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Box Sextant
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Box Sextant

A box (or pocket) sextant works on the same principle as 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. The German explorer, Alexander von Humboldt, had an early example that he described as being "very useful for travelers when forced in a boat to lay down the sinuosities of a river, or take angles on horseback without dismounting." By the mid-nineteenth century, box sextants were said to be particularly useful for military reconnaissance. They were still available in the early twentieth century.

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.

Alexander von Humboldt, Personal Narrative of Travels to the Equinoctial Regions of America During the Years 1799-1804 (London, 1822).


Adie Box Sextant
Blunt Box Sextant
Gilbert Box Sextant
Hughes Box Sextant
Keuffel & Esser Box Sextant
Warren-Knight Box Sextant