The Wealth of Nations by Part 4 Chapter 5 Page 32

enable them to maintain and employ more labourers in raising it. The nature of things has stamped upon corn a real value which cannot be altered by merely altering its money price. No bounty upon exportation, no monopoly of the home market, can raise that value. The freest competition cannot lower it. Through the world in general that value is equal to the quantity of labour which it can maintain, and in every particular place it is equal to the quantity of labour which it can maintain in the way, whether liberal, moderate, or scanty, in which labour is commonly maintained in that place. Woollen or linen cloth are not the regulating commodities by which the real value of all other commodities must be finally measured and determined; corn is.

The real value of every other commodity is finally measured and determined by the