The Wealth of Nations by Part 2 Chapter 4 Page 13

The following very short and plain argument, however, may serve to explain more distinctly the fallacy which seems to have misled those gentlemen.

Before the discovery of the Spanish West Indies, ten per cent seems to have been the common rate of interest through the greater part of Europe. It has since that time in different countries sunk to six, five, four, and three per cent. Let us suppose that in every particular country the value of silver has sunk precisely in the same proportion as the rate of interest; and that in those countries, for example, where interest has been reduced from ten to five per cent, the same quantity of silver can now purchase just half the quantity of goods which it could have purchased before. This supposition will not, I believe, be found anywhere agreeable to the truth, but it is the most