Swiss 18 carat gold open faced jumping hour watch Circa 1927

Gold wandering hour watch
–
A Swiss 18 carat gold open faced jumping hour pocket watch made by Breguet, circa 1927. The manual winding movement is jewelled and has a lever escapement. Silvered dial with a rotating center featuring a guilloché arrow for the minute indication, an aperture for the digital hours, outer minute divisions and outermost Arabic five minute numerals. The plain case with a snap on back. Dial, case and movement signed and numbered. Comes with an Extract from the Archives confirming that this watch, No. 1740, was sold to Mr Migal on November 15, 1927, for 4,100 francs.
–
Diameter: 46 mm
–
Weight: 57.5 g
–
Signed: Breguet Breveté S.G.D.G
–
During the 1920s and 1930s, jump hour watches were not popular. Their production was low and is therefore today considered quite rare. 
–
Jump hour models substitute the hour hand with an underdial hour disk with numerals 1 to 12. When the minutes advance from 59 to 0 at the beginning of a new hour, the hour disk rotates one increment so the new hour is displayed through the aperture. Rather than progressing over the course of 60 minutes as in the analogue display, the hour indication ‘jumps’ at the last minute of the hour, as suggested by the description.
–
In 1926, Breguet patented the design of a watch with jumping hours and a revolving dial. With this new design, the central portion of the dial revolves fully every hour, so that the minutes are indicated by the arrow. As the aperture for hour is located at the tip of the arrow, and thus circumnavigates the dial, this feature is known as a ‘wandering’ hour.