DISSERTATION SECONDi !>*•* 11, 



SECTION IV. 



ASTRONOMY. 



The time was now come when the world was to be 

 enlightened by a new science, arising out of the com- 

 parison of the phenomena of motion as observed in the 

 heavens, with the laws of motion as known on the earth. 

 Physical astronomy was the result of this comparison, a 

 science embracing greater objects, and destined for a 

 higher flight than any other branch of natural knowledge. 

 It is unnecessary to observe, that it was by Newton that 

 the comparison just referred to was instituted, and the 

 riches of the new science unfolded to mankind. 



This young philosopher, already signalized by great 

 discoveries, had scarcely reached the age of twenty-four, 

 when a great public calamity forced him into the situa- 

 tion where the first step in the new science is said to 

 have been suggested ; and that, by some of those com- 

 mon appearances, in which an ordinary man sees nothing 

 to draw his attention, nor even the man of genius, ex- 

 cept at those moments of inspiration when the mind sees 

 farthest into the intellectual world. In 166C, the plague 

 forced him to retire from Cambridge into the country ; 

 and, as he sat one day alone, in a garden, musing on the 

 nature of the mysterious force by which the phenomena 

 at the earth's surface are so much regulated, he observ- 

 ed the apples falling spontaneously from the trees, and 

 the thought occurred to him, since gravity is a tendency 

 not confined to bodies on the very surface of the earth, 

 but since it reaches to the tops of trees, to the tops of 

 rhe highest buildings, nay, to the summits of the most 



