W.V. Snell was born in Leiden, Netherlands in 1591. after his school education he studied law at the University of Leiden, but he was more interested in Mathematics and taught Mathematics ever while he was studying law. Hiw father Rudolph Snell (1546 - 1613) was professor of Mathematics at the University of Leiden. When his father died in 1613 he succeeded his father as the professor of Mathematics.
He discovered experimentally the law of refraction at place surface in 1621, but did not publish it. The law in the original form was stated as follows: The ratio of the cosecant of the angle of refraction by the angle of incidence in costant. Only in 1703 the law became known as Snell's law of refraction when Huygens published Snell's results in Dioptrica. Rene Descartes {1596 -1650 }, Frenchmathematician and philosopher was the first person to drive thelaw of refraction inn terms of the ratio as sine from the corpuscular theory of light. Therefore, in France the law of refraction is generally called Descartes' law. In 1617 Snell determined the size of the earth from measurements of its curvature between two places on its surface.