eriAPTER vii. 



THE LUNAR WORLD. 



THE genuine man of science can never approach the study 

 of the moon without recalling that the orbit of our satellite 

 is a precinct specially associated with the name of Newton. 

 It was obvious to the clear vision of the great philosopher, 

 that some power resided in the earth by which the famous 

 apple was pulled down. The existence of this power was, 

 however, not Newton's discovery ; many a previous in- 

 vestigator, while pondering on the fact that bodies fall 

 downwards to the earth, perceived the obvious analogy to 

 the attraction of a piece of iron by a magnet. To demon- 

 strate the mere existence of that force which we call the 

 attraction of gravitation did not require the intellect of a 

 Newton. One of the discoveries which have given im- 

 mortality to the name of the great philosopher was con- 

 nected with the moon. He soared in thought far above 

 the apple-tree, and he asked himself whether the motion 

 of the moon may not be due to the same force as the fall of 

 the apple. When he had solved that problem, the scheme 

 of the universe lay open before him. 



Let us consider this question of falling. Objects dropped 



