Swiss chronotachymetre pocket watch with chronograph Circa 1903

Silver pocket watch with chronograph
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A fine and rare silver keyless pocket watch with chronograph 15-minute register and Omega’s patented tachometer. Made by Omega, Bienne Switzerland Circa 1903. Four body, bassine and polished case.
White enamel dial with radial Roman numerals, outer minute seconds divisions divided into fifths, sunk 15-minute register, the first five minutes in different colours corresponding to the colours of the outermost tachometer scale, running from 10.5 to 180 km/h and blued steel spade hands.
M. Frosted gilt and 3/4-plate movement with 15 jewels, straight-line lever escapement, cut bimetallic compensation balance with Breguet balance spring, swan-neck micrometre regulator and the chronograph work is set on a separate plate fastened to the back plate.
Dial and case signed.
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Diameter: 59 mm
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Signed: Ω Omega Cadran Brevette S.G.D.G. 
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The present watch was called a ‘Chronotachymetre’ by Omega. This term refers to the dial with its extended tachymeter scale capable of timing speeds both slow, 10.5 kph, to speeds that were not yet achieved by the fastest cars of the day, 180kph. Most tachometers from this period that were graduated to such high numbers were marked UPH as they were more commonly used for production timing. At the time this watch was made such speeds were encountered only in scientific experiments as aviation was in its infancy. This type of dial could be found on both wrist and pocket chronometers from this period. LOB L = Lépine O = Omega calibre B = 15-17 jewels, Breguet balance spring adjusted to less than one minute per day.