330 ON PHYSICAL DATA 



Bacon recommended) by Newton in the mathe- 

 matical principles of natural philosophy. In this 

 work we find, for the first time, a law of nature 

 discovered by a cautious induction of a great 

 variety of phenomena ; and then, from this simple 

 law, by an unequalled sagacity in the application 

 of abstract science, Newton has succeeded in 

 explaining the greater part of those interesting 

 questions which had engaged the attention of 

 mankind from the earliest ages of civilization ; 

 and by this means he has laid the foundation of 

 Physical Astronomy on a basis which never can 

 be shaken, however much the superstructure may 

 be modified by subsequent inquiry. It is true 

 that Kepler established the three primary laws 

 which regulate the motion of the planets, by a 

 laborious process of observation, the results of 

 which he combined with great skill and ingenuity ; 

 but it was reserved for Newton to refer these laws 

 to one great principle, from which he was enabled 

 to deduce the motions of the solar system. In 

 consequence of the success which attended the 

 labours of Newton, in that part of his speculations 

 concerning the application of abstract science to 

 the data obtained by careful observation, other 

 efi'orts have been made with more or less success, 

 having the same object in view which Newton 



