neodymium ring magnet

Folding Edit this paragraph development history neodymium ring magnet The earliest mention of magnetism in Chinese ancient literature is the 4th century BC Guiguzi "natural magnet iron absorption." AD 20-100 hug grace Hang Luoen-heng "natural magnet suck a needle" Shen Kuo 1031-1095 and the first person to write things make navigation compass direction is more accurate.magnetic drawer 12th century Chinese people know with compass navigation.