Jules Lissajous was born March 4, 1822. His doctoral studies were on vibrations of bars “using Chladni’s sand pattern method to determine nodal positions”. This method of viewing vibration patterns entails covering the object with flour or sand, and inducing vibrations, often by stroking with a violin bow (or in a modern lab using amplified sounds at variable frequencies). The vibrations cause the sand or flour to accumulate into a pattern, indicating nodes in the vibrations of the object, locations where the standing waves of the bar have least magnitude.
Lissajous died on June 24, 1880.
Mathematicians with birthdays or death anniversaries during the week of June 22 through June 28:
June 22: Birthday of Hermann Minkowski  (mathematical foundations of space-time theories); death of Felix Klein  (algebraic geometry)
June 23: Birthday of Alan Turing  (foundations of computation)
June 24: Birthday of Oswald Veblen  (geometry, topology); death of Jules Lissajous  (visual study of vibration and sound)
June 25: Death of Alfred Pringsheim  (analysis)
June 26: Birthday of Leopold Löwenheim  (Löwenheim-Skolem Theorem); death of George Udny Yule  (statistics)
June 27: Birthday of Augustus de Morgan  (mathematical induction); deaths of Sophie Germain  (number theory, elasticity) and Max Dehn  (group theory)
June 28: Birthday of Henri Lebesgue  (measure theory)