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 probably belonged to Llewellyn N. Edwards (1874-1952), a structural engineer. It has a silvered scale graduated every 30 minutes from -5° to +150° and read by vernier with swinging magnifier to single minutes of arc. The inscription reads "WARREN-KNIGHT CO. PHILADELPHIA. MADE IN ENGLAND." Warren-Knight began in business in 1912.

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: after 1912

Dealer: Warren-Knight Co.

Location: Currently not on view

Place Made: United Kingdom: England

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

Exhibition:

Exhibition Location:

Credit Line: Bequest of Carolyn H. Edwards

Data Source: National Museum of American History

Id Number: PH.333796Catalog Number: 333796Accession Number: 296611

Object Name: box sextant

Measurements: overall: 3 1/4 in; 8.255 cmoverall: 4 3/8 in x 4 in x 2 in; 11.1125 cm x 10.16 cm x 5.08 cm

Guid: http://n2t.net/ark:/65665/ng49ca746aa-5b47-704b-e053-15f76fa0b4fa

Record Id: nmah_1197882

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