The immense importation also of African and Egyptian grain, which continued from the time of Tiberius down to the very close of the empire, must have occasioned a great additional abstraction of the precious metals from the Roman world. It has already been shown that a very small proportion of the grain imported from these distant provinces was remitted in the shape of tribute. By far the greater part, probably nineteen-twentieths of the whole supply, was imported by private merchants for sale, as it could be got from them cheaper than it could be raised at home. This imported corn, of course, required to be paid for in something. But the inhabitants of the countries from which it came--Spain, Sicily, Africa, and Egypt--for the most part slaves, blessed with a fine climate, requiring little covering, and nearly destitute of artificial wants, did not require, and could not consume, any considerable amount of Italian or Grecian fabrics. Thus, by far the greatest part of the price of the imported grain was paid in gold and silver, for which there is a constant demand in all countries, savage or civilized. A nation which imports foreign grain largely, _must_ in all ages export the precious metals as largely; because the corn, of course, is brought from those countries where it is raised the cheapest--and the countries where this is the case, are those where labour is cheap, money scarce, and artificial wants unknown. Money is what these countries want, and money is what their surplus produce is nearly all exchanged for. And this explains how it happened, that in the decline of the empire, Spain, Africa, and Egypt, alone retained their flourishing aspect, and were the only provinces from which money and soldiers could be obtained, while they required none. The whole commerce between them and Italy, or Greece, was one in which grain was exchanged for the precious metals; and when they once got these, great part was hoarded, as it now is in the East, and very little ever returned.