Pound (mass) | historic use
Historically, in different parts of the world, at different points in time, and for different applications, the pound (or its translation) has referred to broadly similar but not identical standards of mass or force.
The libra (Latin for "scales / balance") is an
A number of different definitions of the pound have historically been used in Britain. Amongst these were the avoirdupois pound and the obsolete Tower, merchant's and London pounds. Troy pounds and ounces remain in use only for the weight of certain precious metals, especially in the trade; these are normally quoted just in ounces (e.g. "500 ounces") and, when the type of ounce is not explicitly stated, the troy system is assumed.
|Avoirdupois||1||175/||= 1.21527||35/||= 1.296||28/||= 1.037||35/||= 0.972||≈ 0.9072||16||14 7/||= 14.583||15 5/||= 15.5||7000||9955 5/||≈ 454||≈ 5/|
|Troy||144/||≈ 0.8229||1||16/||= 1.06||64/||= 0.853||4/||= 0.8||≈ 0.7465||13 29/||≈ 13.17||12||12 4/||= 12.8||5760||8192||≈ 373||≈ 3/|
|Tower||27/||≈ 0.7714||15/||= 0.9375||1||4/||= 0.8||3/||= 0.75||≈ 0.6998||12 12/||≈ 12.34||11 1/||= 11.25||12||5400||7680||≈ 350||≈ 7/|
|Merchant||27/||≈ 0.9643||75/||= 1.171875||5/||= 1.25||1||15/||= 0.9375||≈ 0.8748||15 3/||≈ 15.43||14 1/||= 14.0625||15||6750||9600||≈ 437||≈ 7/|
|London||36/||≈ 1.029||5/||= 1.25||4/||= 1.3||16/||= 1.06||1||≈ 0.9331||16 16/||≈ 16.46||15||16||7200||10240||≈ 467||≈ 7/|
|Metric||≈ 1.1023||≈ 1.3396||≈ 1.4290||≈ 1.1431||≈ 1.0717||1||≈ 17.64||≈ 16.08||≈ 17.15||7716||10974||= 500||= 1/|
In the United Kingdom, weights and measures have been defined by a long series of Acts of Parliament, the intention of which has been to regulate the sale of commodities. Materials traded in the marketplace are quantified according to accepted units and standards in order to avoid fraud. The standards themselves are legally defined so as to facilitate the resolution of disputes brought to the courts; only legally defined measures will be recognised by the courts. Quantifying devices used by traders (weights, weighing machines, containers of volumes, measures of length) are subject to official inspection, and penalties apply if they are fraudulent.
The Weights and Measures Act of 1878 marked a major overhaul of the British system of weights and measures, and the definition of the pound given there remained in force until the 1960s. The pound was defined thus (Section 4) "The ... platinum weight ... deposited in the Standards department of the Board of Trade ... shall continue to be the imperial standard of ... weight ... and the said platinum weight shall continue to be the Imperial Standard for determining the Imperial Standard Pound for the United Kingdom". Paragraph 13 states that the weight in vacuo of this standard shall be called the Imperial Standard Pound, and that all other weights mentioned in the act and permissible for commerce shall be ascertained from it alone. The First Schedule of the Act gave more details of the standard pound: it is a platinum cylinder nearly 1.35 inches (34 mm) high, and 1.15 inches (29 mm) diameter, and the edges are carefully rounded off. It has a groove about 0.34 inches (8.6 mm) from the top, to allow the cylinder to be lifted using an ivory fork. It was constructed following the destruction of the Houses of Parliament by fire in 1834, and is stamped P.S. 1844, 1 lb (P.S. stands for "Parliamentary Standard"). The pound was redefined in the United Kingdom in 1963 relative to the kilogram.
The 1878 Act said that contracts worded in terms of metric units would be deemed by the courts to be made according to the Imperial units defined in the Act, and a table of metric equivalents was supplied so that the Imperial equivalents could be legally calculated. This defined, in UK law, metric units in terms of Imperial ones. The equivalence for the pound was given as 1 lb = 453.59265 g or 0.45359 kg, which made the kilogram equivalent to about 2.2046213 lb. In 1883, it was determined jointly by the Standards Department of the Board of Trade and the Bureau International that 0.4535924277 kg was a better approximation, and this figure, rounded to 0.45359243 kg was given legal status by an
However, in 1963, a new
A troy pound is equal to 12
The troy pound is no longer in general use or a legal unit for trade (it was abolished in the United Kingdom on 6 January 1879 by the Weights and Measures Act of 1878), but the
The system called Tower weight was the more general name for King Offa's pound. This dates to 757 AD and was based on the
The Tower pound was also called the Moneyers' Pound (referring to the Saxon moneyers before the Conquest), the easterling pound, which may refer to traders of eastern Germany, or to traders on the shore of the eastern Baltic sea, or dealers of Asiatic goods who settled at the Steelyard wharf; and the Rochelle Pound by French writers, because it was also in use at Rochelle. An almost identical weight was employed by the Germans for weighing gold and silver.
The mercantile pound (1304) of 6750 troy grains, or 9600 Tower grains, derives from this pound, as 25 shilling-weights or 15 Tower ounces, for general commercial use. Multiple pounds based on the same ounce were quite common. In much of Europe, the apothecaries' and commercial pounds were different numbers of the same ounce.[
The Tower system was referenced to a standard prototype found in the
|1 mercantile pound (15 oz)||=||9,600 Tower grains||=||6,750 troy grains|
|1 Tower pound (12 oz)||=||7,680 Tower grains||=||5,400 troy grains|
|1 Tower ounce (20 dwt)||=||640 Tower grains||=||450 troy grains|
|1 Tower pennyweight (dwt)||=||32 Tower grains||=||22 1⁄2 troy grains|
The merchants' pound (mercantile pound, libra mercantoria, or commercial pound) was considered to be composed of 25 rather than 20
The London pound is that of the
A London pound was equal to 7,200 troy grains (16 troy ounces) or, equivalently, 10,240 tower grains (16 tower ounces).
|1 London pound (16 oz)||=||1 1⁄3 tower (or troy) pounds||=||10,240 tower grains||=||7,200 troy grains|
|1 London ounce (20 dwt)||=||1 tower (or troy) ounce||=||640 tower grains||=||450 troy grains|
|1 London pennyweight||=||1 tower (or troy) pennyweight||=||32 tower grains||=||22 1⁄2 troy grains|
In the United States, the avoirdupois pound as a unit of mass has been officially defined in terms of the kilogram since the
In 1959, the United States National Bureau of Standards redefined the pound (avoirdupois) to be exactly equal to 0.453 592 37 kilograms, which had been designated as the International Pound. According to a 1959
The Byzantines used a series of measurements known as pounds (
The soualia litra was specifically used for weighing olive oil or wood, and corresponded to 4/5 of the logarikē, i.e. 256 g. Some outlying regions, especially in later times, adopted various local measures, based on Italian, Arab or Turkish measures. The most important of these was the argyrikē litra (αργυρική λίτρα, "silver pound") of 333 g, found in
Since the Middle Ages, various pounds (livre) have been used in France. Since the 19th century, a livre has referred to the metric pound, 500g.
The livre esterlin was equivalent to about 367.1 grams (5,665 gr) and was used between the late 9th century and the mid-14th century.
The livre métrique was set equal to the kilogram by the decree of 13 Brumaire an IX between 1800 and 1812. This was a form of official metric pound.
Originally derived from the Roman libra, the definition varied throughout Germany in the Middle Ages and onward. The measures and weights of the
Between 1803 and 1815, all German regions west of the
The Russian pound (Фунт, funt) is an
The Skålpund was a Scandinavian measurement that varied in weight between regions. From the 17th century onward, it was equal to 425.076 grams in Sweden but was abandoned in 1889 when Sweden switched to the metric system.
In Norway, the same name was used for a weight of 498.1 grams. In Denmark, it equalled 471 grams.
In the 19th century, Denmark followed Germany's lead and redefined the pound as 500 grams.
The Portuguese unit that corresponds to the pounds of different nations is the arratel, equivalent to 16 ounces of Colonha, a variant of the Cologne standard. This arratel was introduced in 1499 by Manuel I, king of Portugal. Based on an evaluation of bronze nesting weight piles distributed by Manuel I to different towns, the arrátel of Manuel I has been estimated to be of 457.8 g. In the early 19th century, the arratel was evaluated at 459 g. 
In the 15th century, the arratel was of 14 ounces of Colonha or 400.6 g. The Portuguese libra was the same as 2 arrátels. There were also arratels of 12.5 and 13 ounces and libras of 15 and 16 ounces. The Troyes or Tria standard was also used.
A Jersey pound is an obsolete unit of mass used on the island of
The trone pound is one of a number of
In many countries, upon the introduction of a
Though not from the same linguistic origin, the Chinese jīn (斤, also known as "
Hundreds of older pounds were replaced in this way. Examples of the older pounds are one of around 459 to 460 grams in Spain, Portugal, and Latin America; one of 498.1 grams in Norway; and several different ones in what is now Germany.
Although the use of the pound as an informal term persists in these countries to a varying degree, scales and measuring devices are denominated only in grams and kilograms. A pound of product must be determined by weighing the product in grams as the use of the pound is not