Platinum is found in almost all the auriferous districts of the globe, but generally in such small quantities as not to be worth the collecting. Kuschwa Goroblagodat and Nishne-Tagilsk, in the Ural, furnish annually about eight hundred hundredweight, which is nearly ten times the amount from Brazil, Columbia, St. Domingo, and Borneo. But, in spite of this scanty production, its discovery must be considered as one of the most important conquests which science has made in the material world, as its perfect infusibility, its hardness, its unalterability by air and water, and its property of withstanding the action of the most corrosive simple acids, render it an invaluable material for the fabrication of various chemical vessels, without whose assistance many important discoveries could not possibly have been made. To the manufacturers of sulphuric acid large retorts of platinum are indispensable for concentrating this highly corrosive fluid, which devours every other metallic vase with which it comes in contact. The price of platinum is intermediate between that of gold and silver.
The ores of Antimony played a great part in the labours of the alchemists, but the metal is first mentioned in the works of Basilius Valentinus, who flourished during the second half of the fifteenth century. It is used chiefly in several important alloys. Combined with lead it constitutes type-metal, and united with lead and tin it is employed for making Britannia metal, and the plates on which music is engraved. Nearly all the antimony of commerce is furnished by the grey sulphuret (stibnite), which occurs in Hungary, Saxony, South America, and Australia. Though Cornwall produces a considerable quantity of antimonial ore, our chief supply is derived from Singapore, the emporium of the various mines of Borneo and other parts of the Malayan Archipelago.
The grey antimony ore was employed by the ancients for colouring the hair and the eyebrows, and for staining the upper and under edges of the eyelids—a practice still in use among Oriental nations for the purpose of increasing the apparent size of the eye. According to Dioscorides, it was prepared for this purpose by inclosing it in a lump of dough, and then burning it in the coals till it was reduced to a cinder. It was then extinguished with milk and wine, and again placed upon coals and blown until it was ignited, after which the heat was discontinued, lest, as Pliny says, ‘plumbum fiat’—it become lead. It hence appears that the metal antimony was occasionally seen by the ancients, though not distinguished from lead.
Bismuth, a metal of a dull silver-white colour, inclining to red, is first mentioned in the writings of the alchemists of the Middle Ages. It is almost exclusively furnished by the mines of Schneeberg in Saxony, where it is generally found in a native state. On account of its great fusibility and brittleness it is seldom used alone; but associated with other metals it forms several valuable alloys.
In the Middle Ages the Saxon and Bohemian miners believed all those ores from which, in spite of their promising appearance, they were unable to extract a useful metal, to be a work of the gnomes mocking the industry of man. Some of these ores they called Kobold—an opprobrious name given to these evil subterranean spirits, who were supposed to be of dwarfish stature and intense ugliness; others Nickel—a name probably of the same meaning as our old Nick. The progress of metallurgic industry has fully exculpated the gnomes of all evil intentions, for the last century succeeded in extracting the metals Cobalt and Nickel from those rebellious ores. Cobalt, though as yet but rarely employed, gives promise of some future importance, as it appears to be extremely tenacious. A wire made of pure cobalt will carry nearly double the weight that an iron wire of the same thickness will do.
The cobalt ores, which impart a magnificent blue colour to glass, have lost much of their importance as pigments since the discovery of artificial ultramarine, while the nickel ores which usually accompany them, and were formerly thrown away as rubbish, have become valuable, since the metal which they contain has found some important uses. The small coin of Belgium and Switzerland is now made of nickel instead of copper, and large quantities are employed in the fabrication of German silver, or Argentine plate, an alloy of copper, nickel, and zinc, which, from its hardness and brilliant white colour, furnishes an excellent material for tablespoons and forks. Both the nickel and cobalt ores are produced chiefly by Sweden, Norway, and Germany; our own mines furnish but insignificant quantities. In the United States the Camden works (New Jersey) now produce nickel at the rate of 150,000 pounds a year.
Tungsten, a metal discovered in 1783 by two Spanish chemists, the brothers Juan and Fausto d’Elhujar, in a black mineral called wolfram, which frequently occurs along with tin ores in Cornwall (where it is known under the names of cal, or callen, and gossan), Saxony, Austria, &c., is in its isolated state a mere object of scientific curiosity, but when melted with cast steel or even with iron only, in the proportion of from two to five per cent., it produces a steel which is very hard and fine-grained, and for tenacity and density is superior to any other steel made. Hence wolfram-steel, which is now coming extensively into use in Germany, makes the best knives and razors; but, unfortunately, the rarity and high price of wolfram confine its production within narrow limits. Several of the tungstates, or salts of tungsten, are used as pigments; and the tungstate of soda has the highly valuable property of rendering fabrics uninflammable, and thus furnishes a means for preventing the accidents which constantly occur from the burning of ladies’ dresses.
Albert the Great, a famous alchemist of the thirteenth century, is supposed to have been the discoverer of Arsenic, a tin-white metal, which, however, soon loses its brilliancy when exposed to the air, and turns black. From its poisonous qualities it is only used in some unimportant alloys which serve for the manufacture of insignificant articles, such as buttons or buckles. Some of its ores and combinations, which, from their lively yellow, green, and red colour, would otherwise have been valuable pigments, are likewise for the same reason seldom used. A great number of copper, nickel, lead, cobalt, zinc, and iron ores contain some arsenic; but this dangerous substance is obtained chiefly from the common arsenical pyrites (Mispickel—sulphuret of iron and arsenic), which occurs in Cornwall and Devonshire. The whole supply of arsenical ores amounted in 1866 to about 2,610 tons, of which England and Prussia furnished the greater part.
The metal Uranium, discovered in 1789 by the celebrated Klaproth, in a black heavy mineral, called Pechblende (pitch-blende), occurring in the mines of the Erzgebirge, is not used as such, but is very valuable in porcelain-painting, as it affords a beautiful orange colour in the enamelling fire, and a black colour in that in which the porcelain is baked. A laboratory has been opened at Joachimsthal, where the ore is converted into uranate of soda for this purpose.
Chrome, like cobalt, is used chiefly as a pigment. Several of its salts are splendid yellow colouring matters, and its oxide imparts the finest green tints to porcelain. The metal itself, which was discovered by Vauquelin in 1797, is, as yet, an object of interest only to the chemist, but may one day become important, as in its pure state it is very hard, unalterable by air and water, and even less fusible than platina. Most of its ores belong to the rarer minerals, and but one, chrome-iron, occurs in sufficient abundance for industrial purposes. It is found in Hungary, in Norway (which annually exports about 16,000 tons to Hamburg and Holland), in Siberia, and in large quantities in Maryland and Pennsylvania. The ore employed in England is obtained mostly from Baltimore, Drontheim, and the Shetland Isles, and amounts to about 2,000 tons annually.