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Throughout the centuries the meter has been redefined a number of times. At one point it was defined in relation to the distance from the north pole to the equator. Seeing how that is a bit of an awkward standard to use, a set of platinum bars was made. Each bar as close to a meter as was possible. On the 22nd of June 1799 the most accurate bar was selected and placed in the french national achieves. It is now known as the "mètre des Archives". In 1889 the polar definition was abandoned and a new definition was to be based on a bar called the International Prototype Meter. The IPM was to be minted to the same length as the mètre des Archives. In total 30 bars were created, 1 was made the IPM and the others given out to serve as national standards. This new standard was ultimately abandoned in 1960 and replaced with the (now abandoned) krypton standard. So, my question is, what happened to the bars? Where are they now? I'm pretty sure the IPM and mètre des Archives are still maintained in France by the International Bureau of Weights and Measures. But what of the copies?

Edit: Here's what I've learned so far about the current state of the bars (not including an apparent failed production run that produced bars of unacceptable quality were still internationally distributed)
Country assignment is given by the resolution of the 1st CGPM (French only)

  1. (Italy)
  2. (Switzerland)
  3. (Norway)
  4. (France)
  5. (Not on the table, I don't know why)
  6. Declared the IPM, maintained by the International Bureau of Weights and Measures
  7. (Bavaria/Germany now)
  8. (France)
  9. (Italy)
  10. (Portugal)
  11. (Russian Academy of Sciences)
  12. (Belgium)
  13. (Not on the table, Referred to as a witness meter? (machine translated))
  14. (Hungary)
  15. (Austria)
  16. (UK) Held by the National Physical Laboratory source (thanks Stuart Hall)
  17. (Spain)
  18. (Germany)
  19. (Austria)
  20. (France)
  21. (USA) With 27 source, see page 13
  22. (Japan) Kept in the Paris Observatory (thanks Erik)
  23. (Belgium)
  24. (Spain)
  25. (Royal Observatory of Belgium)
  26. (International Bureau of Weights and Measures)
  27. (USA) Primary national standard, Kept in the NIST museum source source 2 (thanks robert bristow-johnson)
  28. (Russia)
  29. (Sweden)
  30. (Serbia)
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    $\begingroup$ here's one and i am sure the original meter bar still exists at BIPM in Sevres France. but they no longer define the meter. $\endgroup$ – robert bristow-johnson Aug 29 '16 at 18:05
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    $\begingroup$ the IPK is a different prototype object than the IPM. $\endgroup$ – robert bristow-johnson Aug 29 '16 at 18:06
  • $\begingroup$ Your right about the kilogram, I typed the completely wrong thing, corected $\endgroup$ – Justin Gerhardt Aug 30 '16 at 5:59
  • $\begingroup$ Where did you get this list from? Was it Page 40 of this document? $\endgroup$ – Spencer Jul 18 '18 at 15:10
  • $\begingroup$ Yes, the table on page 40 of that document is where the list is sourced from. $\endgroup$ – Justin Gerhardt Jul 18 '18 at 18:44
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The UK copies are still stored at the National Physical Laboratory. See these links: Metre Kilogram

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Number 22 is at the observatory the Paris. Saw it there on 12-07-2018.

Erik

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  • $\begingroup$ Are you sure it was Number 22 (the one issued to japan)? $\endgroup$ – Justin Gerhardt Jul 15 '18 at 3:38
  • $\begingroup$ I think so, see:ibb.co/canwgo $\endgroup$ – Erik Jul 15 '18 at 10:54

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