從前,當人們嘗試去解釋為什麼磁針的一端總是指向北方的時候,他們假想這是來自天上北極星的磁力吸引着羅盤儀的針。關於地球本身是一個大的球形磁鐵,因此對羅盤儀的磁針發生作用這一點,人們在比較長的時期後,約在三百五十年以前才晓得的。偉大的俄羅斯學者羅蒙諾索夫認為觀察羅盤儀磁針在地球各地區的變化有重大的意義,遠在 In the past, when people tried to explain why one end of the needle was always pointing to the north, they assumed that it was the magnetic force from the Polaris in the sky that attracted the compass needle. As for the Earth itself, which is a large spherical magnet, the effect of magnetic needles on compasses has been known only after three hundred and fifty years after a relatively long period of time. The great Russian scholar Lomonosov believes that it is of great significance to observe the changes of compass needles in all regions of the globe.