PEDOMETER (roez, a foot, and mérop, a measure), an ingenious instrument in the form of a watch, designed to ascertain the space of ground over which one has travelled. Of the various contrivances of this sort, that of Payne, watchmaker in Bond Street, London, is decidedly the most convenient. The instrument is so arranged that when the body of the traveller is raised by the spring of his foot in walking, or by the motion of his horse, a small lever is jerked downwards which communicates its motion to the wheel-work of the machine. The distance passed over is pointed out in miles on a dial-plate, by means of an index. In adapting the pedometer to carriage travelling, the ordinary horizontal position of the lever becomes perpendicular, and the instrument is allowed to oscillate like a pendulum.