This durable and portable instrument is marked "OTTO FENNEL SÖHNE CASSEL." It seems to be a Schmidt-type magnetometer with a massive copper damping plate to facilitate quick reading. The U.S. Coast and Geodetic Survey transferred it to the Smithsonian in 1959. Otto Fennel opened a shop in Cassel in 1851, after having served an apprenticeship with G. Breithaupt, and he showed instruments for land and mine surveying at the international exhibition in London in 1862 and at the Special Loan Collection of Scientific Apparatus in London in 1876. The firm was trading as Otto Fennel, Söhne in 1900. It is in business today as geo-Fennel. Scratched onto the base of this instrument is zu 10540".
Currently not on view
Object Name
Physical Description
metal (overall material)
overall: 14 1/4 in; 36.195 cm
Place Made
Deutschland: Hessen, Cassel
ID Number
accession number
catalog number
Measuring & Mapping
Science & Mathematics
Science & Scientific Instruments
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
U.S. Department of Commerce, Coast & Geodetic Survey

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