Signedon scale: Ruhmkorff Rue des Orfèvres, 6 / Paris
FunctionAn astatic galvanometer is a sensitive instrument that measures small current displacements. When an electric current passes through a wire coil, it induces a magnetic field that causes the coil to rotate in proportion to the current deflections, twisting a suspended magnet. The current deflections can be detected using a scale.
ProvenanceFrom the Department of Physics, Harvard University, 11/20/1956.
Related WorksHenry M. Noad, A Manual of Electricity (London, 1859), p. 328, fig. 186. (similar).