Swiss open faced pocket watch with Reaumur thermometer Circa 1835

Gold lever watch with regulator dial attributed to Sylvain Jean-Mairet
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A very fine and slim Swiss gold lever watch with a Réaumur thermometer and regulator dial, circa 1835. This watch features an unsigned damascened movement with lateral lever escapement, a polished steel escape wheel, a bimetallic compensation balance with blued steel arms, and a steel and brass bimetallic thermometer curb with rack and pinion transmission. The white enamel dial includes a sector for the Réaumur thermometer, along with three subsidiary dials for hours with Roman numerals, minutes, and seconds with Arabic numerals. The watch has a gold case with an engine-turned back, milled band, and polished bezel, and is numbered 4292, 2241, and 175. The gold cuvette is engraved with movement details and has apertures for female winding and setting squares, also numbered 92, 2241, and 175.
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Diameter: 44.5 mm
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Signed: No name
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The movement is unable to wind. There is some discolouration visible under certain light on some of the bridges and the barrel, as well as some light surface scratching. The case shows signs of wear, with surface scratching on polished surfaces and some of the engine turning. Overall, it is in good condition. The dial is in good condition, with no visible damage.
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Although unsigned, the watch is likely by Sylvain Mairet, a Swiss watchmaker born in 1805 and raised by his uncle, F.I. Favre-Bulle, who was also a watchmaker. Mairet worked in London from 1831 to 1834 for firms such as Hunt & Roskell and Vulliamy before returning to Switzerland and settling in Le Locle. In 1867, he received a gold medal for his influence on watchmaking in the Canton of Neuchâtel. Mairet was known for his flat watches with thermometers and his lever escapement invented with pointed pallets. For more information on his watches and lever escapements, refer to Jean-Claude Sabrier’s “Frédéric Houriet, The Father of Swiss Chronometry” (pp. 168–172).