Swiss gold minute repeating lever dress watch Circa 1905

Gold lady’s watch made for Tiffany’s
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A very fine Swiss, 18K gold, keyless minute-repeating dress watch, circa 1905. Split-seconds chronograph and instantaneous 60- minute register, made for Tiffany’s.
A polished case, bolt to lock the chronograph at 11 o’clock. Hinged gold cuvette. White enamel dial, Breguet numerals, outer minute track, outermost chronograph divisions divided into fifths, red-painted five minutes/seconds numerals, 60-minute register at 12, subsidiary seconds at 6. Blued steel spade hands. Movement, 38 jewels, straight-line lever escapement, cut-bimetallic compensation balance with blued steel Breguet balance spring, swanneck micrometre regulator, Koehn patented chronograph mechanism, repeating on gongs activated by a slide on the band. Dial, case and movement signed by the retailer.
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Diameter: 45 mm
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Signed: Eduard Koehn  Geneve
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On November 15, 1902, Koehn was granted a patent for an instantaneous minute register in chronograph mechanisms. He implemented it in this watch. Interestingly, the serial numbers of the series of watches he destined for Tiffany coincide with the series of numbers destined by Patek Philippe for Tiffany, which has caused some confusion. This is a rare case, in which the maker may be identified without a doubt. Edouard Koehn Was the son of a watchmaker to the Court of Saxe-Weimar. After his schooling, he worked for Patek Philippe. He progressed rapidly in the firm, becoming a partner at the age of thirty-five. In 1891, Koehn retired from Patek Philippe and bought the H.R. Ekegrèn company, retaining Mr Ekegrèn as chief of manufacture. To Ekegrèn’s calibres, Koehn added new, thinner models and many complicated pieces.