In the past there was a revolution counting instrument that was hung from the axle of a wagon wheel. At the end of the day, the number of revolutions traveled multiplied by the circumference of the wheel yielded the distance traveled that day.
Hi, @Gus Tuason Makes more sense than using such a beefy tool to measure without leaving some kind of divot per number. Who/how were they counted, I wonder? And for what purpose, cartography? If it was intended for either it doesn't look like it was ever used. It's way too clean.