THE PATH OF EVOLUTION 



surpassed those of Mercator, that had caused the 

 general admiration of the learned world. Newton 

 seemed to lose interest in his mathematical proced- 

 ures as soon as they ceased to be novelities to him. 

 He never occupied himself earnestly with two 

 different branches of scientific thought at the same 

 time. His attention was now (1666) strongly drawn 

 to the subject of the refraction of light, in which he 

 had made many experiments with glass prisms. 

 These experiments were begun at first as a mere 

 matter of amusement and curiosity, but soon led to 

 important results. He found that a ray of light from 

 the sun is not a simple and homogenous beam, but is 

 composed of a number of rays of unequal refrangi- 

 bility and of different colors. 



The prevalence of the Plague in the towns of 

 England drove Newton into the country for safety, 

 and put a stop for the time to his scientific work by 

 depriving him of the needed instruments and appli- 

 ances. He retired to his country house at Wools- 

 thorpe, about 110 miles from London. It was here 

 and at this time that Newton saw the apple fall that 

 set him to thinking on the cause of gravity, and on 

 the movements of bodies uniformly accelerated, to the 

 study of which his " method of fluxions" had been 

 applied. Reflecting afterwards upon the nature of 

 this singular power that drew bodies towards the 



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