Italian silver pair cased astronomical pocket watch Circa 1680

Silver pocket watch by Jean Le Maire
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A rare and interesting Italian silver pair cased astronomical watch with straight hairspring, circa 1680. The watch has a gilded full plate movement with a verge escapement, a blued steel wheel, and a click set-up. It also features a decoratively pierced and engraved screwed-on balance cock, a plain flat steel three-arm balance, and a Barrow-type worm-form regulator mounted to the cock’s foot with a corresponding indication scale. Additionally, it includes a fusee and chain, turned baluster pillars, and is signed by Jean Le Maire, à Rome. The dial showcases a gilded, silver chapter ring with Roman numerals and half-hour divisions, along with a gilt annular carrying a blued steel pointer indicating the date on the outer silver ring, a central gilded disc engraved with scrolling foliage and two flowers, and a blued steel pointer indicating the moon age. Furthermore, there is an aperture for moon phases indicated via a silver disc and a blued steel hand. The watch is housed in a plain silver inner case with a shuttered winding aperture and a plain ring pendant, enclosed in a shagreen-covered outer case.
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Diameter: 53 mm
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Signed: Jean Le Maire à Rome
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The watch movement features an early and unique application of a hairspring. One end of a straight spring is connected to the balance, while the other end is held between two curb pins on the balance cock. The watch is regulated by adjusting the length of the spring using a worm screw, which moves a slide along the spring to change its length. The slide corresponds to a scale engraved on the cock’s foot, opposite the worm.
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The dial is attractive with some light scuffs and scratches and is secured by two screws on the chapter ring. The silver inner case has light depressions on the band as expected. The outer shagreen case was originally covered with piqué work, and the fine patterned holes for the pins are visible on the inside back and the underside of the bezel. The movement is running at the time of cataloguing and appears to be in clean condition, with some light scratching on the backplate.