not immediately and necessarily rise or fall with the increased or diminished fertility of the land; but its increased fertility renders it capable of paying at some future time an augmented rent. Land possessed of very little fertility can never bear any rent; land of moderate fertility may be made, as population increases, to bear a moderate rent; and land of great fertility a high rent; but it is one thing to be able to bear a high rent, and another thing actually to pay it. Rent may be lower in a country where lands are exceedingly fertile than in a country where they yield a moderate return, it being in proportion rather to relative than absolute fertility—to the value of the produce, and not to its abundance. Mr. Malthus says, that the "cause of the excess of price of the necessaries of life above the cost of production, is to be found in their abundance rather than their scarcity, and is essentially different from the high price of those peculiar products of the earth, not connected with food, which may be called natural and necessary monopolies."
In what are they essentially different?