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.