Signedon steel plaque on leg of base: LEEDS & NORTHRUP CO. / SCIENTIFIC INSTRUMENTS / PHILADELPHIA
Inscribedon steel plaque on leg of base, (serial number): 216722
FunctionThis is a lamp for a mirror galvanometer that would be used in conjunction with a scale. Both the lamp and the scale would be placed a few meters in front of a reflecting galvanometer. The lamp is shone toward the galvanometer's mirror. It is then reflected back on the scale to measure the tiny mirror's angle of rotation caused by the electric current going into the galvanometer.