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Liquid Compass - click to enlarge

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Liquid Compass

Catalogue number:
PH*39385

Inscriptions:
"E. S. RITCHIE, BOSTON. PATENTED APL. 7. 1863. APL. 10, 1866. MAY 12, 1868. JULY 19, 1870. NOV. 14, 1876" and "10601" and "RITCHIE BOSTON"

Dimensions:
compass diameter 8.5 inches; box 11 inches square

Discussion:
This compass has a brass bowl gimbal mounted in a wooden box. The compass itself may date from the mid-1860s. The graduated ring is curved. The needle float is in the form of crossed cylinders, as described in the patent (#38,125) granted to Ritchie on April 7, 1863.

The gimbal ring, which seems to be of a somewhat later date than the compass, identifies several Ritchie patents in addition to that of 1863. The patent of May 12, 1868 (#77,763) describes a paint that would not deteriorate in the liquid in the compass. The patent of July 19, 1870 (#105,492) describes a way to hold the glass in place with a water-tight joint. And the patent of November 14, 1876 (#184,300) describes a "fascicular magnet" composed of a series of separate drawn wires of steel laid parallel to one another.

The Ritchie ledgers, now held by Ritchie Navigation, indicate that this compass was produced on March 2, 1880, and sold to S. Thaxter & Son in Boston. Smithsonian records indicate that Thaxter donated the compass to the Smithsonian, perhaps for use in the International Fishery Exhibition which opened in Berlin on April 20, 1880.

Further Information:

Ritchie
Compass

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