Odometer

Device for measuring distances covered.
This is a type of wheelbarrow fitted with two toothed discs. Each rotation of the wheel moves the vertical disc one notch. This disc transmits its movement to the horizontal disc that also turns one notch. Pierced with holes containing small balls, this horizontal disc releases them one by one at each rotation of the wheel. You just have to count the balls collected in a small box to find out the distance covered.