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Dry Card Compass

Catalogue number:
PH*314744

Inscriptions:
"JOHN R. S^T JOHN. Inventor-Buffalo, N.Y. U.S.A. 1843" and "Lith. of E. Jones & G. W. Newman" and "128 Fulton S^t New York"

Dimensions:
diameter 9.5 inches

Discussion:
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.

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.

Further Information:

Compass