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Box Sextant

Catalogue number:
PH*318442

Inscriptions:
"Gilbert & Sons, London"

Dimensions:
diameter 2.75 inches

Discussion:
This has a silvered scale that is graduated every 30 minutes from -3^o to +148^o and read by vernier with swinging magnifier to single minutes of arc. Gilbert & Sons operated a Navigation Warehouse in London from 1806 to 1819.

Ref: Gloria Clifton, Directory of British Scientific Instrument Makers 1550-1851 (London, 1995), p. 113.

Further Information:

Box Sextant