"[...]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 [...]".