The Historical Evolution of the Theory of Compass in China.

　　指南針理論在中國歷史上的.演變。

　　The compass was invented in China two thousand years ago.

　　中國在兩千年前發明了指南針。

　　The electronic compass is widely used in the navigation equipments recently.

　　近年來，電子指南針被廣泛的運用于導航設備中。