Swiss single button chronograph with pulsometer Circa 1926

Rare gold single-button chronograph watch with pulsometer
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A rare Swiss, yellow gold open-faced keyless single-button chronograph watch with pulsometer, circa 1926, manual winding nickel lever movement, 20 jewels, cut bimetallic compensation balance, 18k yellow gold hinged cuvette.
White enamel dial, Arabic numerals, outer track calibrated for 30 pulsations, subsidiary dial for constant seconds.
18k Yellow gold polished case, case, dial, movement and cuvette signed.
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Diameter: 50 mm
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Signed: Vacheron Constantin Geneve Suisse
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The company was founded in 1755 by Jean-Marc Vacheron, an independent watchmaker in Geneva, Switzerland. In 1770, his company created the first complication, and nine years later, he designed the first engine-turned dials. The son of Jean-Marc Vacheron, Abraham, took over the family business in 1785. The company could survive the French Revolution (1789–1799) during this period. Later, in 1810, Jacques-Barthélemy Vacheron, the founder’s grandson, became the company’s head. He was the first to initiate the company’s exports to France and Italy. Later, Jacques-Barthélemy realized he could not handle his business alone. He needed a partner to travel overseas and sell the company’s products. Consequently, in 1819 François Constantin became an associate of Vacheron. The company continued its activity under the name Vacheron and Constantin. François Constantin travelled around the world and marketed watches. Thus he helped the company to open new markets. The main market was North America. The company’s motto (which remains today), “Do better if possible and that is always possible,” first appeared in Constantin’s letter to Jacques-Barthélémy.