Edelmann's induction galvanoscope with two coils and a spare torsion tube Edelmann's induction galvanoscope 1876
Edelmann's absolute dynamometer including two loose coils and additional torsion tube Edelmann's absolute dynamometer 1876
Edelmann's mirror galvanometer with two coils Edelmann's mirror galvanometer with two coils and components 1876
Galton's whistle for testing hearing, nickel plated brass, by Edelmann Munich, 1890-1915 Galton's whistle for testing hearing 1890-1915
Du Bois-Reymond's compensating magnet. It allowed the one operating a galvanometer to fine-tune its sensitivity by repositioning a permanent magnet as necessary in order to compensate wholly or partially for the Earth's magnetic pull on the galvanometer needle. The wooden guide was affixed to the center of the galvanometer and could rotate freely; the magnet, in a brass mount, could be precisely positioned at any distance from the center. A pulley and string arrangement allowed the operator to adjust the magnet on the fly while seated a distance away at the reading telescope. Du Bois-Reymond's galvanometer-compensating magnet 1876