Ernst Gehrcke (1.07.1878-25.1.1960) was a German physicist. He was born in Berlin. He graduated from the University of Berlin (1901). In 1901—46 he worked at the Imperial Physico-Technical Institute (head of a department from 1926), and later at the University of Jena.
His work concerned optics, spectroscopy, physiological optics and the study of rarefied gases, cathode rays and geology. He developed a number of spectroscopic instruments of high resolving power (the Lummer — Gehrcke plate, the multiple interference spectroscope and others) and built an oscillograph (1904). Together with R. Seeliger he detected (1912) a qualitative relation between the speed of the electrons that ionise the atoms of a gas and the colour of the light emitted (for each colour there was a lower limit of speeds).