how men totally unacquainted with the nature of metals should first have come to think of digging them out of the earth in the shape of ore, and then applying heat to disengage them from the extraneous matter with which they have almost always been found combined.

According to the prevailing opinion of the ancients, this discovery was made by accident. Lucretius describes it as the result of the burning of woods or forests, which, melting the veins of metals in the earth over which the conflagration passed, revealed to men the existence of substances previously unknown, and also indicated the method by which these might be converted into a state capable of being applied to useful purposes. Aristotle, who is of the same opinion with Lucretius, informs us, that some shepherds of Spain set fire to the woods, in consequence of which the earth became heated to such a degree by the flames that the silver near the surface melted and flowed into a mass, which was afterwards discovered in a fissure occasioned by an earthquake. The same story is told by Strabo, who ascribes to this accident the discovery of the silver mines of Andalusia. Cadmus, who first introduced letters into Greece, is said to have been also the original discoverer of gold; but this has been contested by some mythologists, who attribute the honour of the discovery to various other fabulous personages; as Thoas of Thrace, Mercury the son of Jupiter, and Pisus a king of Italy, who, having left his native country, and gone into Egypt, was elected king of the latter after the death of Mizraim, and, on account of this alleged discovery, was denominated the Golden God. The discovery, not only of gold, but also of all the other metals, is by Aeschylus attributed to Prometheus, whose story, clouded as it is by fable and romance, seems to countenance such a supposition. The copper mines of Cyprus were originally discovered by Cinyra the son of Agryopa; and Hesiod ascribes to the Dactyli Idaei the discovery of the iron mines of Crete, the modern Candia. According to several ancient authors, the invention of the method of extracting tin from its ore was made by Medacritus, in the islands of the Cassiterides, and by him communicated to the natives. It is highly probable, indeed, that these and all other similar [7:15:242] discoveries or inventions were the result of accident rather than of research or investigation. Chance disclosed the hidden treasure, and a happy thought enabled some shrewd observer to turn the casual disclosure to account. Even in modern times, we know that many mines have been discovered in this manner; as, for example, in sea-cliffs rent by the violence of the waves, amongst broken and craggy rocks, by the washing of the tide or by floods, by torrents of water issuing from hills or mountains, by the wearing down of roads, and sometimes by volcanic eruptions. The ingenuity of man consists in taking advantage of those occasions when either nature or fortune puts it in his power to extend his knowledge, or to add to his wealth and comfort.

Our information respecting ancient mines is, we regret to say, extremely scanty and imperfect. The subject has not been specially treated of by any ancient writer with whose works we are acquainted; and the detached notices which occur in the classical authors have not received that anxious and critical examination which is indispensably requisite in order to arrive at just and accurate conclusions. To the general truth of this remark, however, there is one distinguished exception, in Boeckh’s Dissertation on the Silver Mines of Laurion, appended to his very learned and interesting work on the Public Economy of Athens. In a short compass, all that can be gleaned from the ancient authors has been carefully brought together, and treated with a degree of critical ability which has enabled the author to throw much new light upon a subject that had almost entirely escaped the researches of preceding inquirers.

The mines (μέταλλα) belonging to the state of Athens were partly native and partly foreign. But the most considerable were the silver mines of Laιιrion, from which the nation derived no ordinary advantages, since, by the resources which they supplied, Themistocles first raised the naval power of Athens to a state of consequence and efficiency. These mines extended from coast to coast, in a line of about seven English miles, from Anaphlystus to Thoricus∙ The working of them had been commenced at an early period, and appears to have been very profitable in the time of Themistocles; but they became less productive in the age of Socrates and Xenophon, and before that of Strabo they had been so entirely exhausted, that all further mining was discontinued. The ores extracted contained silver and lead, with zinc, and probably copper, but no gold, or at least not enough to allow the ancients, with their imperfect processes of separation, to disengage it with profit. At Thoricus spurious emeralds occurred in combination with the ore; cinnabar was also found there, and occasionally a substance which afterwards came to be much prized in dyeing. The mines were worked by means of shafts and adits, and whole masses were removed, so that supports alone were left standing. The processes of fusion carried on in the furnaces appear to have been the same as those employed in the other mines which were worked in ancient times. The state was the sole proprietor of the mines; but they were never worked at the public expense; nor did the state ever let them for a term of years, like other landed property. They were always granted to private individuals in fee-farm; and these leases were transferred from one person to another by inheritance, sale, and other kinds of legal conveyance. The sale of the mines, or rather of the right of working them, was managed by the poletae; and this right was purchased at an appointed price; in addition to which the possessor paid the twenty-fourth part of the net produce as a perpetual tax. The purchase-money was paid directly to the state, but the contingent rents were very probably let to a farmer-general. The amount of the money obtained from both sources necessarily depended upon a variety of circumstances, such as the number of mines let in the course of the year, the comparative richness or poverty of the veins worked, and the degree of activity with which the business of mining was carried on. When Themistocles proposed to the Athenians to apply the funds obtained from the mines to the building of ships, instead of dividing it as before amongst, the people, the annual receipts appear to have amounted to thirty or forty talents, although the accounts relating to this point are extremely indistinct and uncertain.

Citizens and isoteles were alone entitled to the possession of the mines. The number of the possessors was evidently considerable, and, like the agriculturists, they were considered as a separate class of producers; sometimes they possessed several shares, sometimes they had only one. The common price of a single share was rather more than a talent; and occasionally several partners occur as the joint possessors of a mine. The manual labour was performed by slaves either belonging to the possessors of the mines or hired from others; but although the cheapness of their labour diminished the expenses of mining, the improvements of art in facilitating or abridging the processes of labour were necessarily retarded., The security of this species of possession was guaranteed by severe laws, and the rights of the state were strictly maintained. 1here was a mining law (μεταλλ∕κoς νομοςf and a particular course of legal proceedings in cases relating to mines {δι∙ και μετaλλικαι'), which, for the greater encouragement of the proprietors of mines, were in the time of Demosthenes annexed to the monthly suits. The mines were also free from property taxes, and did not subject the possessor to the performance of liturgies, nor were they transferred in the exchange (αντιδοσις) of property; immunities which did not arise from any wish to encourage the working of the mines, but were founded solely upon the particular nature of the tenure by which they were held. They were considered as public property let to usufructuary possessors in consideration of a fixed rate of payment, like the duties paid by the farmers; and no property, except such as was freehold, and exempted from rent or duty of any kind, subjected the holder to liturgies and property taxes.

That Athens usurped the possession of the mines belonging to her subject allies, cannot be assumed in conformity with the general system of her foreign policy; and we must suppose that these everywhere remained the property of the persons to whom they had belonged previously to the dominion of Athens. The mines of Thrace, however, appear to have formed an exception, and to have been immediately dependent upon Athens; indeed it is probable that they were let in the same manner as the Athenian mines, although we have no certain information on this point. The Thracian gold mines had been first worked by the Phoenicians, along with the mines of Thasos; and afterwards they were carried on by the Thasians of Paros. The gold mines of Scapte Hyle upon the mainland brought to the state of Thasos an annual revenue of eighty talents; those of Thasos were less productive, though notwithstanding they yielded a large sum. When the Athenians had established themselves in Thrace, they entered into a contest with the Thasians for the possession of the mines and harbours of the mainland; Cimon captured thirty-three ships in a naval engagement, besieged and reduced Thasos, and thus obtained for his country the coast, together with the gold mines. Scapte Hyle, and other cities of the mainland, were likewise conquered by the Athenians; but Boeckh conjectures that the gold mines were partly granted to the Athenians in fee-farm, whilst those of the ancient possessors remained in undisturbed occupation. If as many of the names of proprietors of the Thracian as of the Laurion mines had been preserved, we should have been able to speak with more certainty on this point; but the utmost extent of our knowledge is, that Thucydides possessed gold [7:15:243] mines in Thrace; and with regard to him it is doubtful in what manner he acquired such a property, the account most deserving of credit being that he obtained them by marriage with a lady of Scapte Hyle, whose predecessors had perhaps been long in possession of them.^[1. Boeckh, Public Economy of Athens, vol. xxii, p. 18, 19, et seq. and 415, et seq. ]

Of all the metals, copper is that which is most frequently found pure in the ore; and for this reason probably it was also the first amongst them all that was wrought. This appears to have been the case in ancient Rome, where at first there was no coined money {pecunia signata), commodities being either exchanged by barter, or for a certain weight of uncoined brass (aes rude), used as a measure of value. To avoid singularity of expression, we use the word “brass” for what in reality was bronze, or copper rendered fusible by an admixture of zinc or of tin; a metal which was in general use, because masses of it were so easily transformed by fusion that nobody incurred loss by the process. The copper mines of Tuscany, especially in the country about Volterra, although now perhaps exhausted, appear to have been at one time immensely productive; and to this must be added the produce of the mines in Cyprus, now ascertained to have been enormous, and the influx of which into Italy is attested by the Latin name of’copper {cuprum). The dependence of that island upon the Phoenicians in very remote times opened a way for this metal to the Punic markets; and Carthaginian vessels must have brought it into Italy. The low price consequent upon such plenty agrees with every thing that is known concerning the quantity of brass money, and its value in the times anterior to the introduction of silver money, which took place about the commencement of the first Punic war. In fact, it was long a remarkable and distinguishing peculiarity of the nations inhabiting the middle of Italy, that they employed copper or bronze in heavy masses, and not silver; whereas in the southern provinces, and along the coast as far as Campania, silver money was usually employed.^[2. Niebuhr, History of Rome, vol. i. p. 398, et seq. Cambridge, 1828. ]

Anciently Spain yielded an abundant supply of the precious metals, which her quicksilver served to refine. The Asturias, Galicia, and Lusitania, yielded, according to Pliny, twenty thousand pounds of gold annually. Silver was found in still greater quantities, and of the very best quality. “Argentum reperitur omnibus fere provinciis, sed in Hispania pulcherrimum,” says Pliny;^[3. Pliny, Hist. Natural, lib. xxxiii. c. 4 and c. 6. ] and from that country both the Carthaginians and the Romans appear to have derived immense supplies. It is even said that the single mine of Belbel yielded Hannibal three hundred pounds a day; and we further learn, that after Spain had been reduced to complete subjection by the Romans, these proud conquerors drew from it upwards of an hundred and ten thousand pounds of silver in the space of nine years, or at the rate of about twelve thousand four hundred pounds annually. Strabo also informs ns, that neither gold, silver, copper, nor iron, were found in such quantities, or so excellent in quality, in any part of the known world, as in Turdetania.^[4. Strabo, Geograph, p. 194; Anstice’s Essay, p. 11. ]

These notices of the ancient mines are no doubt scanty and meagre; but the want of precise information upon this subject, which is only adverted to in the most cursory manner by the ancient writers, renders it impossible to give any more ample or satisfactory account, either of the localities of the mines, the methods employed in working them, or the processes, rude enough no doubt, by which the metal was separated from the ore. Such being the case, we shall therefore take leave of this part of the subject, and proceed to give as ample details as our limits will admit, of the mines presently worked in Great Britain and Ireland, upon the continent of Europe, in the republic of Mexico and in the different states of South America.

11 ∙—BRITISH MINES.

The mineral riches of Great Britain are immense, and, in some respects, superior to those of any other country. If it cannot boast of gold and silver mines, which are sometimes found in the poorest countries, it possesses a species of mineral wealth which is of still more importance to a manufacturing nation. It commands an inexhaustible supply of excellent coal, which is extensively diffused; its tin mines are the most productive of any in Europe; it has also very valuable mines of copper, lead, manganese, and other substances; and its salt springs, and strata of fossil salt, are alone sufficient to supply the whole world for an indefinite period. 1he most valuable minerals are situated in the western and northern parts of England, and in the southern and middle parts of Scotland. But the English mines are by far the most important, as will appear from subsequent details. In the meanwhile we shall commence our notices of the different minerals with that of coal.

1. Coal Mines.

It is scarcely possible to exaggerate the advantages which England derives from her immense beds of coal. In this climate fuel ranks amongst the principal necessaries of life; without an abundant supply of it the country would be uninhabitable; and it is to the coal mines that we are indebted for a sufficiency of this indispensable article at a cheap rate. Nor is the advantage here stated the only one which we derive from these mines. They are the principal source of our manufacturing and commercial prosperity; and their products constitute the materia prima of our superiority in all the more extensive and important departments of industry. Since the invention of the steam-engine, coal has become of the highest importance as the means of generating the moving power; and no nation, if scantily supplied with this mineral, however favourably it may be circumstanced in other respects, can ever expect to rival those which are so, in most branches of manufacturing industry. To what else are we to ascribe the astonishing increase of Manchester, Birmingham, Leeds, Sheffield, in England, not to mention Glasgow and Paisley in Scotland, and the comparatively stationary or declining state of Canterbury, Winchester, Salisbury, and other towns, except to the abundance and cheapness of coal in the north, and its scarcity, and consequent high price, in the south? The citizens of Manchester, Glasgow, and the other places similarly circumstanced, are enabled, at a comparatively small expense, to put in motion the most powerful and complicated machinery, and to produce results which are altogether beyond the reach of those who do not possess the same command of this mineral. Coal has been happily defined “hoarded labour ;” and it might, with equal justice, be denominated concentrated power. By means of it our manufacturers are supplied with a power of easy control yet of boundless energy, and are enabled to overcome difficulties insurmountable by those who happen to be less liberally supplied with this truly invaluable mineral.

It is uncertain when coal began to be first used as fuel, although, as early as the year 1281, Newcastle seems to have had some trade in this article. In the reign of Edward I. its [7:15:244] use was prohibited in London, on account of the smoke, which was supposed to be injurious; and afterwards this prohibition was renewed at different periods, but without any effect. But experience proved that the smoke was not deleterious; the growing scarcity of timber, and the superiority of coal as an article of fuel, secured its ascendency; and since the reign of Charles I. it has become almost the only description of fuel which is used in the capital, and in most other towns and districts of the kingdom. Excepting in certain parts of Ireland and the Highlands of Scotland, where peat is employed as a substitute, its use is now nearly universal.

The consumption of coal in Great Britain is immense. It has been estimated at 15,580,000 tons annually, exclusively of exports to foreign countries; but this estimate, Mr M*Culloch thinks, is greatly under the mark. According to him, the consumption of Great Britain may be estimated at the rate of about a ton of coal for each individual, exclusively of the consumption in iron-works and other great branches of manufactures. This gives 16,500,000 tons for what may be denominated general or domestic consumption; although, to be within the mark, we shall take it at only 15,000,000 tons. If to this be added the quantities of coal consumed in the making of iron, the cotton manufacture, the woollen, linen, and silk trades, the smelting of copper ores, brass and copper manufactures, salt-works and limeworks, the total annual consumption of coal in Great Britain may be moderately estimated at upwards of 22,000,000 tons. Thus,
[table]

If we suppose that the above quantity, in which no allowance is made for the coal consumed in the manufacture of hardware and cutlery, costs the consumer at an average about seven shillings a ton, then 22,700,000 tons will be worth in all nearly eight millions sterling a year.

The importance of coal as a necessary of life, and an indispensable auxiliary in manufactures, has attracted attention to the question as to the probable duration of the supply, or the period when the exhaustion of the coal mines may be anticipated. But the investigations hitherto made as to the extent and depth of the different coal formations, and the degree to which they are capable of being worked, do not afford sufficient data for even an approximate solution of this question. Vague and unsatisfactory as they are, however, these inquiries leave no room for doubt that many centuries must elapse before posterity can experience any serious inconvenience from a diminished supply of this mineral. According to Mr Taylor, the coal fields of Durham and Northumberland are adequate to furnish the present annual supply for seventeen centuries to come. The extent of these coal fields he estimates at 732 square miles. But, taking the workable coal strata at an average thickness of twelve feet, the contents of one square mile will be 12,390,000 tons, and of 732 square miles 9,069,480,000 tons; or, deducting one-third part for loss by small coal, interceptions by dikes, and other interruptions, 6,046,320,000 tons,—a quantity sufficient to supply the present demand of 3,500,000 tons for a period of 1727 years. It is evident that this estimate of the quantity of coal in Durham and Northumberland can be only a rough approximation, especially as the south-eastern coal district of Durham is yet almost unexplored, and there is also a considerable extent of coal field in the northern and south-western districts of Northumberland, which is nearly in the same situation; but it is sufficient to satisfy the public that no apprehension need be entertained as to this valuable mineral being exhausted for a great many generations to come. Dr Buckland, it· is true, considers Mr Taylor’s estimate as greatly exaggerated; but in his examination before the committee of the House of Commons, he quotes with approbation a statement in Bakewell’s Geology, that the coal fields in South Wales are alone sufficient to supply the whole present demand for coal in England for a period of two thousand years to come.^[5. The passage in question is as follows: “Fortunately we have in South Wales, adjoining the Bristol Channel, an almost exhaustless supply of coal and iron-stone, which are yet nearly unwrought. It has been stated that this coal field extends over about 1200 square miles, and that there are twenty-three beds of workable coal, the total average thickness of which is ninety-five feet; and the quantity contained in each acre is 100,000 tons, or 65,000,000 tons per square mile. If from this we deduct one half for waste, and for the minor extent of the upper beds, we shall have a clear supply of coal equal to 32,000,000 tons per square mile. Now, if we admit that 5,000,000 tons from Northumberland and Durham mines are equal to nearly one third of the total consumption of coal in England, each square mile of the Welsh coal field would yield coal for a hundred years’ consumption; and as there are from 1000 to 1200 square miles in this coal field, it would supply England with fuel for 200'» years, after all our English coal mines are worked out.” See also Treatise on the Collieries and Coal Trade, London, 1835. ] Besides, in the west riding of Yorkshire, there are many extensive coal fields hitherto untouched. In Staffordshire, the coal strata are of immense magnitude, and the bed round Dudley is no less than thirty feet thick. In the present slovenly mode of working the coal, more than two thirds is left in the mine and wasted;^[6. BakewelΓs Geology, p. 183, 4th ed. ] but were any thing like a scarcity of coal apprehended, this wasteful practice would be stopped, and means adopted for clearing out the contents of the mines. For all practical purposes, therefore, the supply of coal may be considered as quite unlimited.

The coal fields of Scotland are of great extent and value, indeed sufficient of themselves to furnish the whole empire with an adequate supply of this mineral for a long series of years. Coal is found in several districts of Scotland, as in Dumfriesshire and Roxburghshire, in the more southern counties; but the great field of Scotch coal stretches from south-west to north-east across the centre of the kingdom; and it is to be found in greater or smaller quantities in the counties of Haddington, Edinburgh, and Linlithgow, Stirling, Clackmannan, Kinross, Fife, part of Perth, Ayr, Renfrew, Lanark, Dumbarton, and part of Argyle. Its average breadth is thirty-three miles, and its length upon the mainland of Scotland ninety-eight miles; so that its total area is 3234 square miles. If from this we deduct 360 miles for the space covered by the Frith of Forth, there will remain 2874 square miles of territory, in most parts of which coal is found at different depths and of various qualities, whilst in about 600,000 acres of the same space it maybe worked with advantage. The depth of coal varies, but in general it seems to be rather nearer the surface in the western than in the eastern division of the country. There is also a great variety in the number of its seams or strata, as well as in their thickness. The greatest thickness in the island is at Quarrelton, where five contiguous strata are upwards of [7:15:245] fifty feet thick. Seams less than eighteen inches are not deemed equivalent to the expense of working them.^[7. General Report of Scotland, vol. i. p. 64. ]

Coal has been discovered in greater or less quantity in seventeen counties of Ireland; but the quality is in general bad, and, according to Mr Wakefield, “there is no vein of coal yet discovered in Ireland which can come into general consumption.” Indeed, almost all the coal used in Dublin, Belfast, and other towns, is imported from England and Scotland. The principal coal districts of Ireland are those of Leinster, Munster, Connaught, and Ulster; the former districts containing carbonaceous or stone coal, the “slaty glance” of Werner, and the latter bituminous or blazing coal. The Leinster district is situated in the counties of Kilkenny, Queen’s County, and Carlow, and extends a short distance into that of Tipperary, being the principal site of the carbonaceous coal. The Munster district occupies a very considerable part of Limerick and Kerry, and a large portion of Cork; it is by much the most extensive in Ireland. The Connaught district is next in importance to those of Leinster and Munster, and may perhaps be found to deserve the first place, when its subterranean treasures shall have been more fully explored. The coal, which is of the bituminous species, seems to be particularly adapted to the purposes of ironworks; and the gray pig-metal made at Arigna is reckoned to be as well smelted as any in the empire. The Ulster district, which is comparatively of trifling importance, commences near Dungannon, in Tyrone, and extends to Coal Island and the neighbourhood of Cookstown. Besides these districts, there are others of less consequence. Bituminous coal has been found near Belturbet in Cavan, and Ballycastle in Antrim; but the Antrim coal district is not very extensive, although the collieries have been wrought for a number of years. The coal is slaty, and resembles that which is found in Ayrshire, the accompanying rocks being likewise similar. These are all the coal districts of Ireland.^[8. See Griffith s Report on the Leinster Coal District; and Phillips’ Introduction to Geology, part i. p. 462. ]

Accidents in coal mines are very frequent, and arise principally from explosions of inflammable gas, but partly also from the presence of carbonic acid gas or choke damp, and partly from other causes. The returns of these casualties are by no means complete; yet, defective as they are, it appears from them that 2070 persons lost their lives in coal mines during the twenty-five years immediately preceding 1835. By an explosion which took place in one of the northern coal mines, more than a hundred men and boys were in a moment destroyed. In many instances not one of those employed in mines where explosions have occurred has survived to tell how the accident arose. Nor have the causes of these explosions, and the means of obviating them, been yet subjected to the continued or searching investigation of scientific men. During the eighteen years which have elapsed since the introduction of Sir Humphry Davy’s safety-lamp, more explosions have taken place in the northern mines than during the preceding eighteen years. This, however, is ascribed not so much to the instrument having disappointed the expectations of the inventor, as to the fact that, by means of it, dangerous, or “fiery mines,” have been wrought, which must otherwise have been long ago abandoned. But it has nevertheless been very clearly established that, in certain circumstances, especially when exposed to a current of air, the safetylamp is no protection at all. In working the more dangerous, or “fiery mines,’’ a vigilant and continued attention is required, which can scarcely r be expected from ordinary workmen, and especially from boys; whilst, on the other hand, the smallest neglect may produce an explosion, and occasion the instant death of hundreds. At present, it seems to be the opinion of the most experienced miners that efficient ventilation is the only thing which can be depended on. But as this indispensable security is, in many instances, too little attended to, it becomes a question whether the legislature should interfere, to the extent at least of prohibiting the working of “fiery mines,” until they have been so ventilated that, with the exercise of ordinary precaution, imminent danger may be avoided. “It is useless,” as Mr M*Culloch observes, “to trust any thing to the disinclination of the pitmen to engage in dangerous mines. By daily exposure to danger, they become habituated to, and careless about it; and, besides, they are apt to trust implicitly to the reports of viewers and others, who are quite as much interested in getting the coal brought cheaply to the pit mouth as in the security of the mine.”

For details explanatory of the construction and the working of coal mines, and also of the machinery required for both purposes, the reader is referred to the article Colliery in this work.

2. Iron Mines.

Iron, which is one of the most useful, is also one of the most abundant of the metals. Of all minerals, indeed, it is the most universally diffused, and exists in every different state, the native alone excepted, in which metallic ores are found. Its presence may be detected in every kind of soil, and in every species of rock, in a greater or smaller proportion; and it is to be met with in every region of the earth. But the black or deep-brown oxides of iron, that is, the ores of iron which contain a large proportion of metal, combined with a small proportion of oxygen, belong exclusively to primitive rocks, of which they constitute an integral part; whilst, on the other hand, the ores of iron composed of the red oxide are generally found amongst secondary rocks, or, if met with in primitive rocks, exist only in veins, without forming a constituent part of these formations, as in the case of the black or deep-brown oxides. The primitive and some of the secondary rocks are the chief repositories of iron ores; but as to iron stones, they are found only amongst the secondary rocks, and sometimes also in alluvial soil. The ores of iron are richer, purer, and more abundant in the northern than in the southern regions of the earth. As there are few countries in the world which do not contain mines of iron, so in most of them some progress has been made in extracting the ores, and converting them to the various useful purposes for which this metal is above all others adapted from its peculiar qualities. But this double process can only be carried on to any extent, or with any degree of success, in those countries where fuel exists in almost equal abundance with the ore.

Iron has been wrought in England since the time of the Romans, by whom works were established in the Forest of Dean, in Gloucestershire. In Kent and Sussex, counties well supplied, not only with iron ore, but also with timber, the only species of fuel then used in the furnaces, works were also established at a very early period. But the production of iron was long retarded, from the nature of the fuel employed in smelting. Complaints were early made of the destruction of timber by the iron-works. In the reign of Elizabeth, the decrease of timber excited a great .deal of attention; and, in 1581, an act was passed prohibiting the manufacturers of iron from using any but small wood, and establishing new works in any place within twenty-two miles of the city of London, and fourteen of [7:15:246] the river Thames, as also in several parts of the county of Sussex. Soon afterwards, Edward Lord Dudley invented a process for smelting iron ore with pit-coal instead of timber, and obtained a patent for his invention, which was exempted from the operation of the act 21 James I. c. 23, setting aside monopolies; but the works of the inventor were destroyed by an ignorant rabble, and he was nearly ruined by his efforts to introduce and perfect a process which has eventually proved of immense benefit to the country. For many years, indeed, the invention seems to have been forgotten; and it was not till about 1750 that the growing scarcity of timber, coupled with the increasing demand for iron, succeeded in drawing the attention of some ingenious persons to Lord Dudley’s process. Necessity is always the mother of art. This process was now revived; and, about the time mentioned, iron was made at Colebrookdale, and in some other places, by means of pitcoal, and proved to be of as good a quality as that made with timber. From this period the business steadily increased, though at first its progress was comparatively slow; and the great demand for iron occasioned by the late war gave an extraordinary stimulus to the manufacture, which has now become one of vast importance and great value. In 1740, the quantity of pig-iron produced in England amounted to about 17,000 tons, produced by fifty-nine furnaces. In 1750, it had increased to 22,000 tons; in 1788 to 68,000 tons, produced by eighty-five furnaces; in 1796 to 125,000 tons, produced by 121 furnaces; in 1806 to 250,000 tons, produced by 169 furnaces; and in 1820 to about 400,000 tons. From inquiries made by government and others during several years preceding 1832, it appears that the total quantities of iron produced in Great Britain in the years 1823, 1825, 1828, and 1830, were, in 1823, 469,561 tons, by 277 furnaces; in 1825, 618,236 tons, by 259 furnaces; in 1828, 703,184 tons, by 278 furnaces; and in 1830, 678,417 tons, by 376 furnaces.

Supposing that the total quantity of pig-iron produced in Great Britain amounts to 700,000 tons a year, and that at an average it is worth L.6 per ton, its total value will be L.4,200,000; and if to this be added L.l,200,000 for the labour expended in converting pig-iron into bar-iron, the manufacture will be worth about five millions and a half annually. The increased production of iron has led to its exportation in large quantities, and at the same time reduced the imports of foreign iron from about 34,000 tons to not more than 16,000 tons, consisting principally of Swedish iron for the purpose of being manufactured into steel. The total number of persons for whom the iron manufacture provides subsistence has been estimated at from 207,000 to 240,000.

The iron-works of South Wales ana Monmouthshire are comprised in a range of country extending in the direction of north-west and south-east about twenty-five miles from the one extremity to the other. The works at Hirwain in Brecknock, and Aberdair in Glamorgan, form the extreme points to the westward. But the great seat of the manufacture is Merthyr Tydvil, from which there is a continued line of furnaces, at Ðowlais, Ro∙mney, Tredegar, Howey, Beaufort, Nantyglo, Blaenafon, Varteg, Abersychan, and Pontypool, forming the principal range in that direction. About the middle of last century, Merthyr Tydvil was an insignificant village. In 1755, the lands and mines for several miles round the village, were let for ninety-nine years at a rent of L.200 a year. In 1831, the population of Merthyr Tydvil exceeded 22,000; Tredegar, which, at the beginning of the present century, was an uninhabited district, has now a population of about 7000 souls; and in several other places the increase has been equally rapid. The Staffordshire iron-works, including those of Warwickshire, are principally situated in the district which extends from Wolverhampton round by Walsall to Birmingham, and thence round by Dudley. The principal seat of the works in Shropshire is Colebrookdale, where the improvement of the manufacture commenced, as above stated.

In Scotland, almost all the iron-works, with the exception of those at Carron contiguous to the Forth, and at Muirkirk in Ayrshire, are situated upon the Clyde, at no great distance from Glasgow. In June 1835, there were in blast twenty-nine furnaces, the annual produce of which was estimated at 75,000 tons; but there were then in preparation six additional furnaces, calculated to produce 13,000 tons a year. The proprietors of the Clyde ironworks have recently begun to employ the hot-blast, or air heated to a high temperature, instead of the cold blast, or a stream of common atmospheric air, in working their furnaces; and this discovery (for some account of which see the article Glasgow) promises to be of material importance, by economising fuel, and also improving the quality of the iron produced. It has been adopted at several works in England, as well as in France. Iron was formerly produced in considerable quantities in various parts of Ireland; but, owing to the scarcity of timber, the works were subsequently in a great measure abandoned. Attempts, however, have recently been made to revive them at Arigna and other places, though not as yet with any very decided success.

3. Tin Mines.

Tin is exclusively produced in Cornwall and in Devonshire, but chiefly in the former. The tin mines of Cornwall appear to have been worked from the remotest antiquity; in fact, those early navigators, the Phoenicians, are supposed to have traded thither for tin; and from this it has been inferred that the discovery of tin in Cornwall must have been made at least 2400 years ago. But it is supposed that the only ore then worked was stream tin, which is most accessible, and at that period probably existed in great abundance; nor is it probable that mining, or digging the ore from the veins, was known or practised until about the tenth century of the Christian era. In more modern times the business of mining has been prosecuted with various skill and success. During the reign of Elizabeth, the processes were improved by some German miners, who were brought over to assist in working the mines. The ores of tin are not numerous. It is chiefly found in the state of oxide, or in combination with other metallic ores, particularly that of copper. They are generally distributed in veins, which are at no great distance from the surface. The tin ore occupies the whole space of the vein, and is closely attached to the granite rock, which itself often contains the ore disseminated throughout its whole substance. Tin also exists in accumulated masses or stockzverks. The general direction of the veins is from east to west, or nearly so; and, if not interrupted or deranged by vertical strata, they preserve the same course in traversing a considerable tract of country. In some places tin and copper veins are united, and run parallel to each other; the tin ore forming one side, and the copper ore the other, of the double vein. The annual produce of the tin mines fluctuated a good deal during the last century. On an average of ten years ending with 1834, it may be taken at about 4500 tons, worth from L.65 to L.80 a ton. In 1834, the exports did not exceed 468 tons, the foreign market being principally supplied with tin from the island of Banca.

All tin produced in Cornwall is subject to a duty of L.4 per ton, payable to the Duke of Cornwall; and that raised in Devonshire is subject to a similar duty of L.l. 13s. 4d. per ton. This duty, which produces from L.15,000 to L.20,000 a year, is felt to be a serious grievance, not only [7:15:247] from its amount, but from the vexatious manner in which it is collected. The miner, whatever his orders may be, is not allowed at once to cast the metal into the form required by his customer, but is obliged, in the first instance, to melt it in the shape of blocks. He is then obliged to convey it some eight or ten miles to one of the coinage towns, where a small piece is struck off one of the corners, impressed with the arms of the duchy, and the duty paid; after which it has to be carried back before it can be shipped, to the place whence it was taken to be coined. The ceremony of coinage is only performed quarterly; and hence, if the demand for tin be ever so pressing in the interval between the stated coinages, the miner cannot supply it. There are likewise certain fees payable on coinage, particularly if it take place during the Christmas and Ladyday quarters; so that if to the duty of L.4 per ton be added these charges, and a reasonable allowance for expense of carriage, trouble, and inconvenience, the whole may be estimated at L.5 per ton. A tax at once so oppressive and vexatious cannot but prove detrimental to the working of the mines.

4. Copper Mines.

This metal is of much more importance than tin, on account of its tenacity, ductility, and malleability, as well as the numerous alloys and combinations which it forms with other metals, and which render it susceptible of being applied to many of the most useful purposes of life. It exists in almost all the different states of metallic ores, being found in those of native copper, alloy, sulphuret, oxide, and also in that of a salt. It is most abundant in Cornwall, where it is produced upon a very large scale, owing to the richness of the mines. These are in veins which traverse the country, frequently accompanying those of tin, and running in the same direction, which is generally from east to west. They are nearly in a vertical position, some of them being from four to five feet in thickness; and at a depth varying from 400 to 600 feet, they continue to be equally productive. The copper ores of Cornwall are chiefly yellow ore or iron pyrites, and vitreous copper ore; and they are commonly accompanied with other metallic ores, as those of lead, zinc, and cobalt, and also with fluor spar, lime spar, barytes, and quartz. Native copper is not an unusual production; it is generally found in that part of the vein which is nearest the surface, and which is the least rich in other ores. Sometimes, however, it is met with at a considerable depth, as in Cook’s Kitchen Mine, which yielded several tons of copper fit for immediate fusion.^[9. Pryce, Μineralog. Cornub., Introd. p. 8. ] Malachite, and many of the varieties of arseniate of copper, are likewise found in these mines.

As the ores of copper and tin frequently occur intermixed, it may be supposed that the former were wrought, to some extent, at as early a period as the latter. But this does not appear to have been the case; and it is only since the beginning of the eighteenth century that the superior importance of the copper mines began to be understood, and that they were worked with spirit and success. From 1736 to 1745, they furnished annually about 700 tons of metal; and from 1756 to 1765 they yielded 1800 tons. In 1775 the produce increased to 2650 tons a year; in 1798 it exceeded 5000 tons; and at present (1837) it amounts to about 12,000 tons. Besides Cornwall, other parts of the kingdom supply considerable quantities of copper. The famous mines in Parys Mountain, in the island of Anglesey, were discovered in 1768. From the peculiar site and disposition of the mineral, it was not necessary to work it, like the Cornish mines, by shafts and levels, but to dig at once into the sides of the mountain, which was composed chiefly of copper ore, and to extract it as if from an open quarry. The ore was obtained by blasting, and for a time the supplies of it were abundant beyond all precedent, forming a vast source of wealth to the adventurers and proprietors. But for many years past the productiveness of these mines has been declining, and they now yield comparatively little. The Parys Mountain is supposed to have furnished in all 85,000 tons of pure metal, which, at L.90 a ton, must have produced the enormous sum of L.7,650,000. At present the entire produce of the mines of Anglesey and Wales does not exceed 900 tons a year. Previously to 1770 the mine of Ecton, in Staffordshire, was one of the most productive in the kingdom. It is supposed to have been worked at a very early period, and at one time a thousand persons were employed in the works. The operations were latterly carried on at a depth considerably exceeding 200 fathoms.

From a statement published in the Transactions of the Cornwall Geological Society, and which appears to be authentic, we learn that the produce, in pure metal, of the copper mines of Great Britain and Ireland, during the five years ending with the 30th June 1827, that is, in 1823, 1824, 1825, 1826, and 1827, was, respectively, 9715, 9836, 10,350, 11,069, and 12,381 tons. Owing to the want of coal the Cornish copper ores are not smelted on the spot, but are shipped at the port nearest the mine for Swansea, where the principal smelting companies have their establishments. The copper produced in Ireland is also conveyed to Swansea to be smelted. Hence, if we take an account of the copper sold in Cornwall, at Swansea, Devon, and Anglesey, we shall obtain a pretty accurate estimate of the total produce of the different mines of the empire. But such an account has been furnished in papers published by the Board of Trade, containing the total sales of each year from 1820 to 1834 both included. From this it appears that the total produce of copper may at present be estimated at about 14,000 tons a year, worth from L.90 to L.100 a ton, or from L.1,260,000 to L.1,400,000. The exports amount to between 8000 and 9000 tons, partly wrought and partly manufactured, more than half of which is shipped for the East Indies and China, and the remainder for France and the United States. Copper is exempted from the tax laid on tin, and consequently from the oppressive regulations to which we have already alluded as growing out of it.

The number of the tin and copper mines of Cornwall is not exactly known, because old workings are frequently given up, and new ones opened, whilst, in many instances, those which were formerly abandoned are again brought into activity. The number of mines at present wrought, however, may be estimated at 140, the greater proportion of which consists of copper mines. The veins or lodes vary in thickness from three inches to thirty feet. The excavations are sometimes wrought to a very great depth. In the consolidated mines there is a shaft, in the parish of Gwennap, between Truro and Redruth, which is 265 fathoms deep. Two large steam-engines are not unfrequently employed upon one mine; and there are instances where the sinking of the shaft, and a single engine with its apparatus, have cost upwards of L.10,000. The power of steam-engines at present employed in the Cornish mines is probably equivalent to that of from 45,000 to 50,000 horses. The mines in Cornwall are generally undertaken by companies of adventurers. If the mine be upon a waste it is the property of the king, as Duke of Cornwall, to whose agents the adventurers apply for a lease; if it be private property its owners are of course applied to, and it is usually let for twenty-one years, or for such portion of that [7:15:248] time as the workings shall be proceeded in. The rent varies, according to circumstances, from one eighth to one thirteenth of the ores raised. The miners are sometimes paid by the piece, and sometimes by a certain per centage upon the ores raised by them. They relieve each other by turns, each set generally continuing in the mine for eight hours; but when working at the bottom of deep shafts they relieve each other every six hours.

Tin and copper mining, like that of the precious metals, is exceedingly precarious. There is no certainty beyond the actual moment. Veins which promise much when first opened sometimes fall off below and occasion immense loss to the adventurers, or continue to be wrought in hopes of improvement, but with little or no profit; whilst, on the other hand, mines and veins which, at the outset, promised little or nothing, come in time to yield very large profits. Hence, if great losses often occur, enormous fortunes are sometimes realised. Crennis copper mine returned a clear profit to the adventurers of L.84,000 in one year; and Huel yielded nearly L.130,000, after defraying every necessary outlay. The expense of working some of the large mines is very great. In that of Huel Vor, 3000 lbs. of candles and 3500 lbs. of gunpowder are consumed in a month. The total amount of capital employed in connection with the tin and copper mines of Cornwall has been estimated at L.2,440,000; and the total number of persons to whom they afford occupation directly or indirectly is supposed to be 76,000. The miners and others engaged in the tin mines of Cornwall and Devonshire are under the especial protection of the Stannary Courts, which were established about five hundred years ago, and have not undergone any material alteration since the reign of Charles II. These courts are held by the lord warden of the stannaries; and no miner or other person really engaged in the mines can be sued in any other court except upon pleas of land, life, or member. From the Stannary Courts no writ of error lies to any court in Westminster Hall; but an appeal may be taken to the privy council of the Duke of Cornwall.^[10. Phillips’ Mineralogy, p. 194, et seq. Guide to Mountsbay, p. 190, second ed. Blackstone’s Commentaries, book iii. c. 6. ]

5. Lead Mines.

With the exception of iron, lead is perhaps the most abundant of the metallic substances found in Europe. The most common ore of this metal is the sulphuret or galena, which occurs massive, or crystallized in various forms, and is met with not only in primitive, but also in secondary mountains, being generally deposited in veins or extensive beds. The rocks in which it is most commonly distributed are gneiss, mica, schistus, limestone, and greywacke; and the mineral substances which constitute the matrix or gangue are quartz, bärytes, lime spar, and fluor spar. The ores of lead are likewise accompanied by a great number of other metallic substances, particularly by some of the ores of zinc, as blende and calamine, iron and copper pyrites, sparry iron ore, and red vitreous silver ore.

1he lead mines of Great Britain are numerous and important. That the mines of Derbyshire were wrought in the time of the Romans, is evident from the blocks of lead which have been found with Roman inscriptions on them.^[11. A block of lead of this kind was discovered on Cromford Moor in the year 1777, with the following inscription :—“The sixth legion inscribes this in memory of the Emperor Hadrian.” Another block was fourni at Matlock Bank in 1783. inscribed thus :—“The property of Lucius Aruconius Verecundus, merchant of London.” The weight of this block was 841bs. A third block, weighing 1⅜ cwt., was subsequently discovered at Matlock, and upon it was found this inscription :—Tι. Cl. Tr. Lut. Br. Exarg., probably meaning Tiberii Claudiani Triumviri Lutudarï Britannorum Exargentaria. The Saxons and Danes, it is also supposed, were engaged in working the lead mines of Derbyshire. ] But, excepting in these, it does not appear that lead was obtained any where in England until theyear1289, when it was discovered in Wales; and the fact having transpired that silver was found intermixed with the Welsh ores, this gave a fresh stimulus to’the business. ^ In other respects, however, the discovery of silver was of no avail, as the quantity obtained proved altogether insufficient to defray the expense of separating it from the lead. At present the most productive lead mines are situated in Allendale and other parts of Northumberland; in Aldstone Moor and its vicinity in Cumberland; in the western parts of Durham; in the hundred of High Peak in Derbyshire; in some parts of Flintshire; at Leadhills and Wanlockhead, and on the confines of Dumfriesshire and Lanarkshire, in Scotland.

It is not easy, for want of returns, to arrive at a correct estimate of the annual produce of these mines; but in the aggregate it must be very considerable, amounting probably to between 45,000 and 50,000 tons. The foreign lead imported is almost all re-exported; and hence the supply obtained from our own mines must not only be sufficient to satisfy the home consumption, which is very great, but, as our exports exceed our imports by from 10,000 to 14,000 tons, to furnish this quantity in addition. Lead has declined in price since the year 1820, owing to the increased supplies obtained from Spain, and the comparatively cheap rate at which these are furnished. This metal is raised in different parts of Ireland, as in the county of Wicklow, at Carne in Wexford, and in Armagh and Donegal; but some of the lead mines which were formerly wrought in Kerry and Mayo have been abandoned.

The mineral called black lead or plumbago is found at Borrowdale in Cumberland, where mines of it have been wrought since the days of Queen Elizabeth, and furnish the best material hitherto discovered for making pencils. Formerly the proprietors of these mines enjoyed a complete monopoly of the market; and by occasionally shutting them up, and thus diminishing the supply of the mineral, they kept its price at a high level, and realised large profits. But, latterly, plumbago has been imported in considerable quantities from Mexicoand Ceylon; and, although inferior in quality, yet, being cheaper than the English, it has superseded the latter for most purposes, except the best kind of pencils. The lead is not found in veins, butin detached pieces; it is often lost, and the miners are frequently engaged for a long time in seeking at random for a new supply. The quality of the mineral differs materially, the lightest being the best. It is cut into the proper form for pencils by the manufacturers of Keswick and London.

6. Salt Mines.

No country is better supplied than England with beds of fossil or rock salt, and also with brine springs. The latter, which occur at Northwich, Winsford, Middlewich, and other places adjacent to the Weaver in Cheshire, and at Droitwich in Worcestershire, have been known and wrought from a remote era. But it was not until a comparatively recent period that the beds of fossil salt were discovered, the first of them having been met with in 1670, about thirty-four yards below the surface, in searching for coal in the vicinity of Northwich. In 1779 a second bed of fossil salt was discovered near Lawton, about forty-two yards below the surface; and others have since been found in different parts of the surrounding country. These beds, or strata, are generally of very great thickness; and, upon cutting through the indurated marl at the bot∙
[7:15:249]

tom of the first stratum, another of still greater thickness has sometimes been discovered below it. In one instance a third bed has been pierced, of twenty-five yards, without reaching the lower surface of the stratum. There are also beds of fossil salt at Droitwich; but as these have not been wrought, comparatively little is known respecting them.

Rock salt, when dug from the mine, is seldom of such purity as to admit of its being used without undergoing some process of refining. The largest portion of the salt produced in Cheshire, and nearly the whole of that produced in Worcestershire, are obtained from the brine springs. In Cheshire, the brine being pumped up from deep wells, is collected in reservoirs, and, being saturated by means of crushed rock salt, is thence conveyed into large, broad, shallow pans, placed over furnaces, where the water which holds the salt in solution is evaporated, and the salt rendered fit for use. Different qualities of salt are produced, according to the mode in which the heat is applied, and the process of evaporation conducted. Animal jelly, butter, and other foreign substances, are sometimes employed to assist in clearing the brine, and in granulating the salt. Salt has been obtained from the brine pits at Droitwich for at least a thousand years. When these are dug to a sufficient depth, the brine ascends to the .surface. But the quantity of white salt made here is very inferior to that produced in Cheshire, and this place does not furnish any supplies of fossil salt. Part of the rock salt of Cheshire is refined at Newcastle and other places.

The consumption of salt in this country is immense. In those provinces of France which had purchased an exemption from the gabelle, Necker estimated the consumption at 19; lbs. for each individual; but, from the difference of our food and habits, the consumption of the people of this country may be estimated a little higher, or at 22 lbs. each person. On this supposition, and taking the population at 16,500,000, the entire consumption of Great Britain, exclusively of Ireland, will amount to 363,000,000 lbs., or 161,000 tons. But, besides this, between 11,000,000 and 12,000,000 bushels, equivalent to about 300,000 tons, are exported to the United States and the British North American colonies, to Holland and Belgium, Russia, Denmark, and other countries. In ancient Rome salt was subject to a duty (vectigal salinarum) ; and it has generally been heavily taxed in modern times. The gabelle, or code of salt laws, formerly established in France, was most oppressive, and its severity had no inconsiderable share in bringing about the Revolution. In this country the duties upon salt, which were first imposed in the reign of William 1II., amounted, in 1798, to 5s. a bushel, and were subsequently increased to 15s. a bushel, or about forty times the cost of the article taxed. So exorbitant a duty was productive of the worst effects, occasioning a great deal of smuggling; and, the opihion of the public having been strongly expressed against it, the tax was finally repealed in 1823.

7. Mines of Manganese and Zinc.

Manganese, a mineral substance of considerable consequence in the arts, exists chiefly in the state of oxide, and sometimes in that of carbonate. The ores appear under a great variety of forms, and it has hitherto been found extremely difficult to reduce them to the metallic state; but it is easy to detect a large quantity by means of the blowpipe, the action of which, with the addition of borax, and a little nitre, produces a violet-coloured glass. This mineral is found at Upton-Pyne in Devonshire, and in the Mendip Hills, Somersetshire, from which it is obtained in quantities sufficient to meet the demand. In Scotland, the ores of manganese have not been discovered in such abundance as to become an object of pursuit.

Zinc has never been met with in the metallic state. It exists in the form of sulphuret, in that of oxide, and also in the state of carbonate. The ores of zinc are very common in several of the lead mines of Great Britain, where the metal is found sometimes in the form of blende, or sulphu∙ ret, and sometimes in that of calamine, or oxide. It is obtained from the mines of Derbyshire, particularly at Castleton, Cromford, Bonsal, and Wirksworth; but Flintshire and the Isle of Man furnish ores of the best quality. At Leadhills, in Scotland, blende, and some of the varieties of calamine, ate frequently met with. The blende is occasionally found in great abundance; sometimes it occurs in detached masses, and sometimes it occupies the whole vein, to the exclusion of the lead ore.

8. Stone and Slate Quarries.

The stone quarries of England are not of any great value or importance. The principal are situated in the Isle of Portland, and in the neighbourhood of Bath. The annual produce of the Portland quarries may be estimated at about 18,000 tons. From them have been obtained the stones employed in the construction of St Paul’s, and in that of most other public buildings in London. The quarries of Gateshead Fell, near Newcastle, furnish the grindstones universally known by the name of Newcastle grindstones. Scotland is distinguished for the number and excellence of its quarries. But those of Craigleith, Cullalo, Fifeshire, and some others, are amongst the most celebrated. The general beauty of the houses in the New Town of Edinburgh attests the excellency of the stone of which they are built, and which has been principally furnished by the Craigleith quarry. Large quantities of granite are shipped from Aberdeen for London, where it is employed in various public works, and likewise in paving the streets. The Liverpool docks have been partly constructed of granite brought from Kirkcudbrightshire.

The principal slate quarries in Great Britain are situated in Caernarvonshire. Those belonging to Mr Pennant are the most extensive and valuable, furnishing employment for about 1500 men and boys. The other slate quarries in Caernarvonshire and North Wales employ generally about 1800 men and boys. There are also extensive quarries in different parts of South Wales, at Ulverstone in Lancashire, and in other places. The principal slate quarries of Scotland are in the island of Easdale, and at Ballachulish in Argyleshire; but, speaking generally, they do not furnish slates of the same size and smoothness as those obtained from the Welsh quarries.^[12. See M ς Culloch s Statistical Account of the British Empire, vol. ii. chap. 2. To this great repository of valuable information we have to acknowledge pre-eminent obligations on the subject of British mines and minerals, which are treated of at length in the chapter above referred to. ] The slate quarries near Dunkeld are worked under great disadvantage, owing to their distance from any port of shipment; and hence the supply is almost wholly limited to the demand of the country immediately adjacent.

III.—CONTINENTAL MINES.

Most of the mineral and metallic substances which abound in Great Britain and Ireland have also been discovered, and to a certain extent excavated, in one or other of the countries of the continent of Europe; and the latter likewise afford a variety of mineral products which, as compared with those of Great Britain, are peculiar to themselves[7:15:250]. In addition to coal, iron, tin, copper, lead, zinc, manganese, &c. they furnish, in greater or less quantities, gold, silver, mercury, and various other metals or mineral substances, some of which are equally valuable and useful. We shall therefore endeavour to give a short account, first, of those minerals and metals which they possess in common with this country; and, secondly, of those which are comparatively peculiar to themselves, or, in other words, what are not found at all, or only to a very trifling extent, in Great Britain and Ireland.

1. Coal Mines.

Before the war of the Revolution, England supplied the maritime parts of France with coal. But the declaration of hostilities having put an end to this trade, and thus deprived these parts of their ordinary supply, the rulers of France directed their attention to the improvement of her internal resources; and, amongst other objects of research, the discovery of coal was too important to be neglected. Wherever any favourable indications presented themselves, the attempt was accordingly made, and it appears in many cases to have been prosecuted with considerable success. Indeed an inspection of the map of France, on which the coal districts are delineated, would lead us to suppose that one half of that country contains coal; but there are many circumstances which tend to show that the extent of the coal strata is much more limited, and that the representations which have been made on the subject, in certain official documents, are greatly exaggerated. In a report addressed to the consular government, it is stated that coal is wrought in forty-seven departments, and that sixteen others afford indications of the same mineral. But of the forty-seven departments in which coal mines are stated to be wrought, reports of the products of thirty-four only were obtained; and, from the estimated annual amount of coal produced in these departments, it appears evident that the total annual produce of the coal mines of France, at the period referred to in the report, could not have exceeded 5,000,000 tons. That a considerably larger supply has since been obtained, cannot admit of any reasonable doubt; but, whether from the comparative barrenness of the mines, the difficulty of working them, or inferiority of skill and less perfect machinery, to say nothing of the relative quality of the coal produced, it appears that, even at the present day, English coal might be exported to France and sold at a price considerably lower than French. The coal which has been found in the southern parts of France is very generally of an inferior quality, the best mines being those which are situated in the department of Aveyron, on the banks of the Lot and the Dordogne. In the central parts it is met with in greater abundance, though not always of a good quality; and the coal on the eastern frontier seems to be of no great importance. In the western parts, the mines of Montrelais have long furnished a considerable supply to the country situated upon the banks of the Loire. But the richest coal mines in the kingdom occur in that part of France which lies between Calais and the Rhine; indeed the produce of the coal mines of the North amounts to nearly three fourths of that of the whole kingdom. The most important coal fields in this part of the country are those of Boulogne, Jemappes, and Anzin.

No coal has yet been discovered in any part of Spain or Italy, nor have any indications of the existence of that mineral presented themselves in either of these countries. But in several parts of Germany, and in Bohemia, there are valuable mines, some of which yield coal in considerable abundance. The northern countries of Europe are, for the most part, entirely destitute of this species of fossil fuel. Coal is indeed found in several parts of the Russian empire, but it is of so bad a quality as to be almost unfit for use. Some appearances of this mineral were observed by Olivier on the shores of the Black Sea; pit-coal has also been met with in the vicinity of the Donetz; and to the north of 1aganrog there is an immense stratum, twenty-four feet in thickness, consisting of slate coal of very inferior quality.

2. Iron Mines.

The iron manufacture of France has been very greatly extended since the commencement of the Revolution, and is protected by high duties, which secure to the native manufacturer the almost exclusive possession of the French market. The iron ores are chiefly met with in the vicinity of the Pyrenees, being deposited in veins, some of which are from six to eight feet in thickness; and iron stones are also abundant in France, particularly in those departments where coal strata prevail. Latterly, great exertions have been made by the French government to encourage and extend the native manufacture of iron;^[13. This is evinced in the able Report made to the director-general of mines in France, by M. Dufrenoy, on the use of hot air in the iron-works of England and Scotland (Paris, 1834, and London, 1836). It is not a little singular, that we sould be indebted to a foreigner for the first detailed account of the progess of an invention which had its birth in Scotland, and which has in that country been attended with signal success. ] but the metal produced is still vastly inferior in quality to the English and Scotch, and is at the same time considerably higher in price. The principal iron mines of Spain are situated in the provinces of Biscay and Catalonia; and the ores from which the metal is extracted consist of the sparry kind, together with red and brown haematites. Many parts of Germany have long been celebrated for the abundance and excellence of the iron extracted from the native ores, particularly in Styria, Carinthia, and Franconia.

The island of Elba possesses one of the richest iron mines in the world, the existence of which appears to have been known from the earliest times. The ore is chiefly of the specular kind, and the mass constitutes an entire mountain, which is surrounded by others consisting of granite, of wfiich the island is almost wholly composed. This mountain, which is called Rio, is about 500 feet in height, and three miles in circumference; and its surface is covered with a reddish ochry earth, which in some places is several feet in thickness, and full of small shining scales of iron ore. Beneath this covering, the mass of the mountain consists of metallic ore, or rather, it is composed of accumulated masses, thrown together without any order or stratification. These masses are deposited in an ochry substance, which may be considered as their matrix; and, besides the specular ore, which predominates, other species and varieties are occasionally met with. The iron mines of Elba were wrought in the time of the Romans, by means of excavations carried into the mountain; but now the ore is extracted by the ordinary process of quarrying. It has been conjectured by some that the mass of iron ore in the island of Elba is part of a great vein of immense extent running into the adjacent continent.

The iron mines of Sweden have long been celebrated on account of the rich ores which they afford, and the superior quality of the iron which is thence obtained. The most remarkable are those of Danemora, distant four Swedish miles from Upsal, and which were first discovered in 1470. The mines are in primitive rocks, and the ore is said by some to be found in enormous masses, though, according to others, it is deposited in the form of a great vein. It is wrought to the day, and the greatest depth is less than [7:15:251] a hundred fathoms. From 1200 to 1500 persons are constantly employed in the different operations connected with these mines. The mountain of Taberg in Smaland is almost entirely composed of iron ore; it consists of a great number of veins running in a vertical position, parallel to each other; and the ore is a mixture of the specular kind with clay and small grains of felspar, thus exhibiting the appearance of porphyritic rock. The mines of Arendal in Norway furnish abundance of iron ore mixed with garnets and other minerals which are found only in primitive rocks. The Ural Mountains, so rich in other metallic ores, contain also mines of iron, from which is derived the greater part of that metal employed in Russia. In one part of Siberia, iron is extracted from an ore consisting of ferruginous fossil wood imbedded in clay and sand.

3. Tin Mines.

That portion of the west of France which is, as it were, projected between Cornwall in England and Galicia in Spain, has been supposed to afford indications of tin, probably from some similarity in geological structure; but, in point of fact, none has yet been discovered. Ores of this metal have, however, been found in Galicia, and on the frontiers of Portugal, where, in the year 1787, a mine was opened, and veins, some of them six feet in thickness, began to be wrought. These veins were included in granite. Tin mines were formerly wrought in the north of Portugal, and traces of the ore are still visible. At Marienberg in Germany a mine is wrought, in a vein about six feet thick, which runs from east to west, like those of Cornwall, with an inclination of about 70°. The mountain in which the tin mines of Ehrenfriedersdorf are situated, contains, within a space of about a hundred fathoms, a great number of parallel veins, running in the same direction, and some of them almost in contact with one another; so that, in the thickness of about three fathoms, there are sometimes found four or five veins, the hanging side of one vein forming the ledger side of the other. These veins traverse a rock of argillaceous schistus, but none of them has been wrought to any great depth. There are also tin mines at Altenberg, Geyer, and Zinnwald, which, with that just mentioned, produce annually about 4000 cwt. of metal. The tin mines of Platte in Bohemia are, as usual, in granite, and the veins traverse the rock in a direction approaching to that of east and west. In the Kaff Mountain there is a tin mine in which iron ore is found at the top of the vein, and tin at a greater depth; and it has been conjectured that, were the mining operations carried to a still lower depth, silver ores would be found. But the most remarkable tin mine of Bohemia is that of Schlackenwald, where the ore is deposited in the form of accumulated masses or Stockwerks. One of these masses, shaped like an inverted cone, is of very considerable magnitude, being from ninety to a hundred fathoms in thickness. It is surrounded by gneiss, and the mass itself is composed of granite, in which are disseminated grains of tin ore. This mine has been wrought for more than five centuries, and has been carried to a depth of about a hundred fathoms; but the ore is so disseminated in the rock, that it requires ten thousand quintals to yield from thirty-five to forty quintals of tin.^[14. The tin of the East Indies, particularly that of. the island of Banca, is considered as purer than the tin of Europe. Great quantities of the former are now imported. The mines of Banca have already yielded more than 4,000,000 lbs. of metal and the veins are still far from being exhausted. ]

4. Copper Mines.

The copper mines of France do not appear to be of any great importance. Those of Bigorre, in the western Pyrenees, are now nearly exhausted, and the mines of Languedoc are not productive; the most valuable are those of Chessy and St Bel near Lyons, the annual produce of which is between 3000 and 4000 quintals of copper. The ore found at the latter place consists chiefly of copper pyrites, which yields only about three per cent. The copper mines of Spain are situated on the frontiers of Portugal, but appear to be of as little consequence as those of France. The ore is copper pyrites, affording from four to six per cent, of metal. There is a tradition that one of these mines was wrought in the time of the Carthaginians. Germany contains some valuable copper mines, amongst which may be mentioned those of Hesse, where the ore is deposited in a bituminous stratum of marl schistus, from four to eight inches in thickness, but of great extent. The ore contained in this stratum or bed consists chiefly of copper pyrites; but vitreous copper ore, and red oxide of copper, are sometimes met with. Of the Hessian mines, the most considerable is that of Riegelsdorf, which yields annually about 2500 quintals of copper. There are similar mines at Frankenberg near Cassel, at Bieber in Hanau, at Eisleben in the county of Mansfeld, and also in the district of Magdeburg. In Hungary there are some valuable copper mines, particularly those of Herengrund near Neu-sohl, where the mineral is found in the form of gray copper ore, deposited in beds of considerable thickness, amongst a breccia of micaceous schistus.

But one of the most extensive and most productive copper mines in the world is that of Fahlun, in the province of Dalecarlia, in Sweden. The mining district occupies a space of nine leagues in length by two and a half in breadth, and is surrounded by a reddish granite, which becomes of a finer grain as it approaches the centre of this space, and is then succeeded by a micaceous rock dividing into rhomboidal fragments. The principal mass, which is of enormous dimensions, consists of iron and copper pyrites lying in a vertical position from north-west to south-east along the valley in which it is deposited. Here there is an immense opening or gulf 840 feet in length, 720 in breadth, and 240 in depth, which was produced in the year 1687, by the falling in of the superincumbent mass, in consequence of the unskilful manner in which the subterranean operations had been conducted. In this celebrated mine the mass of ore is described as lying in the form of an inverted cone, and the excavation has been carried to a depth of more than 200 fathoms; but it is supposed that this is nearly the utmost extent to which the mass of ore penetrates the earth, as latterly the operations have been conducted upon a more limited scale than in former times. It was in this mine that Gustavus Vasa, when driven from his throne, worked for a time, to procure the means of subsistence. In the mine of Garpenberg, which is about eighteen leagues from that of Fahlun, there are fourteen veins in a vertical position, and all parallel to one another, being situated in a quartzose micaceous schistus, which is also disposed parallel to the veins.

In Siberia there are two principal mines of copper, which are both situated in the extensive chain of the Ural Mountains. One of these, that of Goumechefski, about fourteen leagues to the south-west of Katherineberg, is in the central part of the chain, in a kind of plain, upon the border of a lake, surrounded by primitive mountains. The vein is nearly in a vertical position, being disposed between a bed of primitive white marble and an argillaceous schistus in astate of incipient decomposition. The matrix of the ores is a clay of different colours, and they consist [7:15:252] chiefly of native copper in grains and small masses, with some vitreous copper ore; whilst the fissures and cavities are encrusted with malachite, some beautiful specimens of which have been obtained. The length of the vein is about 200 fathoms, and its thickness varies from one to ten fathoms. The ore yields only between three and four per cent, and the amount of copper annually produced is about 4000 quintals. The other Siberian mines are those of Tourinski, on the river Touria, at the eastern base of the Ural chain, and about a hundred leagues north of Katherineberg. The vein is included in a bed of white marble, which in thickness does not exceed four fathoms. The matrix of the ores is clay, but it is rich, and often exhibits a beautiful appearance, being varied with veins of blue and green steatites, red oxide of copper, fragments of malachite, gray ore, and not unfrequently native copper. The ore yields from eighteen to twenty per cent., and the annual produce is about 20,000 quintals.

5. Lead Mines.

France possesses considerable mines of lead, particularly those of Poullaouen and Huelgoet, in the department of Finisterre, which have been worked into two parallel veins included in primitive rocks. There are also mines of lead in the Vosges, where the galena is disseminated in a thick vein of decomposed granite; in the department of Sambre and Meuse, where the veins traverse limestone nearly in a vertical position; and in other places, where, in their distributions and productions, the mines are analogous to those of Great Britain. The produce of the French mines is about 30,000*quintals of lead annually. There are many valuable mines of lead in Germany, particularly in Saxony and the Hartz. Lead ore is also obtained, from the mines of Hungary and Bohemia, which sometimes yield a considerable proportion of silver. The mines of Bleyberg, in Carinthia, where galena is the prevailing ore, furnish the finest specimens of molybdate of lead. At Tarnowitz in Silesia there is a remarkable deposition of lead ore, the beds in which it is distributed reposing on horizontal strata of compact limestone, which contains petrified shells, and is impregnated with bituminous matter. The lead ore is deposited in veins, in rounded masses, and in small grains. The only appearance of lead in the immense chain of the Ural Mountains, so rich in other mineral productions, is in the state of chromate, or red lead, which was first discovered in Siberia, and the principal repository of which is the gold mine of Beresof. It is found in a small vein of ferruginous quartz, traversing a gneiss rock of a reddish colour.

6. Mines of Zinc and Manganese.

In a lead mine about six leagues from Cherbourg in France there is a vein of calamine four fathoms in thickness; and in the neighbourhood of Aix-la-Chapelle there is a prodigious mass of calamine imbedded between two rocks, composed of micaceous schistus and sandstone, intermixed with very hard quartz. The ore is extracted by sinking shafts, from the lower extremities of which galleries have been driven, some of them to a very considerable extent. When the ore is exhausted on this level, the shafts are sunk deeper, and a new series of operations is commenced. An immense mass of blende, or sulphuret of zinc, was discovered by Dietrich in the Pyrenees; and ores of this metal are not uncommon in other parts of France. A pure calamine, containing neither iron, lead, nor sulphur, was found near Alcaraz in La Mancha, Spain, and was extracted for the purpose of being employed in the manufacture of brass carried on in the vicinity of that place; but the work appears to have been latterly discontinued. Some ores of zinc abound in the mines of Saxony, and in those of the Hartz, where they are found in considerable quantities, and also in peculiar repositories. A mass of blende, similar to that observed in the Pyrenees, was discovered in the Hartz, unmixed with any other metal, and capable of affording any quantity of ore.

France possesses some valuable mines of manganese, particularly that of Romanèche, in the department of Saone and Loire, which is situated on the eastern declivity of a chain of primitive mountains, stretching from north-northeast, and composed of granite, limestone, and a siliceous sandstone. The manganese is incumbent on the granite, forming neither a bed nor a vein, but being deposited in a kind of accumulated mass, about ten fathoms in its greatest breadth, and nearly two hundred in length. The thickness of this mass of manganese varies from seven to fifteen feet, and the greater part of it is free from admixture with other minerals, except fluor spar of a deep violet colour, with which it is sometimes found combined. Manganese is also found in other parts of France, as in the Cevennes, where it occurs in a matrix of granite; in the department of the Vosges and the Moselles; and in the neighbourhood of Perigueux, in the department of Dordogne. The manganese mine in the valley of Aoste, Piedmont, has been described by Saussure in his Voyages. It is situated in a mountain of gneiss, the beds of which are nearly horizontal; and the ore is supposed to be deposited in the form of a large mass rather than in that of a bed or vein. This mine affords fine specimens of the carbonate of manganese, crystallized in the form of rhomboidal prisms, and of a beautiful purple-red colour. Ores of this metal are not uncommon in various parts of Germany. The carbonate has been found in the gold mine of Nagyag, and in Other auriferous mines of Transylvania. In the Ural Mountains there is a siliceous sandstone, which is entirely penetrated with manganese, disposed in a dendritical form, throughout the whole mass of the stone.

7. Mines of Pock Salt.

Fossil salt is usually found alternating with beds of clay, accompanying gypsum, sandstone, and limestone; sometimes in considerable beds, but often in detached masses, and also in veins. Mines of rock salt occur in Hungary, the southern part of Germany, at Vic in France, and also at VVielizka in Poland. The last of these are of prodigious extent, and afford annually about 2,000,000 cwt. of this fossil product, without any appearance of exhaustion.

Having thus noticed the various mineral products which the continent of Europe possesses in common with Great Britain, and also indicated their respective localities in the different countries, we now proceed, in conformity with our plan, to give some account of those which may be considered either as peculiar to the Continent, compared with Great Britain, or which occur there in sufficient abundance to be extracted from their ores, and for this reason come within the scope of the present article.

1. Mines of Gold and Platina.

Gold, though one of the scarcest metals, is almost universally distributed. It is most frequently found disseminated, or in detached grains, or in a dendritical form, and sometimes it occurs in a crystallized state. It is often met with in primitive mountains, where-it is usually distributed in veins, and occasionally disseminated in the rock itself. The gangue or matrix of gold, that is, the substances which accompany it, consist of quartz, felspar, limestone, pyrites, some of the ores of silver, and galena; and it is also found in combination, with manganese, cobalt, [7:15:253] and nickel. In a Siberian mine, gold has been discovered surrounded by muriate of silver. It is likewise common to alluvial soil, where it is disseminated in grains, along with siliceous, argillaceous, and ferruginous sands, which form the component parts of certain soils. It is further met with in the sands of many rivers, particularly after floods. Most of the auriferous sands are of a black or reddish colour, and consequently are ferruginous; a circumstance which, taken in connection with the gold of alluvial soil, has led some to suppose that its presence is owing to the decomposition of auriferous pyrites.

Platina exists in the metallic state, and is usually found in the form of small, flat, or rounded grains. Its colour is a light steel gray, or silver white; it is ductile, and in thin plates flexible; but it is infusible without addition. Platina was first known in Europe about the year 1748, and, until Vauquelin detected this metal in a gray silver ore from the mine of Guadalcanal in Spain, it was found only in South America, where it occurred in alluvial soil covered with rounded masses of basalt. It is now found in considerable quantities on the European side of the Ural chain. Platina is accompanied with particles of gold and iron, and with another ore containing osmium and iridium; and it forms the alloy of rhodium and palladium.

Ιhe principal mines of gold and platina in Europe are those belonging to Russia; but before proceeding to give some account of these, we shall shortly advert to the different localities where gold has been found and wrought in some of the other countries of the Continent.

In several parts of France gold has been found, although in exceedingly small quantities. In the year 1781, a vein of gold was discovered at Gardette, in the valley of Oysans, which is situated in the department of the Isère. This vein consisted of quartz, which traversed a gneiss mountain, and contained auriferous sulphuret of iron, besides some fine specimens of native gold; but the quantity obtained was found insufficient to defray the expense of operations. Many of the rivers, as the· Rhone, the Rhine, the Garonne, and others of smaller note, furnish auriferous sand. Veins of auriferous sulphuret of iron traversing gneiss rocks have been discovered at the foot of Mount Rosa in Piedmont; and the sands of some of the rivers, as well as various parts of the soil, on the south side of the Apennine Mountains, are likewise auriferous.

It has been said that the mineral wealth of Spain and Portugal is now almost exhausted; but it would perhaps be nearer the truth· to state, what is undoubtedly the fact, that, in these countries, the search for mineral treasures has long been in a great measure abandoned. From the earliest times the Peninsula has been celebrated as a repository of gold, which was found, not only in the alluvial soil and in the beds of rivers, but also in regular veins, and which might still be discovered in considerable quantities, were it not afforded in much greater abundance by various parts of Africa and South America. This precious metal was collected in the Peninsula by the Phoenicians, and afterwards by the Romans, who, according to the statements of the ancient writers, obtained annually from Portugal, and from Galicia and the Asturias, 30,000 marcs, or 240,000 ounces, of gold.

Amongst the places of Europe which are most, remarkable for mines of gold, and also for auriferous sands, may be mentioned Schemnitz and Kremnitz in Hungary. The gold of Schemnitz is accompanied by silver, lead, and iron pyrites, the native matrix being quartz. The mines of Nagybanya, Kapnik, Felsoebanya, Wiszbanya, and Olapos-janya, all yield gold; whilst those of Nagyag, Korosbanya, Voeroespatah, Boitza, Csertesch, Fatzbay, Almas, Porkura, 3otschum, and Stonischa, furnish chiefly gold and copper. The gold mine of Nagyag furnishes gold in combination vith native tellurium. The whole produce of the Hungarian mines amounts to 5200 marcs or 3250 lbs. troy of gold. At Edelfors in Sweden native gold and auriferous iron pyrites are deposited in a vein of brown quartz traversing a mountain of schistose hornstone. Gold is also met with disseminated in the rock itself.

We come now to the gold and platina district of Russia, of which Humboldt has given a description in a letter to his friend Arago. “We spent a month,” says he, “in visiting the gold mines of Borisoosk, the malachite mines of Goumeselvoki and of l’agilsk, and the washings of gold and platinum. We were astonished at the pepitas (water-worn masses) of gold, from two to three pounds, and even from eighteen to twenty pounds, found a few inches below the turf, where they had lain unknown for ages. The position and probable origin of these alluvia, mixed generally with fragments of greenstone, chlorite slate, and serpentine, was one of the principal objects of this journey. The gold annually procured from the washings amounts to 6000 kilogrammes. The discoveries made between 59 and 60 degrees of N. latitude, are important. We possess the teeth of fossil elephants enveloped in these alluvia of auriferous sand. Their formation, consequent on local irruptions and levellings, is perhaps even posterior to the destruction of the large animals. The amber and the lignites, which we discovered on the eastern side of the Ural, are decidedly more ancient. With the auriferous sand are found grains of cinnabar, native copper, ceylamites, garnets, little white zircons as brilliant as diamonds, anatase, alvite, and other stones. It is very remarkable, that in the middle and northern parts of the Ural, the platinum is found in abundance only on the western European side. The rich gold washings of the Denidor family at Nijneï-Tagilsk are on the Asiatic side, on the two acclivities of the Bartiraya, where the alluvium of Vilkni alone has already produced more than 2800 lbs. of gold.

“The platinum is found about a league to the east of the line of the separation of waters (which must not be confounded with the axis of the high summits) on the European side, near the course of the Oulka, at Sukoi Visnia; and at Martian, Μ. Schevetsov discovered chromate of iron, containing grains of platinum, which an able chemist at Katherineberg, Μ. Helm, has analysed. The washings of platinum are so rich that a hundred poods (about 400 lbs. Russian) of sand afford thirty, and some fifty, solotnicks; whilst the rich alluvia of gold at Vilkni, and other gold washings on the Asiatic side, do not give more than one and a half to two solotnicks of platinum to a hundred poods of sand. In South America, a very low chain of the Cordilleras, that of Cali, also separates the auriferous and non-platiniferous sands of the eastern declivity (Popayan) from the sands of the isthmus of the Raspadura of Choco, which are very rich in platinum, as well as gold. We possess pepitas of platinum many inches in length, in which M. Rose has discovered beautiful groups of crystal of that, metal.

“As to the greenstone porphyry of Laya, in which Μ. Engelhardt observed little grains of platinum, we have examined it on the spot with much care; but the only metallic grains which we have been able to detect in the rocks of Laya, and in the greenstone of Mount Belayr-G<ara, have, appeared to Μ. Rose, to be sulphuret of iron; this phenomenon, however, will be a subject for new research. Osmium and iridium have also a peculiar locality, not amongst the rich platiniferous alluvia of Nijneï-Tagilsk, but near Belemboyevski and Kichtem. I insist upon the geognostical characters drawn from the metals which accompany the grains of platinum at Choco, Brazil, and in the Ural.”

The following table exhibits the produce of the gold and platina mines of Russia from January 1826 to July 1830.
[7:15:254]
[table]

In addition to this, we are enabled to give, from a parliamentary paper,^[15. A comparative Statement of the Value Sterling of Gold and Silver raised in each of the Mining Countries of America and Russia, as far as the same can be ascertained from the British consular agents in those countries. Ordered by the House of Commons to be printed, 8th March 1836. ] a statement of the produce of the Russian gold and platina mines dpring the year 1832; which statement was furnished to Viscount Palmerston by Mr T. J. Gisborne, his majesty’s consul at St Petersburg. This return is dated St Petersburg, 5th April 1833, and is as follows :—
[table]

It is to be observed here, that 36 lbs. English, and 40 lbs. Russian, make a pood.

The annexed tables exhibit the increase of gold, silver, and platina coin in circulation in Russia during ten years from 1824 to 1834. This increase has been most rapid, especially in gold and silver, as will appear from the following table of import and export.
[7:15:255]
[table]

But 420,818,006 rubles, at the average exchange of 10∣d. per ruble, exceed L. 18,375,000 sterling. The above quantities of gold and platina have been coined at the Russian mint; the produce of private mines in the Ural is included in the return.^[16. In the year 182G, when Professor Engelhardt undertook a scientific journey into the Uralian Mountains, he remarked that the sands in the neighbourhood of Koushra, and those at the platina mines at Nijneï-Toura, strikingly resembled the Brazilian sands, in which diamonds are found. Baron Humboldt, during a subsequent residence in the same country, confirmed this resemblance; and examinations having been made, by his advice, a young countryman employed in washing the auriferous sands on the grounds of the Countess Porlier, discovered, on the 20th June 1830, a diamond which is nothing inferior to those of Brazil; and soon afterwards many others were found superior in weight to the first. Thus Russia has added this source of riches to those which of late years she has obtained from the gold and platina mines of the Ural chain of mountains { Revue Encyclopédique, tom. xlv. p. 4G0). Emeralds have also, it seems, been discovered, some of them of large size and considerable puritv∙ ]

The amount of silver produced during the ten years from 1824 to 1834 by the Altai and Dauri mines, averaging above 1000 poods per annum, and therefore amounting to 10,000 poods in all, is not included in the above table. Since 1834, a very considerable quantity of gold has been obtained by the washings on the Altai Mountains. The mines of these mountains occur in the districts of Kolyvan, Zmeof, Tcherepanofsky, Smenofsky, Nicoaisky, Philipofsky, and some others, which, besides gold and silver, produce also a considerable quantity of iron, copper, and lead.

2. Mines of Silver.

The silver mines hitherto discovered in France do not appear to be of any great importance. The mine of Allemont, in the department of the Isère, is situated near the summit of a lofty mountain, composed of beds of gneiss and primitive limestone, inclined in different angles to the west. The veins are numerous, and run in all directions. The ores are native silver, sulphuret of silver, red silver, and a small quantity of muriate of silver; they are accompanied by different ores of cobalt, antimony/nickel, &c.; and the matrix is usually clay mixed with iron, lime spar mixed with asbestos, and some other minerals. Indications of silver have also been observed in the Vosges, where, in a vein of gray copper ore, has been found a certain proportion of this precious metal.

The silver mines of Spain are by far the oldest which are known. They were wrought in the time of the Romans; and, trom the remains of the old workings, it would appear that the operations had been carried on to a great extent. The mine of Guadalcanal, in the Sierra Morena, upon the confines of Andalusia and Estremadura, was formerly very rich, but seems to be now nearly exhausted. The ore which it yields is red silver found in a matrix of compact carbonate of lime.

The mining territory of Freyberg in Saxony abounds with veins of silver, or with lead containing a considerable proportion of that metal. The veins traverse gneiss rocks, and are generally of quartz, lime, and fluor spar; the metallic ores are argentiferous sulphuret of lead, red silver ore, and argentiferous gray copper ore. The richest of the Saxon mines, that of Himmelfurst, is situated two miles south-east of Freyberg. The elevation of the surface above the level of the sea is 1346 feet, and that of the bottom of the mine 263, so that its depth is 1083 feet, or 361 yards. There are five veins in this mine. The principal vein (teichflacke) is from one foot six inches to three feet in width; the others are from six to twelve inches wide. The direction of this vein is nearly north and south, and its “underlie” is west about three feet per fathom. Some of the other veins intersect it. The ores consist of argentiferous sulphuret of lead, native silver, sulphuret of silver, and red silver; and their produce is from six to seven ounces of silver per quintal of 100 lbs., equivalent to 3∣ or 4½ parts of metal in 1000 parts of ore, or from ∣ths to nearly one half per cent. The veinstone is quartz, pearl spar, and calcareous spar; and the ores are accompanied by blende, spathose iron, and a little iron and arsenical pyrites. The Frankenshacht is 180 fathoms, and the adit at this shaft is 47 fathoms in depth. The quantity of silver ore produced annually is stated at 630 tons, yielding 6160 lbs. troy of silver, valued at about L.18,000. The total cost of the mine is L.9500, and the clear profit of the proprietors L.3500. About 700 miners are employed, of whom 550 work under ground. The ores are delivered to the government reduction works in the neighbourhood of Freyberg, where they are partly smelted and partly amalgamated.

The mines of Schemnitz and Kremnitz in Hungary have long been celebrated, not only for their richness, but also for the immense extent to which the operations have been carried. The rocks traversed by these veins are composed of an argillaceous gray stone, mixed with quartz, schorl, or particles of lime spar, and sometimes called metallic rock. There are three principal veins, the course of which is nearly from north to south; they run parallel to the river Gran, following even the windings of its channel. The dip or inclination of these veins is generally from west to east, at an angle varying from 30° to 70°. One of the capital veins alluded to, called the Spitaler vein, is joined at a particular part by an argillaceous white vein which runs along with it on the hanging side, and from the point of junction the latter is found to produce silver. In this vein Baron Born discovered a petrified porpites or simple madrepore included in sound sinople, a mineral resembling red jasper. This petrifaction was found at a depth of about eighty-nine fathoms, in a level driven on the vein. The second great vein at Schemnitz exhibits nearly the same general characters as the first in regard to the distribution and nature of its productions. In the hanging side, to [7:15:256] wards the first vein, it contains lead ores; and on the ledger side there is a layer of clay from one to four feet thick, in which are imbedded nodules of lead ore, yielding from two to five ounces of silver. The third great vein is more irregular in its formation than the two others, sometimes rising vertically, and sometimes dipping in a contrary direction from east to west. The ores of this vein are not very rich in silver, but some of them afford a considerable proportion of gold. This mine appears to have been wrought from a very early period, and the mining operations have been carried to a vast extent. The gallery or level, called the Emperor Francis’s Gallery, is that by which the whole of the mine¾ are drained and cleared of water; it is carried through hard rock, and must have been a work of immense labour and difficulty, being about five English miles in length. This gallery was begun in 1748, and finished in 1765. The mountains around Kremnitz are composed partly of the metallic rock already described, and partly of primitive trap. At this place there is also a gold mine established on a large and rich vein, which at the depth of 160 fathoms continued to be productive. The rock is a white solid quartz, mixed with fine auriferous red and white silver ore. There are also mines at Königsberg, a town some miles to the north-west of Schemnitz. The vein is a gray quartz mixed with auriferous pyrites.

The circle of Saaz in Bohemia abounds in various metallic ores, amongst which those of silver greatly predominate. The prevailing rocks are gneiss and argillaceous schistus. The veins at Katherineberg traverse gneiss, and run generally in a north and south direction, parallel to the mountain in which they are situated. But there are also some powerful veins which cross the mountain, particularly one, which seems to be insensibly blended with the mountain rock, and whose ores are rich silver and copper pyrites, with fluor spar, blende, various copper ores, and sometimes native silver and copper. Joachimsthal, a place in the same circle, is also celebrated for its mines. The prevailing rocks are gray, micaceous, and quartzose clay slate, and the surrounding mountains have a gentle declivity towards the south, but run in lofty ridges to the east, north, and west, and are intersected by deep valleys; an inequality of surface which enables the miners to open numerous galleries converging to the south, and also towards the valley in which stands the town of Joachimsthal. The whole galleries and works of this district are divided into six different fields, and are drained by two deep drifts or levels; one of these runs in a direct line 1600 fathoms, and, including its several branches, is 4500 fathoms in length; the other runs in a direct line 1500 fathoms, and its total length extends to 5600 fathoms. The depth of the former under the summit of the mountain is 170, and that of the latter 190 fathoms; but the operations in the mines have been carried to a much greater depth; indeed, excepting those of the Tyrol, they are considered as amongst the deepest in the world. The metallic veins of this mining district are disturbed by dykes of red porphyry or trap, called by the miners combs. The course of these dykes is very irregular, and their thickness varies from a few inches to forty fathoms; they also unite with metallic veins, and, either running parallel or crossing them, improve, disturb their course, or render them barren. It has been observed that those dykes which run from north to south commonly disturb the course of the metallic veins, which they traverse in a cont⅛ry direction. A dyke of this description, crossing one of the principal veins of the district, was discovered on the sole of one of the great levels, where the thickness was not less than from thirty to forty fathoms. At this place, which is 150 fathoms below the surface, and 3000 fathoms distant from the door of the gallery, an entire tree was discovered.^[17. At the time when this discovery took place, the tree in question was supposed to be a production of the antediluvian world. The exterior appearance, the fibrous structure, the concentric circles, the ramification of the substance into round branches the soft unpetrified bark which adhered to them, and something like leaves found in different parts of it, left no doubt, in the minds of those who had an opportunity of observing it, that it was a vegetable production converted into stony matter. Its specific characters, in as far as these were observed, have not been stated. The tree found in Craigleith quarry, also at a great depth below the surface, was supposed to have belonged to the coniferous species. Soon after the discovery of the former, part of the level gave way, and the water increasing, rendered it impossible afterwards to examine the spot. ] The thickness of the veins varies from one inch to two feet, and the veinstones are a whitish or bluish clay, argillaceous slate, and reddish hornstone or petrosilex. The ores found in this district are, native silver, vitreous silver ore, red silver ore, and white silver ore. The silver mines of Berestadt were formerly rich in native silver, and other ores of that metal.

The silver mines of Stahlberg in Sweden are situated about twenty-eight English miles from Upsal. The ore is an argentiferous galena, in a compact limestone, and produces a marc or a marc and a half of silver per quintal. These mines have been wrought to the depth of 150 fathoms; and the annual profits at an average amount to about L.4000, of which one eighth is paid to the state. The silver mine of Königsberg in Norway is represented as much richer than any of those in Sweden. The mountains are composed of strata nearly vertical; their general direction is from north to south, with an inclination towards the east; and they are generally parallel to each other, but sometimes take a wavy or zigzag course. Some of the strata are composed of mica mixed with garnets and lime spar; others consist of a grayish-white quartz mixed with fine black mica, a httle carbonate of lime, and reddish hornstone; some are composed of alternate layers of quartz and mica, and others of a ferruginous rock. The veins cut these strata transversely, and are from half an inch to two feet and a half in thickness. The ores are chiefly native silver, enormous masses of which have sometimes been found,^[18. Of these one is mentioned which is said to have weighed more than 220 lbs. ] vitreous silver ore, and occasionally red silver ore and galena. The matrix of the ore is granulated limestone, sometimes foliated or mixed with fluor spar and oxide of iron. This mine is most productive in that part where the veins traverse the strata of ferruginous rock. The greatest depth to which the operations have been carried is about 160 fathoms, and the annual produce was at one time nearly 5000 lbs. of silver.

We have already, under the former head, adverted to the mineral riches of that part of the Altaï chain of mountains which is included in Asiatic Russia. The silver mines of Zmeof are situated between the rivers Obi and Irtisch, in a tract extending from 50 to 52 degrees of north latitude. I he annual produce of these mines is stated at 60,000 marcs of silver, which is alloyed with about three per cent, of gold. The mines of Nertschink in Dauri or Daouria, near the river Amur, yield argentiferous galena, producing annually about 36,000 marcs of silver, containing about one and a half per cent, of gold.

3. Quicksilver Mines.

I he continent of Europe, so rich in almost every species of mineral produce, contains also large stores of quicksilver[7:15:257], but limited apparently to a very few favoured spots.^[19. It appears rather singular that a country so rich in almost every variety of mineral produce as Great Britain should be entirely destitute of quicksilver, more especially as the coal formation, in which that metal is most commonly found, is here so largely developed. There is, however, a passage in Bishop Watson’s Chemical Essays, in which be mentions the circumstance of quicksilver having been found in a native state at Berwick-upon-Tweed; and the same thing is stated in the Commercial Magazine (vol. ii. p. 204), and also in Williams’ Natural History of the Mineral Kingdom (vol. ii. p. 378). This discovery is said to have been made in digging out clay for the foundation of a house in the street called Hyde Hill, in the town of Berwick; and it appears to have taken place more than half a century ago. The clay being dug out, lay for some time where it had been deposited, and the mercury was observed to exude from the small fissures or cracks which were formed in it as it dried, being apparently distributed throughout the whole mass of the clay. Many years afterwards, when some workmen penetrated into the same bed of clay, it appeared to be impregnated with mercury, which ran out in small globules. It is remarkable that so important a mineralogical fact did not attract more attention, and lead to some examination of the bed of clay, which appeared to be thus impregnated with quicksilver in the native state. ] The ores of this metal exist in various states, as in that of native mercury, alloy, or amalgam; in that of sulphuret or cinnabar, which is sometimes impregnated with a bituminous clay; and in that of salt, or muriate of mercury. The ores of mercury are but rarely met with in primitive mountains, the greater proportion being found in secondary rocks, as in bituminous schistus, compact limestone, ferruginous sandstone, and sometimes even in ferruginous clay; and these ores are usually distributed in large confused masses, seldom in regular veins. The metallic ores which usually accompany those of mercury are sulphuret of lead, sulphuret of zinc, haematites, iron pyrites, silver, and various ores of copper.

The principal mines of quicksilver on the continent of Europe are those of Almaden in Spain, Idria in Carniola, and the Palatinate, or that part of the Bavarian dominions which is westward of the Rhine.

Mines of Almaden —The most ancient mine of quicksilver known in the world is that of Almaden in Spain. According to Pliny, it was wrought five hundred years before the commencement of the common era; and in his time 10,000 lbs. of cinnabar (sulphuret of mercury) were transported to Rome, for the purpose of being employed in painting. This celebrated mine, or rather cluster of mines, is situated in a branch of the Sierra Morena, upon the confines of Andalusia, about fifteen leagues to the north of Seville. The hill which contains it is about a thousand fathoms in length, six hundred in breadth, and a hundred and twenty in height. It is composed of the same materials as the neighbouring mountains, which consist of sandstone; and its surface exhibits two inclined planes, which, uniting at the summit, form a crest of rock, that is entirely bare, and spotted with sulphuret of mercury. The village of Almaden, from which the mines take their name, is built chiefly on the cinnabar itself. The two principal veins, which traverse the mountain longitudinally and intersect it vertically, are from two to fourteen feet in thickness, and throw out branches in different directions; but towards the middle of the mountain they unite, and form a mass of mineral about a hundred feet in thickness. The veinstones are of the same sandstone as that of which the mountain itself is composed. The more finely-grained matrix affords the greatest quantity of cinnabar; and some of the ore is so extremely rich as to yield nearly ten ounces of mercury in each pound; but from other ores only three ounces can be extracted. The sides of the vein are formed of a black slate in a state of decomposition, and frequently contain a good deal of cinnabar, as well as large, round, and flat masses of pyrites, exhibiting internally some spots of cinnabar. In other parts, there have been discovered veins of aluminous schistus and iron ore, running in the same direction with the mountain, and yielding specimens of ore, in which the iron, the sulphur, and the quicksilver are found closely combined. This fact, which has been noticed in other mines of mercury, shows that nature sometimes produces combinations which cannot be effected by any known process of art. Previously to the year 1752, the annual produce of the mines of Almaden amounted to be tween 5000 and 6000 quintals of mercury, which was exported to Mexicofor the purposes of amalgamation, in extracting gold and silver, particularly the latter, from their ores. About that period, the quicksilver mines of Guancavelica in Peru being nearly exhausted, the mercury required for amalgamation in South America was exported from Almaden; so that the annual amount of quicksilver extracted from this grand reservoir increased from 6000 quintals to 16,000, 18,000, and even 20,000 quintals. At the present day, the mines of Almaden continue to be by far the most productive in the world.

Mines of Idria —The celebrated quicksilver mines in the vicinity of Idria, in Carniola, are situated about eight leagues from Trieste, on the boundary of the province of Friuli. The town of Idria, which gives name to the mines, stands in a deep valley which is surrounded by lofty mountains of limestone, and exhibits a dark-coloured slate included between two beds of limestone, rising to the surface at an angle of from 45° to75°. The ores, consisting of native mercury and cinnabar, are deposited in this schistus, which is about sixty feet thick, and of very considerable extent. The position of the metalliferous stratum is variously inclined, and sometimes horizontal^ The depth of the principal shafts by which the ores are brought up exceeds 120 fathoms. The colour of the schistus from which the ore is obtained varies in different parts of the mine. When it is of a whitish hue, it is poor in metal, but when the colour changes to a blackish shade, the ore yields about sixty per cent. The metallic bed is sometimes intersected by vertical strata, which, according as they are hard or soft, produce opposite effects; for, in the former case, the ore in a great measure disappears, but when they are softer and more brittle than the metalliferous bed itself, the ore becomes more abundant. In some places there occurs a hard slaty rock, containing small shining globules, and yielding little more than two per cent, of quicksilver, called coral ore; and in others there are found small veins of coal impregnated with ore, and affording about the same proportion of pure mercury. The mines of Idria were discovered in the year 1497. The mountain in which they were first established has been exhausted, and the operations are now carried on in an opposite mountain, whence, it is said, a supply of mercury to almost any extent might be obtained; but the quantity extracted is limited to between 3000 and 4000 quintals, which are mostly retained for home consumption, being used for the amalgamation of the gold and silver ores, which are found in greater abundance in the Austrian states than in any other country in Europe, except Russia, which, however, derives part of her supplies from her Asiatic dominions.

The following particulars respecting the mines of Idria are extracted from Silliman’s Journal, to which they appear to have been communicated by an officer of the American navy, who had made a pedestrian tour through Germany, and had, in the course of his travels, visited Idria.

“The mines have nothing corresponding to the ideas of terror which we are apt to connect with such places, except the atmosphere, which throughout the mine must be strongly impregnated with mercurial vapour, and is constantly[7:15:258] producing salivation amongst the workmen. Having descended by 727 steps, reaching to a depth of 120 fathoms, we arrived at the region where the cinnabar is chiefly procured. The mining operations are chiefly carried on in galleries, the friable nature of the rock seldom admitting of larger chambers. The cinnabar is in strata of from two to six inches in thickness, and of a variety of colours, from dark to light red, the quicksilver being sometimes mixed with it, and sometimes occurring in the intervening strata of earth or stone. Sometimes the cinnabar is of a brilliant red, and once I found it in small crystals, but such specimens are rare; it is generally of a dull .red colour, and the stone is so brittle, that nothing 'more than a pickaxe is required. The strata affording the quicksilver appear to have no particular direction, and occupy about one third or one half of the entire mass of the rock. Proceeding a short distance, however, we came to the galleries where the cinnabar is less common, and the quicksilver is the chief object of search. It occurs here sometimes imbedded in a friable rock, sometimes in a kind of earth in appearance and hardness resembling talcose slate, but principally in the former. Generally it is in particles too minute for the naked eye, but often wþen the rock is broken small globules present themselves, varying from a size just large enough to be seen, up to that of a common pin’s head. These globules are not distributed at random throughout the mass, but the substance in which they occur forms strata usually about one inch or two in thickness.”

The traveller, descending still lower, soon came to the richest part of the mine. Here the gangue or matrix consists almost entirely of talcose earth, and the globules are so large that when it is broken they roll out and fall to the bottom of the gallery. The labourers are relieved every four hours, being unable, from the state of the atmosphere, to work longer than this at one time. In the other parts of the mine they work eight hours. The total number employed in the mine is 360, divided into three companies, each of which works eight hours. Their pay is only from fifteen to seventeen kreutzers a day, the usual pay of day-labourers in Germany. Several of them appeared to be suffering from the effects of the mercury. Having returned to the upper mine, the traveller next proceeded to examine the washing-rooms, which are situated a few hundred yards from the mines.

“The gangues containing the metal are carried to this house; and if the ore is of the earthy kind, it is broken up, and thrown upon large sieves, by means of which the loose or native quicksilver, called her e Jungfrau, or virgin quicksilver, is separated from the earth; the latter is then cast into shallow boxes, open at the ends and a little inclined, and a gentle stream of water being made to pass over it, a rake is used, and the earthy matter is carried off. There are seven of these boxes in succession, and by the time the residuum reaches the last of them, it resembles a heavy gray powder, and is sufficiently pure to be carried to the vapour furnace. The stony fragments require only a slight washing to cleanse them from the outward earthy impurities.

“The furnace is half a mile lower down the valley, and at the extreme end of the village. It consists of a circular walled building, about forty feet diameter by sixty in height, on each side of which there is a continuous range of chambers ten or twelve feet square, and nearly as many in height; by means of small square openings in the partition wails, the air is allowed to pass from the centre building to the remotest. Each has also a door communicating with the external air. These buildings are all of stone, and are plastered within. The gangue, after being prepared in the washing-house, as already described, is removed to this edifice, and placed in earthen pans four inches deep and fifteen in diameter, which are piled up so as to fill the centre building. The doors of the chambers are then carefully walled up; and a strong fire having been lighted under the centre building, the quicksilver rises in the form of vapour, and passing into the small chambers, is there condensed by the cold atmosphere around them. Some of the gangue is brought here in the form of the native rock. The expansive power of the vapour, together with the heat of the fire, is sufficient to cause the rock to disintegrate, and thus to allow the escape of the quicksilver. When this process is over, the doorways of the chambers are once more opened, and the quicksilver, which is found chiefly adhering in drops to the sides and ceiling, is scraped off, and running into a hollow in the floor, is taken thence to the cleaning and bottling room. It appears to act on the mortar of the chambers, for I found the latter flaky, and the crevices all filled with small globules.

“The cleaning process is very simple, a piece of canvass being merely spread over a funnel, and the quicksilver being made to pass through this, comes out sufficiently pure. That intended for home consumption is then tied up in sheep-skins, while that for exportation is put in iron bottles, large enough to contain sixty-eight pounds. The furnace is kept in operation only during the winter months, and then the vapour which escapes from it is a serious annoyance to the town; they have a blast three times every fortnight.”

Mines of Bavaria. — Extensive, but now almost neglected, mines of quicksilver, have long been wrought in that part of the Bavarian dominions which is westward of the Rhine, and anciently formed the Palatinate. These mines are situated in the mountainous country to the south of Kreuznach, a town on the southern frontier of the Prussian territory, and they lie chiefly between that place and Wolfstein. This elevated range forms the northern prolongation of the primary chain of the Vosges, and rises to its greatest altitude in the porphyritic summit of the Donnersberg or Mont-Tonnerre. They are entirely within the Bavarian dominions, being in the immediate vicinity of Bingart, Nieder Moschel, Ober Moschel, and Alzens. They are stated to have been worked for about five centuries; and both the excavations below, and the immense piles of attle on the surface, prove that some have been wrought to a considerable extent. The working indeed has never been given up for any length of time; but this part of Germany having been the theatre of the early campaigns of the French revolutionary army, the mines were for a time suspended, and have never since been effectually resumed. Prior to this period their produce must have been considerable, as they were reported, by a commission of French engineers, to have yielded annually 67,000 lbs. of quicksilver.

The deposits of quicksilver are chiefly worked in the sandstone formation, but in some places these appear to extend into the slate. The sandstone is of a pale brownish or grayish colour, usually very compact, and approaching the nature of hornstone. In some of the mines, strata of a much softer description, and of an argillaceous nature, are contained in the sandstone. The quicksilver occurs neither in a bed nor in a vein, but forms rather what may be termed a metalliferous channel of ground, of considerable breadth and extent. The direction of these channels approaches that of north and south, but in some mines there are two or more crossing one another. Their breadth is quite undefined, but they are worked from five to six feet in width, and appear to descend almost perpendicularly into the rock. In these channels exist thin fissures, called klefts, which, although in themselves unproductive, seem to be chiefly depended upon by the miners in guiding their researches. The quicksilver is mostly found in the joints of the rock, which, in the vicinity of the hlefts, appear to [7:15:259] be more or less filled with it to an indefinite extent; but whether it is of contemporaneous formation with the rock, or deposited in cracks which had subsequently opened in it, has not been ascertained. The depth to which the quicksilver extends is also unknown, but none of the mines in this district exceeds 300 feet in depth. The ore is cinnabar, which varies from a bright to a dull red colour, traversing the mass of the rock in all directions, sometimes very abundantly; but its distribution does not appear to follow any general law, or to be exclusively limited to any particular strata. Rich specimens often occur, containing, along with cinnabar, a good deal of native quicksilver disseminated in small globules; but these bear a very small proportion to the poorer ores, or rather the masses of rock containing thin veins of cinnabar. Rich stones of ore, such as are often found in the more productive parts of the deposits, yield from five or six to eighteen or twenty per cent, of quicksilver, and picked specimens as much as fifty or sixty per cent.; but, taking the general average of the stuff raised from the mines, the produce does not probably exceed three per cent.

In the vicinity of Bingart the mines are situated on the declivity of the mountain, at an elevation of about a thousand feet above the valley, and are consequently worked chiefly by adits, which enter the mines at depths varying from twenty to thirty lachters. In some of the mines the workings above the adits are considerable, and “sinks” have penetrated to a depth of nearly twenty lachters below. These mines have been opened chiefly in the sandstone, but one of them appears to extend into the slate.

The Stahlberg mine is situated near Ober Mðschel. It is very ancient, and has been extensively worked, the depth being near 300 feet, and the longitudinal extent of the excavations considerable. It is situated on elevated ground, and drained by an adit, which is driven into the workings nearly at the deepest point; but there are no shafts, access being afforded by levels driven into the side of the mountain. The mine is still worked to some, extent, and produces a good deal of cinnabar. The prevailing rock is a compact sandstone or hornstone, occasionally containing softer argillaceous strata. The great magnitude and extent of the excavations, and the very peculiar manner in which they have been formed, render the appearance of this mine exceedingly picturesque. The excavations consist of a series of irregular chambers fantastically over-arched, and communicating with one another. The height is often considerable, and the width is in some cases twenty or thirty feet. The access to these chambers, and also from one to another, is by rude staircases hewn out in the solid rock, thus furnishing a novel and easy mode of subterranean communication. The unusual light and the broad shadows produced by the lamps of the miners, the spacious but irregular excavations, and the perspective of the rude winding steps by which the various chambers of the mine are entered, form altogether a striking and picturesque scene. See the annexed sketch.

The present operations are chiefly confined to breaking down old pillars and masses of rocky ore left standing in various parts of the mine; and even from these sources considerable produce is obtained.· The cinnabar is generally disseminated throughout the rock, but abounds rather more in some strata than in others. The miners here are but little affected by the mercurial vapours, owing to the spaciousness, dryness, and good ventilation of the workings, with the easy mode of access to them.

The Landsberg mine is about three miles distant from that of Stahlberg, being situated on the declivity of a lofty mountain, covered with wood, and crowned with the ruins of an ancient castle. It is equally extensive with the Stahlberg mine, and has been worked in a similar manner, although at present the operations are carried on upon a limited scale. The mode here practised of reducing quicksilver is one of the simplest operations in metallurgy, consisting merely in a process of distillation.

The furnace in which it is performed is about twenty-four feet in length, twelve in breadth, and six or seven in height; fires are placed at each end, and the heat, passing first through the body of the furnace, goes off by a crossflue in the middle. Forty-eight iron retorts, twenty-four on each side, are arranged in the interior of the furnace, in two rows one above the other, so as to be exposed to the heat in its passage from the fires to the cross-flue in the middle by which it escapes; and the necks of the retorts pass through apertures in the wall, so that smaller retorts upon the outside of the furnace can be luted on to them. This will be better understood by reference to the annexed sketches, the first of which represents an end view, and the second a cross section of the furnace.

In fig. 1, a represents the body of the furnace exteriorly, b the fire-place, cc the outer set of retorts arranged in two rows one above the other, and d the cross-flue in the middle, thus:

In the cross section, fig. 2, α represents the body of the furnace interiorly, b the fire-place, c the ash-pit, ee the small retorts placed outside the furnace to receive the mercurial vapour, and dd the large retorts arranged in the body of the furnace in which the ore is exposed to heat, thus:

From this explanation of the construction of the furnace, the process of reduction will be easily understood. The ore, after being carefully picked and broken, to separate the worthless matter, is put into the large iron retorts, together with a certain quantity of pulverized lime, [7:15:260] and exposed to a moderate heat, which soon drives off any moisture that may be contained in it. The outer set of retorts is then luted on, and a much stronger heat applied, which, being continued for several hours, at length volatilizes the quicksilver, and drives it in the form of vapour into the small retorts outside, where it soon becomes condensed, and assumes the metallic form.

The Bavarian mines are now in the possession of an English company, and are therefore likely to be worked with spirit and success. They possess the advantage of being drained to a great extent by levels, and are therefore almost free from water, whilst coal for the reduction of the ore may be obtained in their immediate vicinity. From the nature of the deposits, it appears that they are capable of yielding an immense mass of rock more or less impregnated with quicksilver; and from the ease with which this produce may be obtained, and the occasional richness of some portions of the mass, these mines appear to offer a very fair field for enterprise.^[20. > Mining Review, No. IX., pp. 9, 10, e t seq. ]

Near Selvena, in the territory of Sienna, in Italy, cinnabar has been discovered; it is distributed in irregular masses, and forms thin veins in a clay mixed with argillaceous marl, but does not appear to be of much importance. There are two mines of mercury at Zalathna, in Transylvania. The ore of the one is cinnabar, which is extracted from a vein in a matrix of quartz and lime spar, traversing a black argillaceous slate and sandstone. The ore of the other mine is granulated cinnabar, included in a vein which runs in limestone. The annual produce of these mines amounted, according to Baron Born, to about 6000 lbs. of pure quicksilver.^[21. Born’s Travels, p. 120. ]

IV. MEXICAN MINES.

Mexico although it contains a variety of metals, as iron, lead, copper, tin, zinc, antimony, arsenic, and manganese, is chiefly celebrated for its gold and silver mines, particularly the latter, which, for the most part, yield also a proportion of gold. According to Humboldt, there are in New Spain no less than three thousand mines of the precious metals, divided into thirty-seven districts, each of which had formerly a council of mines called a deputation. The ores are generally disposed in layers, and masses are comparatively of but rare occurrence. At present, in all the mines, the veins of ore are chiefly worked; and these occur in the primitive and transition rock. But of the different kinds of rock in which veins are found, the porphyries are considered as affording the richest ore. At the beginning of the present century, Humboldt conjectured that, in the northern part of Mexico particularly in the Sierra Madre, great mineral wealth would be discovered in the rocks of secondary formation; and this conjecture has been confirmed by subsequent inquiry and examination. “The Sierra Madre,” says Mr Ward, “has been traversed seven times between Oaxaca and Chihuahua, by a very spirited and intelligent English^traveller, Mr Glennie, whose opinion of its riches confirms all that had been surmised in earlier days; and his conviction of the advantages to be derived from mining speculations in that direction has induced the directors of the United Mexican Company to entrust him with the formation of an establishment at Jesus Maria (one hundred leagues west of Chihuahua, upon the slope of the Sierra Madre), which I consider as a step towards that revolution in the mining affairs of Mexico the probability of which, in the course of twenty or thirty years, I cannot but look forward to.”^[22. Mexicoin 1827, vol. II. p. 135. Mr Ward’s work, here referred to, will be found to contain the most ample information on the subject of the mines of Mexico He has treated the subject in four sections, embracing almost every point of any importance connected with it. In the first he gives a comparative statement of the produce of these mines during a double term of fifteen years before and since the revolution of 1810, with an account of the exportation of specie during the same period. The second section treats of the mining system of Mexicobefore 1810; the changes which occurred from that time till 1823, when the idea of foreign companies was first suggested; the number of these companies established in Mexico the extent of the undertakings in which they are engaged; the difficulties with which they have to contend; and their progress and condition in 1827∙ In the third, Mr Ward discusses the question, whether the large capitals which have been invested in the mines by British subjects are likely to be productive of adequate returns, and within what period, to the adventurers; and also whether those returns are likely to make the general produce of the country equal or even exceed the annual average amount derived from the mines before the year 1810; to each of which he gives a very confident answer in the affirmative. And, in the last section, he makes some general observations on Mexicoas a mining country, and considers the probability of her being enabled, by her mineral treasures, to multiply her commercial relations with Great Britain, and also to acquit herself of the obligations arising from loans contracted in that country. Much of the information contained in these sections is, no doubt, purely commercial; but there is also a great deal which has an immediate relation to the subject under our immediate consideration; and in Mr Ward’s Personal Narrative there will also be found many interesting details respecting the principal mines and mining districts of Mexico ] The gold and silver ore obtained in Mexicobeing much more remarkable for its abundance than its richness, there can be little doubt that if the layers and veins of the Sierra Madre should prove much more productive than those which have been worked upon the table-land, the consequence must be such as Mr Ward has anticipated.

The great mining districts of New Spain, arranged according to the proportional quantities of silver which they yield, have been classified by Humboldt thus :—Guanaxuato, in the intendancy of the same name; Catorce, in the intendancy of San Luis Potosi; Zacatecas, in that of the same name; Real del Monte, in the intendancy of Mexico Bolanos, in that of Guadalaxara; Guarismey, in the intendancy of Durango; Sombre rete, in that of Zacatecas; Tasco, in the intendancy of Mexico Batopilas, in that of Durango; Zimapan, in the intendancy of Mexico Fresnillo, in that of Zacatecas; Ramos, in the intendancy of San Luis Potosi; and Parral, in that of Durango. But, from various causes, particularly the suspension of mining operations consequent on the revolution of 1810, and still more from the recent application of British capital to the working of the Mexican mines, this arrangement would require certain modifications to render it, in all respects, applicable to the actual circumstances of New Spain. At the beginning of the present century, for instance, the richest of all the Mexican mines was that of Valenciana; but at the present time the most productive mines are those of Veta Grande. To exhibita view of the change which, from whatever cause or causes, has since taken place; to indicate results which can only be appreciated in juxtaposition; and, at the same time, to convey, in a condensed form, other information which can scarcely fail to prove interesting; we shall here introduce a comparative table, showing at one view the points both of similarity and of contrast in these two celebrated mines.
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[table]
[7:15:262]

That part of the mountains of Mexico which produces the greatest quantity of silver is situated between the parallels of 2l o and 24° 30′. The celebrated mines of Guanaxuato are not more than ninety miles distant from those of San Luis Potosi. From the latter to Zacatecas the distance is 102 miles; from Zacatecas to Catorce, 93 miles; and from Catorce to Durango, 222 miles. It is not a little remarkable that the sites of the metallic wealth of Mexicoand Peru are, in the two hemispheres, nearly equidistant from the equator.^[23. The mining districts of the north of Mexicoare, in the state of Durango, Guarisamey, San Dimas, Gavilanes, Tayoltita, Canelas, Sianori, Bacis, Tamasula, Ventanas, and San Andres, in the Sierra Madre, and Cuencame (near the river Nazas), Yerva Buena, Mapimi, Indee, El Oro, and Guanasevi, east of the Sierra Madre; in the state of Chihuahua, El Parral, Santa Eulalia, Santa Rosa de Cosiquiriachic, El Pilar, Batopilillas, Rosario, El Potrero, and Milpillas; and in the stale of Sonora and Senaloa, Mulatos, Cosala, Alamos, Arispe, and El Rosario. ] The greater part of the gold of Mexicois found in the veins of silver ore, either native or mixed with silver, from which it is separated by washing; the proportion being seldom more than 1 1 ounce in the 100 lbs. The silver supplied by the veins of this country is extracted from a great variety of ores, which, from the nature of their mixture, bear some analogy to those of Saxony, the Hartz, and Hungary. The greatest quantity is derived from the sulphuret of silver, from arsenical and antimonial gray copper, from muriate of silver, from prismatic black silver, and from red silver ore. Amongst these ores we do not include native silver, because it is not found in sufficient abundance to form any considerable proportion of the total produce of the Mexican mines. Sulphuret of silver and black prismatic silver are common in the veins of Guanaxuato and of Zacatecas, as well as in those of Real del Monte. The richest gray copper ore is that of the Sierra de Pino, and the mines of Ramos. The antimonial gray copper ore is found at Tasco, and in the mine of Rayas, south-east from Valenciana. The muriate of silver, which seldom occurs in the veins of Europe, is very abundant in the mines of Catorce, Fresnillo, and the Cerro San Pedro, near the town of San Luis Potosi. That of Fresnillo is frequently of an olive-green, passing into a deeper shade of the same colour. In the veins of Catorce the muriate of silver is accompanied with molybdate and phosphate of lead. The red silver ore constitutes a principal part of the wealth of Sombrerete, Cosala, and Villalta, in the province of Oaxaca; and from the famous mine La Veta Ne-gra, near Sombrerete, more than 425,000 lbs. troy of silver have been extracted in the space of little more than six months. The true white silver ore is very rare in Mexico but its grayish white variety, rich in lead, is found in the intendancy of Sonora, where it is accompanied with argentiferous galena, red silver, brown blende, quartz, and sulphate of barytes. The martial pyrites found at Pachuca yields as much as three marcs of silver to the hundredweight of ore. In some parts the operations of the miner are directed to a mixture of brown oxide of iron and native silver, disseminated in particles imperceptible to the naked eye. This ochreous compound formed the object of considerable operations at the mines of Angangueo, in the intendancy of Valladolid, and at Yxtepexi, in the province of Oaxaca.

Native silver is much less abundant in America than is generally supposed; yet it has been found in considerable masses, sometimes weighing considerably more than 400 lbs. avoirdupois, in the mines of Batopilas, in New Biscay. In the veins of Mexico as well as in the mountains of Europe, native silver is constantly accompanied by glaserz or prismatic silver, particularly in the mines of Sombrercte, Madrono, Ramos, Zacatecas, Hapujaha, and Sierra de Penos. Throughout Mexico the ore, though infinitely more abundant, is much poorer than in Europe. The average proportion of silver obtained from the common ore is stated at from 0∙0018 to 0∙0025; in other words, sixteen hundred ounces of ore contain only from three to four ounces of silver. “The great mass of Mexican ore is so poor,” says Garces, in his work on Amalgamation, “that the three millions of marcs of silver which the kingdom yields in good years are extracted from ten millions of quintals of ore, partly by heat, and partly by amalgamation.” Indeed, from the vast quantity of silver which Mexicohad for centuries poured into the circulation of Europe (sometimes amounting, previously to the revolution of 1810, to between four and five millions sterling annually), the most extravagant notions were at one time entertained respecting the riches of the Mexican mines; and even the best-informed and the most scientific of travellers, Baron Humboldt, confesses that he had been misled by this erroneous opinion, and was surprised to find that the silver ores of Mexicowere, as already stated, even poorer than those of Europe, and that the mean produce of the whole mass extracted from the mines was only about one part of metal in four hundred of ore, or about one quarter per cent. ; a proportion which probably does not differ much from that which is obtained at the present time.

Of the whole mass of the Mexican ores, a small part only, not perhaps above one fifth, is sufficiently rich in metal to render it adapted to the process of smelting; and the remainder is therefore submitted to that of amalgamation, a method which is costly, from the loss both of mercury and of the precious metals which attends it. Much has been done by the English mining companies to lessen this double evil; but a great deal still remains to be effected, and the high price of quicksilver renders any further amelioration of the process a matter of the first importance to all parties concerned in the working of the Mexican mines.

This process, as actually performed, has been described by Gamboa in his Commentaries on the Mining Ordinances of Spain ; but, from the complicated nature of the operation itself, the obscurity of the technical terms employed, and the difficulty of distinguishing the various changes, chemical and mechanical, which are effected, a description in which the whole subject is as much as possible simplified, and these changes traced in succession as they occur, may not be unacceptable or uninteresting to the reader. The account which follows is more particularly applicable to the process as performed at the extensive hacienda of Sauceda, belonging to the Bolanos Company, because of it very minute information has been received; but it will nevertheless be found to correspond in almost every respect with the general practice pursued in the various mining districts of Mexico

Processes at the Mine. Dressing. — The ores generally consisting of native silver, sulphuret of silver, muriate of silver, argentiferous pyrites, &c. disseminated throughout the veinstone in a state of minute subdivision, are broken into small pieces with hammers, and partially separated from the matrix.

Processes at the Hacienda. Preparatory Operations. — The ore first undergoes the process of dry-stamping by the molinos, which converts it into a coarse powder called granza. The granza then undergoes the process of wet-grinding by the tahonas, which converts it into a very fine mud or slime called lama. Amalgamation. — The lama is first arranged in tortas, or flat circular heaps, in the patio, or paved court of the hacienda, and well mixed with saltierra, or impure muriate [7:15:263] of soda (common salt). No chemical change whatever is effected during these processes.

Processes. — Pulverized calcined magistral, that is, sulphate of copper and iron, is now added to the torta, and by the repaso process which follows is thoroughly mixed up with it. Chemical action then commences, and heat is given out.

Chemical Changes. — By the action of the air and moisture the magistral is decomposed, and its sulphuric acid set free. The sulphuric acid, thus liberated, rapidly combines with the water contained in the moist lama, and great heat is thus evolved, which favours the decomposition of the ores, and the subsequent oxidation of the metal. The sulphuric acid, thus liberated from the magistral, having a strong affinity for soda, decomposes the saltierra, setting free its muriatic acid, and forming with its base sulphate of soda, or Glauber salt. Owing to its strong affinity for silver, the muriatic acid liberated from the saltierra combines with the silver of the ores, and forms muriate or chloride of silver, whilst the portion in excess unites with the copper and iron of the magistral, forming muriates of copper and of iron.

Processes. — Calx or lime is used, when necessary, to cool the mixture. Azogue, or quicksilver, is now applied, by sprinkling it through pieces of coarse cloth, so that it falls in small drops like rain. It is then thoroughly incorporated with the mass, thus forming amalgam. When the first portion of quicksilver is supposed to have been quite taken up, a second supply is added, called el cebo. Finally, a third quantity of quicksilver is added, called el bαηο, During these operations the torta is thoroughly mixed together by the repaso, and other processes. The torta or mass of impure amalgam is then washed in the lavadero, being thoroughly stirred up in a cistern of water, by which process the earthy impurities are kept in a state of suspension, and finally carried away by the refuse water, which flows off at the top.

Chemical Changes. — The lime appears to act by combining with any portion of the sulphuric acid which may be in excess, and thus forming sulphate of lime or gypsum. The superabundant portion of sulphuric acid being thus taken up, the evolution of heat by its absorption of water is prevented, and the torta consequently cools. The mercury, owing to its strong affinity for silver, readily combines with it, forming an amalgam, the muriate appearing to have been previously decomposed by the iron of the magistral. Owing to the necessarily imperfect contact of the minute particles of the two metals, the formation of the amalgam is very gradual; hence the mercury is added at intervals, so as to take up the remaining particles of silver, to insure which it is always greatly in excess. During the washing in the lavadero, the muriates of copper and iron, and the sulphates of soda and lime, being all soluble salts, are dissolved in water, and carried off. The amalgam in the mean time settles at the bottom of the lavadero. Processes. — The amalgam, by a further washing in a tub at the azogueria, is freed from any earthy impurities which may yet remain. It is then placed in a canvass bag, which is suspended over a vat, and the uncombined quicksilver, owing to its weight, filters through. The pure amalgam, now termed pella deplata, is then moulded into wedge-shaped masses, called marquetas. In this form it is taken to the quemadero, and built up into a cylindrical pile, with a hole down the centre. The pile of amalgam, or pina de plata, is then placed on a copper stand, the above aperture opening a communication with the reservoir of cold water below. A large inverted crucible, called the capellina, is then placed over the pina de plata, and luted at the bottom. No chemical change is effected during these processes. A charcoal fire is then kindled around the capellina, the heat of which volatilizes the mercury of the amalgam. The vapour, having no other outlet, passes down the aperture in the middle of the pina deplata, and thence through a pipe into a cistern of cold water, where it is immediately condensed.

Chemical Changes. — Volatilization and subsequent condensation of the mercury.

Process. — When the process of distillation has continued for a sufficient time, the capellina is removed, and the crude silver, now forming a solid mass, is broken up into the original marquetas. The marquetas are then placed in a test with charcoal, and melted down by the action of a blast. By this process the silver is freed from any slight impurities which yet remain attached to it.

Chemical Change. — Silver refined by fusion.

Process. — Whilst in a state of fusion, the silver, now pure, is poured into a mould, and cast into bars, in which form it is sent to the mint for coinage. The general weight of the bars is about 135 Spanish marcs, or 82 lbs. troy, and the value about L.270, although depending, of course, on the fineness of the metal, and sometimes regulated by its containing a ley of gold.^[24. See Mining Review, No. VIII. p. 249, et seq. ]

Having thus explained the process of amalgamation, we shall now proceed to lay before our readers the most recent information which has been obtained respecting the produce of the Mexican mines. The following statement of the coinage in all the mints of the Mexican republic, during the year ending the 31st of December 1834, is contained in a communication by Consul-General O’Gorman, addressed to the Duke of Wellington.^[25. See Parliamentary Paper, entitled Comparative Statement of the Value Sterling of Gold and Silver raised in each of the Mining Countries of America and Russia, p. 6. ]
[table]
[7:15:264]

It appears, however, that the export of the precious metals from Mexicoin 1834 amounted to upwards of twenty-one millions, to which must be added the legal and clandestine exports by Matamoros, supposed to be about two millions, and the smuggled treasure from Vera Cruz and the smaller ports, estimated at one million and a half; so that about twenty-five millions of dollars in gold and silver, equal to L.5,000,000 sterling, were, in 1834, shipped to foreign countries, although the coinage of all the mints of the republic during that year was only 12,040,811 dollars, as shown by the above return, or L.2,400,000. A large proportion of this export was for the United States. “The produce of the Mexican mines,” says Mr O’Gorman, “has evidently increased to a great extent, notwithstanding the exorbitantly high price of quicksilver, which has prevented the reduction of ores of low quality for the last two years; and the riches lately discovered in the mines of Fresnillo, and again at Zacatecas, promise a still greater augmentation of silver.”

V. south AMERICAN MINES.

Under this head it will not be necessary for us to enter into any lengthened details, because ample information on the subject of the mines of South America will be found in the various articles of this work especially devoted to the description of the different countries, or states, into which that great continent is now divided, particularly in the accounts given of Bolivia, Brazil, Buenos Ayres, Chile, Colombia, Peru, &c. to which accordingly the reader is referred. There are few regions of the earth so remarkable for their mineral riches as the vast primitive chain of mountains called the Cordilleras, throughout which nature has distributed ores of the precious metals in greater abundance than in almost any other part of the world; although these are for the most part placed at an elevation which renders the working of them equally difficult and expensive. The most important mines are those of silver; but gold, quicksilver, copper, and lead are also extracted, some of them in very considerable quantities.

In Chile, especially in the province of Coquimbo, there are several mines of silver, and some important ones of copper. The Chileno mines are mostly situated in the interior of a hilly country of difficult access, to which the conveyance of fuel and materials is enormously expensive, and whence the transport of the produce to the places of embarkation is attended with much difficulty. The Chileno miners are described as very expert in following the course of a vein, though entirely ignorant of any thing like science, and even unable to explain the rules by which they are guided in pursuing their operations. The various processes followed in the reduction of the ores are also rude and simple; but being extremely economical, they are perhaps better adapted to the circumstances of the country than those which are employed in less difficult and more accessible regions. The greater proportion of the gold found in Chile is obtained from the auriferous sulphuret of iron, or gold pyrites, which is generally met with in high and lofty ridges, such as those of Illapel and Petorca. Some portion, however, is obtained from veins of rock, where very small grains of gold are disseminated in syenite, so minute as not to be visible to the naked eye, or from an ochreous decomposing syenite, distributed in veins, throughout which native gold is disseminated in thin flakes. Silver is found principally in limestone, or calcareous syenite; and it also occurs in beds of quartz, amongst which it is disseminated in the metallic state. But towards Copiapo it is generally found in lead ores, principally argentiferous galenas; and towards the south it occurs mineralized with sulphur. Copper is most frequently found in the state of sulphuret called bronze, but sometimes in that of carbonate, or sulphuret and carbonate intermixed.^[26. Miers’ Travels in Chile and La Plata, vol. ii. chap. 22 and 23. ]

The richness of the silver mines of Potosi, now included in the territory of Buenos Ayres, may be judged of from the fact, that since the period of their discovery in the year 154o, upwards of 1300 millions of dollars have been coined there. These mines are situated in an insulated mountain, about eighteen miles in circumference, which rises to an immense height, in the form of a sugar-loaf or cone; it is about an hundred leagues distant from the South Sea, near the sources of the river La Plata, is chiefly composed of a yellow, firm, argillaceous slate, and is full of veins which traverse the mountain in all directions, and are filled with ferruginous quartz, which constitutes the matrix of the silver ores. These consist principally of native silver and vitreous silver ore, the latter of which, on the first discovery of the mine, yielded about half its weight of pure silver; but the produce is much less now than formerly, all the richer veins having been wrought out and exhausted. Copper, lead, and tin, are also found in Buenos Ayres, the last occurring in beds of sand or clay, from which it is obtained by washing. On the opposite chain, in a level district, are the silver mines of Guantajaya, famous for the large masses of solid silver which they formerly yielded, and one of which weighed about 800 lbs.

In Peru there are forty districts particularly famous for their gold and silver mines. Gold is chiefly found in the provinces of Guailas and Pataz, and silver in the districts of Guantajaya, Pasco, and Chota. The celebrated mines of Pasco, which, some thirty years ago, produced considerably more than two millions of dollars annually, had, like most of those of South America, been very negligently managed until, in 1816, miners from Cornwall began to work them by means of steam-engines. These mines are properly in the ridge of Yauricoha, and are situated at the great height of 13,500 feet above the level of the sea. The distance of the village of Pasco from Lima is about fifty-eight leagues. The only persons capable of being employed at so great an elevation, where the barometer is always below nineteen inches, arc the Indians of the country, who, being bred upon high table-lands, can alone respire without inconvenience the attenuated atmosphere of so lofty a region. The riches of the metalliferous bed of Yauricoha are at no great depth below the surface, the greater proportion of the pits being somewhat less than 100 feet, and none of them exceeding 400 feet in depth. The length of this bed is about 16,000 feet, its breadth 7200 feet, and its thickness somewhat less than 100 feet. The number of mines does not exceed an hundred. The mineral bed consists of a porous ironstone, throughout which fine silver is disseminated; but patches of a friable white argillaceous earth about ten inches in thickness are sometimes met with in the midst of the large bed, and are often so rich as to yield from 200 to 1000 marcs per caxon. The consequence has been, that many miners, instead of following the bed regularly, have perforated it at random in search of these very uncertain riches, and, from carelessness, have endangered the existence of the whole mine. In fact, it is these perforations which are now denominated mines. The mines of the pfovince of Chota now furnish above 40,000 lbs. troy of silver annually. The quicksilver mine of Guancavelica in Peru is the only one of this kind in the New World. It is about fifty leagues to the eastward of Lima, being situated near the summit of one of the Cordilleras. This mine, which, for a period of two centuries, afforded annually from 7000 to 8000 quintals of [7:15:265] mercury is now nearly exhausted. The cinnabar of Guancavelica is disseminated in a sandstone similar to that of Almaden in Spain, being distributed in an immense accumulated mass, without the form of bed or vein; but the ore has become so poor that fifty quintals do not now yield more than six or eight pounds of mercury.

In the province of Guantajaya, there are mines of rock or fossil salt. To the north of the province of Chota, the Cordilleras are by no means so rich in metals. In New Granada, however, there are several silver mines; at Aroa, in Caraccas, there is a copper mine which yields from 1400 to 1600 cwt. of metal annually; and at Santa Fe de Bogota rock-salt and pit-coal are found. For an account of the gold and diamond mines or districts of Brazil, the reader is referred to the article under that head.

It now only remains to endeavour, by means of the tabular returns obtained from the British consular agents in South America, to exhibit a view of the actual produce of the gold and silver mines of that country. The following is an account of the gold, silver, and copper, raised from the mines in the province of Coquimbo, in Chile, distinguishing the different ports and mining districts from which the metals have been exported and remitted by land during the year ending the 31st December 1831 :—
[table]

The total value of the different quantities above stated, estimated in the currency of Chile, amounted to 2,379,539 dollars. The quantity of gold actually raised from the mines, however, is said to be much greater than that here stated; but no accurate account of the quantity extracted could be procured, owing to the circumstance of the article being chiefly exported in a clandestine manner, in order to avoid the duties, which are about four per cent. ad valorem. For this reason, any returns that can be obtained are comparatively of but little avail, as far as gold is concerned.

The following return of the marcs of gold coined at the mints of Lima and Cuzco between the years 1820 and 1833, is copied from the parliamentary paper to which we have already referred :—
[table]

We shall next exhibit, from the same Comparative Statement, ã return of the amount and value of silver coined at the mint of Lima between the 1st of January 1820 and the 31st of December 1833:—
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The number of marcs of silver coined at the mint of Cuzco between the years 1824 and 1832 was as follows, viz.
[table]
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From this and the preceding return taken together, it therefore appears that the
[table]

The next return which we shall give exhibits the number of marcs of silver of eight ounces reduced to bars at the different smelting houses of the republic of Peru therein specified, during the years from 1819 to 1833 both inclusive, as far as the same could be procured by the consul-general of Great Britain, in that country.
[table]

Tire following table shows the number of marcs of silver smelted at the different smelting houses of Peru during the three quinquennial periods from the beginning of 1819 to the end of 1833, and likewise the value of the silver thus smelted in dollars and pounds, for each separate period of five years :—
[table]

From a return of the silver coined in Peru between the 1st of January and the 3Ist of December 1834, it appears that the total amount of the coinage in 1834 exceeded the total amount of the coinage in 1833 by 18,586 marcs, which are equal to 121,764 dollars, or L.24,352. 8s.; thus showing that the working of the silver mines in that country is at length proceeding with increased spirit, activity, and success. (a.) Mines, Military, denote subterraneous galleries or passages excavated under the walks or ramparts of fortifications, and intended to be blown up by gunpowder.

The gallery or passage of a mine is commonly about four feet square, and at the end of this is the chamber or fourneau the mine, which is a cavity of about five feet in width, the same in length, and about six feet in height; and here the gunpowder is stowed. The saucisson of the mine is the train, for which there is always a small aperture left.

Two ounces of powder have been found, by experiment, capable of raising two cubic feet of earth; consequently 200 ounces, that is, twelve pounds eight ounces, will raise 200 cubic feet, or sixteen feet less than a cubic toise; because 200 ounces, joined together, have proportionally a greater force than two ounces, from being an united force.

All the turnings which a miner employs to carry on his mines, and through which he conducts the saucisson, should be well filled with earth and dung; and the masonry, in proportion to the earth to be blown up, should be as three to two. The entrance of the chamber or fourneau of the mine ought to be firmly shut with thick planks, in the form of a St Andrew’s cross, so that the enclosure be made secure, and the void spaces filled up with dung or tempered earth. If a gallery be formed below or on the side of the chamber, it must absolutely be filled up with the strongest masonry, half as long again as the height of the earth; for this gallery will not only burst, but likewise obstruct the effect of the mine. The powder should always be kept in sacks, which must be opened when the mine is charged, and some of the powder strewed about. The greater is the quantity of earth to be raised, the more decided will be the effect of the mine, supposing it to have the due proportion of powder. Powder has the same effect upon masonry as upon earth; that is, it will proportionally raise either with the same velocity.

The branches which are carried into the solidity of walls seldom exceed three feet in depth, and two feet six inches in width, or thereby. This species of mine, when properly formed, is calculated to blow up the strongest walls.

The weight of a cubic foot of powder should be about 80 lb.; one foot one inch cube should weigh 100 lb., and [7:15:267] one foot two inches and {11 /12 ths, 150 lb.: on the other hand, 200 lb. of powder will be one foot five inches cube; but there is a diversity in this, according to the quantity of saltpetre contained in the gunpowder.

If, when the mines are formed, water be found at the bottom of the chamber, planks are laid there, upon which the powder is placed, either in sacks or barrels of 100 lb. each. The saucisson must have a clear passage to the powder, and should be laid in an auget or wooden trough, through all the branches. When the powder is placed in the chamber, the planks are laid to cover it, and others again across these, then one is placed across the top of the chamber, which is shaped for that purpose; and between it and those which cover the powder, props are placed, which shore it up, some inclining towards the outside, and others to the inside of the wall, all the void spaces being filled up with earth, dung, bricks, and rough stones. Afterwards planks are placed at the entrance of the chamber, with one across the top, upon which are buttressed three strong props, the other ends of which are likewise propped against another plank situated on the side of the earth in the branch; and these props being well fixed between the planks with wedges, the branch should then be filled up to its entrance with the before-mentioned materials. The saucissons which pass through the side branches must be of exactly the same length with that in the middle, to which they are joined. The part which readies beyond the entrance of the mine is that which conveys the fire to the other three; and if the saucissons be of equal length, the mines will spring together.

From a great number of experiments, it appears that the force of a mine is always towards the weakest side, so that the disposition of the chamber of a mine does not at all contribute to determine this effect; that the quantity of powder must be greater or less in proportion to the greater or less weight of the bodies to be raised, and to their greater or less cohesion; that the entonnoir of a mine,^[27. That is, the cavity, aperture, or hole which remains after the explosion. ] if rightly charged, is a cone, the diameter of whose base is double the height taken from the centre of the mine; that when the mine has been overcharged, its entonnoir is nearly cylindrical, the diameter of the upper extreme not much exceeding that of the chamber; and that, besides the shock of the powder against the bodies it takes up, it likewise crushes all the earth which borders upon it, both underneath and sidewise.

To charge a mine so as to produce the most advantageous effect, the weight of the matter to be carried must be known; that is, the solidity of a cone whose base is double the height of the earth over the centre of the mine. Thus, having found the solidity of the cone in cubic fathoms, multiply the number of fathoms by the number of pounds of powder necessary for raising the matter it contains; and if the cone contain matters of different weights, take a mean weight between them all, due regard being always had to their degree of cohesion. As to the disposition of mines, there is but one general rule, which is, that the side towards which the miner would determine the effect be the weakest; but this varies according to occasions and circumstances.

The calculation of mines is generally built upon the hypothesis, that the entonnoir of a mine is the frustum of an inverted cone, the altitude of which is equal to the radius of the excavation of the mine, and the diameter of the whole lesser base is equal to the line of least resistance; and although these suppositions are not quite exact, yet the calculations of mines deduced from them have proved successful in practice; for which reason this principle should be followed until a better and more simple be found out. Μ. de Vallière found that the entonnoir of a mine was a paraboloid, which is a solid generated by the rotation of a semiparabola about its axis; but as the difference between these two solids is very insignificant in practice, that of the frustum of a cone may be used.

The mines of a fortress are denominated counter-mines, the gallery of which runs under the covered way, along the outer margin of the fosse. From this, ramifications (rameaux ) extend under the glacis, whence little passages are formed on both sides, so as to afford means for listening and discovering the subterranean proceedings of the enemy. Galleries made within a fortification, before a place is attacked, and from which branches are carried in different directions, are generally about four feet in width and about five in height. The earth is supported from falling in by arches and walls, as these galleries are intended to remain for a considerable time; but when mines are to be used as soon as formed, the galleries are only three feet or three feet and a half in width, and five feet in height, and the earth is temporarily supported by wooden frames or props.

A word or two now respecting the globe de compression. Suppose a large globe of earth, homogeneous in all its parts, with a certain quantity of powder lodged in its centre, so as to produce a proper effect without bursting the globe; it is evident that, by the ignition of the powder, the explosion will act equally all round, and the particles of earth, being porous, will compress each other in proportion as the expansive force increases the dimensions of the chamber. The particles of earth next to the chamber will communicate a portion of their motion to those adjoining, and the latter to those immediately beyond them; and this communication will continue in a decreasing proportion, until the whole force of the explosion be spent; but beyond that limit the particles of earth will remain in the same state as before. Thus the particles of earth which have been acted upon by the force of the explosion will form a globe, and to a certain extent drive all before them. This is the globe de compression invented by Belidor. Its object is, without any explosion perceptible at the surface, to shake the ground, and to destroy the hostile mines in the immediate neighbourhood.

Fougasses are a sort of small mines constructed before the weakest parts of a fortification, as the salient angles and the faces when not defended by a cross fire. Treffle mines are mines with two chambers only. T-mines, so called from their resemblance to the letter T, are double mines having four lodgments. Double T-mines have eight lodgments and four doors, whilst triple T-mines have twelve lodgments and six doors. Double treffle mines have four lodgments and eight doors; triple treffle mines have six lodgments and twelve doors.

Subterranean warfare has many peculiarities, and requires a rare union of skill, and courage, and perseverance. Sappers and miners are usually armed with pistols and cut-Iasses for their defence, when there is a chance of their meeting a hostile counter-mine; and if a combat ensue, the dead and the wounded are passed backwards from the most advanced workmen to those behind, until the mine is cleared. Balls made of all kinds of substances which produce an offensive stench when ignited, are also lighted, in order to stop the enemy, whenever the mine permits the party who set fire to the ball to effect an easy retreat from the mine. Sometimes mines are excavated in the field, for the purpose of blowing up such of the enemy as can be allured to the spot. In these cases, a small body of men is commonly placed immediately above the mine, to induce the enemy to attack with a superior force; if the stratagem succeed, the mine is instantly sprung (on fait jouer la mine), and, from the very nature of the operation, both parties are sometimes sacrificed.
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