Samuel Pierpont Langley and his Contributions tothe Empirical Basis of Black-Body Radiation

In this paper I deal with an early phase of the history of research on black-body radiation. In this phase,from 1880-1900, the American astrophysicist Samuel Pierpont Langley (1834-1906) invented and useda key instrument, the bolometer, to measure for the first time radiation curves that displayed thecharacteristic features of asymmetry and of a shifting of their maxima to shorter wavelengths withincreasing temperature. I emphasize the complex development of the construction of the bolometer andthe early experiments performed with it. I also discuss how these developments became important fortheoretical research on the black-body radiation formula. My aim is to show that the often-neglectedexperimental part of the history of research on black-body radiation represents an important preconditionfor the theoretical developments that followed.