What the Inch Is Measured Against

A ruler, inches and fractions of an inch. What is an inch measured against? In the United States an inch is a customary unit, but three American documents tie it to the metre: an Act of eighteen sixty-six, a Treasury order of eighteen ninety-three and a notice of nineteen fifty-nine. This film reads them: the Act that made the metric system lawful, the order that made the international metre and kilogramme the fundamental standards with the yard and pound "derived therefrom", and the notice that set the yard at 0.9144 metre, so that the inch is exactly 25.4 millimetres. It is the fifteenth film in a small series about what machines agree on. Chapters 0:00 Opening 0:38 1. Before eighteen sixty-six 2:03 2. The Act of eighteen sixty-six 3:27 3. The prototypes 4:42 4. The order 5:56 5. The chain 7:10 6. Nothing 8:31 7. Nineteen fifty-nine 9:48 8. What it changed 11:52 Closing Scope The film reads the US Act of 28 July 1866, chapter 301, "An Act to authorize the Use of the Metric System of Weights and Measures" (Statutes at Large vol. 14, pp. 339 and 340), and, as the National Bureau of Standards reprinted them in its history "Weights and Measures Standards of the United States" (NBS Special Publication 447), the Mendenhall Order of 5 April 1893 and the Department of Commerce notice of 25 June 1959 (printed in the Federal Register of 1 July 1959). They are United States documents; the film does not read the bulletin of 1893, the Federal Register page itself, or the text of the Metre Convention. The history before 1866 is told only as the order tells it. The figures are the documents' own (39.37 inches to the metre, 3600/3937 of a metre to the yard, 0.9144 metre, 25.4 millimetres); the film's own arithmetic is labelled, and the film does not say that any document is wrong. The film does not say why the United States did not adopt the metric system as its only system, and says nothing about the metre's later definitions, the SI, metrication or today's definitions. It tells no story of any person; offices are named as the documents name them. About the visuals and narration Narration is a synthetic (text-to-speech) voice generated from the film's script. The bars (a metre and a yard drawn to one scale, and a detail of the 1893 and 1959 yards) are original graphics drawn by the film; the difference of two parts in a million is exaggerated 40,000 times in the detail so that it can be seen, and the drawing says so. They are illustrations, not part of any document. The page images are from US Government publications (the Statutes at Large on govinfo.gov, and NBS Special Publication 447 on nvlpubs.nist.gov). The machine-shop and lathe clips are illustrative, are labelled on screen, and are not footage of any standard of length or of any measurement in these units. Main sources (read before the script was written) US Statutes at Large, vol. 14, pp. 339 and 340 (the Act of 28 July 1866): https://www.govinfo.gov/link/statute/... NBS Special Publication 447, "Weights and Measures Standards of the United States: a brief history" (Appendix 3, the Mendenhall Order of 5 April 1893; Appendix 5, the notice of 1959; Section 8): https://nvlpubs.nist.gov/nistpubs/Leg... Credits and licences (via Wikimedia Commons; excerpted) Machine shop B-roll (NASA's Scientific Visualization Studio, "Machining NICER's Patches", Part 1), public domain (Commons tag). Watchmaker's lathe, by Frédéric Bisson, CC BY 2.0: https://creativecommons.org/licenses/... Narration generated with the Kokoro-82M open model (Apache-2.0 per its model card). About this channel Things Quietly Working is about the ordinary systems that run in the background of everyday life: roads, signals, networks and infrastructure, and what is actually underneath them.