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129-499: The imperial system of units , imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments. The imperial system developed from earlier English units as did the related but differing system of customary units of

258-493: A "commercial" or "civil" system (such as the English avoirdupois system) for general trading, and a second system (such as the troy system) for precious metals such as gold and silver. The system for precious metals was usually divided in a different way from the commercial system, often using special units such as the carat . More significantly, it was often based on different weight standards. The apothecaries' system often used

387-667: A "troy" unit (" trooisch pond ") was also in use as a standard for valuable materials and medicine. As in France, the way in which the Flemish troy ounce was subdivided depended on what was weighed. Unlike the French, the Flemish apothecaries divided the scruple into 20 grains. The Flemish troy pound became the standard for the gold and apothecaries' system in the United Kingdom of the Netherlands; it

516-523: A 1 lb (454 g) tin of Lyle's Golden Syrup is always labelled 454 g with no imperial indicator. Similarly most jars of jam and packs of sausages are labelled 454 g with no imperial indicator. India began converting to the metric system from the imperial system between 1955 and 1962. The metric system in weights and measures was adopted by the Indian Parliament in December 1956 with

645-648: A change. The substantial benefit of conversion to a more rational and internationally consistent system of measurement has been recognized and promoted by scientists, engineers, businesses and politicians, and has resulted in most of the world adopting a commonly agreed metric system. The French Revolution gave rise to the metric system , and this has spread around the world, replacing most customary units of measure. In most systems, length (distance), mass , and time are base quantities . Later, science developments showed that an electromagnetic quantity such as electric charge or electric current could be added to extend

774-538: A common practice in Malaysia for people to refer to unnamed locations and small settlements along major roads by referring to how many miles the said locations were from the nearest major town. In some cases, these eventually became the official names of the locations; in other cases, such names have been largely or completely superseded by new names. An example of the former is Batu 32 (literally "Mile 32" in Malay ), which refers to

903-491: A compromise the government maintains legal definitions for and allows use of imperial units as long as metric units are shown as well. The law requires that measured products (such as fuel and meat) be priced in metric units and an imperial price can be shown if a metric price is present. There tends to be leniency in regards to fruits and vegetables being priced in imperial units only. Environment Canada still offers an imperial unit option beside metric units, even though weather

1032-652: A dollar), or the euro and euro cent. ISO 4217 is the international standard describing three letter codes (also known as the currency code) to define the names of currencies established by the International Organization for Standardization (ISO). Throughout history, many official systems of measurement have been used. While no longer in official use, some of these customary systems are occasionally used in day-to-day life, for instance in cooking . Still in use: Apothecaries%27 system The apothecaries' system , or apothecaries' weights and measures ,

1161-519: A free city and became part of Bavaria. From now on the Nuremberg apothecaries' pound was no longer the official apothecaries' pound in Nuremberg; but the difference was only 0.6%. In 1836 the Greek apothecaries' pound was officially defined by this standard, four years after Otto , the son of the king of Bavaria, became the first king of Greece. But only few German states followed the example of Bavaria, and with

1290-580: A goal to metricate by 2019, which was not met, with the help of the German National Metrology Institute . Some imperial measurements remain in limited use in Malaysia , the Philippines , Sri Lanka and South Africa . Measurements in feet and inches, especially for a person's height, are frequently encountered in conversation and non-governmental publications. Prior to metrication, it was

1419-505: A long delay. The apothecaries' pound of 360 g was also adopted in Lübeck, where it was official as of 1861. Austria and the states of the Habsburg monarchy officially had a different standard since 1761, and Prussia , followed by its neighbours Anhalt , Lippe and Mecklenburg , would diverge in the opposite direction with a reform in 1816. But in both cases apothecaries continued to use

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1548-500: A new variant of the apothecaries' system which subdivided a new apothecaries' pound of 12 avoirdupois ounces instead of the troy pound. To allow effective use of the new system, new weight pieces were produced. Since an avoirdupois ounce corresponds to 28.35 g, the proposed system was very similar to that in use in Portugal and Spain, and in some locations in Italy. But it would have doubled

1677-461: A similar reform in France. The British troy pound retained its value of 373.202 g until in 2000 it was legally defined in metric terms, as 373.2417216 g. (At this time its use was mainly confined to trading precious metals.) In the Romance speaking part of Europe the scruple was divided in 24 grains, in the rest of Europe in 20 grains. Notable exceptions were Venice and Sicily, where

1806-520: A subset of the units of the Roman weight system , although the troy pound and its subdivisions were slightly heavier than the Roman pound and its subdivisions. Similar systems were used all over Europe, but with considerable local variation described below under Variants . The traditional English apothecaries' system of weights is shown in the first table in this section: the pound, ounce and grain were identical to

1935-447: A unit close in volume to the ale gallon . The 1824 act defined as the volume of a gallon to be that of 10 pounds (4.54 kg) of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury (102 kPa) at a temperature of 62  °F (17 °C). The 1824 act went on to give this volume as 277.274 cubic inches (4.54371 litres). The Weights and Measures Act 1963 refined this definition to be

2064-402: Is Latin for the seed of the carob tree. Many attempts were made to reconstruct the exact mass of the Roman pound. One method for doing this consists in weighing old coins; another uses the fact that Roman weight units were derived from Roman units of length similar to the way the kilogramme was originally derived from the metre, i.e. by weighing a known volume of water. Nowadays the Roman pound

2193-448: Is a historical system of mass and volume units that were used by physicians and apothecaries for medical prescriptions and also sometimes by scientists. The English version of the system is closely related to the English troy system of weights, the pound and grain being exactly the same in both. It divides a pound into 12 ounces, an ounce into 8 drachms , and a drachm into 3 scruples of 20 grains each. This exact form of

2322-400: Is generally sold in inches. Clothing is usually sized in inches, with the metric equivalent often shown as a small supplementary indicator. Gas is usually measured by the cubic foot or cubic metre, but is billed like electricity by the kilowatt hour . Pre-packaged products can show both metric and imperial measures, and it is also common to see imperial pack sizes with metric only labels, e.g.

2451-459: Is neither imperial nor metric, and altitude is measured in imperial feet. While metrication in Australia has largely ended the official use of imperial units, for particular measurements, international use of imperial units is still followed. The influence of British and American culture in Australia has been noted to be a cause for residual use of imperial units of measure. New Zealand introduced

2580-606: Is not always clearly drawn. Strictly a pound is a unit of mass, but it is commonly referred to as a weight. When a distinction is necessary, the term pound-force may refer to a unit of force rather than mass. The troy pound ( 373.241 7216  g ) was made the primary unit of mass by the Weights and Measures Act 1824 and its use was abolished in the UK on 1 January 1879, with only the troy ounce ( 31.103 4768  g ) and its decimal subdivisions retained. The Weights and Measures Act 1855 made

2709-755: Is now surveyed and registered in metric units whilst initial surveys used imperial units. For example, partitioning of farmland on the prairies in the late 19th and early 20th centuries was done in imperial units; this accounts for imperial units of distance and area retaining wide use in the Prairie Provinces . In English-speaking Canada commercial and residential spaces are mostly (but not exclusively) constructed using square feet, while in French-speaking Quebec commercial and residential spaces are constructed in metres and advertised using both square metres and square feet as equivalents. Carpet or flooring tile

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2838-482: Is often given as 327.45 g, but one should keep in mind that (apart from the other uncertainties that come with such a reconstruction) the Roman weight standard is unlikely to have remained constant to such a precision over the centuries, and that the provinces often had somewhat inexact copies of the standard. The weight and subdivision of the pound in the Holy Roman Empire were reformed by Charlemagne , but in

2967-437: Is purchased by the square foot, but less frequently also in square metres. Motor-vehicle fuel consumption is reported in both litres per 100 km and statute miles per imperial gallon, leading to the erroneous impression that Canadian vehicles are 20% more fuel-efficient than their apparently identical American counterparts for which fuel economy is reported in statute miles per US gallon (neither country specifies which gallon

3096-426: Is routinely used in business and technology within the United Kingdom, with imperial units remaining in widespread use amongst the public. All UK roads use the imperial system except for weight limits, and newer height or width restriction signs give metric alongside imperial. Traders in the UK may accept requests from customers specified in imperial units, and scales which display in both unit systems are commonplace in

3225-406: Is that there was some definition based on some standard. Eventually cubits and strides gave way to "customary units" to meet the needs of merchants and scientists. The preference for a more universal and consistent system only gradually spread with the growth of international trade and science. Changing a measurement system has costs in the near term, which often results in resistance to such

3354-407: Is the only unit of the system in current use; it is used for precious metals. Although the troy ounce is larger than its avoirdupois equivalent, the pound is smaller. The obsolete troy pound was divided into 12 ounces, rather than the 16 ounces per pound of the avoirdupois system. The apothecaries' system was traditionally used in pharmacology , but has now been replaced by the metric system; it shared

3483-579: Is typically measured and reported in metric units in the Canadian media. Some radio stations near the United States border (such as CIMX and CIDR ) primarily use imperial units to report the weather. Railways in Canada also continue to use imperial units. Imperial units are still used in ordinary conversation. Today, Canadians typically use a mix of metric and imperial measurements in their daily lives. The use of

3612-419: Is used). Canadian railways maintain exclusive use of imperial measurements to describe train length (feet), train height (feet), capacity ( tons ), speed (mph), and trackage (miles). Imperial units also retain common use in firearms and ammunition. Imperial measures are still used in the description of cartridge types, even when the cartridge is of relatively recent invention (e.g., .204 Ruger , .17 HMR , where

3741-499: The marc de Paris of 8 ounces. The civil pound of 16 ounces was equivalent to 2 marks, and it was also used as the apothecaries' pound. With 30.6 g, the ounces were considerably heavier than other apothecaries ounces in Romance countries, but otherwise, the French system was not remarkable. Its history and connections to the English and Flemish standards are discussed below under Weight standards named after Troyes . Due in part to

3870-823: The Bahamas . Legally, both the imperial and metric systems are recognised by the Weights and Measures Act 2006. Both imperial units and metric units are used in Belize . Both systems are legally recognized by the National Metrology Act. According to the CIA, in June 2009, Myanmar was one of three countries that had not adopted the SI metric system as their official system of weights and measures. Metrication efforts began in 2011. The Burmese government set

3999-573: The Byzantine Empire it remained essentially the same. Since Byzantine coins circulated up to Scandinavia , the old Roman standard continued to be influential through the Middle Ages. The history of mediaeval medicine started roughly around the year 1000 with the school of medicine in Salerno , which combined elements of Latin, Greek, Arabic, and Jewish medicine. Galen and Dioscorides (who had used

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4128-495: The Standards of Weights and Measures Act , which took effect beginning 1 October 1958. By 1962, metric units became "mandatory and exclusive." Today all official measurements are made in the metric system. In common usage some older Indians may still refer to imperial units. Some measurements, such as the heights of mountains, are still recorded in feet. Tyre rim diameters are still measured in inches, as used worldwide. Industries like

4257-514: The Treaty of Troyes , a statute of Henry V of England gave directions to the goldsmiths in terms of the troy pound . (In 1304 it had apparently not yet been introduced, since it did not appear in the statute of weights and measures.) There is evidence from the 15th century that the troy pound was used for weighing metals and spices. After the abolishment of the Tower pound in 1527 by Henry VIII of England ,

4386-545: The United States and the Philippines . The imperial long ton is invariably spelt with one 'n'. Hong Kong has three main systems of units of measurement in current use: In 1976 the Hong Kong Government started the conversion to the metric system, and as of 2012 measurements for government purposes, such as road signs, are almost always in metric units. All three systems are officially permitted for trade, and in

4515-415: The mile or "li" ( 哩 , li ), the yard or "ma" ( 碼 , maa ), the foot or "chek" ( 呎 , cek ), and the inch or "tsun" ( 吋 , cyun ). The traditional measure of flat area is the square foot ( 方呎, 平方呎 , fong cek, ping fong cek ) of the imperial system, which is still in common use for real estate purposes. The measurement of agricultural plots and fields is traditionally conducted in 畝 ( mau ) of

4644-457: The 1540s, the first pharmacopoeia in the modern sense was also printed there. In 1555, a weight standard for the apothecaries' pound of 12 ounces was set in Nuremberg. Under the name Nuremberg pharmaceutical weight ( German : Nürnberger Medizinalgewicht ) it would become the standard for most of the north-east of Europe. However, some cities kept local copies of the standard. As of 1800 all German states and cities except Lübeck (which had

4773-455: The Chinese system. For the measurement of volume, Hong Kong officially uses the metric system, though the gallon ( 加侖 , gaa leon ) is also occasionally used. During the 1970s, the metric system and SI units were introduced in Canada to replace the imperial system. Within the government, efforts to implement the metric system were extensive; almost any agency, institution, or function provided by

4902-402: The Chinese system. In order to distinguish between the units of the two systems, the units can be prefixed with "Ying" ( 英 , jing ) for the imperial system and "Wa" ( 華 , waa ) for the Chinese system. In writing, derived characters are often used, with an additional 口 (mouth) radical to the left of the original Chinese character, for writing imperial units. The most commonly used units are

5031-505: The Dutch troy standard) followed the Nuremberg standard. It was also the standard for Denmark, Norway, the Russian Empire, and most cantons of Switzerland. Poland and Sweden had their own variants of the standard, which differed from each other by 0.6%. In 1811, Bavaria legally defined the apothecaries' pound as 360.00 g (an ounce of 30.00 g). In 1815, Nuremberg lost its status as

5160-494: The French poids de marc , the Flemish trooisch pond and the English troy pound are unclear. It is known, however, that the numerical relation between the English and French troy ounces was exactly 64:63 in the 14th century. In the Middle Ages the Imperial Free City of Nuremberg , an important trading place in the south of Germany, produced large amounts of nesting weight pieces to various European standards. In

5289-527: The Graeco-Roman weight system) were among the most important authorities, but also Arabic physicians, whose works were systematically translated into Latin. According to De ponderibus et mensuris , a famous 13th-century text that exists in numerous variations and is often ascribed to Dino di Garbo , the system of weights used in Salerno was different from the systems used in Padua and Bologna. As can be seen from

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5418-580: The Grenadines . The United Arab Emirates Cabinet in 2009 issued the Decree No. (270 / 3) specifying that, from 1 January 2010, the new unit sale price for petrol will be the litre and not the gallon, which was in line with the UAE Cabinet Decision No. 31 of 2006 on the national system of measurement, which mandates the use of International System of units as a basis for the legal units of measurement in

5547-603: The Italian range up to 28 g. But there is a relatively large gap between the troy ounces of 31 g and the Habsburg ounce of 35 g. The latter is the product of an 18th-century weight reform. Even in Turkey a system of weights similar to the European apothecaries' system was used for the same purpose. For medical purposes the tcheky (approx. 320 g) was divided in 100 drachms, and

5676-699: The London College of Physicians ( octarius, minim ) were subsequently adopted by the Pharmacopoeias of the United States and Dublin. The pint was given the Latin name octarius and represented by the symbol O, thus distinguishing its Latin name and symbol from that of the pound. The terms for fluid ounce and fluid drachm were distinguished from weight measures by the prefix fluid- (Latin Fluiduncia, Fluidrachma , English fluidounce and fluidrachm ) or in abbreviations by

5805-781: The London and Dublin editions having the force of law. Imperial apothecaries' measures, based on the imperial pint of 20 fluid ounces, were introduced by the publication of the London Pharmacopoeia of 1836, the Edinburgh Pharmacopoeia of 1839, and the Dublin Pharmacopoeia of 1850. The Medical Act 1858 transferred to the Crown the right to publish the official pharmacopoeia and to regulate apothecaries' weights and measures. Metric equivalents in this article usually assume

5934-580: The Napoleonic Kingdom of Italy , fell to Habsburg in 1814 (at a time when even in France the système usuel had been introduced because the metric system was not accepted by the population), an apothecaries' system was officially introduced again, but now based on the Habsburg apothecaries' pound, which weighed almost 30% more. The apothecaries' pound in Venice had exactly the same subdivisions as those in

6063-522: The U.K. As a result, the Imperial and U.S. systems differ in the size of the basic unit (the gallon or the pint , one gallon being equal to eight pints), and in the number of fluid ounces per pint. Apothecaries' systems for volumes were internationally much less common than those for weights. There were also commonly used, but unofficial divisions of the Apothecaries' system, consisting of: In

6192-442: The U.K. and were officially abolished in 1971. In the U.S., they are still occasionally used, for example with prescribed medicine being sold in four-ounce (℥ iv) bottles. Until around 1900, medical prescriptions and most European pharmacopoeias were written in Latin. Here is a typical example from the middle of the 19th century. The use of Latin ensured that the prescriptions could be read by an international audience . There

6321-952: The UK must be capable of displaying miles per hour. Even though the troy pound was outlawed in the UK in the Weights and Measures Act 1878 , the troy ounce may still be used for the weights of precious stones and metals. The original railways (many built in the Victorian era) are a big user of imperial units, with distances officially measured in miles and yards or miles and chains , and also feet and inches, and speeds are in miles per hour. Some British people still use one or more imperial units in everyday life for distance (miles, yards, feet, and inches) and some types of volume measurement (especially milk and beer in pints; rarely for canned or bottled soft drinks, or petrol ). As of February 2021, many British people also still use imperial units in everyday life for body weight (stones and pounds for adults, pounds and ounces for babies). Government documents aimed at

6450-412: The UK with the mandatory use of metric drug measurements from January 1, 1971. In the United States, the apothecaries' system remained official until it was abolished in 1971 in favour of the metric system. English-speaking countries also used a system of units of fluid measure, or in modern terminology volume units, based on the apothecaries' system. Originally, the terms and symbols used to describe

6579-445: The US and, formerly, India retained older definitions for surveying purposes. This gave rise to the US survey foot , for instance. The avoirdupois units of mass and weight differ for units larger than a pound (lb). The British imperial system uses a stone of 14 lb, a long hundredweight of 112 lb and a long ton of 2,240 lb. The stone is not a measurement of weight used in

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6708-432: The US. The US customary system uses the short hundredweight of 100 lb and short ton of 2,000 lb. Where these systems most notably differ is in their units of volume. A US fluid ounce (fl oz), about 29.6 millilitres (ml), is slightly larger than the imperial fluid ounce (about 28.4 ml). However, as there are 16 US fl oz to a US pint and 20 imp fl oz per imperial pint,

6837-462: The United Kingdom (then including Ireland), with none of the traditional subdivisions. This innovation was first used in the United British pharmacopœia of 1864, which recommended the adoption in pharmacy of the imperial avoirdupois pound of 7000 grains and ounce of 437.5 grains, and discontinuation of the drachm and scruple. In practice, however, the old apothecaries' system based on divisions of

6966-554: The United States . The imperial units replaced the Winchester Standards , which were in effect from 1588 to 1825. The system came into official use across the British Empire in 1826. By the late 20th century, most nations of the former empire had officially adopted the metric system as their main system of measurement, but imperial units are still used alongside metric units in the United Kingdom and in some other parts of

7095-584: The United States, metric units are virtually always used in science, frequently in the military, and partially in industry. U.S. customary units are primarily used in U.S. households. At retail stores, the litre (spelled 'liter' in the U.S.) is a commonly used unit for volume, especially on bottles of beverages, and milligrams, rather than grains , are used for medications. Some other non- SI units are still in international use, such as nautical miles and knots in aviation and shipping, and feet for aircraft altitude. Metric systems of units have evolved since

7224-475: The United States, similar measures in use were once: The cited book states, "In almost all cases the modern teacups, tablespoons, dessertspoons, and teaspoons, after careful test by the author, were found to average 25 percent greater capacity than the theoretical quantities given above, and thus the use of accurately graduated medicine glasses, which may be had now at a trifling cost, should be insisted upon." Apothecaries' measures eventually fell out of use in

7353-675: The acts of 1824 and 1825. At the time, apothecaries' weights and measures were regulated "in England, Wales, and Berwick-upon-Tweed " by the London College of Physicians , and in Ireland by the Dublin College of Physicians . In Scotland, apothecaries' units were unofficially regulated by the Edinburgh College of Physicians . The three colleges published, at infrequent intervals, pharmacopoeias ,

7482-440: The adoption of the first well-defined system in France in 1795. During this evolution the use of these systems has spread throughout the world, first to non-English-speaking countries, and then to English speaking countries. Multiples and submultiples of metric units are related by powers of ten and their names are formed with prefixes . This relationship is compatible with the decimal system of numbers and it contributes greatly to

7611-416: The apothecaries' pound of 12 ounces was replaced by the larger civil pound of 16 ounces. The subdivisions of the apothecaries ounce were the same as in the other Romance countries, however, and were different from the subdivisions of the otherwise identical civil ounce. The basic apothecaries' system consists of the units pound, ounce, and scruple from the classical Roman weight system, together with

7740-430: The apothecaries' system, and since the libbra (or the libbra sottile , where different systems were in use for light and heavy goods) generally had a suitable weight for an apothecaries' pound it was often used for this purpose. Extreme cases were Rome and Genoa , where the same system was used for everything, including medicine. On the other hand, there were relatively large differences even between two cities in

7869-663: The area surrounding the intersection between Federal Route 22 (the Tamparuli - Sandakan highway) and Federal Route 13 (the Sandakan- Tawau highway). The area is so named because it is 32 miles west of Sandakan, the nearest major town. Petrol is still sold by the imperial gallon in Anguilla , Antigua and Barbuda , Belize , Myanmar , the Cayman Islands , Dominica , Grenada , Montserrat , St Kitts and Nevis and St. Vincent and

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7998-415: The avoirdupois pound the primary unit of mass. In all the systems, the fundamental unit is the pound , and all other units are defined as fractions or multiples of it. The 1824 Act of Parliament defined the yard and pound by reference to the prototype standards, and it also defined the values of certain physical constants , to make provision for re-creation of the standards if they were to be damaged. For

8127-403: The calibre is expressed in decimal fractions of an inch). Ammunition that is already classified in metric is still kept metric (e.g., 9×19mm ). In the manufacture of ammunition, bullet and powder weights are expressed in terms of grains for both metric and imperial cartridges. In keeping with the international standard, air navigation is based on nautical units, e.g., the nautical mile, which

8256-453: The choice of constants used. Some examples are as follows: Non-standard measurement units also found in books, newspapers etc., include: A unit of measurement that applies to money is called a unit of account in economics and unit of measure in accounting. This is normally a currency issued by a country or a fraction thereof; for instance, the US dollar and US cent ( 1 ⁄ 100 of

8385-499: The construction and the real estate industry still use both the metric and the imperial system though it is more common for sizes of homes to be given in square feet and land in acres. In Standard Indian English , as in Australian , Canadian , New Zealand , Singaporean , and British English , metric units such as the litre, metre, and tonne utilise the traditional spellings brought over from French , which differ from those used in

8514-449: The convenience of metric units. In the early metric system there were two base units, the metre for length and the gram for mass. The other units of length and mass, and all units of area, volume, and derived units such as density were derived from these two base units. Mesures usuelles ( French for customary measures ) were a system of measurement introduced as a compromise between the metric system and traditional measurements. It

8643-685: The country. Sierra Leone switched to selling fuel by the litre in May 2011. In October 2011, the Antigua and Barbuda government announced the re-launch of the Metrication Programme in accordance with the Metrology Act 2007, which established the International System of Units as the legal system of units. The Antigua and Barbuda government has committed to a full conversion from the imperial system by

8772-449: The drachm in (16 kilos or) 64 grains. This is close to the classical Greek weight system, where a mina (corresponding roughly to a Roman libra ) was also divided into 100 drachms. With the beginning of metrication, some countries standardized their apothecaries' pound to an easily remembered multiple of the French gramme . E.g. in the Netherlands the Dutch troy pound of 369.1 g was standardized in 1820 to 375.000 g, to match

8901-408: The first quarter of 2015. System of units In antiquity, systems of measurement were defined locally: the different units might be defined independently according to the length of a king's thumb or the size of his foot, the length of stride, the length of arm, or maybe the weight of water in a keg of specific size, perhaps itself defined in hands and knuckles . The unifying characteristic

9030-540: The former British Empire and the British Commonwealth , but in all these countries they have been largely supplanted by the metric system. They are still used for some applications in the United Kingdom but have been mostly replaced by the metric system in commercial , scientific , and industrial applications. US customary units, however, are still the main system of measurement in the United States . While some steps towards metrication have been made (mainly in

9159-534: The former empire, notably Canada. The modern UK legislation defining the imperial system of units is given in the Weights and Measures Act 1985 (as amended). The Weights and Measures Act 1824 was initially scheduled to go into effect on 1 May 1825. The Weights and Measures Act 1825 pushed back the date to 1 January 1826. The 1824 act allowed the continued use of pre-imperial units provided that they were customary, widely known, and clearly marked with imperial equivalents. Apothecaries' units are not mentioned in

9288-573: The general population especially with height and distance measurements such as feet, inches, and acres as well as for weight with pounds and stones still in common use among people of all ages. Measurements such as yards have fallen out of favour with younger generations. Ireland's railways still use imperial measurements for distances and speed signage. Property is usually listed in square feet as well as metres also. Horse racing in Ireland still continues to use stones, pounds, miles and furlongs as measurements. Imperial measurements remain in general use in

9417-408: The government uses SI units exclusively. Imperial units were eliminated from all public road signs and both systems of measurement will still be found on privately owned signs, such as the height warnings at the entrance of a parkade . In the 1980s, momentum to fully convert to the metric system stalled when the government of Brian Mulroney was elected. There was heavy opposition to metrication and as

9546-637: The height of horses is usually measured in hands , standardised to 4 inches (102 mm). Fuel consumption for vehicles is commonly stated in miles per gallon (mpg), though official figures always include litres per 100 km equivalents and fuel is sold in litres. When sold draught in licensed premises, beer and cider must be sold in pints, half-pints or third-pints. Cow's milk is available in both litre- and pint-based containers in supermarkets and shops. Areas of land associated with farming, forestry and real estate are commonly advertised in acres and square feet but, for contracts and land registration purposes,

9675-467: The imperial gallon is 20% more than the liquid gallon, the same is true for the imperial pint in relation to the liquid pint. Accordingly, in the new imperial system, the number of fluid ounces per pint was adjusted from 16 to 20 so that the fluid ounce was not changed too much by the reform. Even so, the modern U.K. fluid ounce is 4% less than the US fluid ounce, and the same is true for the smaller units. For some years both systems were used concurrently in

9804-401: The imperial pint is about 20% larger. The same is true of quarts , gallons , etc.; six US gallons are a little less than five imperial gallons. The avoirdupois system served as the general system of mass and weight. In addition to this, there are the troy and the apothecaries' systems . Troy weight was customarily used for precious metals , black powder , and gemstones . The troy ounce

9933-444: The large volume of trade with the U.S. There is also considerable use of imperial weights and measures, despite de jure Canadian conversion to metric. A number of other jurisdictions have laws mandating or permitting other systems of measurement in some or all contexts, such as the United Kingdom whose road signage legislation , for instance, only allows distance signs displaying imperial units (miles or yards) or Hong Kong. In

10062-487: The late 1960s and early 1970s), the customary units have a strong hold due to the vast industrial infrastructure and commercial development. While British imperial and US customary systems are closely related, there are a number of differences between them . Units of length and area (the inch , foot , yard , mile , etc.) have been identical since the adoption of the International Yard and Pound Agreement ; however,

10191-468: The latest official definition. Before this date, the most precise measurement of the imperial Standard Yard was 0.914 398 415 metres. Abbreviation of "thousandth of an inch". Also known as mil . The Weights and Measures Act 1824 invalidated the various different gallons in use in the British Empire, declaring them to be replaced by the statute gallon (which became known as the imperial gallon),

10320-740: The metric and imperial systems varies by age. The older generation mostly uses the imperial system, while the younger generation more often uses the metric system. Quebec has implemented metrication more fully. Newborns are measured in SI at hospitals, but the birth weight and length is also announced to family and friends in imperial units. Drivers' licences use SI units, though many English-speaking Canadians give their height and weight in imperial. In livestock auction markets, cattle are sold in dollars per hundredweight (short), whereas hogs are sold in dollars per hundred kilograms. Imperial units still dominate in recipes, construction, house renovation and gardening. Land

10449-436: The metric system and other recent systems, underlying relationships between quantities, as expressed by formulae of physics such as Newton's laws of motion , is used to select a small number of base quantities for which a unit is defined for each, from which all other units may be derived. Secondary units (multiples and submultiples) are derived from these base and derived units by multiplying by powers of ten. For example, where

10578-495: The metric system is the International System of Units ( Système international d'unités or SI). It is a system in which all units can be expressed in terms of seven units. The units that serve as the SI base units are the metre , kilogram , second , ampere , kelvin , mole , and candela . Both British imperial units and US customary units derive from earlier English units . Imperial units were mostly used in

10707-415: The metric system on 15 December 1976. Aviation was exempt, with altitude and airport elevation continuing to be measured in feet whilst navigation is done in nautical miles ; all other aspects (fuel quantity, aircraft weight, runway length, etc.) use metric units. Screen sizes for devices such as televisions, monitors and phones, and wheel rim sizes for vehicles, are stated in inches, as is the convention in

10836-451: The non-Romance countries, but its total weight of 301 g was at the bottom of the range. During the Habsburg reign of 1814–1859 an exception was made for Venice; as a result, the extreme weights of 301 g and 420 g coexisted within one state and in immediate proximity. The Venice standard was also used elsewhere, for example in Udine . In Dubrovnik (called "Ragusa" until 1909) its use

10965-417: The original prototypes in the 1834 Houses of Parliament fire , it proved impossible to recreate the standards from these definitions, and a new Weights and Measures Act 1855 was passed which permitted the recreation of the prototypes from recognized secondary standards . Since the Weights and Measures Act 1985 , British law defines base imperial units in terms of their metric equivalent. The metric system

11094-465: The originally Greek drachm and a new subdivision of the scruple into either 20 ("barley") or 24 ("wheat") grains ( Latin : grana ). In some countries other units of the original system remained in use, for example in Spain the obolo and siliqua . In some cases the apothecaries' and civil weight systems had the same ounces ("an ounce is an ounce"), but the civil pound consisted of 16 ounces. Siliqua

11223-486: The pint). All other goods are required by law to be sold in metric units with traditional quantities being retained for goods like butter and sausages, which are sold in 454 grams (1 lb) packaging. The majority of cars sold pre-2005 feature speedometers with miles per hour as the primary unit, but with a kilometres per hour display. Often signs such as those for bridge height can display both metric and imperial units. Imperial measurements continue to be used colloquially by

11352-418: The political conditions in what would become a united Kingdom of Italy only in 1861, the variation of apothecaries' systems and standard weights in this region was enormous. (For background information, see History of Italy during foreign domination and the unification .) The libbra (pound) generally consisted of the standard twelve ounces, however. The civil weight systems were generally very similar to

11481-414: The prefixed letter f (f℥, fʒ). (However, even in the 20th century the f of the symbols f℥, fʒ was sometimes omitted by physicians in the United States, with fluid ounces and fluid drams represented instead simply by the symbols ℥, ʒ. ) The smallest unit of volume was standardized as precisely a sixtieth of a fluidrachm (1/61,440 of a wine gallon ) and given the name minim . (Subsequently, the old term drop

11610-403: The public may give body weight and height in imperial units as well as in metric. A survey in 2015 found that many people did not know their body weight or height in both systems. As of 2017, people under the age of 40 preferred the metric system but people aged 40 and over preferred the imperial system. As in other English-speaking countries, including Australia , Canada and the United States ,

11739-483: The rest of the world - and a 1992 study found a continued use of imperial units for birth weight and human height alongside metric units. Ireland has officially changed over to the metric system since entering the European Union , with distances on new road signs being metric since 1997 and speed limits being metric since 2005. The imperial system remains in limited use – for sales of beer in pubs (traditionally sold by

11868-427: The retail trade. Metric price signs may be accompanied by imperial price signs provided that the imperial signs are no larger and no more prominent than the metric ones. The United Kingdom completed its official partial transition to the metric system in 1995, with imperial units still legally mandated for certain applications such as draught beer and cider, and road-signs. Therefore, the speedometers on vehicles sold in

11997-494: The rule of the Habsburg monarchy 1814–1859 and therefore had the extremely large Habsburg apothecaries' pound of 420 g. (See below under Habsburg standard .) E.g. in the large city of Milan the apothecaries' system based on a pound of 326.8 g was officially replaced by the metric system as early as 1803, because Milan was part of the Napoleonic Italian Republic . Since the successor of this little state,

12126-493: The same ounces as the precious metals system, although even then the number of ounces in a pound could be different. The apothecaries' pound was divided into its own special units, which were inherited (via influential treatises of Greek physicians such as Dioscorides and Galen , 1st and 2nd century) from the general-purpose weight system of the Romans. Where the apothecaries' weights and the normal commercial weights were different, it

12255-488: The same pound and ounce as the troy system but with different further subdivisions. Natural units are units of measurement defined in terms of universal physical constants in such a manner that selected physical constants take on the numerical value of one when expressed in terms of those units. Natural units are so named because their definition relies on only properties of nature and not on any human construct. Varying systems of natural units are possible, depending on

12384-606: The same state. E.g. Bologna (in the Papal States ) had an apothecaries pound that was less than the local civil pound, and 4% lighter than the pound used in Rome. The weight of an apothecaries' pound ranged generally between 300 g and 320 g, slightly less than that of a pound in the Roman Empire. An important exception to this rule is that the Kingdom of Lombardy–Venetia was under

12513-540: The scruple in exactly the same way as in the Roman system: It divided the ounce into 10 drachms. While there will naturally have been some changes throughout the centuries, this section only tries to give a general overview of the situation that was recorded in detail in numerous 19th-century merchants' handbooks. On the Iberian Peninsula , apothecaries' weights in the 19th century were relatively uniform, with 24 grains per scruple (576 grains per ounce),

12642-408: The scruple was also divided in 20 grains. The Sicilian apothecaries ounce was divided into 10 drachms. Since the scruple was divided into only 20 grains, like in the northern countries, an ounce consisted of 600 grains. This was not too different from the situation in most of the other Mediterranean countries, where an ounce consisted of 576 grains. In France, at some stage

12771-511: The second half of the 15th century. It is an elaborate set of nesting weight pieces, with a total metric weight of 12.238  kg . The set is now shown in the Musée des Arts et Métiers in Paris. The total nominal value of the set is 50 marcs de Troyes or marcs de Paris , a mark being 8 ounces. The ounce poids de marc had therefore a metric equivalent of 30.59 g. The poids de marc

12900-576: The set of base quantities. Gaussian units have only length, mass, and time as base quantities, with no separate electromagnetic dimension. Other quantities, such as power and speed , are derived from the base quantities: for example, speed is distance per unit time. Historically, a wide range of units was used for the same type of quantity. In different contexts length was measured in inches , feet , yards , fathoms , rods , chains , furlongs , miles , nautical miles , stadia , leagues , with conversion factors that were not based on power of ten. In

13029-464: The smallest unit of volume using a graduated glass tube. Before introduction of the imperial units in the U.K., all apothecaries' fluid measures were based on the unit of the wine gallon , which survived in the US under the name liquid gallon or wet gallon . The wine gallon was abolished in Britain in 1826, and this system was replaced by a new one based on the newly introduced imperial gallon. Since

13158-403: The south of Europe and in France, the scruple was generally divided into 24 grains, so that one ounce consisted of 576 grains. Nevertheless, the subdivision of an ounce was somewhat more uniform than that of a pound, and a common feature of all variants is that 12 ounces are roughly 100 drachms (96–128 drachms) and a grain is roughly the weight of a physical grain. It is most convenient to compare

13287-502: The standard in Romance countries. The weight of an apothecaries' pound was 345.1 g in Spain and 344.2 g in Portugal . As in Italy, some of the additional subdivisions of the Roman system, such as the obolo , were still in use there. It was standard to use the marco , defined as 8 ounces, instead of the pound. In 18th century France , there was a national weight standard,

13416-421: The symbol. Since only the units of the apothecaries' system were used in this way, this made it clear that the civil weight system was not meant. The basic form of the apothecaries' system is essentially a subset of the Roman weight system. An apothecaries' pound normally consisted of 12 ounces. (In France this was changed to 16 ounces, and in Spain, the customary unit was the marco , a mark of 8 ounces.) In

13545-457: The system was used in the United Kingdom; in some of its former colonies , it survived well into the 20th century. The apothecaries' system of measures is a similar system of volume units based on the fluid ounce. For a long time, medical recipes were written in Latin , often using special symbols to denote weights and measures. The use of different measure and weight systems depending on the purpose

13674-407: The table, it was also different from the Roman weight system used by Galenus and Dioscorides and from all modern apothecaries' systems: The ounce was divided into 9 drachms, rather than 8 drachms. Centuries later, the region around Salerno was the only exception to the rule that (except for skipping units that had regionally fallen out of use) the apothecaries' ounce was subdivided down to

13803-411: The troy pound was the official basis for English coin weights. The British apothecaries' system was based on the troy pound until metrication, and it survived in the United States and Australia well into the 20th century. Since the modern (English, American and Imperial) troy ounces are roughly 1.5% heavier than the late Paris ounce, the exact historical relations between the original marc de Troyes ,

13932-486: The troy pound, or of the troy ounce of 480 grains, was still widely used until it was abolished by the Weights and Measures Act 1976 (c. 77), since when it may only be used to measure precious metals and stones. (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

14061-454: The troy pound, ounce and grain (also used to measure weights of precious metals; distinct from the avoirdupois pounds and ounces that were used for measurements of other goods.) The confusing variety of definitions and conversions for pounds and ounces is covered elsewhere in a table of pound definitions . To unify all weight systems used by apothecaries, the Irish pharmacopœia of 1850 introduced

14190-549: The unit of length is the metre ; a distance of 1 metre is 1,000 millimetres, or 0.001 kilometres. Metrication is complete or nearly complete in most countries. However, US customary units remain heavily used in the United States and to some degree in Liberia . Traditional Burmese units of measurement are used in Burma , with partial transition to the metric system. U.S. units are used in limited contexts in Canada due to

14319-519: The units are always hectares and square metres. Office space and industrial units are usually advertised in square feet. Steel pipe sizes are sold in increments of inches, while copper pipe is sold in increments of millimetres. Road bicycles have their frames measured in centimetres, while off-road bicycles have their frames measured in inches. Display sizes for screens on television sets and computer monitors are always diagonally measured in inches. Food sold by length or width, e.g. pizzas or sandwiches,

14448-466: The value of the avoirdupois drachm (an existing unit, but by then only used for weighing silk). Therefore, it conflicted with other non-standard variations that were based on that nearly obsolete unit. The Irish proposal was not widely adopted, but British legislation, in the form of the Medical Act 1858 ( 21 & 22 Vict. c. 90), was more radical: it prescribed the use of the avoirdupois system for

14577-410: The various local weight standards by the metric weights of their ounces. The actual mass of an ounce varied by ±17% (5 g) around the typical value of 30 g. The table only shows approximate values for the most important standards; even the same nominal standard could vary slightly between one city and its neighbour. The range from 25 g to 31 g is filled with numerous variants, especially

14706-441: The volume measurements of liquids were the same as or similar to those used to describe weight measurements of solids (for example, the pound by weight and the fluid pint were both referred to with Latin libra, symbol ℔ ). A volume of liquid that was approximately that of an apothecaries' ounce of water was called a fluid ounce, and was divided into fluid drachms and sometimes also fluid scruples. The smallest unit of liquid volume

14835-414: The volume of 10 pounds of distilled water of density 0.998 859  g/mL weighed in air of density 0.001 217  g/mL against weights of density 8.136 g/mL , which works out to 4.546 092  L . The Weights and Measures Act 1985 defined a gallon to be exactly 4.546 09  L (approximately 277.4194 cu in ). These measurements were in use from 1826, when the new imperial gallon

14964-399: The wider society a mixture of all three systems prevails. The Chinese system's most commonly used units for length are 里 ( lei ), 丈 ( zoeng ), 尺 ( cek ), 寸 ( cyun ), 分 ( fan ) in descending scale order. These units are now rarely used in daily life, the imperial and metric systems being preferred. The imperial equivalents are written with the same basic Chinese characters as

15093-405: The yard, the length of a pendulum beating seconds at the latitude of Greenwich at Mean Sea Level in vacuo was defined as 39.013 93 inches. For the pound, the mass of a cubic inch of distilled water at an atmospheric pressure of 30 inches of mercury and a temperature of 62° Fahrenheit was defined as 252.458 grains, with there being 7,000 grains per pound. Following the destruction of

15222-415: Was a technical reason why 3 ʒ was written ʒiij, and 1 ⁄ 2  ʒ as ʒss : Writing iii as iij would prevent tampering with or misinterpretation of a number after it is written. The letters "ss" are an abbreviation for the Latin "semis" meaning "half", which were sometimes written with a ß . In Apothecaries' Latin, numbers were generally written in Roman numerals, immediately following

15351-547: Was also used in this way in Lübeck . (The London troy pound was referred to as the ' trooisch pond ', after metrification.) The Dutch troy mark consisted of 8 Flemish troy ounces, with each ounce of 20 engels, and each engel divided into 32 assen. The Amsterdam Pound of two marks, used in commerce, weighed 10,280 assen, while the Amsterdam Troy pound weighed 10,240 assen, i.e. exactly two troy marks. In 1414, six years before

15480-509: Was an almost universal phenomenon in Europe between the decline of the Roman Empire and metrication . This was connected with international commerce, especially with the need to use the standards of the target market and to compensate for a common weighing practice that caused a difference between actual and nominal weight. In the 19th century, most European countries or cities still had at least

15609-417: Was defined. For pharmaceutical purposes, they were replaced by the metric system in the United Kingdom on 1 January 1971. In the US, though no longer recommended, the apothecaries' system is still used occasionally in medicine, especially in prescriptions for older medications. In the 19th and 20th centuries, the UK used three different systems for mass and weight. The distinction between mass and weight

15738-551: Was divided into 9 drachms, and so an aureo would have been 1 ⁄ 6 of an ounce. As early as 1147 in Troyes in Champagne (in the Middle Ages an important trading town) a unit of weight called marc de Troyes was used. The national French standard until 1799 was based on a famous artifact called the Pile de Charlemagne  [ fr ] , which probably dates back to

15867-430: Was not always clear which of the two systems was used in trade between merchants and apothecaries, or by which system apothecaries weighed medicine when they actually sold it. In old merchants' handbooks, the former system is sometimes referred to as the pharmaceutical system and distinguished from the apothecaries' system. From pound down to the scruple, the units of the traditional English apothecaries' system were

15996-556: Was partially continued for a long time in spite of the official Habsburg weight reform. The measure and weight systems for the large mainland part of the Kingdom of the Two Sicilies were unified in 1840. The area consisted of the southern half of the Italian Peninsula and included Naples and Salerno. The subdivision of apothecaries' weight in the unified system was essentially the same as that for gold, silver, coins, and silk. It

16125-465: Was sometimes viewed as an approximate equivalent of the new minim , based on their nominally equivalent definitions. In fact, the units were qualitatively different because the traditional drop, by the nature of how it was measured, did not actually correspond to a single definite volume. ) Along with the new name of minim, the London Pharmacopoeia of 1809 prescribed a new method of measuring

16254-465: Was the most excentric variant in that the ounce was divided in 10 drachms, rather than the usual 8. The scruple, like in Venice but unlike in the rest of the Romance region, was divided into 20 grains. The existence of a unit called aureo , the equivalent of 1 + 1 ⁄ 2 dramme , is interesting because 6 aurei were 9 dramme . In the original Salerno weight system an ounce

16383-417: Was traditionally a drop (Latin gutta ). Although nominally defined as a sixtieth of the fluid drachm, in practice the drop was a not a standardized unit of volume but was measured by means of releasing literal drops of liquid from the lip of a bottle or vial. The 1809 London Pharmacopoeia introduced modified terminology for apothecaries' measurements of liquid volume. New terms and symbols introduced by

16512-534: Was used as a national French standard for trading, for gold, silver, and jewels, and for weighing medicine. It was also used in international communications between scientists. In the time before the French Revolution , the civil pound also played the role of the apothecaries' pound in the French apothecaries' system, which otherwise remained a standard system of the Romance (24 grains per scruple) type. In Bruges , Amsterdam , Antwerp and other Flemish cities,

16641-499: Was used in France from 1812 to 1839. A number of variations on the metric system have been in use. These include gravitational systems , the centimetre–gram–second systems (cgs) useful in science, the metre–tonne–second system (mts) once used in the USSR and the metre–kilogram–second system (mks). In some engineering fields, like computer-aided design , millimetre–gram–second (mmgs) is also used. The current international standard for

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