ABSTRACT
The modern history of the science of Optics may be taken as beginning with the fundamental researches of Kindest Kepler, or with the accurate formulation of the law of refraction, early in the seventeenth century. The greatest of the mediaeval opticians was the Arab Ibn al-Haitham or Alhazen, whose book remained a standard authority down to the seventeenth century. He taught that light spreads out spherically from each point on a visible object, and he determined refractive indices experimentally, recognizing that Ptolemy’s crude law of refraction holds only for small angles. At the threshold of the modern period stands Johann Kepler, the astronomer, whose principal contributions to optics dealt with refraction, the properties of lenses, and the theory of vision. Isaac Newton became interested in optical problems while he was an undergraduate, when he made attempts to construct telescopes and to eliminate their defects.
