...the backstory is the inspiration came from a 19th century pendulum clock gifted to Felix by his father. The clock was made by Gustave Sandoz for the 1893 World’s Fair in Chicago. It had a regulator style dial which instead of time showed the distance of the Earths rotation at the equator. The pendulum, which was extra long, beats every 2.16 seconds and so each oscillation was 1 KM. The main dial had a scale of 10,000 KM broken into 100 KM units and so each tick (half an oscillation) indicates 500 meters travelled on the earths surface.
That’s the story apparently.