Chronomètre of Loulié

It was invented circa 1694 by Étienne Loulié to record the preferred tempo of pieces of music.

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.

It doubtlessly[citation needed] was these experiments, on top of his lessons to Chartres, that gave Loulié the idea for his chronomètre, a precursor of the metronome.

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.