Octant
date: label: Date made
content: 1778
name: label: business owner
content: Condy, Benjamin
label: maker
content: Condy, Benjamin
notes: label: Description
content: An octant measures angles by bringing two images together—that of the sun, for instance, and the horizon—and was used primarily to determine latitude at sea. The form was described by John Hadley in London in 1731 and still in use in the early twentieth century.
label: Description
content: This instrument made during the American Revolution, and there are faint markings on the scale that may read "equality" and "justice." It has a mahogany frame and index arm, and ivory inset. The boxwood scale is graduated every 20 minutes from -5° to +95° and read by ivory vernier to single minutes of arc. There is also a back sight and a back horizon mirror for measuring angles greater than 90°. The radius is 17.75 inches. The "B. CONDY PHILADELPHIA 1778" inscription refers to the maker, Benjamin Condy (d. 1798).
label: Location
content: Currently not on view
place: label: Place Made
content: United States: Pennsylvania, Philadelphia
topic: label: Subject
content: Revolutionary War
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Measuring & Mapping
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1992.0312.01
label: catalog number
content: 1992.0312.01
label: accession number
content: 1992.0312
objectType: label: Object Name
content: octant
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: ivory (overall material)
label: Measurements
content: average spatial: 7.9 cm x 42.1 cm x 51.8 cm; 3 1/8 in x 16 9/16 in x 20 3/8 in
label: Measurements
content: overall: 4 1/2 in x 22 in x 19 1/2 in; 11.43 cm x 55.88 cm x 49.53 cm