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File:NIST-Library-US-Prototype-meter-bar-colour HR 1.jpg


this was intended for use on en:Iridiumwhere a lower resolution of the same exact image already exists
English: The original definition of a meter was adopted by CGPM (General Conference on Weights and Measures) in 1889 based on a platinum-iridium prototype bar. In 1889, there was one prototype meter, a bar made of a platinum iridium alloy with lines inscribed at each end; the distance between them defined the meter. The length standard was disseminated to the national laboratories through the use of artifact meters, which were accurate (but not identical) replicas of the prototype meter. Each artifact meter was calibrated against the prototype for use as a national standard. This standard remained in place until June 30 1959.
Date 27 February 2008
Author The National Institute of Standards and Technology (NIST)


Public domain This image is in the public domain because it is a work of the United States Federal Government, specifically an employee of the National Institute of Standards and Technology, under the terms of Title 17, Chapter 1, Section 105 of the US Code.

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