French physicist <a href="https://en.wikipedia.org/wiki/Augustin-Jean_Fresnel" id="mwdQ" rel="mw:WikiLink" title="Augustin-Jean Fresnel">Augustin Fresnel</a> submits his prizewinning "Memoir on the Diffraction of Light", precisely accounting for the limited extent to which light spreads into shadows, and thereby demolishing the oldest objection to the wave theory of light.