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1' 



On the Gales of the Atlantic States. 355 



+ 



north-eastern current below, there must be a prodigious 

 condensaiion of aqueous vapour. The reason is obvious, 

 why this change is productive only of n.>rth-castern 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 th- Gulf in any other course, 

 than that north-eastern route which it actually pursues. 

 The competency of the high lands cf Mexico to prevent 

 the escape over them of the moist warm air displaced from 

 die surface of the G^lf, must be evident, from the peculiar 

 dryness of then* 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 lund for many hun- 

 dred leagues lies between the elevation of seven and nine 

 thousand feet. Consistently vvhh the chemical laws, which 

 bave been experimentally ascertained to operate through- 

 out nature, air which has been in contact with wut-r, can 

 Deither be cooled nor rarefied without being rendered 

 cloudy by the precipitation of aqueous particles. It follows 

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

 Gulf of jMexico, 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 

 bigher. 



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

 accumulation of warm moist air upon tile 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 

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

 ^nipede the impulse thus received, from reaching to the 

 shores of Europe. Our own mountains may procrastinate 

 ^e flood, and cause it to be more lasting and more terrific 

 when it ensues. The direction i>f the wind is naturally 

 perpendicular to the boundary of the aquatic region pro- 

 <J"cing it, and to the mountainous barrier wtich delays the 

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

 <*nts mountains, from north-east to south-west, and the 

 gales in question are always nearly north-west, or at right 



VouV...,No. IL 4G 



