Heavy Swiss gold split seconds chronograph watch Circa 1925

Gold split seconds chronograph by Ulysse Nardin
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A heavy and fine Swiss 18 carat gold open faced split seconds chronograph lever pocket watch, circa 1925. Rhodium plated, jewelled, straight-line lever escapement, screw bimetallic compensation balance, blued steel Breguet balance spring, special fine adjustment, visible chronograph mechanism. Gold hinged cuvette.
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White enamel dial with Black Roman numerals, outer minute and fifths of a second chronograph divisions, Arabic five minute numerals, subsidiary seconds dial at 6, original black steel spade hands. Polished case. The signature of the owner is Hector Zavalia is engraved into the cuvette. This pocket watch is a true collector’s item. Both the dial, movement and cuvette bear the name of the maker.
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Diameter: 54 mm
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Weight: 147 g
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Signed: Ulysse Nardin Locle & Genève
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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 chronograph functions. The chronograph and split seconds hands 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. The split seconds chronograph, in its present form, was first introduced in 1880. Split seconds chronograph wristwatches came on the market circa 1922 by Patek Philippe (the first known wristwatch of this kind was Patek Philippe No. 124824, case No. 235326. This timepiece appeared five years prior to the official release of the split seconds chronograph, making Patek Philippe the first manufacture to create this complication in a wristwatch. As they require a highly complicated and technical mechanism, these watches are desirable, very collectible and extremely difficult to produce accounting for their rarity.
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Reference 0025000