Rare Silver Virgule Repeater

A late 18^th Century Swiss quarter repeating virgule in a silver open face case.  Gilt three quarter plate keywind movement, suspended going barrel, polished steel quarter repeat work above.  Plain cock with polished steel regulator, plain three arm gold balance with blue steel spiral hairspring. Rare virgule escapement, brass escape wheel (two teeth repaired).  Push pendant quarter repeating on two polished steel square section gongs.  Later white enamel dial with Roman and Arabic numerals and an inner chapter of red numerals for 13 to 24 hours, blue steel Breguet hands. Engine turned and engraved silver open face case with ribbed middle, winding through the gilt metal cuvette.