A device for measuring the length of a path, consisting of a wheel of known circumference attached to a rod held in the hand, and pushed along a surface, which is usually the ground or a floor. The number of times the wheel makes a complete circle multiplied by the circumference is a measure of the length of the path traversed. It may be used to measure distances on curved as well as straight paths. A variant which registers the miles and rods traversed is sometimes used by surveyors.  [PJC]