,

PREFACE.

economist, is constantly employed, would surprise
 even the metaphysician, who is well aware
of the extensive prevalence and unbounded influence
 of the chameleon-like properties of
language. No writer (as far as the author of the
following pages is acquainted with works on
economical science) has ever taken the trouble to
analyse the meaning involved in the phrase. To
measure value is an expression apparently so
simple, so precise, so free from obscurity, that
it seems superfluous to bestow a single inquiry
on its import. The consequence has been
what it generally proves on such occasions:
the term has been used without any clear perception
 of a definite sense; several ideas
have been unconsciously and indiscriminately
interchanged, and analogies, which had merely
an imaginary existence, have been assumed as
incontrovertible premises or universally conceded
 postulates.