Signedon top of case: Rob. W. Paul / London. N. / CAMPBELL VIBRATION GALVANOMETER / No. 36
on plaque on front of case: IMPORTED BY / JAMES G. BIDDLE / PHILADELPHIA, U.S.A.
Inscribedon case: H.U. 104-A
FunctionThis Campbell's vibration type galvanometer was used in the Engineering School at Harvard. The instrument is equipped with a mirror supported by a pair of upper and lower strings. A small pulley sheave adjusts the vibrating length of the string and the sheave's position can be moved upwards and downwards with a horizontally-mounted lever that tunes the galvanometer to a resonance frequency that is equivalent to the optimal length of the string. A brass adjustment knob for string tension is mounted next to the lever, and there is a spring to load the tension of the vibrational strings next to the suspension tube. When current is introduced into the string (wire) in the presence of a magnetic field, the string moves.
Primary SourcesPaul Instrument Catalog - pg. 691-693
ProvenanceFrom the Harvard Engineering School, 12/19/1956.