the explanation of stellar aberration. 1849 Armand Hippolyte Louis Fizeau (1819–96) begins experiments to determine the speed of light. 1851 Fizeau 's interferometry experiment confirming Fresnel 's theoretical results. 1852 Stokes names and explains the phenomena of fluorescence. Riemann 1854 Bernhard Riemann (1826–66) makes unpublished conjectures about an "investigation of the