portable galvanometer
Datecirca 1926
Inventory Number0437
ClassificationGalvanometer
Subject
Maker
Charles Chase
User
Edwin H. Hall
1855 - 1938
User
Percy Williams Bridgman
1882 - 1961
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions4 × 39.5 × 3.8 cm (1 9/16 × 15 9/16 × 1 1/2 in.)
Material
DescriptionGalvanometer with solid brass cylindrical case hinged on one side and mounted with screw fittings. Case opens to reveal two pairs of coils of fine wire embedded in circular cutouts in each half of case. There is a slot for a fine thread suspension to support small movable magnet and mirror. Three brass binding posts on top of case. The bottom fitting originally screwed into a tripod base and was surrounded by three pipe shields with brass caps.
Signedunsigned
FunctionThis small reflecting galvanometer was made in Jefferson Laboratory by Charles Chase for Professor Edwin H. Hall. Galvanometer used in measuring very low voltage potentials for calibrating equipment. When a current is applied to the galvanometer, a small variation will create a torque motion on the mirror. A light is then beamed on the mirror, which will be redirected away from the galvanometer towards a graduated scale. The position of the reflected light on that scale will indicate the variation of the current detected by the galvanometer.
ProvenanceFrom the Department of Physics, Lyman Lab, Harvard University, 3/16/1961.
Charles-Louis Chevalier
Date: circa 1850
Accessories: 2 convertible objectives: 1, 2, 3 and 0, 00, 000; 2 oculars; 2 magnifiers; forceps; camera lucida; 3 scalpels; 1/100 mm stage micrometer; bull's eye condenser on jointed arm; eyeshield; and a mahogany case with a drawer and key.
Object number: 1116
Charles X. Dalton
Date: 1890
Accessories: One original eyepiece , probably not by Tolles, 33.8 mm O.D. ; 1 objective, "Tolles / Boston", low power, no collar, transferred by E. Gay from 1158.
Object number: 1026
Charles Frodsham
Date: circa 1865
Accessories: winding key.
Object number: 1998-1-1319
Charles-Louis Chevalier
Date: 1835-1840
Accessories: 4 objectives; 4 oculars; inverting ocular; camera lucida; compressorium; galvanic stage; 1/100 mm stage micrometer; liquid trough; 2 bull's eyes; condenser with diaphragm wheel; mechanical stage; trough; eye shield; case with drawer and lid; spare wooden display base.
Object number: 1115
Nalder Brothers & Company
Date: circa 1910
Object number: 0260
Nalder Brothers & Company
Date: circa 1910
Object number: 0261
Queen & Company
Date: circa 1910
Accessories: carrying case (may not be original to instrument)
Object number: 0267a,b
Charles-Louis Chevalier
Date: circa 1833
Accessories: 1 convertible objective, unmarked; 2 oculars; bull's eye condenser on jointed arm; 4 prepared slides, 3 glass slides; wrapped paper with pityriasis versicolor; specimen list on a card; flat case in form of sliding drawer; key.
Object number: 1071a
Charles-Louis Chevalier
Date: circa 1840
Accessories: 2 regular objectives; a high power objective; a low power objective (a variable power dissecting lens) with an extension arm for this lens; 2 dissecting lenses; 1 objective with lieberkuhn; objective with polarizer; 2 regular eyepieces; 1 erecting eyepiece; 1 micrometer eyepiece; stage micrometer, stage bull's eye condenser on jointed arm; camera lucida; tweezers; 3 dissecting tools; pillar extension;
compressorium, 2 objective adaptive mounts (one with Chevalier threads, another with Oberhauser threads); 2 adaptors for Chevalier lenses to other microscopes (one adaptor having Society threads); case.
Object number: 1093