Swiss gold open faced lever watch by Patek Circa 1915

A fine Swiss gold open faced keyless lever pocket watch , circa 1915. Chronometro Gondolo. manual winding nickel lever movement, cut bimetallic balance. Hinged engraved gold cuvette. White enamel dial, Roman numerals, red Arabic outer minute track, subsidiary seconds and dial signed ‘Dr Eduardo Leite Velloso’. 18 Carat gold guilloché case, case back with centred monogram. Case, cuvette and movement signed and numbered, dial signed. With an Extract from the Archives confirming sale in 1915.