Very rare Swiss gold double-sided mystery watch Circa 1890

Mystery watch in gold and with owner’s name, very rare
–
A unique example of an unusual gold pocket watch with hands moved by rotating glass discs and lavishly engraved bezel with blue and red signature Jose Pietranera, circa 1890. Only a few watches of this type were produced in gold.
The gilt cylinder movement relegated to the crescent shaped portion of the watch between the glass dial and the pendant. Keyless with going barrel, the crown turning in one direction only. Small plain three arm gilt balance with blue steel spiral hairspring, polished steel regulator. Polished steel cylinder and steel escape wheel. Glass dial with gilt Arabic numerals and minute ring, decorative engraved gold masks.
The gold spade hands are driven by a glass disc which has a toothed brass wheel attached to its outer edge engaging the train. The miniature motion work for the hands is set between another glass disc and the dial. There is no provision to set the hands apart from moving them manually, which is common in these watches. Engraved gold case glazed back and front. Rectangular button in the band to release the sprung front cover, gold crown and bow.
–
Diameter: 53 mm
–
Weight: 98 g
–
Signed: A.S. & F. Mystérieuse Breveté, S.G.D.G.
–
Armand Schwob & Frère, La Chaux-de-Fonds, Switzerland, watch manufacturers.
Holders of two Swiss Patents, 2445 and 2526, in 1881, and English Patent No 9865 granted in July 1888: Transparent Watches. Examples are usually found in silver cases and occasionally in silver-gilt. Only a few watches of this type were produced in gold. It is also unusual bearing a name that may be Forits Spanish market retailer or, perhaps, that of its original owner – the enamelling is beautifully done.