Swiss pocket watch with patented wind mechanism Circa 1880

Niello silver open faced pocket watch
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A very rare Swiss gentleman’s pocket watch in a rare niello-silver case with patented crown-spring wind mechanism by Isaac Grasset, circa 1880.
Niello silver case decorated with two children and flowers and with a glazed movement. Signed enamel dial with Arabic numerals, auxiliary seconds and blued spade hands. Bridge movement, crown wind via tension spring coiling up the stem, frosted, gilt, signed, “Patent 5019 14528”, screw compensation balance, blued balance spring.
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Diameter: 52 mm
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Weight: 79 g
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Signed: Isaac Grasset & Cie. Genève
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The Swiss Patent 5019 and 14528 by Isaac Grasset In the early 1880’s Isaac Grasset designed an interesting alternative power source in the form of a spring coiling up the stem (Swiss patent No. 120, later improved in No. 5019). In 1897 he patented a stem winding and setting mechanism for the arrangement, as found in this watch (Swiss patent No. 14528). He also patented an interesting constant force escapement and applied it to his design. To date, no example of this is known.