The Wealth of Nations by Part 5 Chapter 2 Page 147

retailers, are likewise finally paid by the consumers of those liquors. Such taxes, though called by the same name, and levied by the same officers and in the same manner with the stamp-duties above mentioned upon the transference of property, are, however, of a quite different nature, and fall upon quite different funds.

Article III Taxes upon the Wages of Labour

The wages of the inferior classes of workmen, I have endeavoured to show in the first book, are everywhere necessarily regulated by two different circumstances; the demand for labour, and the ordinary or average price of provisions.

The demand for labour, according as it happens to be either increasing, stationary, or declining, or to require an increasing, stationary, or declining population,