PREFACE. 
with that minuteness and closeness of attention 
which are due to its importance. Writers on 
political economy have generally contented 
themselves with a short definition of the term 
value, and a distinction of the property de- 
noted by it into several kinds, and have then 
proceeded to employ the word with various 
degrees of laxity. Not one of them has 
brought into distinct view and discussion the 
nature of the idea represented by this term, or 
the inferences which a full perception of its 
meaning immediately suggests; and the neg- 
lect of this preliminary labour has created dif. 
ferences of opinion and perplexities of thought, 
which otherwise could never have existed. 
There has been still more laxity, both of 
thought and expression, regarding the mea- 
surement of value. The vague manner in 
which the word measure, necessarily of fre 
quent occurrence in the pages of the political