Copper was the metal in common use in the early part of the Roman commonwealth. Romulus coined copper money alone. Numa established a college of workers in copper (ærariorum fabrum).[35]
The Latin word æs sometimes signifies copper, and sometimes brass. It is plain from what Pliny says on the subject, that he did not know the difference between copper and brass; he says, that an ore of æs occurs in Cyprus, called chalcitis, where æs was first discovered. Here æs obviously means copper. In another place he says, that æs is obtained from a mineral called cadmia. Now from the account of cadmia by Pliny and Dioscorides, there cannot be a doubt that it is the ore to which the moderns have given the name of calamine, by means of which brass is made. It is sometimes a silicate and sometimes a carbonate of zinc; for both of these ores are confounded together under the name of cadmia, and both are employed in the manufacture of brass.
Solinus says, that æs was first made at Chalcis, a town in Eubœa. Hence the Greek name, χαλκος (chalkos), by which copper was distinguished.
The proper name for brass, by which is meant an alloy of copper and zinc, was aurichalcum, or golden, or yellow copper. Pliny says, that long before his time, the ore of aurichalcum was exhausted, so that no more of that beautiful alloy was made. Are we to conclude from this, that there once existed an ore consisting of calamine and ore of copper, mixed or united together? After the exhaustion of the aurichalcum mine, the salustianum became the most famous; but it soon gave place to the livianum, a copper-mine in Gaul, named after Livia, the wife of Augustus. Both these mines were exhausted in the time of Pliny. The æs marianum, or copper of Cordova, was the most celebrated in his time. This last æs, he says, absorbs most cadmia, and acquires the greatest resemblance to aurichalcum. We see from this, that in Pliny’s time brass was made artificially, and by a process similar to that still followed by the moderns.
The most celebrated alloy of copper among the ancients, was the æs corinthium, or Corinthian copper, formed accidentally, as Pliny informs us, during the burning of Corinth by Mummius in the year 608, after the building of Rome, or one hundred and forty-five years before the commencement of the Christian era. There were four kinds of it, of which Pliny gives the following description; not, however, very intelligible: 1. White. It resembled silver much in its lustre, and contained an excess of that metal. 2. Red. In this kind there is an excess of gold. 3. In the third kind, gold, silver, and copper are mixed in equal proportions. 4. The fourth kind is called hepatizon, from its having a liver colour. It is this colour which gives it its value.[36]
Copper was put by the ancients to almost all the uses to which it is put by the moderns. One of the great sources of consumption was bronze statues, which were first introduced into Rome after the conquest of Asia Minor. Before that time, the statues of the Romans were made of wood or stoneware. Pliny gives various formulas for making bronze for statues. Of these it may be worth while to put down the most material.
1. To new copper add a third part of old copper. To every hundred pounds of this mixture, twelve pounds and a half of tin[37] are added, and the whole melted together.
2. Another kind of bronze for statues was formed, by melting together 100lbs. copper, 10lbs. lead, 5lbs. tin.
3. Their copper-pots for boiling consisted of 100lbs. of copper, melted with three or four pounds of tin.
The four celebrated statues of horses which, during the reign of Theodosius II. were transported from Chio to Constantinople; and, when Constantinople was taken and plundered by the Crusaders and Venetians in 1204, were sent by Martin Zeno and set up by the doge, Peter Ziani, in the portal of St. Mark; were in 1798, transported by the French to Paris; and finally, after the overthrow of Buonaparte, and the restoration of the Bourbons in 1815, returned to Venice and placed upon their ancient pedestals. The metal of which these horses had been made was examined by Klaproth, and found by him composed of Copper, 993 Tin, 7 1000 [38]