commodities from century to century by the quantities of silver which were given for them. We cannot estimate it from year to year by the quantities of corn. By the quantities of labour, we can, with the greatest accuracy, estimate it, both from century to century, and from year to year. From century to century, corn is a better measure than silver, because, from century to century, equal quantities of corn will command the same quantity of labour more nearly than equal quantities of silver. From year to year, on the contrary, silver is a better measure than corn, because equal quantities of it will more nearly command the same quantity of labour.
But though, in establishing perpetual rents, or even in letting very long leases, it may be of use to distinguish between real and nominal price; it is of none in buying and selling, the more common and ordinary transactions of human life.
At the same time and place, the real and the nominal price of all commodities are exactly in proportion to one another. The more or less money you get for any commodity, in the London market, for example, the more or less labour it will at that time and place enable you to purchase or command. At the same time and place, therefore, money is the exact measure of the real exchangeable value of all commodities. It is so, however, at the same time and place only.
Though at distant places there is no regular proportion between the real and the money price of commodities, yet the merchant who carries goods from the one to the other, has nothing to consider but the money price, or the difference between the quantity of silver for which he buys them, and that for which he is likely to sell them. Half an ounce of silver at Canton in China may command a greater quantity both of labour and of the necessaries and conveniencies of life, than an ounce at London. A commodity, therefore, which sells for half an ounce of silver at Canton, may there be really dearer, of more real importance to the man who