This is a Kew pattern unifilar magnetometer that is marked ";Dover, Charlton Kent No. 145" and that belonged to the Survey Branch of the U.S. Navy Hydrographic Office. While the ";Dover, Charlton Kent" signature was used between 1859 and 1920, the serial number suggests that this example was made around 1900. The U.S. Coast and Geodetic Survey repaired, cleaned, adjusted, and calibrated this instrument around 1950, and transferred it to the Smithsonian in 1959.

Ref: J. E. H. Gordon, A Physical Treatise on Electricity and Magnetism (London, 1880), vol. I, pp. 166-177.

Currently not on view
Object Name
Physical Description
wood (overall material)
metal (overall material)
overall: 21 1/8 in x 11 1/4 in x 11 3/4 in; 53.721 cm x 28.575 cm x 29.845 cm
Place Made
United Kingdom: England, London, Charlton
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
Additional Media

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.