Fizeau's measurement of the speed of light in air
1848 experiment by Hippolyte Fizeau / From Wikipedia, the free encyclopedia
This article is about the experiment to measure the absolute speed of light in air. For Fizeau's experiment to measure the relative speed of light in a moving medium, see Fizeau experiment.
In 1848−49, Hippolyte Fizeau used a toothed wheel apparatus to perform an absolute measurement of the speed of light in air.
Subsequent experiments performed by Marie Alfred Cornu in 1872–76 improved the methodology and made a more accurate measurement.