Adolfo Bartoli and the problem of radiant heat

Summary In 1876 the Italian physicist and physical chemist Adolfo Bartoli (1851–1896) discussed a thought experiment in which he connected the second law of thermodynamics with the hypothetical pressure of radiation. Bartoli's work, published in Italian, exerted some influence on the subsequent development of black-body theory and light pressure research. This influence was mainly due to Boltzmann, who came to the Stefan-Boltzmann radiation law via a reworking of Bartoli's thought experiment. However, contrary to what is usually assumed, Bartoli was himself reluctant to admit the existence of light pressure and soon rejected the hypothesis. Bartoli's work is discussed and related to other work in the areas of radiometer research and thermodynamics.