Swiss silver open faced military pocket watch Circa 1918

Silver watch made for the U.S. Corps of Engineers
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A Swiss silver military keyless winding pocket watch by International Watch Co. in Geneva, circa 1918. Made for the U.S. Corps of Engineers, caseback engraved with the mention Property of/Corps of Engineers/U.S.A./No. 6319. The case is made by Huguenin Frères, Le Locle. White enamel dial with suspended luminescent Arabic hour numerals, an outer minute track, subsidiary seconds at 6 o’clock and blued steel skeleton hands. A gilded brass movement with going barrel, gold screwed chatons, straight line lever escapement, cut bimetallic compensated balance with gold poising screws and blued steel hairspring with terminal curve, polished steel index regulator with swan neck spring and a micrometric screw. The dial, case and movement are signed.
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Diameter: 53 mm
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Weight: 97 g
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Signed: International Watch Co.  Geneva
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Accompanied by a copy of the invention patent.
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Movement based on the Swiss invention patent No. 55 231, delivered on March 28, 1911, to Uhrenfabrik von J. Rauschenbach’s Erben, vormals International Watch Co., Schaffhausen, for a “Zifferblattbefestigungsvorrichtung” (Dial fixing device).
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Corps of Engineers, U.S.A.
In 1918, several Swiss horological manufacturers (Vacheron Constantin, IWC, Ulysse Nardin, etc.) started the production of pocket watches, with or without chronograph, intended for the “Corps of Engineers” of the United States Army. Following the U.S. entry into the war in 1917, the Americans set up a purchasing office for equipment for their expeditionary forces, The American Expeditionary Forces, which ordered several thousand watches until 1920. Especially designed for engineers, they are made of stainless steel, withstand temperature differences and have luminescent numerals and hands.