CONTENTS. 



Page 

 LECTURE XVI. 



The Mechanic Powers - - 232 



ASTRONOMY. 



LECTURE XVII. 



System of the Universe - - 250 



LECTURE XVIII. 

 Of the Sun, and his real and apparent Motions 270 



LECTURE XIX. 



The Primary Planets; the Mode of calculating 

 their Distances, &c. - 280 



LECTURE XX. 



The Secondary Planets - -312 



LECTURE XXI. 



The Earth ... . 3? g 



LECTURE XXII. 

 The Tides - - - - 343 



