German physicist who developed the spectroscope and the science of emission spectroscopy with Bunsen. Kirchhoff also concluded that dark line spectra were obtained when light was passed through a gas corresponding to the wavelengths of emission lines in incandescent elements. Using the spectroscope, Kirchhoff showed that each element, when heated to incandescence, produced a characteristic pattern of emission lines. This led to the identification of cesium in 1860 (named in Latin for the sky blue color of its emission lines), and rubidium in 1861 (named in Latin for the red color of its emission lines).

Bunsen

Additional biographies: MacTutor (St. Andrews)