Macedonio Melloni (April 11, 1798 – August 11, 1854) was an Italian physicist, notable for demonstrating that radiant heat has similar physical properties to those of light.

Life

Born at Parma, in 1824 he was appointed professor at the University but was compelled to escape to France after taking part in the revolution of 1831. In 1839 he went to Naples and was soon appointed director of the Vesuvius Observatory , a post that he held until 1848.

He died at Portici , near Naples, of cholera.

Work

Melloni's reputation as a physicist rests principally on his discoveries in radiant heat, made with the aid of the thermomultiplier, a combination of thermopile and galvanometer. In 1831, soon after the discovery of thermoelectricity by Thomas Johann Seebeck, he and Leopoldo Nobili employed the instrument in experiments especially concerned with characteristics of (in modern language) black body radiation transmitted by various materials.

He used an optical bench fitted with thermopiles, shields and light and heat sources, such as Locatelli's lamp and Leslie's cube, in order to show that radiant heat could be reflected, refracted and polarised in the same way as light.

His most important book, La thermocrose au la coloration calorifique (Vol. I., Naples, 1850), was unfinished at his death.

He also studied the magnetism of rocks, electrostatic induction and photography.

Honours

• Rumford Medal of the Royal Society, (1834);
• Correspondent of the Académie des Sciences, (1835);
• Foreign member of the Royal Society, (1839).