BOOK I. 



FORMATION OF THE GLOBE. 



CHAPTER I. 



APPEARANCE OF ANIMALS AND PLANTS. 



When learned men began to occupy themselves with the 

 theory of the earth, they became divided into two very 

 clearly defined opposite parties : 



The Plutonists, who attributed the formation of the crust 

 of the globe exclusively to fire ; and 



The Neptunists, who, on the contrary, derived everything 

 from the action of water. 



The truth is that fire and water have had their share by 

 turns. One part of the terrestrial crust is the result of 

 heat, the other that of the deposit from water. 



It is evident that the globe was originally a purely incan- 

 descent mass. Descartes had divined this great fact, and 

 had stated that the earth was only a sun crusted over and 

 partially extinguished, the chilled skin of which hid the 

 central furnace from view. 



Leibnitz developed this hypothesis in his " Protogaea." It 

 was afterwards successively confirmed, partly by the obser- 

 vations of Buffon and Cuvier, partly by the calculations of 

 Cordier, La Place, and Fourier. 



