Swiss silver watch early tourbillon in original sales box Circa 1905

Pocket watch with a tourbillon patented movement
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A tourbillon “Mobilis” pocket watch probably one of the earliest made, by the Courvoisier Frères in la Chaux-de-Fonds, Switzerland, circa 1905. The case of this watch is crafted from silver and the face has a decentralised dial with Arabic hour numerals and a view to the patented tourbillon and the lever escapement.
Case and movement have matching numbers.
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Diameter: 54 mm
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Weight: 104 g
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Signed:
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The patent was filed in 1905 and all tourbillons made according to this patent have four up to six digit serial numbers. The present tourbillon is one of the earliest, possibly the earliest “Mobilis” tourbillon still in existence from the 1^st year of manufacture.