Liquid Compass
date: label: date made
content: 1863
name: label: maker
content: Ritchie, Edward S.
notes: label: Description
content: Edward S. Ritchie of Boston developed the first successful liquid compass in 1862 and introduced several improvements over the course of the next two decades. This is the model for Ritchie’s third patent (#38,126) of April 7, 1863. Three features should be noted. The magnetic needle is enclosed in an air-tight metallic case and, with the card, is very nearly the same specific gravity as the liquid. The needle float is in the form of crossed cylinders. An elastic chamber compensates for the unequal expansion of the liquid and the bowl.
label: Description
content: The U.S. Patent Office transferred this compass to the Smithsonian in 1926. An attached Patent Office tag reads: "No. 38,126 E. S. Ritchie. Mariner’s Compass. Patented Apl 7th 1863."
label: Description
content: Ref: "Improved Ship’s Compass," <i>Scientific American</i> 11 (1864): 52.
label: Description
content: "The Liquid Compass," <i>Journal of the Franklin Institute</i> 85 (1868): 218-221.
label: Location
content: Currently not on view
place: label: place made
content: United States: Massachusetts, Boston
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
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.308535
label: catalog number
content: 308535
label: patent number
content: 38,126
label: accession number
content: 89797
objectType: label: Object Name
content: Nautical Compass (Liquid)
label: Object Type
content: Patent Model
physicalDescription: label: Measurements
content: overall: 3 5/8 in x 5 1/4 in x 7 1/4 in; 9.2075 cm x 13.335 cm x 18.415 cm
label: Measurements
content: overall: 3 1/2 in x 7 1/2 in x 5 1/4 in; 8.89 cm x 19.05 cm x 13.335 cm