extraordinary profits without any new rivals. Secrets of this kind, however, it must be acknowledged, can seldom be long kept; and the extraordinary profit can last very little longer than they are kept.
Secrets in manufactures are capable of being longer kept than secrets in trade. A dyer who has found the means of producing a particular colour with materials which cost only half the price of those commonly made use of, may, with good management, enjoy the advantage of his discovery as long as he lives, and even leave it as a legacy to his posterity. His extraordinary gains arise from the high price which is paid for his private labour. They properly consist in the high wages of that labour. But as they are repeated upon every part of his stock, and as their whole amount bears, upon that account, a regular proportion to it, they are commonly considered as extraordinary profits of stock.
Such enhancements of the market price are evidently the effects of particular accidents, of which, however, the operation may sometimes last for many years together.