For its size the United Kingdom is remarkably well endowed with minerals. The variety of Britain's geology is such that a full survey of economic possibilities is out of the question here. All that can be attempted is some account of economically important metals and other minerals, like salt, of which Britain has large deposits. For most of its commercial history Britain produced and exported raw materials rather than manufactured goods. The Phoenicians came for tin, the Romans for silver, lead and iron, and Florentine merchants in the fourteenth century for wool. By the end of the eighteenth century Britain seems to have been the world's msyor producer of base metals — lead, copper and tin — as well as a substantial and rapidly rising maker of iron. By recent standards Britain's output of metals at the start of the industrial revolution may seem pitifully small: the output of copper and tin amounted to only a few thousand tons a year, and of lead perhaps 50 or 60 thousand tons. These tonnages, however, may have amounted to half or even three-quarters of world output. Nowadays, world output of copper and lead, and of aluminium and zinc, is measured in millions of tons. Only tin output, which has multiplied a mere fifty times, remains at the comparatively low level of about 200,000 tons a year. Iron-making was more widespread and undertaken on a larger scale. Even so, on the basis of fragmentary evidence and informed guesswork, British output of pig iron was approaching only 200,000 tons at the end of the eighteenth century, and the rest of the world was making as much again, or rather more. Some pig iron was used for castings, but most was probably turned into bar or wrought iron; the production of steel was slow, laborious and very small. World output of iron and steel has since advanced at least as rapidly as the output of base metals, * having multiplied perhaps a thousandfold in less than 200 years. Half a million tons of pig iron in 1800 contrasts with half a billion tons of steel produced today.