Newton was the first person to try and explain the physics of light in a systematic scientific manner. Newton thought there were particles of light which he called 'corpuscles'. They are emitted by lighted bodies, can travel through translucent materials, and be reflected off non-translucent surfaces. Refraction must be due to short-range acting on light corpuscles depending on density of material. Colors are due to different kinds of corpuscles, each a particular color.
Colored corpuscles are normally mixed and appear white.
As Newton was developing a 'particle' theory for light, a Dutch physicist named Huygens developed a 'wave' theory of light. It was obvious from general observation that certain physical processes could be explained by the action of waves. Many of the properties of light noted above can be explained by light behaving in a 'wave-like' manner. In fact, one could explain refraction without need of a special short-range force as proposed by Newton. He proposed a 'luminiferus ether', which is weightless and transparent, which permeates the entire universe.