Treatise on Light

Treatise on Light: In Which Are Explained the Causes of That Which Occurs in Reflection & Refraction is a book written by Dutch <a href="/facts/Polymath/eqIfjQRu">polymath</a> <a href="/facts/Christiaan_Huygens/GtBqoBVm">Christiaan Huygens</a> that was published in French in 1690. The book describes Huygens's conception of the nature of <a href="/facts/Light/jeofpMn4">light propagation</a> which makes it possible to explain the laws of <a href="/facts/Geometrical_optics/gIFu84Tm">geometrical optics</a> shown in <a href="/facts/Ren%C3%A9_Descartes/ohqj6DMf">Descartes's</a> <a href="/facts/Dioptrique/4PN9knCp">Dioptrique</a>, which Huygens aimed to replace.
Unlike <a href="/facts/Isaac_Newton/4L7gTncN">Newton</a>'s <a href="/facts/Corpuscular_theory_of_light/8bq1oJym">corpuscular theory</a>, which was presented in the <a href="/facts/Opticks/07BYGLH3">Opticks</a>, Huygens conceived of light as an irregular series of shock waves which proceeds with very great, but finite, velocity through the ether, similar to <a href="/facts/Sound/DlKXlPuF">sound waves</a>. Moreover, he proposed that each point of a <a href="/facts/Wavefront/5XVoVtDQ">wavefront</a> is itself the origin of a secondary spherical wave, a principle known today as the <a href="/facts/Huygens%E2%80%93Fresnel_principle/t7lsjjA3">Huygens–Fresnel principle</a>. The book is considered a pioneering work of <a href="/facts/Theoretical_physics/Cs2Y12rQ">theoretical</a> and <a href="/facts/Mathematical_physics/sLKg8T1G">mathematical physics</a> and the first mechanistic account of an <a href="/facts/Unobservable/1JPxGEna">unobservable</a> physical phenomenon.

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Treatise on Light