- An instrument for detecting or measuring minute extension
or movements of solid bodies. It consists essentially of a small rod,
disk, or button of carbon, forming part of an electrical circuit, the
resistance of which, being varied by the changes of pressure produced
by the movements of the object to be measured, causes variations in the
strength of the current, which variations are indicated by a sensitive
galvanometer. It is also used for measuring minute changes of
temperature.
Definition
[ n.]