Luigi Giuseppe Lagrange (1736–1813) entered into the controversy about the forms assumed by a string made to vibrate, with some articles about sound. However, we will overlook the details of how much he felt himself, at least at the beginning, closer to Euler than to d"Alembert or to Daniel Bernoulli, as is well known. Among other things, our mathematician from Turin believed in the possibility that mathematics could illuminate physics; indeed, in his famous book about analytical mechanics, he would have desired to reduce the latter to the former.