That Sauveur and Loulié had been on a collision course for some time must have been evident to both men, for in 1696, around the time their research commenced, Loulié’s Élements ou Principes de Musique, the musical primer dedicated to his former student, the Duke of Chartres, appeared in print. Sauveur would familiarize himself with this work, particularly its closing pages, which featured a description and a diagram of what Loulié deemed his chronomètre, his musical timekeeper. Whether or not Loulié consulted with Sauveur about the instrument’s design, we might easily imagine Loulié’s device sparking in Sauveur no small pang of envy or jealousy. The musician, not the scientist, had been the first to propose a means of accurately measuring musical time. For his part, Sauveur would come to regard Loulié’s concept as faulty and short-sighted and was inspired to realize what he believed was a more practical solution.

Part I of Loulié’s Élements was a simple singing manual for children, covering basic musical knowledge—the seven notes of music, the C clef, accidentals, note names and so on, “elements” Loulié would have frequently taught others during his experiences as a tutor. Part II was intended for more advanced students, covering the concepts of scales, clefs and meter, all of which Loulié proudly proclaimed were “presented in a very methodical and novel manner.” Students and teachers alike no doubt found the first two portions of Élements of great value but it is in Part III, by far the most advanced, that Loulié’s most memorable contributions lie. At the start of this final section Loulié outlined his concept for a monochord, a device about the size of a spinet, with immovable bridges at either end, across which one or more strings could be strung and stretched to the desired tightness with pegs. Another bridge, this one moveable and placed toward the center, would stop the string at a desired length or division, allowing for the study of pitch and vibration.

Of course, the study of a vibrating string was hardly a novel undertaking.