galvanometer

(gal-van-om’et-er) [galoanic + Gr. μέτρον measure]. An instrument for measuring galvanic electricity. Einthoven’s g., string g., thread g., an apparatus for detecting very minute electric currents, consisting of a delicate thread of silvered quartz or platinum stretched between the poles of a strong magnet. The thread may be illuminated by an arc light and the shadow of the thread thrown upon a screen after being magnified by a microscope.