AT DIFFERENT PERIODS. 79
*“ The value of a commodity,” says he, ““ or
the quantity of any other commodity for which
it will exchange, depends on the relative quan-
tity of labour which is necessary for its produc-
tion, and not on the greater or less compensa-
tion which is paid for that labour.”

In the first part of this sentence he appears
to be speaking of contemporary commodities,
but in the latter clause he has changed his
ground : it does not form a proper logical coun-
terpart to the former: there is, I think, an im-
plied although an unconscious reference to the
same commodity at different periods. For if
not, if he is speaking in the latter clause also
of contemporary commodities, the amount of
the proposition would be this :—

“ The values of two contemporary commo-
dities, A and B, are to each other as the quanti-
ties of labour necessary to their production,
and they are not to each other as the values of
the labour employed in their production.”
But if commodities are to each other as the
quantities, they must also be to each other as the