Hilger & Watts Vertical Force Variometer

Description

For use with a tripod and levelling tool, this variometer measures the change in the vertical component of Earth’s magnetic field. It contains a latitude-adjusted axis from which a magnet is suspended, floating [magnetic] East-West – perpendicular to the magnetic meridian. The magnet is tilted by variations in the vertical force. The amount of tilt is measured, and can be directly related to the magnitude of the change in the vertical component of the magnetic field.

Note: a magnetic variometer measures the change in a magnetic field. An instrument that measures the absolute components of a magnetic field is called a magnetometer.

Bruckshaw, J 1954, Magnetic variometers of the Schmidt type: their full use and maintenance illustrated by details of the Hilger & Watts variometers, Hilger and Watts, London.