CONTENTS. Xlll 



LETTER XIIL 



Page 

 THE WINDS ... ... ... ... 210 



LETTER XIV. 



THE WINDS, CONTINUED; THEIR INFLUENCE ON 



CLIMATE ... ... ... ... 227 



LETTER XY. 



THE MOISTURE OF THE AIR, AND THE FALL OF WET 241 



LETTER XVI. 



THE ELECTRICITY OF THE AIR, AND LIGHTNING ... 263 



