French gunmetal military 24 hour navigation watch Circa 1905

A navigation watch with day and night display
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A, probably, military 24 hour navigation watch with a solar compass and day and night display, made by Émile Lainé in Lille, France, circa 1905. This watch features a numbered case crafted from burnished iron and an extremely unusual and perfectly preserved enamel navigation dial that features a two colour day and night marking, cardinal points, a 24 hour scale, an outer track with Arabic 5 minute numerals, a subsidiary seconds dial at 24 o’clock, has markings in red for South, Ouest, Nord and Est, is marked “Boussole Solaire” (solar compass) Breveteé S.G.D.G. (patented without government guarantee). The movement is equipped with a cylinder escapement.
The dial is signed.
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Diameter: 51 mm
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Signed: Émile Lainé, Lille
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Laine
Émile Lainé was a French watchmaker based in Lille at the turn of the 20^th century, best known for his invention of the Boussole Solaire (Solar Compass) watch around 1905. This specialised timepiece was designed as a military grade navigation tool, combining a traditional mechanical watch with a sun based compass system for use in the field.