Some examples of magnets attracting iron and repelling the same sex are also recorded in ancient Chinese books. For example, Historical Records? 6? 1 The Book of Zen Buddhism says that Emperor Wu of the Han Dynasty ordered the alchemist Luan Da to use the chess pieces made of magnets to "touch each other"; And the "Zhuan Nan Wan Bi Shu" (Liu An, Western Han Dynasty) also has a detailed record of "taking chicken blood and grinding it with a needle to match with a magnet, painting the chess head, exposing it to dry, and refusing to stop at the board". In the Southern and Northern Dynasties (512 ~ 518), the Notes on Shui Jing (Li Daoyuan) and another book, San Fu Huang Tu, it was recorded that Qin Shihuang built the north gate of Epang Palace with magnets, and those who had hidden armor and concealed the door would be found out. Book of Jin? 6? The story of "The Biography of Malone" can be used for reference: It is said that Malone, who was both wise and brave in the 3rd century, ordered soldiers to pile a large number of magnets on a narrow path during a battle. All the enemy troops in armor are attracted by magnets, while Malone's soldiers will wear rhinoceros armour and act as usual. The enemy thought that Malone's soldiers were magic soldiers, so they were defeated ("The road was tired of magnets, the thief was bored with iron, and he couldn't move forward. Long died of rhinoceros armour, and there was nothing to hinder him").
in ancient times, magnets were often used for medical treatment. In Historical Records, there is a record of "Five Stones Powder" for oral treatment, and the magnet is one of the five stones. The medical record of using a magnet to suck out the iron needle in the Jin Dynasty. In the Song Dynasty, some people put magnets in their ears with iron blocks in their mouths, thus curing deafness.
Magnets can only absorb iron, but not other metals such as gold, silver and copper, which has long been known by ancient Chinese. In Huainanzi, there is a saying that "Ci Shi can absorb iron, but it doesn't work for copper", and that "Ci Shi can connect with iron, but it is difficult to draw tiles from it".