THE EXPLANATION OF LAWS 101 



bodies on the earth, that the planets were subject to 

 forces, and had determined what those forces were. 



t more could he do ? What explanation of his result 

 could be offered or even demanded. He had ordered the 

 solar system, and who could be so foolish as to ask why 

 the order was that which he had found and no other ? 

 But after his morning's work which finally completed his 



icoming treatise on the matter, he sat in his orchard 

 and was visited by some of his friends from Cambridge. 

 Perhaps they too were natural philosophers and he talked 

 to them about what he had been doing ; but it is more 

 likely that they sat idle, talking the thin-blooded intel- 

 lectual scandal that must have always flourished in 

 academic society, while Newton played with the historic 

 kitten. 



And then the apple fell from the tree. Newton was 



suddenly silent in a reverie ; the kitten played unheeded 



with the fallen fruit ; and his friends, used to such sudden 



moods, laughed and chattered. After a few moments he 



must have paper ; he rushes to his desk in the house ; 



scribbles a few hasty figures ; and now the theory of 



gravitation is part of the structure of the universe. The 



falling apple, a trivial incident which he had seen a 



1 times before, had loosed a spring in his mind, 



set uncr :v by all his previous thought. He had 



nsciously asked himself why the moon was pulled 



rth until, in an instant of revelation, the 



le appeared to him not " falling " (the meanin 

 word A ays used before), but pulled towards the 



earth. The idea flashed on him quicker than it could 

 be spoken. If both the moon and the apple are pulled 

 towards the earth, may they not be pulled by 1 1 



not the force that makes the apple " fall " 

 be tl ,10011 in its orbit ' A simple 



n will 

 moon is from the earth and how the force on r 



