Wooden backstaff or Davis quadrant made by John Gilbert on Tower Hill

Made:
1730; 1967 in Tower Hill
maker:
John Gilbert
and
Science Museum, Workshops
Wooden backstaff Gilbert

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Wooden backstaff Gilbert
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Wooden backstaff or Davis quadrant made by John Gilbert on Tower Hill, London, England in 1730 for Thomas Wells. The navigational instrument is fitted with boxwood circular scales (30°arc 0-25, 60°arc 0-65 & 0.5’ divisions), signed ivory insert and decorative stars are stamped on the frame and arcs. The backstaff is fitted with a replacement Flamsteed Lens and a shadow vane made in the Science Museum workshops in 1967 (copied from Inv. No.1908-158).

Details

Category:
Navigation
Object Number:
1884-18
Materials:
wood (unidentified), boxwood, ivory and glass
Measurements:
overall: 650 mm x 360 mm x 130 mm,
type:
back-staff
credit:
Day, J.