Dip needle compass.

Dip needle compass. This 'Dip-Needle' apparatus can be used in two different ways: 1) It can be placed horizontally on the table, and the magnetic compass needle will indicate the direction of magnetic north. 2) Once magnetic north is determined, the apparatus is set up vertically and aligned with magnetic north. Now, the dip needle indicates the angle of the magnetic flux coming up through the earth.
UCB Index: 
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Demo Diagram: 

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