I checked out one of the links [0], which lead to an article presumably by the same author, with this accompanying picture of a plaque installed at the site of

I checked out one of the links [0], which lead to an article presumably by the same author, with this accompanying picture of a plaque installed at the site of measurement on Mount Wilson [1]. It clearly says velocity of light - so that might have been where the author got it from. [0] https://www.otherhand.org/home-page/physics/historical-speed-of-light-measurements-in-southern-california/the-mount-wilson-station-1922-1928/ https://www.otherhand.org/home-page/physics/historical-speed... [1] https://www.otherhand.org/wp-content/uploads/2012/04/Mt-Wilson-plaque.jpg https://www.otherhand.org/wp-content/uploads/2012/04/Mt-Wils...