Snell's Law - History

History

Ptolemy, a Greek living in Alexandria, had found a relationship regarding refraction angles, but it was inaccurate for angles that were not small. Ptolemy was confident he had found an accurate empirical law, partially as a result of fudging his data to fit theory (see: confirmation bias). Alhazen, in his Book of Optics (1021), came closer to discovering the law of refraction, though he did not take this step.

The law of refraction was first accurately described by Ibn Sahl, of Baghdad, in the manuscript On Burning Mirrors and Lenses (984). He made use of it to work out the shapes of lenses that focus light with no geometric aberrations, known as anaclastic lenses.

The law was rediscovered by Thomas Harriot in 1602, who however did not publish his results although he had corresponded with Kepler on this very subject. In 1621, Willebrord Snellius (Snel) derived a mathematically equivalent form, that remained unpublished during his lifetime. René Descartes independently derived the law using heuristic momentum conservation arguments in terms of sines in his 1637 treatise Discourse on Method, and used it to solve a range of optical problems. Rejecting Descartes' solution, Pierre de Fermat arrived at the same solution based solely on his principle of least time.

According to Dijksterhuis, "In De natura lucis et proprietate (1662) Isaac Vossius said that Descartes had seen Snell's paper and concocted his own proof. We now know this charge to be undeserved but it has been adopted many times since." Both Fermat and Huygens repeated this accusation that Descartes had copied Snell. In French, Snell's Law is called "la loi de Descartes" or "loi de Snell-Descartes."

In his 1678 Traité de la Lumiere, Christiaan Huygens showed how Snell's law of sines could be explained by, or derived from, the wave nature of light, using what we have come to call the Huygens–Fresnel principle.

Read more about this topic:  Snell's Law

Famous quotes containing the word history:

    America is the only nation in history which, miraculously, has gone directly from barbarism to degeneration without the usual interval of civilization.
    Attributed to Georges Clemenceau (1841–1929)

    Let us not underrate the value of a fact; it will one day flower in a truth. It is astonishing how few facts of importance are added in a century to the natural history of any animal. The natural history of man himself is still being gradually written.
    Henry David Thoreau (1817–1862)

    ... that there is no other way,
    That the history of creation proceeds according to
    Stringent laws, and that things
    Do get done in this way, but never the things
    We set out to accomplish and wanted so desperately
    To see come into being.
    John Ashbery (b. 1927)