The History of Chemistry (Vol.1&2). Thomas Thomson
memorable load.
For this he bids those nervous artists vie
That teach the disk to sound along the sky.
Let him whose might can hurl this bowl, arise;
Who farthest hurls it, takes it as his prize:
If he be one enrich’d with large domain
Of downs for flocks and arable for grain,
Small stock of iron needs that man provide,
His hinds and swains whole years shall be supplied
From hence: nor ask the neighbouring city’s aid
For ploughshares, wheels, and all the rural trade.”
The mass of iron was large enough to supply a shepherd or a ploughman with iron for five years. This circumstance is a sufficient proof of the high estimation in which iron was held during the time of Homer. Were a modern poet to represent his hero as holding out a large lump of iron as a prize, and were he to represent this prize as eagerly contended for by kings and princes, it would appear to us perfectly ridiculous.
Hesiod informs us, that the knowledge of iron was brought over from Phrygia to Greece by the Dactyli, who settled in Crete during the reign of Minos I., about 1431 years before the commencement of the Christian era, and consequently about sixty years before the departure of the children of Israel from Egypt: and it does not appear, that in Homer’s time, which was about five hundred years later, the art of smelting iron had been so much improved, as to enable men to apply it to the common purposes of life, as had long before been done by the Egyptians. The general opinion of the ancients was, that the method of smelting iron ore had been brought to perfection by the Chalybes, a small nation situated near the Black Sea,54 and that the name chalybs, occasionally used for steel, was derived from that people.
Pliny informs us, that the ores of iron are scattered very profusely almost every where: that they exist in Elba; that there was a mountain in Cantabria composed entirely of iron ore; and that the earth in Cappadocia, when watered from a certain river, is converted into iron.55 He gives no account of the mode of smelting iron ores; nor does he appear to have been acquainted with the processes; for he says that iron is reduced from its ore precisely in the same way as copper is. Now we know, that the processes for smelting copper and iron are quite different, and founded upon different principles. He says, that in his time many different kinds of iron existed, and they were stricturæ, in Latin a stringenda acie.
That steel was well known and in common use when Pliny wrote is obvious from many considerations; but he seems to have had no notion of what constituted the difference between iron and steel, or of the method employed to convert iron into steel. In his opinion it depended upon the nature of the water, and consisted in heating iron red-hot, and plunging it, while in that state, into certain waters. The waters at Bilbilis and Turiasso, in Spain, and at Comum, in Italy, possessed this extraordinary virtue. The best steel in Pliny’s time came from China; the next best, in point of quality, was manufactured in Parthia.
It would appear, that at Noricum steel was manufactured directly from the ore of iron. This process was perfectly practicable, and it is said still to be practised in certain cases.
The ancients were acquainted with the method of rendering iron, or rather steel, magnetic; as appears from a passage in the fourteenth chapter of the thirty-fourth book of Pliny. Magnetic iron was distinguished by the name of ferrum vivum.
When iron is dabbed over with alumen and vinegar it becomes like copper, according to Pliny. Cerussa, gypsum, and liquid pitch, keep it from rusting. Pliny was of opinion that a method of preventing iron from rusting had been once known, but had been lost before his time. The iron chains of an old bridge over the Euphrates had not rusted in Pliny’s time; but a few new links, which had been added to supply the place of some that had decayed, were become rusty.
It would appear from Pliny, that the ancients made use of something very like tractors; for he says that pain in the side is relieved by holding near it the point of a dagger that has wounded a man. Water in which red-hot iron had been plunged was recommended as a cure for the dysentery; and the actual cautery with red-hot iron, Pliny informs us, prevents hydrophobia, when a person has been bitten by a mad dog.
Rust of iron and scales of iron were used by the ancients as astringent medicines.
6. Tin, also, must have been in common use in the time of Moses; for it is mentioned without any observation as one of the common metals.56 And from the way in which it is spoken of by Isaiah and Ezekiel, it is obvious that it was considered as of far inferior value to silver and gold. Now tin, though the ores of it where it does occur are usually abundant, is rather a scarce metal: that is to say, there are but few spots on the face of the earth where it is known to exist. Cornwall, Spain, in the mountains of Gallicia, and the mountains which separate Saxony and Bohemia, are the only countries in Europe where tin occurs abundantly. The last of these localities has not been known for five centuries. It was from Spain and from Britain that the ancients were supplied with tin; for no mines of tin exist, or have ever been known to exist, in Africa or Asia, except in the East Indies. The Phœnicians were the first nation which carried on a great trade by sea. There is evidence that at a very early period they traded with Spain and with Britain, and that from these countries they drew their supplies of tin. It was doubtless the Phœnicians that supplied the Egyptians with this metal. They had imbibed strongly a spirit of monopoly; and to secure the whole trade of tin they carefully concealed the source from which they drew that metal. Hence, doubtless, the reason why the Grecian geographers, who derived their information from the Phœnicians, represented the Insulæ Cassiterides, or tin islands, as a set of islands lying off the north coast of Spain. We know that in fact the Scilly islands, in these early ages, yielded tin, though doubtless the great supply was drawn from the neighbouring province of Cornwall. It was probably from these islands that the Greek name for tin was derived (κασσιτερος). Even Pliny informs us, that in his time tin was obtained from the Cassiterides, and from Lusitania and Gallicia. It occurs, he says, in grains in alluvial soil, from which it is obtained by washing. It is in black grains, the metallic nature of which is only recognisable by the great weight. This is a pretty accurate description of stream tin, which we know formerly constituted the only ore of that metal wrought in Cornwall. He says that the ore occurs also along with grains of gold; that it is separated from the soil by washing along with the grains of gold, and afterwards smelted separately.
Pliny gives no particulars about the mode of reducing the ore of tin to the metallic state; nor is it at all likely that he was acquainted with the process.
The Latin term for tin was plumbum album. Stannum is also used by Pliny; but it is impossible to understand the account which he gives of it. There is, he says, an ore consisting of lead, united to silver. When this ore is smelted, the first metal that flows out is stannum. What flows next is silver. What remains in the furnace is galena. This being smelted, yields lead.
Were we to admit the existence of an ore composed of lead and silver, it is obvious that no such products could be obtained by simply smelting it.
Cassiteros, or tin, is mentioned by Homer; and, from the way in which the metal is said by him to have been used, it is obvious that in his time it bore a much higher price, and, consequently, was more valued than at present. In his description of the breastplate of Agamemnon, he says that it contained ten bands of steel, twelve of gold, and twenty of tin (κασσιτεροιο).57 And in the twenty-third book of the Iliad (line 561), Achilles describes a copper breastplate surrounded with shining tin (φαεινου κασσιτεροιο). Pliny informs us, that in his time tin was adulterated by adding to it about one-third of white copper. A pound of tin, when Pliny lived, cost ten denarii. Now, if we reckon a denarius at 7¾d., with Dr. Arbuthnot, this would make a Roman pound of tin to cost 6s. 5½d. But, as the Roman pound was only equal to three-fourths of our avoirdupois pound, it is plain that in the time of Pliny an avoirdupois pound of tin was worth 8s. 7¼d., which is almost seven times the price of tin in the present day.
Tin, in the time