NATURAL HISTORY. 2^ 



In several places, earthquakes have formed consider- 

 able hollows, and even some large gaps in mountains 

 All other inequalities are coeval with the mountains 

 themselves, and owe their existence to currents in the 

 ocean. 



From what has been said, it is easy to perceive hcnr 

 much subterraneous fires have contributed to change 

 both the surface and internal part of the globe. But 

 it is difficult to conceive how any sensible alteration 

 upon the land can be produced by the winds. Their do- 

 minion would appear to be confined to the sea ; yet it 

 is well known that the winds raise mountains of sand 

 in Arabia and Africa;, and that they frequently carry 

 these sands many leagues into the sea, where they 

 form banks, downs, and even islands. Every body 

 knows that hurricanes are the scourge of the Antilles, 

 of Madagascar, and of other countries, and that their 

 impetuosity is so violent as to drive back rivers, to 

 overthrow rocks and mountains, to scoup out holes and 

 gulphs in the earth, and totally to change the face of 

 those unhappy countries which they infest. 



But the greatest changes upon the surface of the 

 earth are produced by rains, rivers, and torrents from 

 the mountains. These derive their origin from va- 

 pours raised by the sun from ihe surface of the ocean, 

 and which are transported bv the winas through eve- 

 ry climate. The progress of these vaponrs is inter- 

 rupted by the tops of 'the mountains, where they ac- 

 cumulate into ciouds and descend in the form of rain, 

 dew, or snow. By their intrinsic gravity, they run 

 to the bottom of the mountain's, and penetrating or 

 dissolving the lower grounds, they sweep along with 

 them sand and gravel, furrow the plains, and thus 

 open passages to the sen, which always gains as much? 



