Why is Ibn Sahl left out of history? The Muslim genius who pioneered Snell's Law long before it was recognized.
Ibn Sahl (d. 1000), was a Muslim mathematician and physicist, who flourished in Baghdad. He was the first to discover the law of refraction (Snell's law).
Ibn Sahl uses this law to derive lens shapes that focus light with no geometric aberrations, known as anaclastic lenses.
Ibn Sahl is the first Muslim scholar known to have studied Ptolemy's Optics. Ibn Sahl dealt with parabolic mirrors, ellipsoidal mirrors, biconvex lenses, and techniques for drawing hyperbolic arcs.
$HYPER $APE $D