Gold Centre Seconds Lever with up/down Dial

A late 19^th Century English centre seconds lever with power reserve indication in a gold open face case.   Gilt three quarter plate keyless movement with going barrel.  Engraved cock with polished steel regulator, compensation balance with blue steel overcoil hairspring.  English table roller lever escapement, screwed in jewelling, escape and lever pivots with endstones.  Signed and numbered white enamel dial with centre seconds, subsidiary at six o'clock showing the state of winding.  Roman numerals, blue steel centre seconds hand, gilt hands.  Substantial plain 18 carat open face case with slide in the band to stop the balance.  Plain gold cuvette, maker's mark "S.Y", flat crystal glass.