226 Dv Forry on the Climate of the United States. 



the theory, in regard to the difference of temperature east 

 and west of the Alleghanies, was naturally sviggested. In- 

 stead of deducing general laws from imiversal facts, this 

 theory of Volney and Jefferson was, as will be seen, a pre- 

 mature deduction — the result of hasty and partial generali- 

 zation. 



M. Volney also presents an extended investigation of the 

 system of winds in the United States ; and the ignorance of 

 this celebrated ti'aveller in thus attempting to explain the 

 meteorological phenomena peculiar to the region of the great 

 lakes, shews how little was known, forty-five years ago, of 

 the laws of meteorology. In reference to the Trans- Alle- 

 ghany region, he thus remarks : — " I think I have clearly de- 

 monstrated, that the south-west 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 Kentucky. 

 From this datum flows a natural and simple solution of the 

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

 te/ij/ the temperature of the western country is hotter by 3° of 

 latitude than that of the Atlantic coast, though only separated 

 from it by the Alleghany mountains. The reasons of this 

 are so palpable, that it would be only wearying the reader 

 to give them. Another consequence of this datum is, that 

 the south-west winds being the cause of a higher tempera- 

 ture, it will extend the sphere of this temperature so much 

 the farther, the greater the facility with which it can per- 

 vade the country ; and this affords a very favourable presage 

 for the parts that lie in its way, and are exposed to its 

 influence, namely, those in the vicinity of Lakes Erie and 

 Ontario, and even all the basin of the river St Lawrence, 

 into which the south-west wind penetrates." 



Now, these are the opinions still maintained at the pre- 

 sent day, to account for the supposed fact of the higher tem- 

 perature of our tramontane region. It is a good rule in 

 philosophy to ascertain the truth of a fact before attempting 

 its explanation — a truism, the observance of which would 

 have saved M. Volney the labour of constructing his com- 



