Page:Popular Science Monthly Volume 53.djvu/556

538 night of the ages. It has hardly been more than a century since chemists first succeeded in accounting for the reactions and in improving upon them by the aid of more precise notions founded on the theories of modern science; and our own age has witnessed a still more radical transformation in metallurgy resultant upon the discoveries in electro-chemistry. But everything rested, in antiquity, upon empiricism, unguided, except by vague analogies.

The metals which the ancients thus obtained and made use of were not always pure metals. The ancients had a number of varieties of copper and of lead. First, a distinction was made between black lead and white lead; the first being our modern lead, while the second has become our tin. These names were, however, applied to other metals and alloys, including antimony, which was obtained by roasting and reducing its sulphuret, under conditions which are described by Dioscorides; and some alloys of silver originally designated by the name of cassiteros, which was afterward applied to our tin. The stannum of Pliny also has this double meaning.

The white alloys, of brilliant and little changeable surface, were given a special name—asem, or Egyptian silver—a name which was continually reappearing with the Greek alchemists, and was confounded with the name of silver without definite title—asemon—a designation which was given to very diverse substances, from pure tin to electrum. So it was with the metal called chalkes in Greek, aes in Latin—a name which included innumerable species; whence modern translators use indifferently the words brass, copper, and bronze to represent it. modern pure copper is too soft to be used for forging arms or solid tools, and the Greek and Latin names usually refer to alloys. The ancients had copper of different colors, and specified the species by adjectives derived either from these colors, or from the place of origin of the substance. Thus, they had red copper and Cyprian copper, aes Cyprium—an epithet which, in the time of the Roman Empire, became the name of the metal, cuprum—besides yellow copper, white copper, etc. Yellow copper in its turn included several varieties, for its composition varied greatly. First, there were the bronzes, alloys of copper and tin, used for many centuries in the manufacture of arms, till they were dethroned by the advances in the manufacture and tempering of iron. In the Roman Empire one of these alloys, which was used for mirrors, was designated, after the name of Brindisium, where the manufacture was carried on, aes Brundusinum, whence our word bronze is derived; in other alloys of various shades, yellow or whitish, copper was combined with lead or zinc—a metal which the ancients did not know in a state of purity, but of which they were acquainted with the minerals, natural cadmies or calamies