Sir Isaac Newton, held the theory that light<span> was </span>made<span> up of tiny particles. In 1678, </span>Dutch<span> physicist, </span>Christiaan Huygens<span>, believed that </span>light<span> was </span>made<span> up of waves vibrating up and down perpendicular to the direction of the </span>light<span> travels, and therefore formulated a way of visualizing wave propagation.</span>
The cornea is the only part of the eye that touches air.
