Gold English Duplex

A fine early 19^th Century English duplex with temperature compensation in a gold consular case.  Full plate gilt keywind fusee movement with signed and numbered gilt dust cover.  Harrison's maintaining power.  Engraved cock with garnet endstone, polished steel regulator, with bi-metallic compensation curb, silver sector index.  Plain three arm gilt balance with blue steel spiral hairspring.  Duplex escapement, ruby locking jewel, large brass escape wheel, pivots with endstones.  White enamel dial with subsidiary seconds, Roman numerals, blue steel seconds hand, serpentine gold hands.  Engine turned 18 carat open face case with ribbed middle, maker's mark "WM" and number corresponding to that on the movement.