Swiss 18k gold watch with power reserve indicator Circa 1915

Gold watch with patented affix auxiliary compensation 
–
A fine and rare 18K yellow gold Swiss keyless pocket watch, circa 1915. With patented affix auxiliary compensation and power reserve indication. Patented Auxilliary Compensation – Power Reserve Indication by Paul Ditisheim, Solvil.
A polished bassine, engine-turned back. Hinged gold cuvette.

White enamel dial with Arabic numerals, outer minute track, subsidiary seconds at 6, power reserve indication at 12. Blued steel épée hands. A rhodium-plated movement, Geneva striping decoration, 16 jewels, straight-line lever escapement, gold fork, monometallic balance with two applied bimetallic strips and four adjustments, Breguet balance spring, index regulator. Movement and case signed.
–
Diameter: 49 mm
–
Signed: Paul Ditisheim, Solvil à Genève
–
Paul Ditisheim designed and patented small bimetallic straps affixed to monometallic balances. Watches equipped with them are today very rare. Solvil was founded early in 1920 to exploit Ditisheim’s invention, which was offered as an alternative to precision watches fitted with the more expensive Guillaume balances. The current lot incorporates a special type of balance invented by renowned Swiss chronometer-maker Paul Ditisheim (1868-1945). He attached two small bimetallic blades, known as an affix, to the rim of a monometallic balance. This affix carried several tiny screws, which could be switched around for fine adjustment of temperature compensation. For this reason, this type of balance is known as the affix balance. Ditisheim was also known as a tireless researcher, publishing several works on the influence of atmospheric pressure and magnetic fields on the performance of chronometers. Apart from his work leading to advances in temperature compensation, he was also a prominent figure in the introduction of modern watch oils.