Magnetometer n. (Physics) An instrument for measuring the intensity of magnetic forces; also, less frequently, an instrument for determining any of the terrestrial magnetic elements, as the dip and declination.
... in an aside, "if you want a better explanation of that effect, you might look up the maintenance manual on the proton gyroscopes that Sad Cow uses. Or the manuals for the M.R. analyzer in the chem lab. Or the magnetometer we use to keep a check on Earth's ... — Where I Wasn't Going • Walt Richmond
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