Otto Richard Lummer (17.07.1860-5.07.1925) was a German experimental physicist. He was born in Gera. He graduated from the University of Berlin (1884) and became an assistant to H. Helmholtz. In 1888 — 1904 he worked at the Physico-Technical Institute in Berlin (professor from 1894). From 1904 he was professor at the university in Breslau.
His research was in the field of optics, spectroscopy and thermal radiation. In 1897, together with F. Kurlbaum, he verified the Stefan — Boltzmann law for temperatures from 290 to 1500 °C. Together with E. Pringsheim he confirmed experimentally Wien's displacement law and established (1899) appreciable deviations from Wien's law of thermal radiation in the region of long wavelengths, and showed that Wien's formula holds in the region of short wavelengths and the Rayleigh — Jeans formula in the region of long ones. In 1895, together with W. Wien, he realised a model of a black body, and he built a number of sensitive radiation detectors, in particular, with Kurlbaum, a highly sensitive bolometer (1892), with which the accuracy of measurements of energy in the spectrum was brought to 0.01 %. He is also known for the Lummer — Brodhun photometer (1889) and the Lummer — Gehrcke plate (1901).