Swiss gunmetal pocket chronograph with tachometer Circa 1906

Gunmetal double-dialled pocket watch
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A rare Swiss gunmetal and copper-gilt keyless double-dialled pocket watch, circa 1906. With a chronograph, semi-instantaneous 15-minute register and two tachometer scales, one being Omega’s patented (CH) scale. Glazed on both sides with gilt bezels, bow hinges and crown. White enamel dial, upright dauphine 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 250 km/h. Gold spade hands.
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The other side with white enamel chapter ring printed with a 1/5th second timing scale and tachymeter graduated from 7-180 kph mm. A frosted gilt movement, 3/4-plate, 15 jewels, straight-line lever escapement, cut bimetallic compensation balance with Breguet balance spring, swan-neck micrometre regulator, the chronograph work is set on a separate plate fastened to the back plate. Dial signed. This watch is sold with a box and certificate of authenticity.
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Diameter: 57.5 mm
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Signed: Omega Cadran Brevete S.G.D.G.  Swiss