The Wealth of Nations by Part 1 Chapter 7 Page 13

linen and woolen cloth is liable neither to such frequent nor to such great variations as the price of corn, every man’s experience will inform him.

The price of the one species of commodities varies only with the variations in the demand: that of the other varies, not only with the variations in the demand, but with the much greater and more frequent variations in the quantity of what is brought to market in order to supply that demand.

The occasional and temporary fluctuations in the market price of any commodity fall chiefly upon those parts of its price which resolve themselves into wages and profit. That part which resolves itself into rent is less affected by them. A rent certain in money is not in the least affected by them either in its rate or in its value.