What's the difference between a compass and a compass?

The invention of compass with physical direction indication consists of trilogy: Sina, magnetic needle and compass.

The South Guide Car, also known as the South Guide Car, is a device used to indicate the direction in ancient China. It is different from a compass in that it uses geomagnetic effect, and it does not use magnetic force. It is a mechanical device that uses gear transmission system to indicate the direction. The principle is that the vehicle is driven by manpower (Song Shi said that there are eighteen drivers), and the rotation of the wheel drives the rotation of the gear, and then the rotation of the gear drives the Woodenhead on the vehicle to indicate the direction. No matter where the car turns, Woodenhead's hand always points to the south. "Although the car was brought back, the hand has been guiding."

Compass is the result of the understanding of the magnetism of objects by the working people of ancient Han nationality in long-term practice. As one of four great inventions of ancient china, its invention has played an inestimable role in the development of human science, technology and civilization. In ancient China, the compass was first used for rituals, etiquette, military affairs and divination, and to determine the orientation when looking at geomantic omen. 1 1 At the end of the century or at the beginning of the 2nd century, China ships began to use compasses for navigation. Zhou Ping can talk in the Northern Song Dynasty: "The shipowner (helmsman) knows geography, watches the stars at night, watches the sun by day, and watches the compass in the dark."