It is in this manner that the rent of the cultivated land, of which the produce is human food, regulates the rent of the greater part of other cultivated land. No particular produce can long afford less, because the land would immediately be turned to another use; and if any particular produce commonly affords more, it is because the quantity of land which can be fitted for it is too small to supply the effectual demand. In Europe, corn is the principal produce of land, which serves immediately for human food. Except in particular situations, therefore, the rent of corn land regulates in Europe that of all other cultivated land. Britain need envy neither the vineyards of France, nor the olive plantations of Italy. Except in particular situations, the value of these is regulated by that of corn, in which the fertility of Britain is not much inferior to that of either of those two countries. If, in any country, the common and favourite vegetable food of the people should be drawn from a plant of which the most common land, with the same, or nearly the same culture, produced a much greater quantity than the most fertile does of corn; the rent of the landlord, or the surplus quantity of food which would remain to him, after paying the labour, and replacing the stock of the farmer, together with its ordinary profits, would necessarily be much greater. Whatever was the rate at which labour was commonly maintained in that country, this greater surplus could always maintain a greater quantity of it, and, consequently, enable the landlord to purchase or command a greater quantity of it. The real value of his rent, his real power and authority, his command of the necessaries and conveniencies of life with which the labour of other people could supply him, would necessarily be much greater.