沈括
The study of magnetism in Ancient China dates back to the 4th century BCE. (in the "Book of the Devil Valley Master"), A main contributor to this field was Shen Kuo (1031–1095), a polymath and statesman who was the first to describe the magnetic-needle compass used for navigation, as well as establishing the concept of true north. In optics, Shen Kuo independently developed a camera obscura.