Léon Foucault:
a Rapidly Rotating Mirror


Improving on Fizeau

" Leon Foucault improved on the Fizeau method a year later by using rotating mirrors and got the much more accurate answer of 298,000 km/s. His technique was good enough to confirm that light travels slower in water than in air. "


From the U of Alberta, Canada: Rotating miror experiment (local copy)
Pasco's speed of light apparatus Rotating Mirror Pasco's Speed of light Manual (local copy)
A quote for the Pasco equipment.