François Jean Dominique Arago (1786-1853), was a French mathematician, physicist, astronomer and politician. Arago warmly supported Augustin-Jean Fresnel's optical theories, helping to confirm Fresnel's wave theory of light by observing what is now known as the spot of Arago. The two philosophers conducted together those experiments on the polarization of light which led to the inference that the vibrations of the luminiferous ether were transverse to the direction of motion, and that polarization consisted of a resolution of rectilinear propagation into components at right angles to each other. Read more