MISTS. 321 



rents of hot air, and the moisture-laden currents from the sea 

 rush in to take their place, passing over the lowlands and dis- 

 charging themselves in storms on the elevated plateaux, which are 

 near the sea at Rio, and far from it at Pernambuco. In winter, 

 the reverse is the case. 



Mists. 



"Mists" (firouillards ; but I cannot call them_;^^.f, as these are 

 so mixed up with the idea of our smoky fogs) " are constant in the 

 morning on the great rivers of the interior, and equally frequent 

 in the morning, during the winter, near the coast, especially in the 

 valleys and bays, as in the bay of Rio de Janeiro. Those on the 

 banks of the rivers in the interior occur in the dry as well as in 

 the wet season, and are due to the great excess of the temperature 

 of the water above that of the morning air, an excess of 3° or 4° 

 centigrade, the former sometimes rising to 60° centigrade. These 

 mists sustain the vigour of the vegetation on the banks during the 

 dry season, and the trees there retain their leaves. They lose them, 

 on the contrary, away from the river-banks, owing to the dryness ; 

 and this circumstance even occasions a special riparian flora 

 nearly approaching in its characteristics that of the virgin forests." 



