other revenue is ultimately derived from some one or other of these.

Whoever derives his revenue from a fund which is his own, must draw it
either from his labour, from his stock, or from his land. The revenue
derived from labour is called wages; that derived from stock, by the person
who manages or employs it, is called profit; that derived from it by the
person who does not employ it himself, but lends it to another, is called
the interest or the use of money. It is the compensation which the borrower
pays to the lender, for the profit which he has an opportunity of making by
the use of the money. Part of that profit naturally belongs to the borrower,
who runs the risk and takes the trouble of employing it, and part to the
lender, who affords him the opportunity of making this profit. The interest
of money is always a derivative revenue, which, if it is not paid from the
profit which is made by the use of the money, must be paid from some other
source of revenue, unless perhaps the borrower is a spendthrift, who
contracts a second debt in order to pay the interest of the first. The
revenue which proceeds altogether from land, is called rent, and belongs to
the landlord. The revenue of the farmer is derived partly from his labour,
and partly from his stock. To him, land is only the instrument which enables
him to earn the wages of this labour, and to make the profits of this stock.
All taxes, and all the revenue which is founded upon them, all salaries,
pensions, and annuities of every kind, are ultimately derived from some one
or other of those three original sources of revenue, and are paid either
immediately or mediately from the wages of labour, the profits of stock, or
the rent of land.

When those three different sorts of revenue belong to different persons,
they are readily distinguished; but when they belong to the same, they are
sometimes confounded with one another, at least in common language.