Allen Sextant

Description
The "J. Allan, Baltimore" signature on this sextant refers to John Allen (b. 1786), an "optician and mathematical instrument maker" who appears in Baltimore city directories from 1810 to 1819. He was the son of James Allen, a noted instrument maker in London. And he boasted: "As all Instruments sold by me are graduated by my father’s improved self-correcting engine, for which the Society of Arts voted him their Gold Medal, on the 19th of May, 1810–they are warranted and will be kept in repair one year, gratis."
This sextant has a brass frame. The silvered scale is graduated every 20 minutes from -5° to +145° and read by vernier with tangent screw and magnifier to 1 second of arc. It belonged to the College of the Holy Cross in Worcester, Massachusetts.
Ref: Deborah J. Warner, "American Octants and Sextants: The Early Years," Rittenhouse 3 (1989): 86-112, on 89.
John Allen advertisement in the American & Commercial Daily Advertiser (June 12, 1816).
Location
Currently not on view
Object Name
sextant
date made
1810-1819
maker
Allen, John
Measurements
radius: 7 in; 17.78 cm
place made
United States: Maryland, Baltimore
ID Number
PH*326932
accession number
264083
catalog number
326932
subject
Measuring & Mapping
Navigation
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Medicine and Science: Physical Sciences
Navigation
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
College of the Holy Cross
Additional Media

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