French physicist <a href="https://en.wikipedia.org/wiki/Augustin-Jean_Fresnel" id="mwiQ" rel="mw:WikiLink" title="Augustin-Jean Fresnel">Augustin Fresnel</a> signs his preliminary "Note on the Theory of Diffraction" (deposited on the following day). The document ends with what we now call the <a href="https://en.wikipedia.org/wiki/Fresnel_integral" id="mwig" rel="mw:WikiLink" title="Fresnel integral">Fresnel integrals</a>.