dip needle

American  

noun

1. an early form of magnetometer, consisting of a magnetic needle pivoted through its center of gravity and having its axis through the vertical plane of the earth's magnetic meridian so as to point in the direction of maximum magnetic intensity.

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dip needle British  

noun

1. a magnetized needle pivoted through its centre of gravity able to rotate freely in a vertical plane, used to determine the inclination of the earth's magnetic field See also dip circle

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Example Sentences

When used, the dip needle must be set so that the plane in which the needle swings contains the magnetic meridian, as indicated by the horizontal needle.

From Project Gutenberg

At Paterson, N. J, seven young engineering students—George Duggan, Henry Walstenholme, Richard Jenkinson, Julian and Edward Yzewyn, Tice Van Dyk and Frederick Bomelyn—have been improving their summer evenings by prowling along the shores of the Passaic River with a dip needle, the instrument used to locate subsurface metals.

From Time Magazine Archive