During the 19th century there was a great deal of scholarly debate and political controversy regarding the use of bimetallism in place of a gold or silver standard (monometallism). Bimetallism was intended to increase the supply of money, stabilize prices, and facilitate setting exchange rates. Some scholars argued that bimetallism was inherently unstable owing to Gresham's law, and that its replacement by a monometallic standard was inevitable. Other scholars claimed that in practice bimetallism had a stabilizing effect on economies. The controversy became largely moot after technological progress and the South African and Klondike Gold Rushes increased the supply of gold in circulation at the end of the century, ending most of the political pressure for greater use of silver. It became completely academic after the 1971 Nixon shock; since then, all of the world's currencies have operated as more or less freely floating fiat money, unconnected to the value of silver or gold. Nonetheless, academics continue to debate, inconclusively, the relative use of the metallic standards.