Swiss gold repeating split seconds chronograph Circa 1910

Minute repeating chronograph by Audemars Piguet
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A very fine Swiss 18 carat gold open faced minute repeating split seconds chronograph keyless lever pocket watch with progressive 30 minute register, circa 1910. Rhodium plated movement, 33 jewels, wolf’s tooth winding, straight-line lever escapement, cut bimetallic compensation balance adjusted, blued steel Breguet balance spring, swan neck micrometer regulator, visible chronograph work, repeating on gongs activated by a slide on the band. Gold hinged cuvette. White enamel dial with painted black Breguet numerals, outer minute/seconds, 1/5th seconds divisions with red five minute numerals, subsidiary dials for the seconds and progressive 30 minute register, repaired original black spade hands. Solid, polished case. Dial and movement signed, case numbered.
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Diameter: 47 mm
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Signed: Audemars Piguet & Co Geneva
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A split seconds chronograph or ‘rattrapante’ is a type of chronograph watch with two coaxial superimposed centre seconds hands that are controlled by two push buttons. One push button controls the split seconds hand to stop or join the chronograph hand. The other push buttons control both hands and all the functions of the chronograph. The chronograph hand and the split seconds hand are used for timing several events that start simultaneously, but are of different durations. To operate the split seconds chronograph, both hands are started and remain superimposed. Then at the end of the first duration, the split seconds hand can be stopped while the chronograph hand continues to move. The duration of the first event can be read. After recording, the split seconds hand can be released to instantly move and join the chronograph hand, synchronizing with it and thus being ready for another recording. At the end of each event the hands then can be stopped and returned to zero.