On the Gales of the Jlilantic States. 355 



north-eastern current below, there must be a prodigious 

 condensation of aqueous vapour. The reason is obvious, 

 why this change is productive only of north-eastern gales ; 

 and that we have not northern gales, accompanied by the 

 same phenomena. The course of our mountains is from 

 the north-east to the south-west. Thus no channel is af- 

 forded for the air proceeding to the Gulf in any other course, 

 than that north-eastern route which it actually pursues. — 

 The competency of the high lands of Mexico to prevent 

 the escape over them of the moist warm air displaced from 

 the surface of the Gulf, must be evident, from the peculiar 

 dryness of their climate; and the evidence of Humboldt. 

 According to this celebrated traveller, the clouds formed 

 over the Gulf, never rise to a greater height than four thou- 

 sand nine hundred feet, while the table land for many hun- 

 dred leagues lies between the elevation of seven and nine 

 thousand feet. Consistently with the chemical laws, which 

 have been experimentally ascertained to operate through- 

 out nature, air which has been in contact with water, can 

 neither be cooled nor rarefied without being rendered 

 cloudy by the precipitation of aqueous particles. It follows 

 then, that the air displaced suddenly from the surface of the 

 Gulf of Mexico, by the influx of cold air from the north- 

 east, never rises higher than the elevation mentioned by 

 Humboldt as infested by clouds. Of course, it never 

 crosses the table land which at the lowest is 2,000 feet 

 higher. 



Our north-western winds are produced, no doubt, by the 

 accumulation of warm moist air upon the surface of the 

 ocean, as those from the north-east are by its accumulation 

 on the Gulf of Mexico. But in the case of the Atlantic, 

 there are no mountains to roll back upon our hemisphere 

 the air displaced by the gales which proceed from it, and to 

 impede the impulse thus received, from reaching to the 

 shores of Europe. Our own mountains may procrastinate 

 the flood, and cause it to be more lasting and more terrific 

 when it ensues. The direction of the wind is naturally 

 perpendicular to the boundary of the aquatic region pro- 

 ducing it, and to the mountainous barrier which delays the 

 crisis. The course of the North American coast is, like that 

 of its mountains, from north-east to south-west, and the 

 gales in question are always nearly north-westj or at right 



Vor.. V....NO. II. 46 



