SIR ISAAC NEWTON. 33 



unabated through life. Though she was twice 

 married, he never paid a visit to Woolsthorpe 

 without going to see her, and liberally relieved 

 her from little pecuniary embarrassments, when 

 his own circumstances had become easy. How 

 the world loves constancy; an affection which 

 knows no change ! That he would have been 

 happier in those quiet years of study, even in his 

 poverty, had he married, is probable ; but that the 

 world gained by his undivided devotion to science, 

 is equally probable. 



On July 8, 1661, Newton entered college, and 

 soon, through the study of Descartes' Geometry, 

 showed his skill in higher mathematics. And now 

 began an almost unexampled development of mind. 



At twenty-two, he was studying a comet so 

 closely, and the circles and halo round the moon, 

 that he impaired his health by sitting up late at 

 night. In 1665, May 20, when he was twenty- 

 three, he committed to writing his first discovery 

 of fluxions " the infinitely small increase or de- 

 crease of a variable or flowing quantity in a cer- 

 tain infinitely small and constant period of time." 



The same year, when the college had been dis- 

 missed on account of the plague in Cambridge, 

 Newton made his immortal discovery of the At- 

 traction of Gravitation. While sitting alone in his 

 garden at Woolsthorpe, and observing an apple fall 

 to the ground, it occurred to him that as the same 

 power by which the apple fell was not sensibly 

 diminished at the summits of the loftiest spires, 



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