The Wealth of Nations by Part 1 Chapter 4 Page 8

worth of goods, he was obliged to weigh the farthing. The operation of assaying is still more difficult, still more tedious, and, unless a part of the metal is fairly melted in the crucible, with proper dissolvents, any conclusion that can be drawn from it, is extremely uncertain. Before the institution of coined money, however, unless they went through this tedious and difficult operation, people must always have been liable to the grossest frauds and impositions, and instead of a pound weight of pure silver, or pure copper, might receive in exchange for their goods an adulterated composition of the coarsest and cheapest materials, which had, however, in their outward appearance, been made to resemble those metals.

To prevent such abuses, to facilitate exchanges, and thereby to encourage all sorts of industry and