§ 9. #Notable changes in prices#. In most cases the true effects of monetary changes escape recognition. In a few cases, however, the change has been so great as to cause an economic revolution. Such was the change in prices following the discovery of America, which occurred soon after the old feudal dues had come to be generally expressed in terms of money instead of labor services. In modern times, since the mass of debts has become greater than ever before, such changes bring even graver economic consequence. The increase in the output of gold in 1849-57,[15] caused what was the most rapid, if not the greatest money inflation that had occurred since the sixteenth century. The substitution of gold for silver by some countries at that time, by making a great additional market for gold, helped to check the fall in its value. Indeed, a considerable decline in the output of gold after 1870 combined with its widening use to cause in 1873 the beginning of a great fall of gold prices. The resulting increase in the burden of outstanding debts was felt by all debtors, but particularly by great numbers of the agricultural classes both in Europe and in America. Their tribulations were aggravated by the fact that at that time (especially from about 1873 to 1896) the prices of their products were falling much more rapidly than were general prices, as a result of the very rapid extension of the agricultural land supply.[16] There was complaint, agitation, and demand for relief on the part of many interests in France, Germany, England, and the United States. As a result, the money question became in this country a leading political issue and continued to be such between 1873 and 1900. § 10. #Nature and object of bimetallism.# First came "the greenback movement," which, lasted until after 1880.[17] This then gave way to an agitation for bimetallism. _Bimetallism_ is the plan of using two metals as standard moneys. Bimetallism is legally authorized when both metals are admitted to the mints for free coinage at an established ratio of weight. Bimetallism may be legally authorized, but not actually working, for, if the market-value long continues to vary appreciably from the legal ratio, only one of the metals may in fact be left in circulation. This situation is called _limping_ bimetallism (or the halting double standard), tho this is a contradiction of terms. National bimetallism is confined to a single country, as was the case in the United States before the Civil War, or in France before 1867. International bimetallism is that resulting from an agreement among several nations to use two metals on the same terms.