CHAPTER IV.
SILVER.
We come next to speak of silver ore, another egregious folly of mankind. Silver is never found but in shafts sunk deep in the ground, there being no indications on the surface to raise hopes of its existence, no shining sparkles, as in the case of gold. The earth in which it is found is sometimes red, sometimes of an ashy hue. It is impossible, too, to melt it, except in combination with lead or galena, the latter being the name given to the vein of lead that is mostly found running near the veins of the silver ore. When submitted to the action of fire, part of the ore precipitates itself in the form of lead, while the silver is left floating on the surface, like oil[201] on water.
Silver is found in nearly all our provinces, but the finest of all is that of Spain; where it is found, like gold, in uncultivated soils, and in the mountains. Wherever one vein of silver has been met with, another is sure to be found not far off: a fact that has been remarked in the case of nearly all the metals, which have thus derived their Greek name of “metalla.”[202] It is a remarkable fact, that the shafts opened by Hannibal in the Spanish provinces are still worked, their names being derived from the persons who were the first to discover them. One of these mines, still called Bæbelo at the present day, furnished Hannibal with three hundred pounds’ weight of silver per day. The mountain is excavated for a distance of fifteen hundred paces; and throughout the whole of this distance water-bearers stand night and day, baling out the water in turns, by the dim light of torches.
The vein of silver that is found nearest the surface is known by the name of “crudaria,” raw silver. In ancient times, the excavations used to be abandoned the moment alum was met with, and no further search was made. Of late, however, the discovery of a vein of copper beneath alum, has withdrawn any such limits to man’s hopes. The exhalations from silver-mines are dangerous to all animals, particularly to dogs. The softer they are, the more beautiful gold and silver are considered.
There are two kinds of silver. On placing a piece upon an iron-shovel at a white heat, if the metal remains perfectly white, it is of the best quality: if it turns a reddish color, it is inferior; but if it becomes black, it is worthless. Fraud, however, has devised means of stultifying this test even; for by keeping the shovel immersed in ammonia, the piece of silver absorbs it as it burns, and so displays a fictitious whiteness.
CHAPTER V.
MIRRORS.
It is generally supposed among us that only the very finest silver admits of being laminated, and so converted into mirrors. Pure silver was formerly used for the purpose, but, at the present day, this has been corrupted by the devices of fraud. But, really, it is a very marvellous property that this metal has, of reflecting objects. If a thick plate of this metal is highly polished, and is rendered slightly concave, the image or object reflected is enlarged to an immense extent. Even more than this—drinking-cups are now made in such a manner, as to be filled inside with numerous concave facets, like so many mirrors; so that if but one person looks into the interior, he sees reflected a whole multitude of persons.
Mirrors invented to reflect monstrous forms have been consecrated in the Temple at Smyrna. It makes all the difference whether the surface has a concave form like the section of a drinking cup, or whether it is convex like a Thracian buckler; the peculiar configuration of the surface which receives the shadows, causing them to undergo corresponding distortions: for, in fact, the image is nothing else but the shadow of the object collected upon the bright surface of the metal.
However, to finish our description of mirrors on the present occasion—the best, in the times of our ancestors, were those of Brundisium, composed of a mixture of stannum and copper: at a later period those made of silver were preferred, Pasiteles being the first Roman who made them, in the time of Pompey the Great.
The people of Egypt stain their silver vessels, that they may see represented in them their god Anubis; and it is the custom with them to paint, and not to chase, their silver. This usage has now passed to our own triumphal statues; and, a truly marvellous fact, the value of silver has been enhanced by deadening its brilliancy. The following is the method adopted: with the silver are mixed two-thirds of the very finest Cyprian copper, that known as “coronarium,” and a proportion of live sulphur equal to that of the silver. The whole of these are then melted in an earthen vessel well luted with potter’s clay, the operation being completed when the cover becomes detached from the vessel. Silver admits also of being blackened with the yolk of a hard-boiled egg; a tint, however, which is removed by the application of vinegar and chalk.