The action of the negative pole of a magnetic needle is just as real as the action of the positive pole.
一根磁针的磁极作用，无论正负都是一样的真实。
The action of the negative pole of a magnetic needle is just as real as the action of the positive pole .
这个效应表明，有一种垂直于圈平面的力作用在磁极上。
The direction of the earth's magnetic pole, to which the north-seeking pole of a magnetic needle points when free from local magnetic influence.
地球磁极的方向，当不受当地磁场影响时，用来寻找北方磁极指示的方向。
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