On Dartmoor the stream tin can thus be run out of the ore with a peat fire. And the Dartmoor stream tin has this merit: it is absolutely pure, whereas tin elsewhere is mingled with wolfram, that makes it brittle as glass; and to separate wolfram from tin requires a second roasting and is a delicate process.
Another Cornish story is to the effect that Joseph of Arimathea came in a boat to Cornwall, and brought the Child Jesus with him, and the latter taught him how to extract the tin and purge it of its wolfram. This story possibly grew out of the fact that the Jews under the Angevin kings farmed the tin of Cornwall. When tin is flashed, then the tinner shouts, "Joseph was in the tin trade," which is probably a corruption of "S. Joseph to the tinner's aid!"
We will now shortly take the history of tin mining in Devon and Cornwall.
Whether the west of Cornwall and Scilly were the Cassiterides of the ancients is doubtful. But one thing is sure: that they had their tin, or some of it, from Britain.
Diodorus Siculus, who flourished in the time of Augustus, says so:--
"The inhabitants of that extremity of Britain which is called Belerion both excel in hospitality"--they do so still--"and also, by reason of their intercourse with foreign merchants, are civilised in their mode of life"--very much so. "These prepare the tin, working very skilfully the earth which produces it. The ground is rocky, but it has in it earthy veins, the produce of which is brought down and melted and purified. Then, when they have cast it into the form of cubes, they carry it to a certain island adjoining Britain, called Ictis. During the recess of the tide the intervening space is left dry, and they carry over abundance of tin in carts.... From thence the traders who purchase the tin of the natives transport it to Gaul, and finally, travelling through Gaul on foot, in about thirty days bring their burdens on horses to the mouth of the Rhine."
Ictis has been variously supposed to be S. Michael's Mount, the Isle of Wight, and Romney in Kent.
Whether the Romans worked the tin in Devon and Cornwall is very questionable. No evidence has been produced that they did so. The Saxon invasion must have destroyed what little mining activity existed in the two counties, at least in Devon. It is noticeable that, although Athelstan penetrated to Land's End and crossed to Scilly, he is not said to have paid any attention to the tin workings, which he assuredly would have done had they then been valuable. To the incursions of the Saxons succeeded those of the Danish freebooters, who ran up the rivers and burnt Tavistock and Lydford in 997, and carried fire and sword through the stannary districts of Devon.
Under the Norman rule mining revived. The general use of bells in churches caused a considerable demand for tin, more particularly as those for cathedrals were of large calibre. The chief emporium of the tin trade was Bruges, whence the merchants of Italy obtained the west of England tin and distributed it through the Levant. There exists an interesting record of Florentine commercial industry by one Balducci, composed between 1332 and 1345, in which is described the trade in Cornish tin, and how it was remelted into bars at Venice and stamped with the lion of S. Mark.
In King John's time the tin mines were farmed by the Jews. The right to it was claimed by the king as Earl of Cornwall.