Interesting. The meter was defined in 1791. James Bradley got the speed of light correct to about 1% in 1728, and I think that value stood in 1791. That valu

Interesting. The meter was defined in 1791. James Bradley got the speed of light correct to about 1% in 1728, and I think that value stood in 1791. That value was less accurate than either the 10000km pole-to-equator or 1-second-pendulum, as measurable in 1791. And until special relativity, the idea of speed of light being constant wasn't really firmly established. Ultimately, I think in 1791 I think using the speed-of-light as the basis wasn't really practical. P.S. Not really necessary but in writing this comment, I read these documents, each of which taught me something new: https://interestingengineering.com/science/a-brief-history-of-the-speed-of-light https://interestingengineering.com/science/a-brief-history-o... https://spie.org/publications/tt82_25_speed_of_light https://spie.org/publications/tt82_25_speed_of_light https://en.wikipedia.org/wiki/Luminiferous_aether https://en.wikipedia.org/wiki/Luminiferous_aether