An Inquiry into the Nature and Causes of the Wealth of Nations

by Adam Smith

Let us suppose, for example, that in the greater part of employments the productive powers of labour had been improved to tenfold, or that a day's labour could produce ten times the quantity of work which it had done originally; but that in a particular employment they had been improved only to double, or that a day's labour could produce only twice the quantity of work which it had done before. In exchanging the produce of a day's labour in the greater part of employments for that of a day's labour in this particular one, ten times the original quantity of work in them would purchase only twice the original quantity in it. Any particular quantity in it, therefore, a pound weight, for example, would appear to be five times