Quarter Repeating Chronometer by Ganthony

A large early 19^th Century quarter repeating chronometer by Ganthony in a purpose made silver open face case.  Full plate gilt keywind fusee movement, barrel under a bridge with blue steel setup ratchet and spring.  Harrison's maintaining power.  Plain cock with diamond endstone in a polished steel setting, polished steel regulator with bimetallic temperature compensation curb, gilt index on the plate.  Plain three arm gold balance with deep rim, blue steel spiral hairspring.  Screwed in jewelling.  Earnshaw type spring detent escapement, jewelled locking and discharge, escape pivots with endstones.  Push pendant quarter repeating on two blue steel gongs. White enamel dial with subsidiary seconds, Roman numerals, blue steel seconds hand, gold hands. Substantial purpose made plain silver open face case hallmarked London 1873.  Silver push pendant and bow, wound through the plain silver cuvette, maker's mark "JW & Co" in a rectangle, number corresponding to that on the movement.