English watch with tortoiseshell magnifying glass painting Circa 1760

Large 3 fold case verge watch with beautiful enamel dial
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A large 3 fold case verge watch with tortoiseshell magnifying glass painting, made by Williamson in London, Great Britain, circa 1760. It has a very rare 3 fold relief case made of silver depicting a beetle surrounded by foliage, an exceptionally beautiful enamel dial with blue numerals and blue Longines signature under red glass with colourless cartridges and steel hands and a Longines lever movement.
Dust cover, dial and movement signed.
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Diameter: 52 mm
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Weight: 101 g
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Signed: Williamson, London