Dry Card Compass with Binnacle
date: label: date made
content: 1880
name: label: maker
content: J. White
notes: label: Description
content: This is the model that accompanied William Thomson's 1880 application for an American patent for an improved mariner’s compass. The U.S. Patent Office transferred it to the Smithsonian in 1926. This compass has eight short magnetic needles suspended by threads. The card is relatively large, but its central part is cut away. The binnacle has large iron balls designed to compensate for the magnetism of the ship itself. Thomson claimed that his design offered five advantages: greater steadiness of the compass card and diminished wear of the bearings; greater steadiness of the compass in vessels of war during gun-fire; improved method of applying correctors for the semicircular error; improved auxiliary instruments to correct the heeling error; and improved compass card. The inscription reads "SIR WM THOMSON’S PATENT. J. WHITE, MAKER GLASGOW."
label: Description
content: Ref: W. Thomson, "Mariner's Compass," U.S. Patent #232,718.
label: Location
content: Currently not on view
place: label: place made
content: United Kingdom: Scotland, Glasgow
setName: label: See more items in
content: Medicine and Science: Physical Sciences
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content: Navigation
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content: Measuring & Mapping
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.308557
label: accession number
content: 89797
label: catalog number
content: 308557
label: patent number
content: 232,781
objectType: label: Object Name
content: Nautical Compass (Dry Card)
label: Object Type
content: Patent Model
physicalDescription: label: Measurements
content: overall: 30.5 cm x 18.5 cm x 15.5 cm; 12 in x 7 5/16 in x 6 1/8 in
label: Measurements
content: overall: 12 1/2 in x 8 in x 7 in; 31.75 cm x 20.32 cm x 17.78 cm