German 18K gold open faced triple calendar lever Circa 1886

Gold triple calendar by A. Lange & Söhne
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A Glashütte rarity, 18 carat gold open faced pocket watch with a triple calendar according to the Fleischhauer patent, circa 1886. Moritz Grossmann/A. Lange precision lever movement of best quality 1A with screwed gold chatons, gold lever and gold escape wheel. Enamel dial, two rotating rings with day and date indication and aperture for the month, filigree Louis XV gold hands, subsidiary seconds. Plain case, monogram to the back, dome inscribed ‘PATENT’.  The Fleischauer triple calendar movements, manufactured by Moritz Grossmann and taken over and sold by A. Lange & Söhne after his death, can be characterized as follows: Date indications by numerals and letter rings outside the dial and connected to the gear. Winding, time and date setting in the typical manner of Grossmann with a large symmetric rocker, which can be used by two pushers on the right and left of the pendant. Dial and movement signed, case and movement with matching numbers. Comes original box and extract from the archives.
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Diameter: 52 mm
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Weight: 120 g
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Signed: A. Lange & Söhne Glashütte B/Dresden 19074
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Otto Fleischhauer in Berlin had the idea of a calendar watch and sent vague ideas with sketches to the Berlin Patent Office on July 15th, 1883. These sketches did not contain any ideas about required parts or proportions. In order to realize the idea of the calendar watch, a completely new construction was necessary. So Fleischhauer asked Moritz Grossmann to realize his ideas and he re-designed the whole watch type. His ideas were then confirmed by drawings of this watch. In 1884, Fleischhauer patented his idea in England as well, but offered the patent for sale just one year later, immediately after Grossmann’s death. According to Glashütte museum documents, all 20 watches that Grossmann had already manufactured and not yet sold, were exclusively taken over and sold by the Lange & Söhne company. All watches got the signature of the Lange & Söhne company on the dial and movement. Excluded from this is the first watch with the number 6141 and the other watches of the first small series with the numbers 8262, 8263, 8264 and 8265, which have no signature on the dial and are not included in Huber’s ‘Langeliste’ of 1999.