^d Mechanical Philosophy, [Chap. I. 



his grand discoveries ; but it was reserved for this 

 himinary of the first magnitude to shed a degree 

 of light on the Jaws of our planetary system, which 

 has served to guide every exertion, and point out 

 the way to the progress which has since been made. 

 It was he who first applied the simple principle of 

 gravitation to account for the movements of the 

 celestial bodies ; who laid down the laws of this 

 great and all pervading attraction ; and thence, by 

 the assistance of a sublime geometry, deduced the 

 revolutions of the planetary orbs, both primary 

 and secondary, including the minute irregularities 

 of each, with some errors indeed, but with a degree 

 of conformity to nature and subsequent observa- 

 tion, which must ever astonish and delight the in- 

 quiring mind. The British philosopher leaving 

 astronom.y in this improved state, no wonder that 

 those who came after him should at once, with 

 growing ardour, and with greater ease, pursue a 

 course which he had so happily marked out. 



At the beginning of the century under review, 

 we find Flamstead*, the first Astronomer Royal of 

 England, devoting himself to this science with 

 great zeal and success. He particularly directed 

 his attention to ihe Jixed stars ; and after a series 

 of patient and most laborious observations, pub- 

 lished, in 1719, a catalogue of stars, more exten- 

 sive and accurate than had ever been formed .by 

 one man. To him, both in office, and in astrono- 

 mical fame, succeeded Dr. Ilallcy|, who made a 



* The Rev. John Flnmstoad was born in l646; appointed As- 

 tronomer Jloyal in 16/4 ; and died in 1719. 



t Edmund Halley was born in Londori, in the year \65Q ; suc- 

 o^f-ded Flamhtcad as Astronomer Royal in l/ic) ; and died in 1742. 



