Isaac Grasset & Cie. à Genève, Movement No. 441, Case No. 441, 51 mm, 73 g, circa 1880

A gentleman's very rare, almost as new pocket watch with patented crown-spring wind mechanism by Isaac Grasset
Case: silver, glazed movement. Dial: enamel. Movm.: bridge movement, crown wind via tension spring coiling up the stem, "Patent 5019 14528", screw compensation balance.

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.
Lit.: Antiquorum Geneva