21 - ED. JAEGER “Split-Seconds” No. 9465. Circa 1910

ED. JAEGER “Split-Seconds” No. 9465. Circa 1910 18k gold (750) pocket watch with split-seconds chronograph Case: round, push-button back, master’s hallmark, back inscribed with the initials “ERB,” numbered on the inside Dial: patinated with Roman numerals, two vertical sub-dials, stylized blued steel hands, outer minute track graduated in 1/5th of a second, signed “E.D. JAEGER PARIS” Movement: mechanical with crown winding, lever escapement, balance spring with fast-and-slow adjustment, signed “E.D. JAEGER” Diameter: 48 mm - Gross weight: 62.6 g We thank the Jaeger-LeCoultre Manufacture for the information provided from their archives: “Individual Number: 9465; Caliber: 17/18JCCRV; Year of creation: 1910.” - E.D. JAEGER: From pocket watch to chronograph with split-seconds function: Born in Alsace, Edmond Jaeger (1858–1922) moved to Paris with his family during the Franco-Prussian War and opened his watchmaking workshop there in 1880. A specialist in chronographs and speed-measuring instruments, he supplied his first shipboard chronometers to the French Navy in 1890. His business then expanded to include instruments for the automotive and aviation industries. This career, marked by a pursuit of precision, sheds light on the appeal of a split-seconds chronograph bearing his signature. In 1903, his meeting with Jacques-David LeCoultre led to a collaboration focused in particular on ultra-thin and complicated movements. This collaboration led, in 1907, to the creation of the Caliber 145, just 1.38 mm thick, designed for a pocket watch with a winding mechanism. That same year, Jaeger signed an exclusive agreement with Cartier to supply movements developed with LeCoultre. He gradually withdrew from the business beginning in 1918 and died in 1922. The Jaeger-LeCoultre brand, founded in 1937, perpetuated the union of the two names after his passing. Dated 1910 according to the manufacturer’s archives, this gold pocket watch is equipped with a split-seconds chronograph, a complication designed to measure split times or to compare two events that begin simultaneously but have different durations. Two central chronograph hands, initially superimposed, move together. Pressing the split-seconds push-button stops one of them to allow the reading of an initial time, while the other continues to time. Pressing the button again releases the stopped hand, which instantly catches up with its companion and resumes running alongside it: this “catching up” gives the function its name. The operation can be repeated during a single measurement, particularly to record the times of several competitors during a sporting event. Developed in the 19th century, the split-seconds mechanism adds a specific stopping and resynchronization mechanism to the chronograph. In its traditional design, a clamp holds the split-seconds wheel in place; once released, a spring-loaded lever acts on a heart-shaped cam to return the hand to the same position as the chronograph hand. The coordination of these components and the precision of their adjustment make this function a demanding mechanical complication. On the example presented here, the peripheral scale marked in fifths of a second complements its purpose of measuring short intervals. To the best of our knowledge, only one other example of this type—made of platinum with a double peripheral scale and also bearing the signature “E.D. JAEGER, Paris,” is known; it was sold by Antiquorum on October 20, 1991. Expert: Mr. Geoffroy ADER