vibration galvanometer (Duddell's Patent)
Datecirca 1910
Inventory Number0260
ClassificationGalvanometer
Subject
Maker
Nalder Brothers & Company
founded 1884
User
Harvard Engineering School
1918 - 1951
Cultural Region
Place of Origin
Place of Use
Dimensions32.5 × 18.7 × 18.7 cm (12 13/16 × 7 3/8 × 7 3/8 in.)
Material
DescriptionVibration galvanometer has bifilar suspension with small mirror and moving wire surrounded by heavy magnet. Length of wire may be tuned by adjusting frets using two thumbscrews below. Cylindrical brass case with wooden top and cutout for black brass suspension tube. Round wooden base with three leveling screws and two binding posts. Identical to instrument 0261 in this collection.
Signedon top of case: DUDDELL'S PATENT / 1779 - 1908 / NALDER BROs & Co / WESTMINSTER / No 28,482
Inscribedon top of case (serial number): No 28,482
on case: Harvard University 1194
FunctionThe Duddell Patent galvanometer was used to measure very high frequencies. The small magnet and mirror hang on a fine wire suspension or string, and the vibrations of the string are converted into rotations of the mirror.
ProvenanceFrom the Harvard Engineering School, 11/1956.
Nalder Brothers & Company
Date: circa 1910
Object number: 0261
Nalder Brothers & Company
Date: 1900-1910
Object number: 0229a,b,c,d
Cambridge Instrument Company, Ltd.
Date: circa 1930
Object number: 0225
Robert W. Paul Instrument Company
Date: 1900-1919
Object number: 0262a,b,c,d
Elliott Brothers
Date: circa 1930
Object number: 0232
Nalder Brothers & Company
Date: late 19th-early 20th Century
Object number: 0359