NEWTON AND COMPOSITION OF LIGHT 



reign of the Dutchman, William of Orange. In 

 his old age he saw the first of the Hanoverians mount 

 the throne of England. Within a decade of his death 

 such scientific path-finders as Cavendish, Black, and 

 Priestley were born men who lived on to the close of 

 the eighteenth century. In a full sense, then, the age 

 of Newton bridges the gap from that early time of 

 scientific awakening under Kepler and Galileo to the 

 time which we of the twentieth century think of as 

 essentially modern. 



THE COMPOSITION OF WHITE LIGHT 



In December, 1672, Newton was elected a Fellow of 

 the Royal Society, and at this meeting a paper de- 

 scribing his invention of the refracting telescope was 

 read . A few days later he wrote to the secretary, making 

 some inquiries as to the weekly meetings of the society, 

 and intimating that he had an account of an interesting 

 discovery that he wished to lay before the society. 

 When this communication was made public, it proved 

 to be an explanation of the discovery of the composi- 

 tion of white light. We have seen that the question 

 as to the nature of color had commanded the attention 

 of such investigators as Huygens, but that no very 

 satisfactory solution of the question had been attained. 

 Newton proved by demonstrative experiments that 

 white light is composed of the blending of the rays of 

 diverse colors, and that the color that we ascribe to 

 any object is merely due to the fact that the object in 

 question reflects rays of that color, absorbing the rest. 

 That white light is really made up of many colors 

 blended would seem incredible had not the experi- 



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