Johann Carl Friedrich Gauss (Brunswick, Germany, 30 April 1777 – Hanover, Germany, 23 February 1855) was a German mathematician and physicist who made significant contributions to many fields in mathematics and science.

He was rare among mathematicians in that he was a calculating prodigy, and he retained the ability to do elaborate calculations in his head most of his life. Impressed by this ability and by his gift for languages, his teachers and his devoted mother recommended him to the duke of Brunswick in 1791, who granted him financial assistance to continue his education locally and then to study mathematics at the University of Göttingen from 1795 to 1798.

Magnetometers are measurement instruments used to measure the magnetization of a magnetic material like a ferromagnet, or to measure the strength and, in some cases, the direction of the magnetic field at a point in space. They are also widely used to measure the Earth's magnetic field and in geophysical surveys to detect magnetic anomalies of various kinds.

In 1833, as director of the Göttingen Geomagnetic Observatory, he published an article on the measurement of the Earth's magnetic field. He described his invention, a new instrument consisting of a permanent magnetic bar suspended horizontally from a gold fiber. The difference in the oscillations when the bar was magnetized and when it was demagnetized allowed him to calculate an absolute value for the strength of the Earth's magnetic field.

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