mutton to the baker, or the brewer, in order to exchange them for bread or for beer; but he carries them to the market, where he exchanges them for money, and afterward exchanges that money for bread and for beer. The quantity of money which he gets for them regulates too the quantity of bread and beer which he can afterward purchase. It is more natural and obvious to him, therefore, to estimate their value by the quantity of money, the commodity for which he immediately exchanges them, than by that of bread and beer, the commodities for which he can exchange them only by the intervention of another commodity; and rather to say that his butcher's meat is worth threepence or fourpence a pound, than that it is worth three or four pounds of bread, or three or four quarts of small beer. Hence it comes to pass, that the exchangeable value of every commodity is more frequently estimated by the quantity of money, than by the quantity either of labor or of any other commodity which can be had in exchange for it.
Gold and silver, however, like every other commodity, vary in their value, are sometimes cheaper and sometimes dearer, sometimes of easier and sometimes of more difficult purchase. The quantity of labor which any particular quantity of them can purchase or command, or the quantity of other goods which it will exchange for, depends always upon the fertility or barrenness of the mines which happen to be known about the time when such exchanges are made. The discovery of the abundant mines of America reduced, in the sixteenth century, the value of gold and silver in Europe to about a third of what it had been before. As it cost less labor to bring those metals from the mine to the market, so when they were brought thither
