The Wealth of Nations by Part 4 Chapter 7 Page 131

has fallen considerably, as it certainly has, it must have fallen still lower, had not the monopoly established by that act contributed to keep it up.

But whatever raises in any country the ordinary rate of profit higher than it otherwise would be, necessarily subjects that country both to an absolute and to a relative disadvantage in every branch of trade of which she has not the monopoly.

It subjects her to an absolute disadvantage; because in such branches of trade her merchants cannot get this greater profit without selling dearer than they otherwise would do both the goods of foreign countries which they import into their own, and the goods of their own country which they export to foreign countries.

Their own country must both buy dearer and sell