Metrication

A speedometer used in American and British cars, showing the speed of the vehicle in miles per hour (outer, in white) and kilometres per hour (inner, in red) - for Canadian^[1] vehicles the locations are reversed

A speedometer from an Australian car, showing the speed of the vehicle only in kilometres per hour.

Metrication refers to the introduction and use of the SI metric system, the international standard for physical measurements. This has involved a long process of independent and systematic conversions of countries from various local systems of weights and measures. Metrication began in France in the 1790s and spread widely during the following two centuries. The process is sometimes called metrification.

Overview

According to the CIA Factbook only Burma (Myanmar), Liberia, and the United States have yet to adopt the International System of Units as their official system of measurement.^[2][3] Some sources, though, identify Liberia as metric while reports from Burma suggest that that country is planning to adopt the metric system. However, they all have adopted metric measures to some degree through international trade and standardisation^[3] for example, Sierra Leone switched to selling fuel by the litre in May 2011.^[4] The United States mandated the acceptance of the metric system in 1866 for commercial and legal proceedings, without displacing their customary units.^[5] Both Liberia and Myanmar are substantially metric countries, trading internationally in metric units. Visiting advocates of metrication also claim that they use metric units for many things internally with exceptions such as old petrol pumps in Myanmar, calibrated in British Imperial gallons.^[6]

A number of jurisdictions have laws mandating or permitting other systems of measurement in some or all contexts, such as the United Kingdom, which still uses many imperial measures, such as miles and yards for road-sign distances, road speed limits in miles per hour, lb/oz, pints, etc. for many products, and inches for clothes.^[7][8] Most countries have adopted the metric system officially over a transitional period where both units are used for a set period of time. Some countries such as Guyana, for example, have officially adopted the metric system, but have had some trouble over time implementing it.^[9] Antigua, also 'officially' metric, is moving toward total implementation of the metric system, but slower than expected.^[10] The government of Antigua and Barbuda have announced that they have plans to convert their country to the metric system by the first quarter of 2015.^[11] Other Caribbean countries such as Saint Lucia are officially metric but are still in the process toward full conversion.^[12]

In the European Union, the European Council (of Ministers) used the Units of Measure Directive to attempt to achieve a common system of weights and measures and to facilitate the European Single Market. Throughout the 1990s, the European Commission helped accelerate the process for member countries to complete their metric conversion processes. During these negotiations, the United Kingdom secured permanent exemptions for the mile and yard in road markings, and (with Ireland) for the pint of beer sold in pubs^[13] (see Metrication in the United Kingdom). In 2007, the European Commission also announced that (to facilitate trade with the United States) it was to abandon the requirement for metric-only labelling on packaged goods, and to allow dual metric-imperial marking to continue indefinitely.^{[citation needed]}

Other countries using the imperial system completed metrication during the second half of the 20th century.^{[citation needed]} The most recent to complete this process was the Republic of Ireland, which began metric conversion in the 1970s and completed it in early 2005.^{[citation needed]}

In January 2007 NASA agreed to use metric units for all future moon missions due to pressure from other space agencies.^[14]

The United States and the United Kingdom have some active opposition to metrication, particularly where attempts are made to stamp out the use of their indigenous systems of measurements. Other countries, like France and Japan, that once had significant popular opposition to metrication now have complete acceptance of metrication.^{[citation needed]}

Before the metric system

For more details on this topic, see History of measurement.

In mediaeval Europe, local laws on weights and measures were set by trade guilds on a city-by-city basis. For example, the ell or elle was a unit of length commonly used in Europe, but its length varied. It was 40.2 centimetres in one part of Germany, 70 centimetres in The Netherlands and 94.5 centimetres in Edinburgh. A survey of Switzerland in 1838 revealed that the foot had 37 different regional variations, the ell had 68, there were 83 different measures for dry grain, 70 measures for fluids and 63 different measures for "dead weights".^[15] When Isaac Newton wrote Philosophiae Naturalis Principia Mathematica in 1687, he quoted his measurements in Parisian feet so readers could understand the size. Examples of efforts to have local intercity or national standards for measurements include the Scottish law of 1641, and the British standard Imperial unit system of 1845, which is still commonly used in the United Kingdom. At one time Imperial China had successfully standardised units for volume throughout its territory, but by 1936 official investigations uncovered 53 dimensions for the chi varying from 200 millimetres to 1250 millimetres; 32 dimensions of the cheng, between 500 millilitres and 8 litres; and 36 different tsin ranging from 300 grams to 2500 grams.^[16] However, revolutionary France was to produce the definitive International System of Units which has come to be used by most of the world today.

The desire for a single international system of measurement derives from growing international trade and the need to apply common standards to goods. For a company to buy a product produced in another country, they need to ensure that the product will arrive as described. The medieval ell was abandoned in part because its value could not be standardised. It can be argued that the primary advantage of the International System of Units is simply that it is international, and the pressure on countries to conform to it grew as it became increasingly an international standard. SI is not the only example of international standardisation; several powerful international standardisation organisations exist for various industries, such as the International Organisation for Standardisation, the International Electrotechnical Commission, and the International Telecommunication Union.

Forerunners of the metric system

Decimal numbers are an essential part of the metric system. Although the Indians used decimal numbers for mathematical computations, it was Simon Stevin who in 1585 first advocated the use of decimal numbers for everyday purposes in his booklet De Thiende (old Dutch for 'the tenth'). He also declared that it would only be a matter of time before decimal numbers were used for currencies and measurements. His notation for decimal fractions was clumsy, but was overcome by the introduction of the decimal point, generally attributed to Bartholomaeus Pitiscus who used this notation in his trigonometrical tables (1595).

In his Essay towards a Real Character and a Philosophical Language, published in 1668, John Wilkins proposed a system of measurement that was very similar in concept to today's metric system. He proposed retaining the second as the basic unit of time and proposed that the length of a pendulum which had a period of one second should be the base unit of length. This length, for which he proposed the name "standard", would have been 994 mm. His base unit of mass, which he proposed calling a "hundred", would have been the mass of a cubic standard of distilled rainwater. The names that he proposed for decimal multiples and subunits of his base units of measure were the names of units of measure that were in use at the time.

In 1670, Gabriel Mouton published a proposal that was in essence similar to Wilkins' proposal, except that his base unit of length would have been 1/1000 of a minute of arc (about 2.04 m) of geographical latitude. He proposed calling this unit the virga. Rather than using different names for each unit of length, he proposed a series of names that had prefixes, rather like the prefixes found in SI.

In 1790, Thomas Jefferson submitted a report to the United States Congress in which he proposed the adoption of a decimal system of coinage and of weights and measures. His proposed base unit of length was the foot which he suggested should be either 3/10 or 1/3 of the length of a pendulum that had a period of one second – that is 3/10 or 1/3 of the "standard" proposed by Wilkins over a century previously. His base unit of mass was to be the bushel, which would have been the mass of a cubic foot of water. Like Wilkins, the names that he proposed for multiples and subunits of his base units of measure were the names of units of measure that were in use at the time.

Conversion process

The metric system was officially introduced in France in 1799. In the 19th century, the metric system was adopted by the following European countries: Portugal (1814),^[17] Netherlands, Belgium and Luxembourg (1820), Switzerland (1835), Spain (1850s), Italy (1861), Germany (1870, legally from 1 January 1872^{[clarification needed]}), Austria (1876, but the law was adopted in 1871^{[clarification needed]}). Denmark adopted the metric system in 1907.

Chronology and status of conversion by country

Links in the country point to articles about metrication in that country.

year of conversion	country	previous system of measure	status of metrication
1795[citation needed]	France	French	4complete
1814[citation needed]	Brazil	Portuguese	4complete
1814[citation needed]	Portugal	Portuguese	4complete
1820[citation needed]	Belgium	various	4complete
1820[citation needed]	Netherlands	Dutch	4complete
1848[citation needed]	Chile	Spanish	3almost entirely complete
1852[citation needed]	Mexico	unknown	4complete
1852[citation needed]	Spain	Spanish	4complete
1861[citation needed]	Italy	various	4complete
1862[citation needed]	Peru	Spanish	3almost entirely complete
1864[citation needed]	Romania	Romanian	4complete
1871[citation needed]	Austria	various	4complete
1872[citation needed]	Germany[18]	various	4complete
1875[citation needed]	Norway	Norwegian	4complete
1876[citation needed]	Sweden	Swedish	4complete
1876[citation needed]	Switzerland	various	4complete
1876[citation needed]	Hungary	various	4complete
1886[19]	Finland	Finnish	4complete
1908[citation needed]	Costa Rica	Spanish	4complete
1908[citation needed]	Denmark	Danish	4complete
1912[citation needed]	Dominican Republic	unknown	4complete
1918[20][21]	Russia	Russian	4complete
1923[22][23]	Thailand	various	33rd method, almost entirely complete
1925[citation needed]	Republic of China	Chinese	3almost entirely complete
1954[citation needed]	India	various	4complete
1954[citation needed]	Sudan	various	4complete
1957[citation needed]	Japan	Japanese	3almost entirely complete
1959[24]	Greece	Old Greek	4complete
1946[citation needed]	Indonesia	various	3almost entirely complete
1948[citation needed]	South Korea	Japanese	2partially complete
1963[citation needed]	Laos	unknown	4complete
1963[citation needed]	Vietnam	unknown	4complete
1967[citation needed]	Ireland	Imperial before 1807, Old Irish after 1807, Imperial	4complete
1967[citation needed]	Pakistan	unknown	4complete
1969[citation needed]	New Zealand	Imperial	4complete
1970[citation needed]	Australia	Imperial	4complete
1971[citation needed]	South Africa	Imperial	4complete
1973[citation needed]	Canada	Canadian Imperial	2partially complete
1998[citation needed]	Jamaica	Imperial	4complete
2005[citation needed]	Saint Lucia	Imperial	4complete

There are three common ways that nations convert from traditional measurement systems to the metric system. The first is a quick, so called "Big-Bang" route which was used by India in the 1960s and several other nations including Australia and New Zealand since then. The second way is to phase in units over time and progressively outlaw traditional units. This method, favoured by some industrial nations, is slower and generally less complete. The third way is to redefine traditional units in metric terms. This has been used successfully where traditional units were ill-defined and had regional variations.

The "Big-Bang" way is to simultaneously outlaw the use of pre-metric measurement, metricate, reissue all government publications and laws, and change education systems to metric. India's changeover lasted from 1 April 1960, when metric measurements became legal, to 1 April 1962, when all other systems were banned. The Indian model was extremely successful and was copied over much of the developing world.

The phase-in way is to pass a law permitting the use of metric units in parallel with traditional ones, followed by education of metric units, then progressively ban the use of the older measures. This has generally been a slow route to metric. The British Empire permitted the use of metric measures in 1873, but the changeover was not completed in most Commonwealth countries until the 1970s and 1980s when governments took an active role in metric conversion. Japan also followed this route and did not complete the changeover for 70 years. In the United Kingdom, the process is still incomplete. By law, loose goods sold with reference to units of quantity have to be weighed and sold using the metric system. In 2001 the EU directive 80/181/EEC stated that supplementary units (imperial units alongside metric including labelling on packages) would become illegal from the beginning of 2010. In September 2007^[13] a consultation process was started which resulted in the directive being modified to permit supplementary units to be used indefinitely.

The third method is to redefine traditional units in terms of metric values. These redefined "quasi-metric" units often stay in use long after metrication is said to have been completed. Resistance to metrication in post-revolutionary France convinced Napoleon to revert to mesures usuelles (usual measures) and to some extent the names remain throughout Europe. In 1814, Portugal adopted the metric system but with the names of the units substituted by Portuguese traditional ones. In this system the basic units were the mão-travessa (hand) = 1 decimeter (10 mão-travessas = 1 vara (yard) = 1 meter), the canada = 1 liter and the libra (pound) = 1 kilogram.^[17] In the Netherlands, 500 g is informally referred to as a pond (pound) and 100 g as an ons (ounce), and in Germany and France 500 g is informally referred to respectively as ein Pfund and une livre ("one pound").^[25] In Denmark, the re-defined pund (500 g) is occasionally used, particularly among older people and (older) fruit growers, since these were originally paid according to the number of pounds of fruit produced. In Sweden and Norway a mil (Scandinavian mile) is informally equal to 10 km, and this has continued to be the predominantly used unit in conversation when referring to geographical distances. In the 19th century, Switzerland had a non-metric system completely based on metric terms (e.g. 1 fuss (foot) = 30 cm, 1 zoll (inch) = 3 cm, 1 linien (line) = 3 mm). In China the jin now has a value of 500 g and the liang is 50 g.

It is difficult to judge the degree to which ordinary people change to using metric in their daily lives. In countries that have recently changed, older segments of the population tend to still use the older units. Also, local variations abound in which units are round metric quantities or not. In Canada, for example, ovens and cooking temperatures are usually measured in degrees Fahrenheit and Celsius. Except for in cases of import items all recipes and packaging includes both Celsius and Fahrenheit so Canadians are typically comfortable with both systems of measurement. This extends to manufacturing where companies are able to use both imperial and metric since major export is for the U.S. but metric is required for both domestic and for nearly all other export. This may be due to the overwhelming influence of the neighbouring United States; similarly, still many English Canadians (unlike most French Canadians) often use non-metric measurements in day-to-day discussions of height and weight, and for clothing sizes, which are invariably measured in inches, though most driver's licences and other official government documents record weight and height only in metric (Saskatchewan driver licences, prior to the introduction of the current one-piece licence, indicated height in feet and inches but have switched to centimetres following the new licence format). In Canadian schools though metric is the standard except when it comes up in recipes, where both are included, or in practical lessons involving measuring wood or other materials for manufacturing. In the United Kingdom, Fahrenheit is seldom encountered (except when some people talk about hot summer weather) while other metric units are often used in conjunction with older measurements, and road signs use miles rather than kilometres. Another example is "hard" and "soft" metric. Canada converted liquid dairy products to litres, 500 g and 250 g sizes, which caused some complaining at time of conversion, as a litre of milk is 35 imperial ounces, while the former imperial quart used in Canada was 40 ounces. This is a "hard" metric conversion. Conversely, butter in Canada is sold primarily in a 454 g package, which converts to one Imperial pound. This is considered "soft" metric. Such countries could be said to be "semi-metric". However unlike in the rest of Canada, metrication in the Francophone province of Quebec has been more implemented and metric measures are more consistently used in Quebec than elsewhere in Canada.

Exceptions

As of 2007, in most countries of the world the metric system officially dominates; but traditional units are still used in many places and industries. For example, automobile tyre pressure is measured as psi in countries such as Brazil, Argentina, Australia and Chile which are otherwise completely metric. Office space is often rented in traditional units, such as square foot in Hong Kong and India, tsubo in Japan or pyeong in Korea. Traditional measurements are still used in some areas: e.g., in plumbing the diameters of pipes are still measured in inches in some countries (in the United Kingdom all new pipes are metric). Automotive wheel diameters are still set as whole inch measurements (although tyre widths are measured in millimetres) and dots per inch continues to be used in describing graphical resolution in the computer industry. Television and monitor screen diameters are still commonly cited in inches in many countries; however, in Australia and South Africa, centimetres are often used for television sets, whereas CRT computer monitors and all LCD monitors are measured in inches. The only exception to the metrication process in Ireland was the pint in bars, pubs, and clubs; although alcohol sold in any other location is in metric units (usually 330 ml (canned beer), 500 ml (bottled beer), 750 ml (wine), or 1 l (spirit)). In Australia, a pint of beer was redefined to 570 ml (see Australian beer glasses). In both metric and non-metric countries, racing bicycle frames are generally measured in centimetres, while mountain bicycle frames are measured in either or both. In Spain and former colonies i.e. Americas and Philippines certain pre-metric units are still used e.g. the quiñón for land measurement in the Philippines, the fanega, ferrado and atahúlla to name three used in Spain and other former possessions. The pulgada (inch) is 23 mm so 2 mm shorter than the English inch.

An example of metrication of British consumer products. Two of the four items are purely metric. Milk is often sold as "1.136 litres / 2 pints". The sausages are labelled "340 g / 12 oz"

In some countries (such as Antigua, see above), the transition is still in progress. The Caribbean island nation of Saint Lucia announced metrication programmes in 2005 to be compatible with CARICOM.^[26]

United Kingdom

See also: Metrication in the United Kingdom

In the United Kingdom, the metric system is used by most businesses^{[citation needed]} and is used for most transactions.^[27] Metric units must be used for the retail sale of consumer goods that are sold by weight or volume and imperial units can continue to be displayed in parallel.^[27] British law has enacted the provisions of European Union directive 80/181/EEC which catalogues the units of measure that may be used for "economic, public health, public safety and administrative purposes".^[28] These units consist of the recommendations of the General Conference on Weights and Measures^[29] supplemented by some additional units of measure that may be used for specified purposes. The metric system had been legal for nearly a century before metrication efforts began in earnest. The government had been making preparations for the conversion of the Imperial unit since the 1862 Select Committee on Weights and Measures recommended the conversion^[30] and the Weights and Measures Act of 1864 and the Weights and Measures (Metric System) Act of 1896 legalised the metric system.^[31] In 1965, with lobbying from British industries and the prospects of joining the Common Market, the government set a 10 year target for full conversion and created the Metrication Board in 1969. Metrication did occur in some areas during this time period, including the re-surveying of Ordnance Survey maps in 1970, decimalisation of the currency in 1971, and teaching the metric system in schools. No plans were made to make the use of the metric system compulsory, and the Metrication Board was abolished in 1980 following a change in government.^[32] The United Kingdom avoided having to comply with the 1989 European Units of Measurement Directive (89/617/EEC), which required all member states to make the metric system compulsory, by negotiating derogations (delayed switchovers), including for miles on road signs and for pints for draught beer, cider, and milk sales.^[33]

United States

See also: Metrication in the United States

A measuring cup, manufactured and sold in the U.S. (circa 1980) features graduations in both metric and U.S. Customary systems. Held in the right hand, a person would have the metric graduations in front, facing them. But in filling the measuring cup from another container, right-handed people would hold it in their left hand, and read from the customary gradations.

Over time, the metric system has influenced the United States through international trade and standardisation. The use of the metric system was made legal as a system of measurement in 1866^[34] and the United States was a founding member of the International Bureau of Weights and Measures in 1875.^[35] The system was officially adopted by the federal government in 1975 for use in the military and government agencies.^[36] In 1985, the metric system was made the preferred (but predominantly voluntary) system of weights and measures for United States trade and commerce. It has remained voluntary for federal and state road signage to use metric units, despite attempts in the 1990s to make it a requirement.^[37] A 1992 amendment to the Fair Packaging and Labeling Act (FPLA), which took effect in 1994, required labels on federally regulated "consumer commodities"^[38] to include both metric and U.S. customary units. As of June 2007, all but two US states (New York and Alabama) have passed laws permitting metric-only labels for the products they regulate.^[39] Likewise, Canada also legally allows for dual labelling of goods provided that the metric unit is listed first and that there is a distinction of whether a liquid measure is a U.S. or a Canadian (Imperial) unit.^[40] Today, the American public and much of the private business and industry still use U.S. customary units despite many years of informal or optional metrication.^[41] At least two states, Kentucky and California, have even moved towards demetrication of highway construction projects.^[42][43][44]

Air and sea transport

Air and sea transport use the nautical mile. This is about one minute of arc of latitude along any meridian arc and is precisely defined as 1852 metres (about 1.151 miles). It is a non-SI unit (although accepted for use in the SI by the BIPM). The prime unit of speed for maritime and air navigation remains the knot (nautical mile per hour).

The prime unit of measure for aviation (altitude) is usually estimated based on air pressure values and, in many countries, is still described in nominal feet though many others employ nominal metres. The policies of the International Civil Aviation Organization (ICAO) relating to measurement are:

• there should be a single system of units throughout the world
• the single system should be SI
• the use of the foot for altitude is a permitted variation

Consistent with ICAO policy, aviation has undergone a significant amount of metrication over the years; for example, runways are usually given in metres. The United States metricated the data interchange format (METAR) for temperature reports in 1996.^[45] Metrication is also gradually taking place in cargo weights/dimensions and fuel volume/weight.

Accidents and incidents

Confusion over units during the process of metrication can sometimes lead to accidents. One of the most famous examples was during Canada's metrication: in 1983, an Air Canada Boeing 767, nicknamed the "Gimli Glider" after the incident, ran out of fuel in mid-flight. The incident was caused, in a large part, by the confusion over the conversion among litres, kilograms, and pounds, resulting in the aircraft receiving 22,300 pounds of fuel instead of the required 22,300 kg.^[46]

While not strictly an example of national metrication, the use of two different systems was a contributing factor in the loss of the Mars Climate Orbiter in 1998. NASA specified metric units in the contract. NASA and other organisations worked in metric units but one subcontractor, Lockheed Martin, provided thruster performance data to the team in pound force seconds instead of newton seconds. The spacecraft was intended to orbit Mars at about 150 kilometres (93 mi) altitude but the incorrect data meant that it descended to about 57 kilometres (35 mi) and most likely burned up in the Martian atmosphere.

On 25 September 2009, the British Department for Transport published a draft version of legislation to amend its road signage legislation^[47] for comment. Amongst the proposed changes is an amendment to existing legislation to make dual unit height and width warning and restriction signs mandatory. This is justified in Paragraph 53 of the Impact Analysis^[48] by the text "... Based on records from Network Rail’s incident logs since April 2008, approximately 10 – 12% of bridge strikes involved foreign lorries. This is disproportionately high in terms of the number of foreign lorries on the road network." This proposal was shelved with the change of government in 2010.

Opposition

Main article: Metrication opposition

See also: Metrication in the United Kingdom

Only the United States continues to see significant popular opposition to metrication, the main objections being based in localism, tradition, cultural aesthetics, economic impact, or distaste for measures viewed as "foreign". Japan had significant popular opposition at one time for similar reasons. Popular opposition in the United Kingdom exists to a lesser degree and can be associated with anti-European Union sentiment. France, where the measures were largely invented, saw popular opposition during the early 19th century, though not for long. Thus, with the exception of the United States, metrication is now fully or substantially accepted in nearly all countries.

See also

Anti-metrication Conversion of units Language reform Metric clothes sizes (EN 13402) French units of measurement Metrication in Chile Metrication in the United Kingdom

Metrication in the United States Metrication in Canada Metric yardstick Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States Preferred numbers Change management, a field studying how changes can be efficiently implemented in modern communities

Notes

1. ^ Canadian DX model accessdate = 2011-08-04
2. ^ "Appendix G – Weights and Measures". The World Factbook. CIA. 2006. https://www.cia.gov/library/publications/the-world-factbook/appendix/appendix-g.html. Retrieved 8 August 2006. 
3. ^ ^{a b} "Metric usage and metrication in other countries". US Metric Association. 2009. http://lamar.colostate.edu/~hillger/internat.htm. Retrieved 23 May 2009. 
4. ^ "Introduction of the metric system and the prices of petroleum products". Washington DC, United States: Sierra Leone Embassy. 9 May 2011. http://embassyofsierraleone.net/latest-embassy-news/188-introduction-of-the-metric-system-and-the-price-of-petroleum-products-. Retrieved 9 May 2011. 
5. ^ "Metric Act of 1866". Metric Program, Weights and Measures Division, United States National Institute of Standards, Technology and Technology. http://ts.nist.gov/WeightsAndMeasures/Metric/upload/HR-596-Metric-Law-1866.pdf. Retrieved 10 November 2009. 
   "U.S. Metric System (SI) Legal Resources". Metric Program, Weights and Measures Division, United States National Institute of Standards, Technology and Technology. http://ts.nist.gov/WeightsAndMeasures/Metric/Federal_Metric_Policy.cfm#legal. Retrieved 11 November 2009. 
6. ^ Pat Naughtin (2005). "Editorial". Metrication Matters Number 31. http://www.metricationmatters.com/mm-newsletter-2005-12.html#editorial. Retrieved 23 May 2009. 
7. ^ "Department for Transport statement on metric road signs". British Weights and Measures Association. 2002. http://www.bwmaonline.com/Transport%20-%20DfT%20memo.htm. Retrieved 23 May 2009. 
8. ^ "Units of Measurement and Permitted Symbols or Abbreviations of Units of Measurement Lawful for Use for Trade". Hong Kong Weights and Measures Ordinance. 1997. http://www.legislation.gov.hk/blis_ind.nsf/d2769881999f47b3482564840019d2f9/ca7c0e7895c7f088c82564760077b0c9?OpenDocument. Retrieved 23 May 2009. 
9. ^ Warwick Cairns (2007). About the Size of It. Pan Macmillan. p. 145. ISBN 978-0230016286. 
10. ^ "Improving Trade Conformity in Antigua and Barbuda". Commonwealth News and Information Service Issue 225. Commonwealth Secretariat. 2005. http://www.thecommonwealth.org/news/142849/improving_trade_conformity_in_antigua_and_barbuda.htm. Retrieved 5 November 2007. 
11. ^ "Finance minister outlines metrication plans, goals and timetable". Antigua Obsever. 18 October 2011. http://www.antiguaobserver.com/?p=66070. Retrieved 12 November 2011. 
12. ^ Associated Press (2005). "St Lucia begins drive to implement metric system to catch up with region". The Jamaica Observer. Archived from the original on 18 October 2007. http://web.archive.org/web/20071018000003/http://jamaicaobserver.com/news/html/20050322T200000-0500_77361_OBS_ST_LUCIA_BEGINS_DRIVE_TO_IMPLEMENT_METRIC_SYSTEM_TO_CATCH_UP_WITH_REGION.asp. Retrieved 5 November 2007. 
13. ^ ^{a b} "EU gives up on 'metric Britain". BBC News. 11 September 2007. http://news.bbc.co.uk/1/hi/uk/6988521.stm. Retrieved 23 May 2009. 
14. ^ "Metric Moon". NASA. 2007. http://science.nasa.gov/science-news/science-at-nasa/2007/08jan_metricmoon/. Retrieved 6 April 2010. 
15. ^ Thomas McGreevy, Peter Cunningham (1995). The Basis of Measurement: Historical Aspects. Picton Publishing. ISBN 0-948251-82-4. 
16. ^ Witold Kula (1986). "For all peoples; for all time". Measures and Men. Richard Szreter (trans.). Princeton University Press. ISBN 0691054460. 
17. ^ ^{a b} Fátima Paixão, Fátima Regina Jorge, Success and constraints in adoption of the metric system in Portugal, The Global and the Local: History of Scinece and the Cultural Integration of Europe, 2006
18. ^ Prior to German Unification in 1871, Germany was a collection of independent states. Many German states, particularly those under French tutelage during the Napoleonic Wars (Rheinbund) adopted the meter 1806-15.
19. ^ http://lamar.colostate.edu/~hillger/internat.htm
20. ^ (in Russian)ru:Собрание узаконений РСФСР (66): 725. 1918. 
21. ^ (in Russian) Настольный Советский Календарь [Desk Soviet Calendar]. The New International Publishing, New York. 1920. p. 8. http://books.google.com/books?id=cjQkAQAAIAAJ&dq=%D0%BC%D0%B5%D1%82%D1%80%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B0%D1%8F%20%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B0&pg=PA8#v=onepage&q&f=false. 
22. ^ "History of weights and measures in Thailand.htm" (in English). Northern Weights and Measures Center (Thailand). April 2004. http://www.nwmc.go.th/history_eng.html. Retrieved September 26, 2011. "The King Rama VI has been graciously pleased to enact the “Weights and Measures Act, B.E. 2466” [1923 A.D.] as the country’s master law on metrological units. In the following year, the first ministerial regulation has been issued for the execution of the Act. [superseded by ] “Weights and Measures Act, B.E. 2542”, ...promulgated in the Government Gazette, Royal Decree Version, Volume 116, Part 29 a, dated 21 April 1999, that was effective since 18 October 1999" 
23. ^ "ประวัติชั่งตวงวัดไทย" (in Thai). Northern Weights and Measures Center (Thailand). April 2004. http://nwmc.go.th/his1.html. Retrieved September 26, 2011. 
24. ^ [www.e-themis.gov.gr/Portal/files/volumes/temp/ΤΟΜΟΣ%205.doc]
25. ^ Hubert Fontaine. "Confiture de rhubarbe". Archived from the original on 28 September 2007. http://web.archive.org/web/20070928081538/http://www.hubertlejardinier.com/confiture.htm. Retrieved 5 November 2007.  (French) "1 zeste de citron par livre (500g) de rhubarbe"
26. ^ "St Lucia moving to metric system". Caribbean Net News. 2005. http://www.caribbeannetnews.com/2005/03/17/moving.shtml. Retrieved 27 August 2006. 
27. ^ ^{a b} "Weights and measures legislation - hallmarking and metrication". Business Link. UK Government. http://www.businesslink.gov.uk/bdotg/action/detail?itemId=1084635751&type=RESOURCES. Retrieved 28 October 2011. 
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External links

• Online Metric Conversion Application