The Wealth of Nations by Part 1 Chapter 11 Page 192

equal to the hundred-and-twentieth part of this annual importation at the rate of six millions a year. The whole annual consumption of gold and silver, therefore, in all the different countries of the world where those metals are used, may perhaps be nearly equal to the whole annual produce. The remainder may be no more than sufficient to supply the increasing demand of all thriving countries. It may even have fallen so far short of time demand as somewhat to raise the price of those metals in the European market.

The quantity of brass and iron annually brought from the mine to the market is out of all proportion greater than that of gold and silver. We do not, however, upon this account, imagine that those coarse metals are likely to multiply beyond the demand, or to become gradually cheaper and cheaper.