II. Extraction and Use of Metals.
The art of extracting the metals from their ores, lying, as it does, at the very foundation of the means by which the useful arts advance, cannot be said to have reached a high point of perfection in Greece, Rome, or the other countries from which they derived their supply. An idea of mining processes can scarcely be better given than by a description of those used in the Attic silver mines at Laurium.
The veins of silver were situated in a range of pine-covered hills of no considerable height, affording quarries of good marble, in contact with which substance the silver ore was mostly found. These mines were probably opened at a very early period, but the precise date does not appear. The ore, or “silver earth,” as the Greeks called it, was extremely hard and probably very pure and rich in the yield of metal, as the Greeks, from their defective knowledge of chemical processes, could not extract the silver with profit when united with large proportions of other metals. Contrary to common experience, the ore appears to have assumed the form of layers rather than of veins.
The mines were worked, either by perpendicular shafts, or by tunneling the side of the hill. Pillars of the ore were of course left, or the superincumbent mass was supported by props of timber, which was largely imported for the purpose. The noxious vapors exhaling from the mines were carried off by shafts of ventilation. The ore was removed partly by simple machines, partly by unassisted labor. On reaching the mouth of the mine it was broken small with iron pestles in stone mortars. These pieces were then ground down smaller, washed, strained through sieves, and sorted into qualities of different richness.
The art of smelting the ore thus obtained was imperfect, when viewed in comparison with the greater skill of the moderns. “Even in the time of Strabo, when considerable improvements had been effected, there was still no profit to be gained by the extraction of silver from lead ore, in which it was present in small proportions.”[[2]] But that some improvement took place is evident from the fact, that much ore rejected by the earlier operators was at a later period profitably employed. Crucibles have been found in Egypt similar to those in modern use. Similar ones were probably known to the Greeks, and old remains of bell-shaped smelting furnaces have been met with, furnished with a channel for the escape of the molten metal, which renders it probable that such furnaces were employed in Greece and Rome.
In the silver ore of Laurium lead was largely present, and according to Pliny, the ore was first melted down to the substance called “Stannum,” a union of lead with silver. This was taken to the refining oven, where the silver was separated by heat, and the lead remained half glazed in the form of litharge, which in its turn was reduced. But the ancients were also familiar with the use of quicksilver in the extraction of other metals, and the moderns have only a claim to re-discovery in this respect. The bellows and charcoal were employed to produce the extreme heat required in refining processes.
Various substances are mentioned as the products of these ancient metallic operations; the “flower” of gold and of copper; the “foam” of silver, with some others, all of which were used in medicine. In the mines of Laurium, copper, cinnabar, and “sil,” a lightish yellow earth much used by painters, and containing iron, were also found.
But though Greece had mines of silver and even of gold, still great part of the precious metals in circulation was imported from Asia and Africa. India, the great source of wealth and luxury in all times, furnished copious supplies for those large deposits of bullion stored in the temples and treasuries of Greece.
A very natural transition leads us to the Greek and Roman coinage. Silver money was first coined at Ægina, so early as 869 B. C., and was originally the only current coin in Greece. The early coins are rather rough in appearance, and bear a rude mark on the reverse, as if from a puncheon on which the metal was placed for striking the piece. The Athenian silver money was remarkably pure, indeed so much so as to be taken at a premium throughout Greece. Some coins contained only one-sixtieth part of their weight in baser metal, whilst our own silver coinage contains a twelfth. Among the Greeks, gold coinage was subsequent to silver, and bronze was still later introduced.
The earliest Roman coins were composed of bronze, and were cast in a mould instead of being struck as in Greece. Some remains of Roman coinage show the cut edge of the line of metal which united adjacent coins when taken from the mould, in which the whole row had been cast together; and some such rows are still found in an undivided state. The cumbrous nature of the early Roman coinage was such that each piece weighed a pound. In fact, in this respect it seemed to come near the weighty iron coinage of Sparta, of which we may add that no remains exist.
In Athens and Rome the smallest silver coins were very minute indeed. The Athenians possessed separate silver coins, running from the piece of four drachmæ, in value about 3s. 4d., down to the quarter of an obolus, which was less in value than our halfpenny. The silver coin responding to this value was very minute, weighing less than three grains. There were Roman silver coins even smaller than this; probably some existed of no more than 1½ grain in weight, or considerably less than one quarter of the size of our silver pence. But the great inconvenience of such small coins led to the striking of corresponding values in bronze, and these “silver scales,” for they had just the appearance of such, went out of use.
A gold coinage in Greece probably did not exist before the age of Alexander the Great, though their near neighbors in Asia undoubtedly possessed gold money from an early age; and pieces of this became current in Greece. The few remaining gold coins of Greece appear not to have been struck before the period mentioned above. But on the rise of the Macedonian empire gold coins became plentiful through the country.
Gold was first coined in Rome B. C. 207, sixty years after the commencement of their silver currency. The common size of their pieces was probably about the same with that of our sovereign; but some existed in size only one quarter of our half sovereigns, and representing about 2s. 6d. in silver.
It is necessary in this place to give some account of the bronze of the ancients, a compound fulfilling the most important uses in Greece and Rome. “Money, vases, and utensils of all sorts, whether for domestic or sacrificial purposes, ornaments, arms offensive and defensive, furniture, tablets for inscriptions, musical instruments, and, indeed, every object to which it could be applied, was made of bronze.”[[3]] Zinc, like steel, was unknown to the ancients. The discovery of a case of surgical instruments in Pompeii, in which the lancets are made of bronze, almost demonstrates to a certainty a want of the art of making steel, and the same conclusion is supported by the existing remains of Greek and Roman weapons. Their bronze was composed of copper and tin, and contained about seven parts of the former to one of the latter. The Corinthian bronze was most valued for the purposes of art, and there were certain varieties of this, into the composition of which silver and even gold were introduced, so as to produce a white or yellow shade in the color. The Delians and Æginetans also excelled in the manufacture of bronze.
The ancients cast metals in moulds, worked them into plates with the hammer, or engraved and embossed them elaborately, as in the manufacture of their metal vases. Their colossal statues, of which the one at Rhodes, 100 feet high, is the most famous example, were mostly cast of bronze.
A constant source of employment to the workers in metal was the manufacture of arms, offensive and defensive. Among the latter may be mentioned shields, greaves, cuirasses, helmets, and coats of mail, consisting either of forged rings linked one within the other, or of scales and rings fastened to some firmly-woven linen or woollen cloth. The offensive arms must have been defective, owing to the ignorance of steel. Iron, silver, and gold were all used in making or ornamenting arms, besides the more common bronze. With the welding of iron, and the use of a kind of solder, the workmen in those days appear to have been familiar.
The necklaces, eardrops, rings, brooches, collars, crowns, goblets, salvers, and vases, manufactured of the precious metals or the finer sorts of bronze, and often set with precious stones, may be enumerated as the chief articles of the jeweler’s and silversmith’s trade. The various tools employed by workmen, the variety of form and modes of working, were all very similar to those of modern days.