Search results
Results from the WOW.Com Content Network
Troy weight is a system of units of mass that originated in the Kingdom of England in the 15th century [1] and is primarily used in the precious metals industry. The troy weight units are the grain , the pennyweight (24 grains), the troy ounce (20 pennyweights), and the troy pound (12 troy ounces).
The grain was the legal foundation of traditional English weight systems, [5] and is the only unit that is equal throughout the troy, avoirdupois, and apothecaries' systems of mass. [6]: C-6 The unit was based on the weight of a single grain of barley which was equal to about + 4 ⁄ 3 the weight of a single grain of wheat.
In all of these systems, the fundamental unit is the pound (lb), and all other units are defined as fractions or multiples of a pound. The tables of imperial troy mass and apothecaries' mass are the same as the corresponding United States tables, except for the British spelling "drachm" in the table of apothecaries' mass.
Irish gold pistole, bearing its weight (4 dwt 7 gr) (National Museum of Ireland – Decorative Arts and History). A pennyweight (dwt) is a unit of mass equal to 24 grains, 1 ⁄ 20 of a troy ounce, 1 ⁄ 240 of a troy pound, 48 ⁄ 875 avoirdupois ounce [1] and exactly 1.55517384 grams. [2]
Troy weight, avoirdupois weight, and apothecaries' weight are all built from the same basic unit, the grain, which is the same in all three systems. However, while each system has some overlap in the names of their units of measure (all have ounces and pounds), the relationship between the grain and these other units within each system varies.
(The troy pound had already been declared illegal for most other uses by the Weights and Measures Act 1878 (41 & 42 Vict. c. 49), but this act allowed the sale of drugs by apothecaries' weight as an exception.) Apothecaries' units of any kind became obsolete in the UK with the mandatory use of metric drug measurements from January 1, 1971. [24]
This value was subsequently called the pennyweight and formed the basis of the Troy units of weight—the troy ounce used to this day for weighting precious metals. [ 3 ] : 44–48 Edward I (1272–1307) broke the link between a coin's value and its weight when he debased the English coinage by introducing a groat (four pence) which weighed of ...
63 — Weights and Measures Act 1835 abolished local and customary measures, including the Winchester bushel; made heaped measure illegal; required trade to be carried out by avoirdupois weight only, except for bullion, gems and drugs (which were to be sold by troy weight instead); decreed that all forms of coal were to be sold by weight and ...