9. Tin was procured from Britain at a very early period. The Phœnicians are said by Strabo to have passed the Pillars of Hercules, now the Straits of Gibraltar, about 1200 years before Christ. But the time at which they discovered the tin islands, which they denominated Cassorides, cannot be ascertained from history, although it is evident from many circumstances, that the Scilly Islands, and the western ports of Britain, were the places from which these early navigators procured the tin with which they supplied the parts of the world to which they traded.
10. For a long time, the Phœnicians and the Carthaginians enjoyed the tin trade, to the exclusion of all other nations. After the destruction of Carthage by the Romans, a colony of Phocean Greeks, established at Marseilles, carried on this trade; but it came into the hands of the Romans, after the conquest of Britain by Julius Cæsar.
11. The Cornish mines furnish incontestable proofs of having been worked many hundred years ago. In digging to the depth of forty or fifty fathoms, the miners frequently meet with large timbers imbedded in the ore. Tools for mining have also been found in the same, or similar situations. The mines, therefore, which had been exhausted of the ore, have, in the course of time, been replenished by a process of nature.
12. To what purposes the ancients applied all the tin which they procured at so much labor and cost, is not precisely known. It is probable, that the Tyrians consumed a portion of it, in dyeing their purple and scarlet. It formed then, as it now does, many important alloys with copper. The mirrors of antiquity were made of a composition of these metals.
13. The method of extracting tin from its ores was probably very defective in ancient times. At least, it was so for several centuries before the time of Elizabeth, when Sir Francis Godolphin introduced great improvements in the tin works. The use of the reverberatory furnace was commenced, about the beginning of the eighteenth century, and soon after pit-coal was substituted for charcoal.
14. This metal, in its solid state, is called block-tin. It is applied, without any admixture with any other metal, to the formation of vessels, which are not to be exposed to a temperature much above that of hot water. A kind of ware, called biddery ware, is made of tin alloyed with a little copper. The vessels made of this composition, are rendered black by the application of nitre, common salt, and sal ammoniac. Foil is also made by pressing it between steel rollers, or by hammering it, as in the case of gold by the gold-beaters.
15. But tin is most extensively applied as a coating to other metals, stronger than itself, and more subject to oxydation. The places which are usually denominated tin, are thin sheets of iron coated with this metal. The iron is reduced to thin plates in a rolling-mill, and these are prepared for being tinned, by first steeping them in water acidulated with muriatic acid, and then freeing them from oxyde by heating, scaling, and rolling them.
16. The tin is melted in deep oblong vessels, and kept in a state of fusion by a charcoal fire. To preserve its surface from oxydation, a quantity of fat or oil is kept floating upon it. The plates are dipped perpendicularly into the tin, and held there for some time. When withdrawn, they are found to have acquired a bright coating of the melted metal. The dipping is performed three times for single tin plate, and six times for double tin plate. The tin penetrates the iron, and forms an alloy.
17. Various articles of iron, such as spoons, nails, bridle-bits, and small chains, are coated with tin, by immersing them in that metal, while in a state of fusion. The great affinity of tin and copper, renders it practicable to apply a thin layer of the former metal to the surface of the latter; and this is often done, as stated in the article on the coppersmith.
18. Tin and quicksilver are applied to the polished surface of glass, for the purpose of forming mirrors. In silvering plain looking-glasses, a flat, horizontal slab is used as a table. This is first covered with paper, and then with a sheet of tin foil of the size of the glass. A quantity of quicksilver is next laid on the foil, and spread over it with a roll of cloth, or with a hare's foot.