Gilbert & Sons Box Sextant

Gilbert & Sons Box Sextant

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Usage conditions apply
A box (or pocket) sextant works like a traditional sextant, but here the mechanism is enclosed in a brass box of about 3 inches diameter. William Jones, a leading instrument maker in London, introduced the form in 1797.
This example has a silvered scale that is graduated every 30 minutes from -3° to +148° and read by vernier with swinging magnifier to single minutes of arc. The "Gilbert & Sons, London" inscription above the magnifier refers to a Navigation Warehouse in London that flourished from 1806 to 1819.
Ref: William Jones, "Description of a New Pocket Box Sextant," in George Adams, Geometrical and Graphical Essays, 2nd ed. by William Jones, (London, 1797), pp. 283-285.
Currently not on view
Object Name
box sextant
date made
early 19th century
Gilbert and Sons
place made
United Kingdom: England, London
overall: 2 3/4 in; 6.985 cm
overall: 1 1/4 in x 2 3/4 in; 3.175 cm x 6.985 cm
ID Number
accession number
catalog number
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Medicine and Science: Physical Sciences
Measuring & Mapping
Data Source
National Museum of American History
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