The Wealth of Nations by Part 4 Chapter 7 Page 87

which they sent to the colonies, and, consequently, to get back as much as possible of the duties which they advanced upon their importation into Great Britain. They might thereby be enabled to sell in the colonies either the same quantity of goods with a greater profit, or a greater quantity with the same profit, and, consequently, to gain something either in the one way or the other. It was likewise for the interest of the colonies to get all such goods as cheap and in as great abundance as possible. But this might not always be for the interest of the mother country. She might frequently suffer both in her revenue, by giving back a great part of the duties which had been paid upon the importation of such goods; and in her manufactures, by being undersold in the colony market, in consequence of the easy terms upon which foreign manufactures could be carried thither by means of those drawbacks.