Search results
Results from the WOW.Com Content Network
A tower pound is equal to 12 tower ounces and to 5,400 troy grains, which equals around 350 grams. [30] The tower pound is the historical weight standard that was used for England's coinage. [31] Before the Norman conquest in 1066, the tower pound was known as the Saxon pound.
The avoirdupois weight system is thought to have come into use in England around 1300. [citation needed] It was originally used for weighing wool. In the early 14th century several other specialized weight systems were used, including the weight system of the Hanseatic League with a 16-ounce pound of 7200 grains and an 8-ounce mark.
The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 pennyweights), and the troy pound (12 troy ounces). The troy grain is equal to the grain unit of the avoirdupois system, but the troy ounce is heavier than the avoirdupois ounce, and the troy pound is lighter than the avoirdupois pound. Legally, one troy ounce ...
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.
A pennyweight (dwt) is a unit of mass equal to 24 grains, 1 ⁄ 20 of a troy ounce, 1 ⁄ 240 of a troy pound, approximately 0.054857 avoirdupois ounce [1] and exactly 1.55517384 grams. [2] It is abbreviated dwt , d standing for denarius – (an ancient Roman coin), and later used as the symbol of an old British penny (see £sd ).
Weight is measured in ounces and pounds (avoirdupois) as in the U.S. Volume is measured in imperial gallons, quarts, pints, fluid ounces, fluid drachms, and minims. The imperial gallon was originally defined as 10 pounds (4.5359 kg) of water in 1824, and refined as exactly 4.54609 litres in 1985.
An ounce-force is 1 ⁄ 16 of a pound-force, or about 0.2780139 newtons. It is defined as the force exerted by a mass of one avoirdupois ounce under standard gravity (at the surface of the earth, its weight). The "ounce" in "ounce-force" is equivalent to an avoirdupois ounce; ounce-force is a measurement of force using avoirdupois ounces.
Another difference arose when Britain abolished the troy pound (373.241 7216 g) on 1 January 1879, leaving only the troy ounce (31.103 4768 g) and its decimal subdivisions, whereas the troy pound (of 12 troy ounces) and pennyweight are still legal in the United States, although they are no longer widely used.