Since Mr. Mill wrote, two great changes in the production of the precious metals have occurred. The discoveries of gold, briefly referred to by him, have led to an enormous increase of the existing fund of gold (see chart No. IX, Chap. VI), and a fall in the value of gold within twenty years after the discoveries, according to Mr. Jevons’s celebrated study,(227) of from nine to fifteen per cent. Another change took place, a change in the value, of silver, in 1876, which has resulted in a permanent fall of its value since that time (see chart No. X, Chap. VII). Before that date, silver sold at about 60_d._ per ounce in the central market of the world, London; and now it remains about 52_d._ per ounce, although it once fell to 47_d._, in July, 1876. In spite of Mr. Mill’s expressions of confidence in their stability of value—although certainly more stable than other commodities—the events of the last thirty-five years have fully shown that neither gold nor silver—silver far less than gold—can successfully serve as a perfect “standard of value” for any considerable length of time. When gold and silver had become virtually a medium of exchange, by becoming the things for which people generally sold, and with which they generally bought, whatever they had to sell or to buy, the contrivance of coining obviously suggested itself. By this process the metal was divided into convenient portions, of any degree of smallness, and bearing a recognized proportion to one another; and the trouble was saved of weighing and assaying at every change of possessors—an inconvenience which, on the occasion of small purchases, would soon have become insupportable. Governments found it their interest to take the operation into their own hands, and to interdict all coining by private persons. § 3. Money a mere contrivance for facilitating exchanges, which does not affect the laws of value.