{
  "name": "The metric system in U.S. law and in the unit definitions, 1866–2019",
  "desc": "One row per document from the 1866 act to the 2019 kilogram: date, kind of document, citation, what it says in brief, its effect on U.S. customary units, and how fully it was read.",
  "lic": "CC BY 4.0",
  "lic_url": "https://creativecommons.org/licenses/by/4.0/",
  "by": "The Yardstick Almanac",
  "url": "https://theyardstickalmanac.com/units/metric-system-united-states/",
  "from": [
    "United States Code, 2024 edition, 15 U.S.C. §§204–205b (acts of 1866, 1975, 1988 and 2007)",
    "Metric Conversion Act of 1975, Pub. L. 94-168, 89 Stat. 1007",
    "Yard and pound: National Bureau of Standards and U.S. Coast and Geodetic Survey notice, Federal Register 24 FR 5348 (July 1, 1959)",
    "Mendenhall Order of April 5, 1893, and the 1960 wavelength announcement, as reprinted in NBS Special Publication 447",
    "BIPM, The International System of Units (SI), 9th edition, version 4.01, Appendix 1 (CGPM resolutions of 1960, 1983 and 2018), CC BY 4.0"
  ],
  "how": "Compiled by The Yardstick Almanac from the data listed",
  "data_by": [
    "Summarized from the U.S. Code (2024 edition), Pub. L. 94-168, 24 FR 5348, NBS SP 447, and the SI Brochure, 9th edition, version 4.01, by the BIPM, CC BY 4.0 (adapted: summarized one document per row); 2026-11-01"
  ]
}