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Sir William Thomson's 1880 compass patent model

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Sir William Thomson's 1880 compass patent model
Smithsonian Institution, Negative #: 45,613A


This object appears in the following sections:

Marine Patent Models — Complete Catalog: 1876-1880

Marine Patent Models — Steering the Way

Mariner's compass patent model
Catalog #: 308,557 , Accession #: 89,797
In collection
From the Smithsonian Collection

William Thomson developed an improved compass card in the 1870s through experiments he conducted aboard his private. His compass supplemented improvements he had already patented to ship's binnacles, or compass stands. As a result, Thomson's patent model seen here places the card in a fully modeled binnacle. Thousands of compasses and binnacles employing Thomson's patents were employed the world over in the late nineteenth century.

Physical Description

The model measures 12.5" H x 7" W x 6" D. It is missing one internal magnet.

Date Made:
Transfer from the U.S. Patent Office

William Thomson (1824-1907), a resident of Glasgow, Scotland, was a leading mathematician, physical scientist, and engineer. In a long and active career, he made significant contributions to the study of thermodynamics, electricity, and magnetism. In the 1850s and 1860s, he was centrally involved in efforts to create the transatlantic telegraph cable. This engineering work brought him wide public note, and his patents for electrical devices brought him considerable wealth. Knighted in 1866 for his work on the transatlantic cable, he was honored further with a peerage and the title Baron Kelvin of Largs in 1892. The Kelvin scale of absolute temperature, developed from his initial ideas, is named for him.

Participation in cable-laying expeditions encouraged Thomson's existing interest in the sea and seafaring, and in 1870, after the death of his first wife, he purchased his own yacht. Practical experience gained aboard the yacht, coupled with his considerable scientific and engineering skill led him to develop improvements to navigational equipment, and within the decade he patented a new deep-sea sounding apparatus and made significant improvements to the marine compass.


Sir William Thomson, Mariner's Compass, U.S. patent no. 232,781, Sept. 28, 1880.

Alan Gurney, Compass: A Story of Exploration and Innovation (New York, 2004), 235 ff.

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