Dollar silver. The US Mint continues to make silver $1-denomination coins, but these are not intended for general circulation. The quantity of silver chosen in 1792 to correspond to one dollar, namely, 371.25 grains of pure silver, is very close to the geometric mean of one troy pound and one pennyweight. In what follows, "dollar" will be used as a unit of mass. A troy pound being 5760 grains and a pennyweight being 240 times smaller, or 24 grains, the geometric mean is, to the nearest hundredth, 371.81 grains. This means that the ratio of a pound to a dollar (15.52)
Troy weight town of Troyes in France where English merchants traded at least as early as the early 9th century. The name "troy" is first attested in 1390, describing the weight of a platter, in an account of the travels in Europe of the Earl of Derby. Charles Moore Watson (1844–1916) proposes an alternative etymology: "The Assize of Weights and Measures" (also known as "Tractatus de Ponderibus et Mensuris"), one of the statutes of uncertain date from the reign of either Henry III or Edward I, thus before 1307, specifies "troni ponderacionem"—which the Public Record Commissioners translate as "troy weight". The word