OF VALUE,

97

first to one and then to the other: it is far from
being so much as this: it is merely like calcu-
lating the ratio of length between the two
pieces of timber, after we are informed how
many feet are contained in each. For of each
commodity A and c the value in relation to B
must be given, or, in other words, their value
must be expressed in a common denomination,
before their mutual relation can be ascertained ;
just as in the case supposed the relation of each
piece of timber to the foot-rule must be given,
before their relation to each other can be de-
duced. The actual application of the foot rule
is that part of the process which is alone en-
titled to the appellation of measuring, the rest
being mere calculation, but to this there is no-
thing at all analogous in any possible attempt
to ascertain value. The way in which the
commodity B would be used, in the above
instance, is in truth as a medium of compari-
son, not a measure, yet it is the only process
which bears any analogy to measurement.
It appears, therefore, that all we can under-