THE GENESIS OF THE LAW OF GRAVITY 331 



ness. His enemies thought that they had vanquished him and his 

 ideas. They even attempted to blot out his memory from among men by 

 refusing to allow his grave to be marked. How little they knew ! 

 Already through Huygens the new knowledge had made great advances ; 

 and in the very year of Galileo's death was born the man whose mighty 

 intellect was to flood with light the dark places of nature and to carry 

 Galileo's work to a proud completion. 



The year 1660 was in England an important year for science. This 

 is the year of the founding of the Boyal Society, and in the same year 

 Isaac Newton, a young man of eighteen, entered the University of 

 Cambridge from the town of Woolsthorpe in Lincolnshire. In 1663 

 the society received a royal charter, and some time after King Charles 

 is said to have sent it a weighty problem with which to test its powers. 

 " "Why is it," said the king, " that the same fish weighs less when alive 

 and swimming in a pan of water, than when dead and floating on its 

 surface ? " There must have been rapid improvement in the caliber 

 of its meetings, for in 1665 its members are listening to Eobert Bo} T le's 

 brilliant papers on the air-pump and the barometer. 



In the meantime, Isaac Xewton, destined for twenty-five years to be 

 president of the society, was pursuing his studies at Cambridge and in 

 1665 was given the A.B. degree. This and the following }'ear were 

 the years of the great plague. For a time the Royal Society took refuge 

 in Oxford, while the University at Cambridge was, in the fall of 1666 

 " sent down," the students and faculty scattering to escape contagion. 



Newton returned home, his mind teeming with new ideas and hard 

 problems. He had already mastered the most advanced scientific works 

 of his time — Kepler's " Optics," Descartes's " Anal} r tical Geometry " 

 and "VTallis's " Arithmetica Infinitorum." In reading, Xewton was in 

 the habit of noting what seemed to him capable of improvement. At 

 this time (1666) he had already projected experiments in optics which 

 were to be the first of his achievements to make him known to the world. 

 In mathematics he had originated the binomial theorem and had laid 

 the foundations of the infinitesimal calculus. Armed with this new 

 weapon of analysis, Kewton pushed his mathematical researches in 

 many directions, solving with ease problems that had so far baffled 

 attack. "Whatever he touched turned to gold under his hand. So 

 rapidly did his mind work that he seems not to have needed to work 

 out each step in detail : his printed papers sometimes read like a list of 

 answers to difficult propositions. For example, he presents a classifica- 

 tion of cubic curves, giving seventy classes in all. Yet in all this list 

 there is no suggestion of the process by which the results were obtained. 

 Among the books that Xewton read was Galileo's " Dialogues on 

 Motion," and here as elsewhere he found abundant material for work. 

 In this field of mechanics his mind worked with its usual clearness and 



