The Wealth of Nations by Part 4 Chapter 5 Page 102

agriculture, to raise the money price of corn as high as possible, and thereby to occasion, as much as possible, a constant dearth in the home market. By the discouragement of importation, the supply of that market, even in times of great scarcity, was confined to the home growth; and by the encouragement of exportation, when the price was so high as forty-eight shillings the quarter, that market was not, even in times of considerable scarcity, allowed to enjoy the whole of that growth.

The temporary laws, prohibiting for a limited time the exportation of corn, and taking off for a limited time the duties upon its importation, expedients to which Great Britain has been obliged so frequently to have recourse, sufficiently demonstrate the impropriety of her general system. Had that system been good, she would not so