CONTENTS. Vll 



Page 



CHAPTER XIX. 



On the Decomposition of atmospheric Mat- 

 ter, and the means by which it is effected 

 On the formation of Rain 385 



CHAPTER xx. 



On Comets Or the Means by which the 

 Matter belonging to every part of the 

 Planetary System is limited and bounded, 

 cmd prevented from interfering with the 

 Spheres of other Planets 389 



CHAPTER XXI. 



On the Laws of Motion 40 



