French mathematician,philosopher and theorist. One of the leading French thinkers of the 17th century, he lived in Paris from 1619 as a Jesuit priest. His work is central to the academic and scientific movements of his time, and a major part of it is devoted to music. On the basis of practical experiment and observations, he made important discoveries concerning the nature and behaviour of sound, which are the foundation of the science of acoustics in later times. He also wrote on the theory and practice of music. His principal musical treatise is the Harmonie universelle