Centre Seconds Calendar Verge

A late 18^th Century French centre seconds verge with date calendar in a nickle open face case.  Full plate gilt fusee movement.  Finely pierced and engraved bridge cock with steel coqueret, plain three arm gilt balance with blue steel spiral hairspring.  Silver regulator dial with blue steel indicator.  Small lateral stop lever under the bezel at three o'clock.  Winding through the signed white enamel dial with centre seconds, small chapter for the time with Arabic numerals and another for the day of the month above, blue steel hands.  Plain open face nickle case with ribbed middle.