fl. c. 260
Chinese alchemist who created an early compass. Using differential gears, Ma Chün developed what he called a "south-pointing carriage." The design of his compass was probably much like that of the ones that have continued to be used in China communities for the divination art of feng shui: a spoon made of lodestone or magnetite ore on a cast bronze plate inscribed with symbols indicating the directions of various constellations. The name reflects early Chinese alchemists' mistaken belief that certain kinds of metal cause a compass to point southward.