Dutch silver and rock crystal shell-shaped pendant watch Circa 1700

Rock crystal shell-shaped by Jacob Ratsma
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A large Dutch silver and rock crystal shell-shaped pendant watch with date, circa 1700. Circular brass full plate movement with chain and fusee, a verge escapement and three arm brass balance. Silver champlevé dial with Roman hours, a minute track with Arabic five minute numerals, a blued center with applied silver ornaments, an aperture for indication of the date and finely cut hands. The case with an engraved frame and fluted rock crystal on both sides. Dial and movement signed.
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Dimensions: 55 x 91 x 43 mm
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Weight: 203 g
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Signed: Ratsma Amsterdam
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Jacob Harmens Ratsma came from a large family of smiths and watch- and clockmakers. He donated a town clock to Harlingen, Friesland, in exchange for the position of town clockmaker for himself and his descendants. Ratsma died in Harlingen in 1758 at the age of 85. His son Tjeert Jacobsz Ratsma (1696-1781) was particularly successful as a maker of timepieces. He went to Amsterdam as a young man to learn the trade and after his training he returned to Harlingen as a master watch and clockmaker.