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Sir William Thomson's compensating binnacle patent model

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Sir William Thomson's compensating binnacle patent model
Smithsonian Institution, Photo by Richard Strauss, Negative #: 2006-9752


This object appears in the following sections:

Marine Patent Models — Complete Catalog: 1876-1880

Marine Patent Models — Steering the Way

Compensating binnacle patent model
Catalog #: 1999.0028.01, Accession #: 1999.0028
In collection
From the Smithsonian Collection

William Thomson, through experiments conducted aboard his private yacht in the 1870s, developed an improved mechanism to compensate for the interference magnetic compasses received from iron ships' hulls. First patented in the United Kingdom, his binnacle received U.S. patent protection in 1878 as a result of an application that included this model. Thousands of 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:
Gift of Gwinn Owens

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.

Donor Gwinn Owens received this binnacle model from his aunt when his uncle, the yachtsman, collector, and retired B&O Railroad executive W. S. Galloway, died in 1948. The museum’s Division of Medicine and Science holds two other Thomson patent models, a deep-sea sounding apparatus (pat. 210,067, November 19, 1878) and a marine compass that includes improvements to this binnacle design (pat. 232,781, September 28, 1880). In addition, 16 electrical meters made under Thomson’s patents reside in the electricity collections.


William Thomson, Improvement in Mariners’ Compasses, U.S. Patent no. 210,069, November 19, 1878.

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

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