This paper reviews some aspects of the Fizeau and Michelson-Morley experiments, and gives some historical perspective on their evolution and their interpretation in terms of the special theory of relativity. Although some guesses were made in the first half of the 20th century about the impossibility of permeating buildings by the aether, no author ever remarked, even after the complete removal of the aether hypotheses, that the Michelson interferometer is completely at rest with respect to the air, which is the medium actually supporting light propagation. In our opinion, this is the only real explanation of its null result. Then, we analyze the possibility of measuring the velocity of any body with respect to vacuum by taking advantage of an appropriately modified version of the experiment.
