160 ON METHODS OF

which carry so profound and paradoxical an
air, really amount to nothing but this, that a
commodity may rise or fall in relation to one
commodity and not to another, and therefore
that the estimation of commodities in different
media will necessarily yield different results.
It may be here remarked, that Mr. Ricardo
employs the term estimate in a manner altogether
 incorrect. In the preceding pages it
has been shown, that we can express the value
of a commodity only by the quantity of some
other commodity, for which it will exchange.
Now if to estimate has the same meaning as to
express value, with the accessory idea of computation
 annexed, it follows that we can estimate
 value only in the same manner. Should
we therefore at any time employ labour as the
medium of estimation, it must be the labour
for which a commodity will exchange. But
Mr. Ricardo speaks of estimating commodities
by the labour which is required to produce
them. Nor is this to be regarded merely as a
verbal inaccuracy, for it appears to have led