Portable moving-coil ammeter in wooden case, early electrical test instrument. The scale marked “AMPERES – Full Scale Deflection With Current Marked on Shunt” indicates it was designed to be used with an external shunt to measure higher currents. Such meters were used by electrical engineers and technicians for testing generators, distribution systems, and industrial equipment. Typical laboratory and field instrument, early 20th century, c.1910s–1920s.
