§ 9. OTHER MINING INDUSTRIES--There remain one or two industries that require a passing mention, but which were not in the eighteenth century of much importance. As to the metals, the foreign trade in tin and lead has been already mentioned. In the reign of John the tin-mines of Cornwall were farmed by the Jews, and the tin and lead trade must have attained considerable proportions in the fourteenth century, for the Black Prince paid his own expenses in the French wars by the produce of his mines of those metals in Devonshire. Copper, also, was mined in the northern counties, and in a statute of 15 Edward III. (1343) we find grants of mines given at Skeldane, in Northumberland; at Alston Moor, in Cumberland; and at Richmond, in Yorkshire; a royalty of one-eighth going to the king, and one-ninth to the lord of the manor. Keswick was at that time a centre of this industry; but there cannot have been any great output, for copper had to be imported from Germany in the fifteenth century. The mines were also very primitive, the approaches being {142} made not by shafts, but by adits in the side of a convenient hill. Another mineral, which is very abundant in England, especially in Worcestershire and Cheshire, was at this period hardly utilized. Salt was a necessary of life to the English householder, for he had to salt his meat for the winter; but he did not know how to mine it himself, and either got it imported from south-west France or contented himself with the inferior article evaporated on the sea-coast, until the end of the seventeenth century. In this place, too, we may mention that brickmaking was a lost art from the fifth to the fifteenth century, and bricks were not even imported. The first purchase of bricks to be recorded was at Cambridge, in 1449; but before the end of the fifteenth century it became a common building material in the eastern counties, and in the sixteenth century was generally used in London and in the counties along the lower course of the Thames.