French gold repeating à toc et à tac verge watch Circa 1780

Gold quarter repeater by Rengaw
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A rare “à toc et à tact” quarter repeating verge pocket watch with original carnelian winding key, circa 1780. 
An 18 carat gold pocket watch, open work decoration around the edge, rear bell,  ename dial, roman numerals,  full plate movement, chain/fusee, two hammers, pierced balance bridge with the initials of the watchmaster “JGW”, three-arm brass balance.
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Diameter: 43 mm
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Weight: 76 g
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Signed:  Rengaw   Paris
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This clock was produced in Friedberg; Johann Georg Wagner, however, spelled his name backwards (Rengaw) and added the designation “Paris” to his signature like a French maker would,
to achieve a higher sales price.
In addition to Wagner, there were another 24 makers in Friedberg at the time whose names (spelled backwards) can be found with a fake designation such as London, Paris or Augsburg.
Johann Georg Wagner was born in Mulhouse in 1714; he married in Friedberg in 1746 and died there in 1791.