or by the quantity of labour which must be employed, and consequently of
corn which must be consumed, in order to bring any particular quantity of
silver from the mine to the market. But the value of silver, though it
sometimes varies greatly from century to century, seldom varies much from
year to year, but frequently continues the same, or very nearly the same,
for half a century or a century together. The ordinary or average money
price of corn, therefore, may, during so long a period, continue the same,
or very nearly the same, too, and along with it the money price of labour,
provided, at least, the society continues, in other respects, in the same,
or nearly in the same, condition. In the mean time, the temporary and
occasional price of corn may frequently be double one year of what it had
been the year before, or fluctuate, for example, from five-and-twenty to
fifty shillings the quarter. But when corn is at the latter price, not only
the nominal, but the real value of a corn rent, will be double of what it is
when at the former, or will command double the quantity either of labour, or
of the greater part of other commodities; the money price of labour, and
along with it that of most other things, continuing the same during all
these fluctuations.

Labour, therefore, it appears evidently, is the only universal, as well as
the only accurate, measure of value, or the only standard by which we can
compare the values of different commodities, at all times, and at all
places. We cannot estimate, it is allowed, the real value of different
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