Italian physicist famous for his important, pioneering studies on the behavior of radiating heat (infrared rays). He demonstrated that infrared rays, like light, could be reflected, refracted, polarized, and so on. A political exile, Melloni spent several years in Paris, and after returning to Italy served as director of the Vesuvian Observatory. "Melloni's bench," an apparatus fitted with multiple accessories for the study of infrared rays, used a thermopile (thermo-electric battery) as a detector. It became one of the essential instruments in nineteenth-century physics laboratories.