208 ON THE CAUSES

or, as it is stated by the author of the Tem-
plars’ Dialogues, “ commodities are to each
other in value as the quantities of labour em-
ployed in their production*;” or, as it is laid
down by Mr. M‘Culloch, « the exchangeable
value, or relative worth of commodities, as
compared with each other, depends exclusively
on the quantities of labour necessarily required
to produce them ;” then it follows, that any
two commodities, which at any time exchange
for each other (putting aside all fluctuations
of market value), must have been produced by
exactly the same quantity of labour. If a
quarter of wheat is exchanged for a piece of
linen, these two commodities must have re-
quired the same labour to bring them to the
condition in which they are exchanged.

* Dialogue 1, passim.
t A Discourse on the Science of Political Economy,
p. 66.
t This is stated in the strongest conceivable terms by the
second-mentioned writer. ¢¢ No cause can possibly affect
the value of any thing, 7. e. its exchangeable relation to