CHAPTER XXXI.
THE NEW METALS.
Zinc—The Ores, but not the Metal, known to the Ancients—Rapid Increase of its Production—Chief Zinc-producing Countries—Platinum—Antimony—Bismuth—Cobalt and Nickel—Wolfram—Arsenic—Chrome—Manganese—Cadmium—Titanium—Molybdenum—Aluminium—Aluminium Bronze—Magnesium—Sodium—Palladium—Rhodium—Thallium.
The metals known to the ancients were either such as occur in a native state and whose lustre must attract even the attention of the savage, or such as are easily extracted from their ores by the simple agency of fire and carbon, and consequently require no complicated metallurgic treatment. Their number is limited to the seven substances described in the preceding chapters; but the art of the modern chemist has greatly extended our knowledge of metals, and revealed to us the existence of no less that fifty-six of these elementary bodies.
Some have been found to lurk under the obscure disguise of alkaline and earthy matters, such as clay and chalk, magnesia and sand, soda and potash; others have been discovered in the water of mineral springs, or under the brilliant mask of precious stones. Most of these were unknown before the beginning of the present century, nor can there be a doubt that future researches will make us acquainted with many metals whose existence is still a secret to mankind.
Most of these new metals are as yet mere objects of curiosity, either from their rarity or the great difficulty and cost of their production; but some of them are already of considerable use, and within the last fifty years zinc has obtained a rank among the most important products of the mineral world. Calamine, the chief ore which provides us with this metal, was indeed known to the ancients, who by smelting it with copper ores obtained an alloy similar to our brass;[[61]] but the metal itself seems to have been first discovered by the famous alchemist Bombastus Paracelsus, who flourished towards the end of the fifteenth century. Zinc, however, remained unnoticed as a useful metal until the year 1805, when Hobson and Sylvester’s discovery that it is malleable at a temperature of 300° F., and can then be worked to any shape with great facility, caused it to replace lead for many purposes, in which its hardness and other valuable qualities render it superior. As it is very easily extended into thin sheets, and combines the advantages of lightness, salubrity, and durability, it is frequently used for the roofing of houses and for the sheathing of ships. Many of our domestic utensils, particularly those which serve for the holding of liquids, are now made of zinc. Large quantities are moulded into architectural ornaments; and the splendid white colour of the oxide of zinc has made it a triumphant rival of ceruse, or white-lead. To provide for so many uses, the production of zinc has in a short time made strides without a parallel in the history of metals. While before 1808 from 150 to 200 tons sufficed for the annual consumption of Europe, more than 110,000 tons are now required, so that in little more than half a century the demand has increased more than five hundred times, and a metal previously almost unnoticed is now produced in masses worth several millions of pounds.
The chief zinc-producing countries of Europe are Prussia and Belgium. The Prussian mines, which in 1866 yielded 1,204,419 hundredweight, or about 60,000 tons, are situated in Silesia, Westphalia, and the Rhenish provinces. In the same year Belgium produced 35,500 tons, chiefly from the mines of the Vieille Montagne, near Aix-la-Chapelle, where calamine occurs in a large mass, imbedded in chalk, and is worked like an open quarry.
In England calamine is, next to galena, the most important ore obtained from the Derbyshire mines, and of late years large quantities of blende or sulphuret of zinc—an ore which, on account of the special difficulties offered by its treatment, had hitherto been neglected—are likewise furnished by the Isle of Man, Denbighshire, Flintshire, and Cornwall.
In 1864 our entire production of zinc amounted to no more than 4,040 tons; but since that period it has been considerably increased by the importation of immense quantities of Sardinian, Swedish, and Spanish ores, which are for the most part reduced in the works of Messrs. Vivian, at Swansea.
For many years the United States depended upon Europe for their whole supply of zinc; but as nature seems to have denied none of her mineral riches to the great republic, the discovery of immense deposits of calamine and blende in the state of Tennessee has enabled them to compete successfully with foreign produce, and the works of Leehigh and Lasalle now furnish a large proportion of the zinc consumed in the country.
Platinum, the heaviest body in nature, was first discovered by the Spaniards, in the gold mines of Darien, probably in the first half of the sixteenth century;[[62]] but as it remained infusible in the strongest heat, and no method was known for purifying its ore, in which it is remarkably combined with six or even seven other metals, it continued for a long time to be a mere object of curiosity. In 1772 Count Sickingen discovered that it can be welded like iron when urged to a white heat, and first succeeded in producing platinum wire and platinum leaves. A few years after the celebrated Swedish chemist, Bergmann, isolated it from the metallic substances associated with its ore, and proved it to be a peculiar metal.