St. John Dry Card Compass

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In 1852, John Ransome St. John obtained an American patent for this mariner’s compass designed to determine local changes in magnetic variation. Although the instrument was complex and largely useless, it garnered a gold medal at the American Institute fair of 1849 and a Prize Medal at the Crystal Palace exhibition held in London in 1851.
The instrument bears the inscriptions "JOHN R. ST JOHN. Inventor-Buffalo, N.Y. U.S.A. 1843" and "Lith. of E. Jones & G. W. Newman" and "128 Fulton St New York."
Ref: Patent (#8,785) granted to John R. St. John on March 2, 1852.
"John R. St. John’s Variation Compass and Velocimeter," Transactions of the American Institute (1851): 204-205.
Currently not on view
date made
ca 1850
St. John, John R.
place made
United States: New York, New York
overall: 9 1/4 in x 12 7/8 in x 11 9/16 in; 23.495 cm x 32.7025 cm x 29.36875 cm
bowl: 9 1/2 in; 24.13 cm
overall: 9 1/4 in x 12 3/4 in x 11 1/2 in; 23.495 cm x 32.385 cm x 29.21 cm
ID Number
catalog number
accession number
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Medicine and Science: Physical Sciences
Measuring & Mapping
Data Source
National Museum of American History


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