classroom demonstration galvanometer
Date: 1850-1875
Inventory Number: 0446
Classification: Galvanometer
Subject:
Maker: Heinrich Daniel Ruhmkorff (1803 - 1877)
User: Department of Physics, Harvard University (founded 1884)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
42.2 × 41.9 × 25.1 cm (16 5/8 × 16 1/2 × 9 7/8 in.)
Description:
A demonstration astatic galvanometer with one needle within the coils, one above on same shaft, mounted vertically with pointer and scale and contained in large removable wooden case with glass cover. There are four leveling screws and four binding posts on the wooden base. One of the binding posts has been dislodged. The dial for registering the deflection of the needle is marked every five degrees with large numbers 40-0-40.
Signedmarked on scale: Ruhmkorff à Paris
FunctionSuch an instrument is used to measure electric currents. A compass needle is pivoted in the middle of a coil. Passing a current through the coil exerts a torque on the needle, which then aligns itself with the resulting magnetic field.
Curatorial Remarks(Description from original card): "Astatic galvanometer movement -- one needle within the coils, one above on same shaft, mounted vertically with pointer 2 scale 17' long contained in large demountable care with glass cover. Large numbers 40-0-40 on scale."
ProvenanceFrom the Department of Physics, Mallinckrodt Laboratory, Harvard University, 1954.