in the production of some other article which is in demand in the
foreign country, we may be able to obtain a greater return to our labour
and capital by employing none of it in producing the article in which
our advantage is least, but devoting it all to the production of that in
which our advantage is greatest, and giving this to the foreign country
in exchange for the other. It is not a difference in the _absolute_ cost
of production, which determines the interchange, but a difference in the
_comparative_ cost. It may be to our advantage to procure iron from
Sweden in exchange for cottons, even although the mines of England as
well as her manufactories should be more productive than those of
Sweden; for if we have an advantage of one-half in cottons, and only an
advantage of a quarter in iron, and could sell our cottons to Sweden at
the price which Sweden must pay for them if she produced them herself,
we should obtain our iron with an advantage of one-half, as well as our
cottons. We may often, by trading with foreigners, obtain their
commodities at a smaller expense of labour and capital than they cost
to the foreigners themselves. The bargain is still advantageous to the
foreigner, because the commodity which he receives in exchange, though
it has cost us less, would have cost him more. As often as a country
possesses two commodities, one of which it can produce with less labour,
comparatively to what it would cost in a foreign country, than the
other; so often it is the interest of the country to export the first
mentioned commodity and to import the second; even though it might be
able to produce both the one and the other at a less expense of labour
than the foreign country can produce them, but not less in the same
degree; or might be unable to produce either except at a greater
expense, but not greater in the same degree.

On the contrary, if it produces both commodities with greater facility,
or both with greater difficulty, and greater in exactly the same degree,