The Wealth of Nations by Part 2 Chapter 2 Page 114

dealers, being ultimately destined to be sold to the consumers. The circulation between the dealers, as it is carried on by wholesale, requires generally a pretty large sum for every particular transaction. That between the dealers and the consumers, on the contrary, as it is generally carried on by retail, frequently requires but very small ones, a shilling, or even a halfpenny, being often sufficient. But small sums circulate much faster than large ones. A shilling changes masters more frequently than a guinea, and a halfpenny more frequently than a shilling. Though the annual purchases of all the consumers, therefore, are at least equal in value to those of all the dealers, they can generally be transacted with a much smaller quantity of money; the same pieces, by a more rapid circulation, serving as the instrument of many more purchases of the one kind than of the other.