The Wealth of Nations by Part 4 Chapter 5 Page 68

price. This contract price is settled according to what is supposed to be the moderate and reasonable, that is, the ordinary or average price, which before the late years of scarcity was commonly about eight-and-twenty shillings for the quarter of wheat, and for that of other grain in proportion. In years of scarcity, therefore, the corn merchant buys a great part of his corn for the ordinary price, and sells it for a much higher. That this extraordinary profit, however, is no more than sufficient to put his trade upon a fair level with other trades, and to compensate the many losses which he sustains upon other occasions, both from the perishable nature of the commodity itself, and from the frequent and unforeseen fluctuations of its price, seems evident enough, from this single circumstance, that great fortunes are as seldom made in this as in any other trade.