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. 262 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.
the triumvir antonius alloyed the silver denarius with 263 iron: and in spurious coin there is an alloy of copper employed. it is truly marvellous, that in this art, and in this only, the various methods of falsification should be made a study:[203] for the sample of the false denarius is now an object of careful examination, and people absolutely buy the counterfeit coin at the price of many genuine ones!
