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Description: | 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). | License: | http://creativecommons.org/licenses/by-nc-sa/2.5/ | Subjects: | back-staff | Temporal: | 1730 | Source: | Science Museum | Creator: | Gilbert, John | Identifier: | 1884-18 | Go to resource |
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