Accession No

1459

Brief Description

box sextant, by W. and S. Jones, English, 1800 (c)

Origin

England; London; Holborn

Maker

W. and S. Jones

Class

surveying

Earliest Date

1800

Latest Date

1800

Inscription Date

Material

metal (brass, white metal, oxidized brass); glass

Dimensions

diameter 69mm; height 38mm

Special Collection

Provenance

Inscription

‘W & S. Jones, Holborn London ‘ (outside scale)

Description Notes

Box sextant, by W. and S. Jones, English, 1800 (c).

Circular brass box with screw-fit lid. Aperture fitted with sliding telescope. Index mirror rotated by milled screw operating rack and pinion. Vernier arm fixed on index mirror axis, measuring rotation on silvered scale. Scale divided 0 - 130 numbered by 10 subdivided to 30’. Read by vernier to 1’. Magnifying glass, which is held centrally in clip when not in use. Adjusting square for horizon mirror. Sliding cover for telescope. Lever operates 2 dark glasses for sighting of the sun. Lid can be screwed onto base for use as a hand-grip. Engraved table on lid (for function see file)

Condition good; complete

References

Events