Odometer composed of an ebony rule, whose edges carry two ivory strips with scales in inches. Two wheels with graduated scales are connected to a mobile pointer pivoting on a central quadrant with a double scale. By sliding the rule (at right angles to its length) on a geographic map or sea chart, one obtained directly the distance between two points. The instrument is signed Dollond, but the maker's identity cannot be conclusively established because many Dollonds worked as instrument-makers between the late eighteenth and early nineteenth centuries. Provenance: Lorraine collections.