Dr. Forry on the Climate of the United States, frc. 233 



is deemed supererogatory. The phenomena observed by Tolney 

 are truly facts; but the causes being unknown, the theory in re- 

 gard to the difference of temperature east and west of the Alle- 

 ghanies, was naturally suggested. Instead of deducing general 

 laws from universal facts, this theory of Yolney and Jefferson was, 

 as will be seen, a premature deduction— the result of hasty and 

 partial generalization. 



M. Volney also presents an extended investigation of the sys- 

 tem of winds in the United States ; and the ignorance of this cel- 

 ebrated traveller in thus attempting to explain the meteorological 

 phenomena peculiar to the region of the great lakes, shows how 

 little was known forty-five years ago of the laws of meteorology. 

 In reference to the Trans-Alleghany region, he thus remarks :— 

 ''I think I have clearly demonstrated that the southwest wind of 

 the United States is nothing but the trade-wind of the tropics 

 turned out of its direction and modified, and that consequently 

 the air of the Western country is the same as that of the Gulf of 

 Mexico, and previously of the West Indies, conveyed to Ken- 

 tucky. From this datum flows a natural and simple solution of 



e problem, which at first must have appeared perplexing, why 



the tem perature of the Western country is hotter by 3° of latitude 



ton that of the Atlantic coast, though only separated from it by 



the Alleghany mountains. The reasons of this are so palpable that 



would only be wearying the reader to give them. Another 

 ^sequence of this datum is, that the southwest winds bein 



e cause of a higher temperature, it will extend the sphere of 



S 



o r 1 ■• •-- — — -- - t 



s ter nperature so much the farther, the greater the facility with 



cn 't can prevade the country ; and this affords a very favor- 



. e P res age for the parts that lie in its way, and are exposed to 



s influence, namely those in the vicinity of Lakes Erie and On- 



j*no,and even all the basin of the river St. Lawrence, into which 



^southwest wind penetrates." 



ow these are the opinions still maintained at the present day, 



account for the supposed fact of the higher temperature of our 

 a niontane region. It is a good rule in philosophy to ascertain 

 e truth of a fact before attempting its explanation, — a truism, 

 e observance of which would have saved M. Volney the labor 



constructing his complex theory of the winds. All thermo- 

 e ncal results confirm the law, that in proportion as we recede 



m tlle ocean or inland seas, the climate grows more excessive ; 



