Chronomètre of Loulié
The chronomètre is a precursor of the metronome. It was invented circa 1694 by Étienne Loulié to record the preferred tempo of pieces of music.
The Device
Musician Étienne Loulié collaborated with mathematician Joseph Sauveur on the education of Philippe, Duke of Chartres, who subsequently asked the pair to work together on a scientific study of acoustics sponsored by the Royal Academy of Science circa 1694.To measure scientifically the number of beats per second caused by different dissonances, they used the "seconds pendulum" invented by Galileo earlier in the century. It doubtlessly was these experiments, on top of his lessons to Chartres, that gave Loulié the idea for his chronomètre, a precursor of the metronome.
In his Éléments — which resumes the lessons Loulié had given to Chartres and is dedicated to the prince — Loulié described this invention, complete with an engraving of the device.
The device is basically a Galilean seconds pendulum disguised as a classical column. It consists of a six-foot-tall vertical "ruler" marked off in inches, with a little peg-hole at every inch. From the right-angle bar that protrudes at the capital of the Ionic capital, hangs a string with a plumb bob at the end. The length of the string — and therefore the speed of the pendulum swings — can be adjusted by moving the peg at the other end of the string up and down the vertical board and inserting it in one peg-hole or another. The shorter the string, the more rapid the swings; the longer the string, the slower the swings.
To specify the tempo of a piece, the composer could henceforth test the tempo at a variety of peg holes and, having determined the right tempo, could mark at the top of a piece the note value that represented the musical beat, plus the number of the hole into which the peg had been inserted.
Sauveur subsequently criticized the device because it was measured in inches, which did not conform with any known relation to the duration of a second. His échomètre tried to remedy this shortcoming, by marking the vertical ruler with the small units that the Sauveur was creating for his Nouveau système. When Loulié died in 1702, Louis Léon Pajot, comte d'Onsenbray, acquired Loulié's model and presented his own variant to the Academy of Sciences in 1732. It was measured in seconds and made the swings of the pendulum audible. The size of all three devices rendered them too cumbersome for widespread use.
Its utility
On pages 85–86 of his Éléments, Loulié emphasized the usefulness of his device:Loulié's allusions to the airs of Jean Baptiste de Lully are particularly meaningful within the broader context of Loulié's business activities. Loulié was directing a workshop that copied Lully's airs, probably for sale by his friend Henri Foucault, the music-paper dealer and disseminator of Lully's works in both manuscript and print.