NEWTON AND COMPOSITION OF LIGHT 



of that image was detected to be no other than that 

 light consists of rays differently refrangible, which, 

 without any respect to a difference in their incidence, 

 were, according to their degrees of refrangibility, trans- 

 mitted towards divers parts of the wall." 1 



THE NATURE OF COLOR 



Having thus proved the composition of light, New- 

 ton took up an exhaustive discussion as to colors, which 

 cannot be entered into at length here. Some of his 

 remarks on the subject of compound colors, however, 

 may be stated in part. Newton's views are of par- 

 ticular interest in this connection, since, as we have 

 already pointed out, the question as to what constituted 

 color could not be agreed upon by the philosophers. 

 Some held that color was an integral part of the sub- 

 stance; others maintained that it was simply a re- 

 flection from the surface ; and no scientific explanation 

 had been generally accepted. Newton concludes his 

 paper as follows: 



" I might add more instances of this nature, but 

 I shall conclude with the general one that the colors of 

 all natural bodies have no other origin than this, 

 that they are variously qualified to reflect one sort 

 of light in greater plenty than another. And this I 

 have experimented in a dark room by illuminating 

 those bodies with uncompounded light of divers 

 colors. For by that means any body may be made to 

 appear of any color. They have there no appropriate 

 color, but ever appear of the color of the light cast 

 upon them, but yet with this difference, that they are 

 most brisk and vivid in the light of their own daylight 



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