But even Almaden and Idria have lost much of their former importance since the discovery of the rich mines of New Almaden in California, which in 1865 yielded 4,000 hundredweight of mercury. As the uses of mercury are few, the falling off in price has been the consequence. But the greater cheapness of mercury has had a most favourable influence on the production of silver in Mexico, Peru, Bolivia, &c., as many of the poorer ores can now be profitably worked; and thus California, which by its gold placers threatened to disturb the relative value of the two precious metals, has, by promoting at the same time the production of silver, largely helped to maintain the former equilibrium and to relieve the fears of many political economists. It is a remarkable circumstance that, while Europe has for the last three centuries received almost all its silver from America, Mexico and Peru were all the time dependent upon the old world for the mercury without which Potosi and Guanaxuato would have been comparatively unproductive. Quicksilver, it is true, had been found here and there, but the only mine of importance was that of Huancavelica in Peru, the discovery of which in the year 1567 is attributed to the Indian Gonzalo Navincopa, though, according to Humboldt, it was already known to the Incas, who made use of cinnabar to paint their cheeks, as Roman senators and Athenian archons had done before them. Here, at a height surpassing that of the Peak of Teneriffe by 1,500 feet, from 4,000 to 6,000 cwt. of quicksilver were annually obtained, until the folly of a director ruined the chief mine. Ever since 1780 Huancavelica had with difficulty supplied the growing wants of the Peruvian silver mines, for at a greater depth the ore was found to be mixed with sulphuret of arsenic, which greatly deteriorated its quality. As the lode forms an enormous mass, strong pillars had been left standing to support the roof, and these props the above-mentioned director had the improvident temerity to remove, in order to increase the produce of the mine. What anyone with a little experience or common-sense might have foreseen, took place. The rock, deprived of its supports, gave way, the roof fell in with a tremendous crash, and the mine was ruined—a memorable warning against the greed which, snapping at a shadow, loses the substance. 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.