Swiss tula silver observatory deck chronometer Circa 1921

Historically interesting observatory deck chronometer
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An historically interesting observatory deck chronometer, made by the apprentice watchmaker Henri Gerber in Switzerland, circa 1919. The numbered open faced case of this watch was crafted from tula silver and has a decorated back lid. The white enamel dial has Arabic five seconds- and Roman hour numerals, a thirty minutes counter at 12 o’clock, a subsidiary seconds dial at 6 o’clock and blued steel hands. The numbered movement has an exquisite anker chronometer escapement and a chronograph.
Case and movement have matching numbers and the cuvette is signed.
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Diameter: 53,5 mm
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Weight: 118 g
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Signed: Henri Gerber, 1921
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Gerber
Henri Gerber was one of the most successful regulators in Neuchâtel and one of the best watchmakers of the 20^th century and became technical director at Omega. The chronometer presented here was entered in the chronometer competition at the Neuchâtel Observatory in 1921.
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Tula silver
Tula or niello silver is black mixture, usually of sulphur, copper, silver, and lead, used as an inlay on engraved or etched metal, especially silver. It is added as a powder or paste, then fired until it melts or at least softens, and flows or is pushed into engraved lines in the metal. It hardens and blackens when cool, and the niello on the flat surface is polished off to show the filled lines in black, contrasting with the polished metal around it. It may also be used with other metalworking techniques to cover larger areas. The metal where niello is to be placed is often roughened to provide a key. In many cases, especially in objects that have been buried underground, where the niello is now lost, the roughened surface indicates that it was once there.