Magnetometer
![Helium Vector Magnetometer (HVM) of the Pioneer 10 and 11 spacecraft](/Images/godic/202501/14/Pioneer_10-11_-_P50_-_fx3048.jpg")
![Coast and Geodetic Survey Magnetometer No. 18., used in the magnetic survey of Maryland conducted in the 1890s](/Images/godic/202501/14/Coast_and_Geodetic_Survey_Magnetometer_Plate_XV_Fig_1_WBClark_18973048.jpg")
![A uniaxial fluxgate magnetometer.](/Images/godic/202501/14/Magnetometr_transduktorowy_by_Zureks3049.jpg")
![A fluxgate compass/inclinometer.](/Images/godic/202501/14/Floating_core_fluxgate_inclinometer_compass_autonnic3049.jpg")
Magnetometers are measurement instruments used for two general purposes: 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.
The first magnetometer was invented by Carl Friedrich Gauss in 1833 and notable developments in the 19th century included the Hall Effect which is still widely used.