The Wealth of Nations by Part 4 Chapter 9 Page 10

completely all those necessary expenses, affords a net produce of this kind that this class of people are in this system peculiarly distinguished by the honourable appellation of the productive class. Their original and annual expenses are for the same reason called, in this system, productive expenses, because, over and above replacing their own value, they occasion the annual reproduction of this net produce.

The ground expenses, as they are called, or what the landlord lays out upon the improvement of his land, are in this system, too, honoured with the appellation of productive expenses.

Till the whole of those expenses, together with the ordinary profits of stock, have been completely repaid to him by the advanced rent which he gets from his land, that advanced rent ought to be