Rare French silver double keyless chronograph watch Circa 1900

Open faced chronograph with phonotelemetre and tachymeter
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An exceptional and distinctive French silver double open faced keyless chronograph watch featuring a Thouvenin phonotelemetre/tachymeter, circa 1900. This watch features a movement with a lever escapement and a compensation balance. Two dials: front – white enamel with Roman numerals and concentric outer distance scales calibrated for kilometres, and a central indicator hand; second – white enamel adorned with bands of pink and blue, calibrated for a 15 second chronograph, with a subsidiary minute register and concentric scales for a telemeter and tachymeter, plus an outer ring calibrated for 15 seconds. The front dial is signed A. Francois, Paris and marked Curvimetre International. The watch has a silver case with plain bezels, a small compass set within the winding crown, a numbered bezel, and a knurled wheel on the band for adjusting the distance gauge hand to the front dial.
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Diameter: 52 mm
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Signed: A. Francois, Paris
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Movement is running intermittently. The chronograph operates for short periods, and the minute register functions, but the chronograph often becomes stuck. The minute register resets to 2 instead of 0. The dials are in good condition, with only slight chipping at the edge of the chronograph dial between the blue 1 and 2, which the bezel covers. The case is tarnished and dirty, featuring a small indentation on the band.
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Tachymeter 
An instrument used to measure speed. In watchmaking, it refers to a chronograph or sports counter featuring a scale that indicates speed in kilometres per hour (kph) or another unit.
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Phonotelemeter
A device used to estimate the distance of firearms in action by measuring the interval between the flash and the arrival of the sound from the discharge.