104

ON MEASURES

respective ratios to it: but the invariable relation
 of value between A and B can tell me nothing
 of the mutual value of ¢ and bp; or, to
vary the language, the power which a has to
command B, can tell me nothing of that which
c has to command p. I do not in any sense
measure the relation of value between two
commodities, by that existing between two
other commodities. Invariable value, therefore,
 can be of no service. The only meaning
to be attached to the phrase measuring value,
the only operation implied in it, is, as we have
seen, that comparison of the values of two objects
 which we are enabled to make by their separate
 relations to a third, or, in other words,
by having these values expressed in a common
term or denomination. But the capability of
expressing the values of commodities has nothing
 to do with the constancy of their values,
either to each other or to the medium employed;
 neither has the capability of comparing
 these expressions of value any thing to
do with it. Whether A is worth 4 8 or 6 5,
and whether ¢ is worth 8 8 or 12 B. are cir-