“Foucault’s {{w|Léon Foucault#Middle years|recent experiment on the velocity of light}}, though of a less popular character than his {{w|Foucault pendulum|celebrated pendulum experiment}} to prove the {{w|earth's rotation}}, will, nevertheless, attract even more attention among men of science. If its results are placed beyond doubt, they will affect astronomy to a degree not possible for the pendulum experiment, unless it had come as early as the time of Galileo.”