Rare Swiss silver lever poor man’s tourbillon watch Circa 1900

Silver open faced pocket watch by Courvoisier Frères
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A rare Swiss silver open faced one minute tourbillon pocket watch according to Paul Loichot’s Swiss Patent No. 30754, circa 1900. This timepiece features an engine turned case with a central vacant cartouche on the back. The off center silvered hour dial is adorned with Arabic hour numerals, spade hands and a visible tourbillon with an engraved balance bridge. The watch is powered by a gilt full plate movement after Swiss Patent No. 30754, a screw compensation balance and signed Mobilis.
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Diameter: 53 mm
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Weight: 99 g
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Signed: Mobilis 
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Courvoisier Frères
In 1842, the brothers Henri-Louis and Philippe Auguste established their trading business under the name Courvoisier Frères. In 1882, the name was changed to Courvoisier Fils when additional brothers joined the partnership. They specialized in crafting high quality pocket watches and were commissioned by the city of La Chaux-de-Fonds to create a watch for the Prussian King Frederick William IV. This piece was reputed to be the thinnest watch in the world at that time. The innovative tourbillon movement invented by Swiss watchmaker Paul Loichot was registered by the Courvoisier brothers under the trade name Mobilis on July 4th, 1905, with Patent No. 19062. This movement was turned inside the case to make it visible on the dial side and it was a significant achievement in the watchmaking industry.