The Wealth of Nations by Part 4 Chapter 5 Page 113

By the same statute the old bounty of five shillings upon the exportation of wheat ceases so soon as the price rises to forty-four shillings the quarter, instead of forty-eight, the price at which it ceased before; that of two shillings and sixpence upon the exportation of barley ceases so soon as the price rises to twenty-two shillings, instead of twenty-four, the price at which it ceased before; that of two shillings and sixpence upon the exportation of oatmeal ceases so soon as the price rises to fourteen shillings, instead of fifteen, the price at which it ceased before. The bounty upon rye is reduced from three shillings and sixpence to three shillings, and it ceases so soon as the price rises to twenty-eight shillings instead of thirty-two, the price at which it ceased before.

If bounties are as improper as I have