capillary electrometer
Date1880-1910
Inventory Number0248
ClassificationElectrometer
Subject
Maker
E. Ducretet & Cie
1864 - 1931
Cultural Region
Place of Origin
Dimensions51.4 x 18.1 x 13.4 cm (20 1/4 x 7 1/8 x 5 1/4 in.)
Material
Bibliography
DescriptionA capillary tube of mercury, with scale (0 - 7) and magnifier lens, is set between two test tubes (one broken) which were also filled with mercury and acted as electrodes (contacts are attached to the bottoms of tubes). The electrometer is mounted on rectangular hard rubber panel. It is supported by a brass column terminated in a cabriole metal tripod painted so it resembles copper.
Signedon dial: E. Ducretet & Cie à Paris
on mounting: E. DUCRETET / & Cie / A PARIS
Curatorial RemarksThere is a blue triangle on this instrument, which indicates it was use in the Physics 3 course at Harvard in the late 1920's.
This capillary electrometer, or galvanoscope, is somewhat similar but not exactly identical to the one mentioned in the catalogue cited here.
FunctionUsed to measure electromotive forces. The chief element consists in a small drop of mercury in a horizontal capillary tube that moves under the influence of an electric field applied to the two electrodes. Gabriel Lippmann (1845-1921) invented this type of instruments, which was more precise than most other electrometers. It was not only employed in physics, but also in physiology, showing the electrical variation produced by muscular contractions (muscle, heart, etc.).
This is a simple model, sometimes called Lippmann galvanoscope. Instead of microscope, a simple magnifier lens is used to measure the position of the mercury inside the capillary. Most likely used in lecture demonstrations.
This is a simple model, sometimes called Lippmann galvanoscope. Instead of microscope, a simple magnifier lens is used to measure the position of the mercury inside the capillary. Most likely used in lecture demonstrations.
ProvenanceFrom the Physics Department, Harvard University.
Spindler & Hoyer
Date: 1900-1950
Object number: 1996-1-0636
Arthur H. Thomas Company
Date: 1958
Object number: 2015-1-0005