Diagram of a Ming dynasty mariner's compassMain article: CompassThe earliest reference to magnetism in Chinese literature is found in a 4th century BC book called Book of the Devil Valley Master (鬼谷子): "The lodestone makes iron come or it attracts it."The earliest reference to a magnetic device used as a "direction finder" is in a Song Dynasty book dated to AD 1040-44. Here there is a description of an iron "south-pointing fish" floating in a bowl of water, aligning itself to the south. The device is recommended as a means of orientation "in the obscurity of the night." However, the first suspended magnetic needle compass was written of by Shen Kuo in his book of AD 1088.
For most of Chinese history, the compass that remained in use was in the form of a magnetic needle floating in a bowl of water. According to Needham, the Chinese in the Song Dynasty and continuing Yuan Dynasty did make use of a dry compass, although this type never became as widely used in China as the wet compass.The dry compass used in China was a dry suspension compass, a wooden frame crafted in the shape of a turtle hung upside down by a board, with the loadstone sealed in by wax, and if rotated, the needle at the tail would always point in the northern cardinal direction. Although the 14th century European compass-card in box frame and dry pivot needle was adopted in China after its use was taken by Japanese pirates in the 16th century (who had in turn learned of it from Europeans), the Chinese design of the suspended dry compass persisted in use well into the 18th century.