CHLADNI, ERNST FLORENS FRIEDRICH 1827), German physicist, was born at Wittenberg, on Nov. 3o, 1756. He was educated in law but left it to study science after the death of his father. Inspired by the works of Euler and Ber noulli, Chladni became a pioneer in experimental sound. He investigated the torsional vibrations of rods and the longitudinal vibrations of strings and rods applying the latter to the deter mination of the velocity of sound in solids. Chladni measured the velocity of sound in gases other than air by filling an organ pipe with the gas and measuring the pitch of the note emitted. His observations on vibrating plates are well known, and the dust fig ures formed at the nodes of such plates are called "Chladni's Fig ures." In 1809 he exhibited his "figures" to the French Institute; the demonstration was so warmly received that he showed them to Napoleon who gave Chladni 6,000 francs so that his book Die Akustik (1802) might be translated into French. In order to earn his living Chladni travelled in Germany, France and Italy giving scientific lectures and performing on an instrument designed and constructed by himself which he called a euphonium. He died at Breslau on April 3, 1827, leaving his money to the poor box of his native town and his collection of meteorites to the royal collection in Berlin.
Chladni was the author of a number of papers in the Berlin Monthly Musical Notes, of Neue Entdeckungen fiber die Theorie des Klanges (1787) and Neue Beitrdge zur Akustik (1817).