A mid 19^th Century centre seconds duplex made for the Chinese market in a pearl set silver gilt and enamelled open face case.  Keywind gilt bar movement with richly engraved bridges and suspended going barrel, blue steel stop work and screws. Engraved sector cock with garnet endstone, polished steel regulator.  Five arm polished steel balance.  Duplex escapement, brass escape wheel, pivots with endstones.   White enamel dial with centre seconds, slender Roman numerals, gilt hands.  Unusual silver gilt open face case, the front bezel, front of the oval pendant and bow set with split pearls.  On the reverse the bezel, pendant and bow are decorated with blue champleve enamel.  The back of a finely painted polychrome enamel portrait of a young lady on a blue background.  Wound and set through the sprung gilt cuvette.