A very rare mid 19th Century Swiss jumping centre seconds lever made for the Chinese market in a silver gilt and enamel open face case. Keywind gilt bar movement with richly engraved plate bearing the Chinese signature for Bovet. The bridges secured by blue steel screws and suspended going barrel with blue steel stop work also richly engraved. Sector shaped cock, polished steel regulator. Polished steel three arm balance with three blue steel affixes, blue steel spiral hairspring. Very rare lever escapement designed to allow the centre seconds hand to beat second. White enamel centre seconds dial, slender Roman numerals, blue steel hands. Silver gilt open face case, the bezels set with a row of large split pearls. The back depicting a bird of paradise in a mountainous landscape on a pale blue ground. Silver gilt oval pendant and bow set with split pearls. Wound and set through the glazed sprung cuvette with engraved gilt bezel. The inside of the back cover with Chinese signature of Bovet and number matching that stamped on the movement. An attractive watch made for the Chinese market with a very rare form of escapement in excellent overall condition. We have not previously seen this escapement. Its primary purpose is to enable the seconds hand to move forward one second at a time which was a feature desired by Chinese customers. This was normally achieved by use of a crab tooth duplex, also known as a Chinese Duplex. This lever escapement is more robust and appears to give a small amount of impulse in the resting phase while at the same time reducing friction. The steel escape wheel has twelve upright teeth arranged in pairs and additionally a six toothed brass wheel mounted on its arbor. This brass wheel imparts the main impulse to the balance via a steel lever at right angles on the lever. The first of one of the pairs of the two steel teeth then falls against a curved sapphire pallet at the centre of the lever. On the return swing of the balance this tooth is released onto a second curved sapphire pallet allowing the other raised steel tooth to engage with the first sapphire pallet. During this resting phase the second hand does not move perceptibly. When the second steel tooth is released impulse is again given to the balance by the brass when and the hand jumps forward by one second. An ingenious and somewhat complicated solution to providing beating seconds which works surprisingly well.