International yard and pound

The international yard and pound are two units of measurement that were the subject of an agreement between six nations signed on 1 July 1959. The six nations were the United States, the United Kingdom, Canada, Australia, New Zealand and South Africa. The agreement defined the yard as exactly 0.9144 meter and the pound as exactly 0.45359237 kilogram.[1]

History

In 1866 the United States legalized the use of the metric system, but at a time when metric units were poorly defined by antiquated physical standards. As a result, the US Congress supplied definitions of the meter and kilogram in terms of the yard and pound. By the 1890s the situation had reversed, with the metric system having superior physical standards. As a result, the Mendenhall Order of 1893 reversed the definitions of 1866, defining the yard and pound in terms of the meter and kilogram.[2][3]

In the UK, a similar situation developed with the Weights and Measures Act of 1897 legalizing the metric system,[4] and Order in Council 411 (1898) defining the meter and kilogram in terms of the yard and pound.[5] As a practical matter the UK definitions were reversed, resulting in a de facto definition of the imperial yard as 36/39.370113 meter.[6]

In the 1890s, A A Michelson began conducting experiments in interferometry that led in 1903 to demonstrating the feasibility of using light waves as units of linear measurement. In 1908, two teams of researchers, one led by Michelson, defined the length of the international prototype meter in terms of light waves. In 1927 the International Bureau of Weights and Measures provisionally adopted the 1908 light-wave definition of the meter as a supplemental standard.[7]

In 1930 the British Standards Institution adopted an inch of exactly 25.4 mm based on the 1927 light-wave definition of the meter. The American Standards Association followed suit in 1933. By 1935 industry in 16 countries had adopted the "industrial inch" as it came to be known.[8][9]

In 1946 the Commonwealth Science Congress recommended a yard of exactly 0.9144 metres - i.e. exactly 36 industrial inches - for adoption throughout the British Commonwealth.[10] This was adopted by Canada in 1951.[11] The United States, the United Kingdom, Canada, Australia, New Zealand and South Africa signed a treaty agreeing to the same standards on 1 July 1959.[1]

Implementation

In the USA, the international yard and pound were adopted effective 1 July 1959.[12] Canada adopted the international yard and pound in 1951.[13] The UK adopted the international yard and pound for all purposes through the Weights and Measures Act of 1963, effective 1 January 1964.[14] In Australia, the international yard and pound were instituted through Statutory Rule No. 142 of 1961, effective 1 January 1964.[15]

See also

Notes

  1. 1 2 United States. National Bureau of Standards (1959). Research Highlights of the National Bureau of Standards. U.S. Department of Commerce, National Bureau of Standards. p. 13. Retrieved 15 September 2012.
  2. ↑ National Bureau of Standards, Refinement of values for the yard and pound
  3. ↑ Bewoor, Arand K; Kulkarni, Vinay A (2009). Metrology & Measurement. Tata McGraw-Hill Education. p. 18. ISBN 978-0-07-014000-4. Retrieved 16 September 2012.
  4. ↑ John Mews, ed. (1897). "Statutes of the Realm - 60-61 Victoria". The Law journal reports 66. London: The Law Journal Reports. p. 109. Retrieved 16 September 2012.
  5. ↑ Great Britain; Pulling, Alexander; Great Britain. Statute Law Committee (1904). The statutory rules and orders revised: being the statutory rules and orders (other than those of a local, personal, or temporary character) in force on December 31, 1903 ... 13 (2nd ed.). section 4 - Weights and Measures: HMSO. pp. 4:25–27. Retrieved 17 September 2012.
  6. ↑ Connor, R D (1987). The Weights and Measures of England. H.M. Stationery Office. ISBN 978-0-11-290435-9. Retrieved 17 September 2012.
  7. ↑ Estermann, Immanuel (1959). Classical Methods. Academic Press. p. 27. ISBN 978-0-12-475901-5. Retrieved 16 September 2012.
  8. ↑ National Conference on Weights and Measures; United States. Bureau of Standards; National Institute of Standards and Technology (US) (1936). Report of the ... National Conference on Weights and Measures. US Department of Commerce, Bureau of Standards. p. 4. Retrieved 2 August 2012.
  9. ↑ Wandmacher, Cornelius; Johnson, Arnold Ivan (1995). Metric Units in Engineering--going SI: How to Use the International Systems of Measurement Units (SI) to Solve Standard Engineering Problems. ASCE Publications. p. 265. ISBN 978-0-7844-0070-8. Retrieved 2 August 2012.
  10. ↑ Report of the British Commonwealth Scientific Conference. Official Conference, London, 1946. Cmd. 6970. H.M. Stationery Office, 1946
  11. ↑ National Conference on Weights and Measures; United States. Bureau of Standards; National Institute of Standards and Technology (US) (1957). Report of the ... National Conference on Weights and Measures. US Department of Commerce, Bureau of Standards. pp. 45–6. Retrieved 2 August 2012.
  12. ↑ Lewis Van Hagen Judson; United States. National Bureau of Standards (1976). Weights and measures standards of the United States: a brief history. Dept. of Commerce, National Bureau of Standards : for sale by the Supt. of Docs., U.S. Govt. Print. Off. pp. 30–1. Retrieved 16 September 2012.
  13. ↑ Canadian Journal of Physics, 1959, 37(1): 84, 10.1139/p59-014
  14. ↑
  15. ↑ Australian Government ComLaw Weights and Measures (National Standards) Regulations - C2004L00578

External links

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