PERAMBULATOR

, an instrument for measuring distances; called also Pedometer, Waywiser, and Surveying Wheel.

This wheel is contrived to measure out a pole, or 16 1/2 feet, in making two revolutions; consequently its circumference is 8 1/4 feet, and its diameter 2.626 feet, or 2 feet 5 1/2 inches and 12/1000 parts, very nearly. It is either driven sorward by two handles, by a person walking; or is drawn by a coach wheel, &c, to which it is attached by a pole. It contains various movements, by wheels, or clock-work, with indices on its face, which is like that of a clock, to point out the distance passed over, in miles, f<*>longs, poles, yards, &c.

Its advantages are its readiness and expedition; being very useful for measuring roads, and great distances on level ground. See the fig. Plate xvii, fig. 6.