reflecting galvanometer
Date: 1963
Inventory Number: 1997-1-1031
Classification: Reflecting Galvanometer
Subject:
Maker: Rubicon Company (fl. 1930s - 1960s)
Maker: Honeywell (1885-present)
User: Department of Geology and Geography, Harvard University (1890 - 1961)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
19 × 13 × 21 cm (7 1/2 × 5 1/8 × 8 1/4 in.)
Description:
Self-contained galvanometer in rectangular wooden case housing mirror and battery-powered lamp. Top of case has rectangular bakelite panel with oval window showing scale graduated from 25-0-25 with switch marked "LAMP" underneath. There is a raised circular scale with compass needle mounted on the panel marked from 15-0-15 with two coarse adjustment knobs directly below. White plastic instrument card swings out from underneath base with specifications. Case rests on four rubber feet.
Signedon metal plaque mounted on wooden case: MINNEAPOLIS-HONEYWELL REG. CO. / Rubicon Instruments / PHILADELPHIA 32, PA. MADE IN U.S.A. / SERIAL NO. 113325
Inscribedon black sticker with raised white letters: GEOLOGY / ELECTRONIC
FunctionThis self-contained galvanometer was used in the Hoffman Laboratory in the Geology Department Harvard to detect and measure electrical current. It has a movable coil wrapped around the frame of the galvanometer and a battery-powered lamp. The coil is suspended between the poles of a magnet, and when a current is applied, the coil twists in response to the interaction of the current through the coil and the magnetic field generated by the magnet. When the light beam reflects from the mirror on the galvanometer movement, this deflection can then be read from the scale on the exterior of the wooden cabinet.
Curatorial RemarksInstrument's specifications: CAT. NO. 3072 / SER. NO. 113325 / SENS 8.2 mm / RESIS. 300 ohms / PERIOD 1.7 seconds / Date 3-20-63 / Rubicon Company / PHILADELPHIA
ProvenanceFrom the Hoffman Laboratory, Department of Geology, Harvard University, 1/24/1984, courtesy of Steve Dubos.