The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards. It was issued on April 5, 1893, by Thomas Corwin Mendenhall, superintendent of the United States Coast and Geodetic Survey, with the approval of the United States Secretary of the Treasury, John Griffin Carlisle. The order was issued as the Survey's Bulletin No. 26 – Fundamental Standards of Length and Mass.
Standards before the order
In October 1834, the United Kingdom Houses of Parliament were destroyed in a fire, and the British standards of length and mass were also destroyed. "When the new imperial standards to replace them were completed in 1855, two copies of the yard and one copy of the avoirdupois pound were presented to the United States". These were superior to the yard then in use, so one of them was adopted as the United States national standard yard. These yards were taken to England and re-compared with the imperial yard in 1876 and 1888. The pound provided by the United Kingdom agreed with the United States mint pound, which remained the national standard according to Barbrow and Judson. Hockert claims the UK pound replaced the mint pound.
These were the fundamental standards for customary length and mass measurements in the United States, but the Office of Weights and Measures had other standards for metric measurements.
Official recognition of the metric system
The Metric Act of 1866 was passed by Congress and allowed, but did not require, the use of the metric system. Included in the law was a table of conversion factors between the traditional and metric units. The United States Coast Survey (which in 1878 became the U.S. Coast and Geodetic Survey) Office of Weights and Measures had on hand a number of metric standards, and selected the iron Committee Meter and the platinum Arago Kilogram to be the national standards for metric measurement. The standard yard and pound previously mentioned continued to be the standards for customary measurements.
A series of conferences in France between 1870 and 1875 led to the signing of the Metre Convention and to the permanent establishment of the International Bureau of Weights and Measures, abbreviated BIPM after the French name. The BIPM made meter and kilogram standards for all the countries that signed the treaty; the two meters and two kilograms allocated to the United States arrived in 1890, and were adopted as national standards.
Reasons for the change
The imperial standard yard of 1855 was found[when?] to be unstable and shortening by measurable amounts. Also, the mint pound was found to be "likewise unfit for use". For several years before the Mendenhall order was actually issued, the Office of Weights and Measures was "practically forced" to use the metric standards because of their superior stability, and because they were better designed for carrying out precision comparisons. The Office found that the conversion tables in the 1866 law were satisfactory and used them to derive customary length and mass from the metric standards. The conversions were 1 yard = 3600⁄3937 meter and 1 pound = 0.4535924277 kilogram. Therefore, the Mendenhall order amounted to a formal announcement of a change that had already occurred in practice.
Another motivation for the order was that later that year, in August 1893, an International Electrical Congress would be held in connection with the World's Fair in Chicago. Associated with the Congress would be a "Chamber of Delegates", officially organized for the purpose of coming to an international agreement on units of electrical quantities. As Mendenhall wrote,
In view of the probable success of this movement and of the certainty that such definitions would be built upon a metric foundation, it was deemed wise to have definite recognition of these national prototypes [of the meter and the kilogram] as the fundamental standards of reference in all metrological operations in which the United States Government was concerned.
Refinement of the conversions
The definitions of 1893 remained unchanged for 66 years, but increasing precision in measurements gradually made the differences in the standards in use in English-speaking countries important. By the international yard and pound agreement of July 1, 1959, Australia, Canada, New Zealand, South Africa, the United Kingdom, and the United States agreed that 1 yard = 0.9144 meter and that 1 avoirdupois pound = 0.45359237 kilogram (but see U.S. survey foot).
Standards versus systems
Mendenhall ordered that the standards used for the most accurate length and mass comparison change from certain yard and pound objects to certain meter and kilogram objects, but did not require anyone outside of the Office of Weights and Measures to change from the customary units to the metric system.
See also
- Metric system in the United States
References
- Barbrow, Louis E.; Judson, Lewis V. (1976) [1963]. Weights and measures standards of the United States: A brief history (PDF). NBS Special Publication 447. Washington D.C.: US Department of Commerce - Superintendent of Document.
- Mendenhall, T.C. (6 October 1922). "The United States Fundamental Standards of Length and Mass". Science. New Series. 56 (1449): 337–380. Bibcode:1922Sci....56..377M. doi:10.1126/science.56.1449.377. ISSN 0036-8075. JSTOR 1647062. PMID 17833047. Retrieved 8 May 2021.
Footnotes
- Mendenhall 1922.
- Barbrow & Judson 1976, p. 9.
- "Bronze Yard No. 11". National Institute of Standards and Technology (NIST). Archived from the original on 26 August 1999. Retrieved 8 May 2021.
- "Imperial Avoirdupois Pound". National Institute of Standards and Technology (NIST). Archived from the original on 11 November 1999. Retrieved 8 May 2021.
- Hockert, Carol. (21 July 2015). "Address to the National Conference on Weights and Measures to Commemorate Their 100th Meeting". National Institute of Standards and Technology.
- "Committee Meter". National Institute of Standards and Technology (NIST). Archived from the original on 26 August 1999. Retrieved 8 May 2021.
- "Arago Kilogram". National Institute of Standards and Technology (NIST). Archived from the original on 11 November 1999. Retrieved 8 May 2021.
- Barbrow & Judson 1976, p. 10.
- "National Prototype Meter No. 27". National Institute of Standards and Technology (NIST). Archived from the original on 11 November 1999. Retrieved 8 May 2021.
- "Prototype Kilogram 20, replica". National Institute of Standards and Technology (NIST). Archived from the original on 11 November 1999. Retrieved 8 May 2021.
- Barbrow & Judson 1976, p. 16.
- "Fischer Transverse Invar Beam Comparator". National Institute of Standards and Technology (NIST). Archived from the original on 12 April 2000. Retrieved 8 May 2021.
- Mendenhall 1922, p. 379.
- Barbrow & Judson 1976, p. 20.
Further reading
- Mendenhall, T. C. (1893). "Fundamental Standards of Length and Mass". Reprinted in Barbrow, Louis E. and Judson, Lewis V. (1976). "Weights and measures standards of the United States: A brief history (NBS Special Publication 447)." Washington D.C.: Superintendent of Documents. pp. 28–29.
The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards It was issued on April 5 1893 by Thomas Corwin Mendenhall superintendent of the United States Coast and Geodetic Survey with the approval of the United States Secretary of the Treasury John Griffin Carlisle The order was issued as the Survey s Bulletin No 26 Fundamental Standards of Length and Mass Standards before the orderIn October 1834 the United Kingdom Houses of Parliament were destroyed in a fire and the British standards of length and mass were also destroyed When the new imperial standards to replace them were completed in 1855 two copies of the yard and one copy of the avoirdupois pound were presented to the United States These were superior to the yard then in use so one of them was adopted as the United States national standard yard These yards were taken to England and re compared with the imperial yard in 1876 and 1888 The pound provided by the United Kingdom agreed with the United States mint pound which remained the national standard according to Barbrow and Judson Hockert claims the UK pound replaced the mint pound These were the fundamental standards for customary length and mass measurements in the United States but the Office of Weights and Measures had other standards for metric measurements Official recognition of the metric systemThe Metric Act of 1866 was passed by Congress and allowed but did not require the use of the metric system Included in the law was a table of conversion factors between the traditional and metric units The United States Coast Survey which in 1878 became the U S Coast and Geodetic Survey Office of Weights and Measures had on hand a number of metric standards and selected the iron Committee Meter and the platinum Arago Kilogram to be the national standards for metric measurement The standard yard and pound previously mentioned continued to be the standards for customary measurements A series of conferences in France between 1870 and 1875 led to the signing of the Metre Convention and to the permanent establishment of the International Bureau of Weights and Measures abbreviated BIPM after the French name The BIPM made meter and kilogram standards for all the countries that signed the treaty the two meters and two kilograms allocated to the United States arrived in 1890 and were adopted as national standards Reasons for the changeThe imperial standard yard of 1855 was found when to be unstable and shortening by measurable amounts Also the mint pound was found to be likewise unfit for use For several years before the Mendenhall order was actually issued the Office of Weights and Measures was practically forced to use the metric standards because of their superior stability and because they were better designed for carrying out precision comparisons The Office found that the conversion tables in the 1866 law were satisfactory and used them to derive customary length and mass from the metric standards The conversions were 1 yard 3600 3937 meter and 1 pound 0 453592 4277 kilogram Therefore the Mendenhall order amounted to a formal announcement of a change that had already occurred in practice Another motivation for the order was that later that year in August 1893 an International Electrical Congress would be held in connection with the World s Fair in Chicago Associated with the Congress would be a Chamber of Delegates officially organized for the purpose of coming to an international agreement on units of electrical quantities As Mendenhall wrote In view of the probable success of this movement and of the certainty that such definitions would be built upon a metric foundation it was deemed wise to have definite recognition of these national prototypes of the meter and the kilogram as the fundamental standards of reference in all metrological operations in which the United States Government was concerned Refinement of the conversionsThe definitions of 1893 remained unchanged for 66 years but increasing precision in measurements gradually made the differences in the standards in use in English speaking countries important By the international yard and pound agreement of July 1 1959 Australia Canada New Zealand South Africa the United Kingdom and the United States agreed that 1 yard 0 9144 meter and that 1 avoirdupois pound 0 453592 37 kilogram but see U S survey foot Standards versus systemsMendenhall ordered that the standards used for the most accurate length and mass comparison change from certain yard and pound objects to certain meter and kilogram objects but did not require anyone outside of the Office of Weights and Measures to change from the customary units to the metric system See alsoMetric system in the United StatesReferencesBarbrow Louis E Judson Lewis V 1976 1963 Weights and measures standards of the United States A brief history PDF NBS Special Publication 447 Washington D C US Department of Commerce Superintendent of Document Mendenhall T C 6 October 1922 The United States Fundamental Standards of Length and Mass Science New Series 56 1449 337 380 Bibcode 1922Sci 56 377M doi 10 1126 science 56 1449 377 ISSN 0036 8075 JSTOR 1647062 PMID 17833047 Retrieved 8 May 2021 Footnotes Mendenhall 1922 Barbrow amp Judson 1976 p 9 Bronze Yard No 11 National Institute of Standards and Technology NIST Archived from the original on 26 August 1999 Retrieved 8 May 2021 Imperial Avoirdupois Pound National Institute of Standards and Technology NIST Archived from the original on 11 November 1999 Retrieved 8 May 2021 Hockert Carol 21 July 2015 Address to the National Conference on Weights and Measures to Commemorate Their 100th Meeting National Institute of Standards and Technology Committee Meter National Institute of Standards and Technology NIST Archived from the original on 26 August 1999 Retrieved 8 May 2021 Arago Kilogram National Institute of Standards and Technology NIST Archived from the original on 11 November 1999 Retrieved 8 May 2021 Barbrow amp Judson 1976 p 10 National Prototype Meter No 27 National Institute of Standards and Technology NIST Archived from the original on 11 November 1999 Retrieved 8 May 2021 Prototype Kilogram 20 replica National Institute of Standards and Technology NIST Archived from the original on 11 November 1999 Retrieved 8 May 2021 Barbrow amp Judson 1976 p 16 Fischer Transverse Invar Beam Comparator National Institute of Standards and Technology NIST Archived from the original on 12 April 2000 Retrieved 8 May 2021 Mendenhall 1922 p 379 Barbrow amp Judson 1976 p 20 Further readingMendenhall T C 1893 Fundamental Standards of Length and Mass Reprinted in Barbrow Louis E and Judson Lewis V 1976 Weights and measures standards of the United States A brief history NBS Special Publication 447 Washington D C Superintendent of Documents pp 28 29
