CHAPTER XV. METALS. How the metals are distinguished and diversified-In what a variety of situations they are found-Peculiar characteristics of this order of Minerals-Different forms in which they appear-Malleable Metals-Platina-Gold-Mercury, or Quicksilver.-A monument to the memory of conjugal affection and female virtue.-Silver-Copper. "On vermil beds, in Idria's mighty caves, "And copper sparkles next in ruddy streaks."—GARTH. WE come now to consider THE ORDER OF METALS; and what a variety of these present themselves,-malleable and brittle—ductile and fragile; and by what different degrees of lustre and sonorosity, as well as specific gravity and tenacity, are these distinguished, from the Gold of Ophir, and other metals of the ancients, to the modern Platina, with its usual accompaniments Palladium and Iridium-Osmium and Rhodium-and glass, or that created by the operation of the blow-pipe-before which the elements themselves shall be burnt up with a fervent heat, and the most indestructible of earth's perishing toys be dissolved! the still more modern Cadmium, discovered so lately as the year 1818.* And in what a variety of situations are they to be found!-Some, we observe, are carefully locked up in veins, or hid deep in the heart of primitive formations; -Some are widely disposed in the regions of secondary strata, and scattered about in beds and masses in these capacious repositories which approximate nearer to the surface of the earth;-Some, even some of the most precicus kinds, are found at the surface, mingling with the sands and pebbles of the rivulet, and by a very simple process may be washed from the alluvion soil.+ * Blumenbach mentions the following, as metals at present known: But besides these, there are a few others mentioned by Mr Mawe, which are not here enumerated, as also the newly discovered metals by Sir Humphry Davy. "What," in the words of Mr Mawe, " are called the gold mines of Brazil and Africa, are on the surface. The simple act of washing peculiar places, separates the gold from the gravel, and by this means great quantities are found. In Brazil alone, above twenty tons weight are annually procured, which forms a large share of the circulating medium of Europe. The mining district is called Minas Gerais; and the reader will learn with surprise, that it does not contain one deep mine or one subterranean excavation. What is there termed a mine, -is a peculiar place, or superficies of greater or less extent, where the surface is raked from or dug to the solid rock, consisting of rounded substances, earthy matters, sometimes precious stones, as topaz, aquamarines, &c. besides gold and diamonds, of which it There are a few characteristics which peculiarly bes long to this order of minerals. The first, is that peculiar brightness which pervades their whole substance, and which being their most apparent distinguishing characteristic, is called their metallic lustre-the second, is their perfect opacity, notwithstanding this refulgent lustre-the third, is their great weight when compared with other substances, the lightest of them being more than 6, while the heaviest of the earths is only about 5 times heavier than water. Metals are also insoluble in water, and in the act of fusion in an earthen vessel, present a convex or rounded surface.* Of the metals known, or, at least, that have been enu is the great receptacle. Platina is found also in grains, the same way as gold." How these precious fragments came to be disposed in such situations is another question, as these cannot be supposed to be their na tive soils; but it may be easily accounted for upon the same principle, that these two valuable minerals are always so found, in their native metallic state, because of their extreme durability,-by which, being with difficulty acted upon by the Chemical Agents which nature employs in the decomposition of rocks and other depositories of these precious materials, they are left exposed in their native state, at the bottom of streams, or mixing with the debris, after the bulky parts of the masses that contained them have been washed away or crumbled into dust. t • You will observe, that although some of them are found in certain quantities in a pure or native state, the greater part are mixed or combined with other substances, from which they have to be separated by heat and other means, and in that condition are called Ores; yet, when separated from the other substances with which they had been combined in a state of ore, metals are brought to as-. sume the same appearance, and are possessed of the same properties or qualities, as if they had been at first obtained from the earth, in a native, genuine, and pure state. merated, twelve only are possessed of that property of extension by beating with the hammer, in consequence of which, they are distinguished by the name of malleable metals; and these are, platina, gold, silver, mercury, lead, copper, tin, iron, zinc, palladium, nickel, and cadmium-the others are denominated brittle, or fragile metals.* To commence our observations with some of the malleable metals, that, which seems to claim our more immediate attention, is Platina, which, although a metal of modern date, and not quite so malleable and ductile as gold and silver, deservedly stands at the top of the list on account of its being harder, and consequently better adapted to some important purposes than either, platina being the heaviest and most difficult of fusion of all known metals.t This metal was unknown in Europe until about the year 1735, when it was first brought from South America, and till lately, that a small portion of it was detected in a grey silver ore in the mines in Spain, it was only to be found in that quarter of the globe in alluvial soil, It may seem rather odd, to rank mercury, which will not bear the least pressure without separating into parts, if it has room to fly off, among the malleable metals. By the effect, however, of artificial cold, mercury becomes solid metal, and, as such, may be extended and beaten out with a hammer. ↑ This extraordinary metal is of a silvery colour-is of a specific gravity heavier than gold, formerly the heaviest of all known metals -in ductility, or capacity of being drawn out into wire, it ranks next to silver-in malleability it stands next to tin-is considerably harder than iron, and not liable to rust, and is so extremely difficult to melt that it is not fusible by a forge.. from which it was extracted by the simple process formerly mentioned.* Not such, however, is the case with that more plentiful commodity Gold, which, although in several places it is to be met with in small quantities only, is to be found in one shape or other, in almost every country of the world-and being frequently met with in the veins of primitive mountains, and disseminated in the rock itself, as well as in alluvial formations, before noticed, this valuable metal may be considered as occupying, in some degree, a place in all or most of the different strata that lie between these extreme points.† • In a periodical publication for March 1821, we are, however, informed, that "a Negro slave, in the gold mines of Condoto, in the government of Choco, in South America, found a mass of platina of extraordinary magnitude, and which is now deposited in the Royal Muscum at Madrid. It weighs rather more than one and one-third of a pound, and is the largest piece of this metal hitherto met with!" And, among the recent valuable discoveries made in the Russian domains, mention is made of a platina mine, containing a small quantity of gold, situated in the district of Goroblahadat, government of Perm, two versts from Kouchversk, and twelve from the Isa, as being discovered in March 1825. The metallic sand lies about one archive and a half below the surface, and the thickness of the strata is about two archives and a half. In five pouds of the sand, half a zolotuik of gold and five parts of platina have been obtained. The strata have been examined for a considerable distance, and are found to be very rich, containing at least 10 zolotuiks of metal to every 100 pouds. † Spain may be considered, from the experiments made in the Austurian mines before the discovery of America, as very rich in gold, although the principal mines now worked in Europe are those of Hungary and Salzburg. It is pretty widely diffused through the whole extent of Asia. Of the gold used by the ancients, a consider. able quantity was obtained from Africa, where it is still to be found |