Box Sextant

Description:

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.

Date Made: early 19th century

Maker: Gilbert and Sons

Location: Currently not on view

Place Made: United Kingdom: England, London

See more items in: Medicine and Science: Physical Sciences, Navigation, Measuring & Mapping

Exhibition:

Exhibition Location:

Data Source: National Museum of American History

Id Number: PH.318442Accession Number: 234476Catalog Number: 318442

Object Name: box sextant

Measurements: overall: 2 3/4 in; 6.985 cmoverall: 1 1/4 in x 2 3/4 in; 3.175 cm x 6.985 cm

Guid: http://n2t.net/ark:/65665/ng49ca746aa-694a-704b-e053-15f76fa0b4fa

Record Id: nmah_1197879

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