Eppur si muove : Dayton Miller’s Work on the Ether-drift effect

In the 1920s, Dayton C. Miller (1866-1941) carried out several ether-drift experiments similar to the more famous 1887 Michelson-Morley one. Miller's results showed a periodic second-order effect that he interpreted as a proof of the absolute motion of the Earth. Since the fringes shift he measured corresponded to a velocity of the Earth lower than the one expected in a stagnant-ether theory, he argued the existence of an ether dragged by Earth. Miller's data were explained in the context of the relativistic research program only in 1955 by Shankland and his team. My study has the aim to broaden the understanding of the knowledge and interpretation of Miller's data inside the international physics community.