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ON MEASURES

but we shall never be able by such means to
discover the relation of value existing between
them. We shall never extort from them a single
 fact with which we were before unacquainted.
 What then is it possible to do in the
way of measuring value? What kind of measurement
 is intended, when the term is so frequently
employed? All that is practicable appears to
be simply this : if I know the value of A in relation
 to B, and the value of B in relation to c, 1
can tell the value of A and c¢ in relation to each
other, and consequently their comparative power
in purchasing all other commodities. This is
an operation obviously bearing no resemblance
at all to the process of measuring length. There
is no unknown fact discovered by a physical
operation: itis in truth a calculation from certain
 data, a mere question in arithmetic. It is
not, let it be observed, what on a first glance
it may appear, like ascertaining the comparative
 length of two pieces of timber which cannot
 be brought into juxta-position, by means of
a foot rule or other instrument which we apply