The Wealth of Nations by Part 1 Chapter 9 Page 3

much more difficult; and to judge of what it may have been formerly, or in remote periods of time, with any degree of precision, must be altogether impossible.

But though it may be impossible to determine, with any degree of precision, what are or were the average profits of stock, either in the present or in ancient times, some notion may be formed of them from the interest of money. It may be laid down as a maxim, that wherever a great deal can be made by the use of money, a great deal will commonly be given for the use of it; and that wherever little can be made by it, less will commonly be given for it.

According, therefore, as the usual market rate of interest varies in any country, we may be assured that the ordinary profits of stock must vary with it, must sink as it sinks, and