116

ON MEASURES

has been the medium of comparison. But
after these quantities have been ascertained,
there can be no place whatever in the subsequent
 comparison for any medium, no conceivable
 function for it to perform.
Should it be urged, that when we compare
the price of corn in one year with its price in
another, we use money as a medium of comparison,
 in the same way as when we compare
the prices of corn and cloth at the same point
of time, the answer is not difficult.
In the latter case it is obvious, that the facts
furnished to us are the relations of cloth and
corn to money, or, the quantities of money for
which definite portions of them are exchanged ;
and from these we infer another circumstance,
namely, the relation of value between corn and
cloth, and consequently their comparative power
of purchasing all other commodities.
In the former case, on the other hand, the facts
furnished to us are the prices of corn, or the relations
 between corn and money, at two different
periods: but from these we deduce no other rela-