St. John Dry Card Compass

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
Object Name
dry card compass
date made
ca 1850
St. John, John R.
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
place made
United States: New York, New York
ID Number
catalog number
accession number
Measuring & Mapping
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center

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