指南针指南针,指示方位的一种简单仪器。在战国时已有用天然磁铁矿琢磨成的指南针,称为“司南”。最早的记载见于《韩非子·有度》,其著作年代约在公元前3世纪。北宋沈括的《梦溪笔谈》中,对于磁石磨成的指南针已有了详细记载。人们把某些物质能吸引铁、镍、钴等物质的属性称为磁。我国古代就已发现一种称为磁石的天然矿物(Fe_3O_4)具有磁 A simple instrument that indicates the position of a compass. In the Warring States period has been used to compose the natural magnetite into a compass, known as “Secretary Nan”. The earliest record found in “Han Feizi · degree”, its writings about the third century BC. Northern Song Shen Kuo, “Meng Xi Bi Tan”, the compaction of the magnet has been documented in detail. People refer to the properties that certain substances can attract such as iron, nickel, and cobalt. Ancient China has found that a natural magnet called magnetite (Fe_3O_4) has a magnetic