Important, very early Scottish 18k gold chronometer Circa 1791

Chronometer with rare combination Earnshaw and Arnold by Thomas Reid
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Important, very early Scottish 18 carat gold pair cased chronometer, rare combination Earnshaw and Arnold, circa 1791. Fine gilt English full plate movement, chain and fusee and power maintaining mechanism, spring detent escapement in manner of Earnshaw, compensation balance in OZ shape in manner of John Arnolds patent from 1782, cylindrical gold weights and screwed weights, blued hairspring, diamond endstone. White enamel dial with Roman numerals and blued steel hands, peripheral lever for stopping the movement. Comes with a short gold watch chain with matching gold watch key. Oval engraving on case with a pointed morning star and signature ‘Cave Adsum’ (beware, I watch) to the back of the case, casemaker’s punch AL. Movement signed and numbered.
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Diameter: 58 mm
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Weight: 171 g
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Signed: Thomas Reid Edinburgh N. 1208
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Thomas Reid (1746-1831) apparently belonged to one of the numerous Scottish watchmaker dynasties. About 10 Reids are known from and around Edinburgh, of which Thomas became the best known. The mixture of construction shapes in this chronometer: Arnold OZ balance with flat hairspring and regulator pointer, but Earnshaw spring detent escapement, in addition the outer stop device for the balance shows an experimental watchmaker.