The Wealth of Nations by Part 5 Chapter 2 Page 40

A tax upon the rent of land which varies with every variation of the rent, or which rises and falls according to the improvement or neglect of cultivation, is recommended by that sect of men of letters in France who call themselves The Economists as the most equitable of all taxes.

All taxes, they pretend, fall ultimately upon the rent of land, and ought therefore to be imposed equally upon the fund which must finally pay them. That all taxes ought to fall as equally as possible upon the fund which must finally pay them is certainly true. But without entering into the disagreeable discussion of the metaphysical arguments by which they support their very ingenious theory, it will sufficiently appear, from the following review, what are the taxes which fall finally upon the rent of the land, and what are those which fall finally upon some other fund.