114

ON MEASURES

mon bond of connection between the measurements
 of space in all ages. But this circumstance
 can evidently have no existence in the
measurement of value, which is the ascertainment
 of a relation between contemporary commodities,
 and not between objects at different
periods. The two cases would be analogous
if we supposed no physical measure of length
to be transmitted from one period to another, but
only a record of the lengths of different objects
expressed in a common denomination. Under
these circumstances, all that we could do would
be to compare the relative dimensions of objects
 in our own days, with the relative dimensions
 of similar objects in past times, as recorded:
 but we should have no common medium
 of comparison between one age and another.
 Now what in this case would be owing
to the want of a transmitted measure, arises in
the other case from the very nature of the relation
 with which we have to do. The nature
 of that relation itself interposes as complete
 a disconnection between different ages, as