J. White Dry Card Compass with Binnacle

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."
Ref: W. Thomson, "Mariner's Compass," U.S. Patent #232,718.
Currently not on view
Object Name
dry card compass
date made
J. White
overall: 30.5 cm x 18.5 cm x 15.5 cm; 12 in x 7 5/16 in x 6 1/8 in
place made
United Kingdom: Scotland, Glasgow
ID Number
accession number
catalog number
patent number
Measuring & Mapping
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.