Johann von Lamont, director of the astronomical and meteorological observatory at Bogenhausen, introduced this type of theodolite magnetometer in the 1840s. This example is marked "Wm. Grunow, New York." It belonged to the U.S. Military Academy at West Point and probably dates from the period 1873-1883. William Grunow was a native of Berlin who, together with his brother Julius, immigrated to the United States in 1849 and made microscopes in New York, New Haven, and again New York. When the partnership dissolved in the late 1860s, William began making instruments for physics research. He moved to West Point in 1883.

Ref: D. J. Warner, "Julius & William Grunow," Rittenhouse 3 (1989): 41-48.

Johann von Lamont, Handbuch des Erdmagnetismus (Berlin, 1849).

Currently not on view
Date made
Grunow, William
Place Made
United States: New York
Physical Description
metal (overall material)
horizontal circle: 11 in; 27.94 cm
horizontal scale: 36 in; 91.44 cm
suspension: 36 in; 91.44 cm
overall; long case: 6 in x 44 in x 10 5/8 in; 15.24 cm x 111.76 cm x 26.9875 cm
overall; large case: 18 1/2 in x 13 3/4 in x 14 1/4 in; 46.99 cm x 34.925 cm x 36.195 cm
ID Number
accession number
catalog number
Credit Line
U.S. Department of Defense, U.S. Military Academy
Science & Scientific Instruments
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Science & Mathematics
Data Source
National Museum of American History


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