would commence on No. 1; for either there must be two
rates of profit on agricultural capital, or ten quarters, or the value
of ten quarters must be withdrawn from the produce of No. 1, for some
other purpose. Whether the proprietor of the land, or any other person,
cultivated No. 1, these ten quarters would equally constitute rent; for
the cultivator of No. 2 would get the same result with his capital,
whether he cultivated No. 1, paying ten quarters for rent, or continued
to cultivate No. 2, paying no rent. In the same manner it might be shewn
that when No. 3 is brought into cultivation, the rent of No. 2 must be
ten quarters, or the value of ten quarters, whilst the rent of No. 1
would rise to twenty quarters; for the cultivator of No. 3 would have
the same profits whether he paid twenty quarters for the rent of No. 1,
ten quarters for the rent of No. 2, or cultivated No. 3 free of all
rent.

It often, and indeed commonly happens that before No. 2, 3, 4, or 5, or
the inferior lands are cultivated, capital can be employed more
productively on those lands which are already in cultivation. It may
perhaps be found, that by doubling the original capital employed on No.
1, though the produce will not be doubled, will not be increased by 100
quarters, it may be increased by eighty-five quarters, and that this
quantity exceeds what could be obtained by employing the same capital on
land, No. 3.

In such case, capital will be preferably employed on the old land, and
will equally create a rent; for rent is always the difference between
the produce obtained by the employment of two equal quantities of
capital and labour. If with a capital of 1000_l._ a tenant obtain 100
quarters of wheat from his land, and by the employment of a second
capital of 1000_l._, he obtain a further return of eighty-five, his
landlord would have the power at the expiration of his lease, of
obliging him to pay fifteen quarters, or an equivalent value, for
additional rent; for there cannot be two rates of profit. If he is
satisfied with a diminution of fifteen quarters in the return for his
second 1000_l._, it is because no employment more profitable can be
found for it. The common rate of profit would be in that proportion, and
if the original tenant refused, some other person would be found willing
to give all which exceeded that rate of profit to the owner of the land
from which he derived it.

In this case, as well as in the other, the capital l