320 Expedition to the 



contain tables of meteorological observations, showing the 

 variations of temperature from September 30th 1817 to Janu- 

 ary 31st 1818. The country, in which these obsei rations 

 were made, is that between the Arkansa, at Fort Smith, and 

 the Red river, at the mouth of the Kiamesha, about the Hot 

 Springs of the Washita, and the settlement of the Cadron. 

 Here we find, in the month of January, the mercury at zero, 

 and shortly after at 58*^, a degree of cold that would not 

 discredit the climate of Moscow, and a rapidity of change 

 and violence of vicissitude comparable with the ever vary- 

 ing temperature of the Atlantic States. We might expect 

 in the latitude of 34°, and in a region placed along the south- 

 western slope of a moderately elevated range of mountains, 

 a mild and uniform climate. But almost every portion of 

 the territory of the United States seems alijce exposed to the 

 influence of the western and north-western winds refrigerated 

 in their passage over the wide and frozen regions of the 

 Rocky Mountains, and rushing down unobstructed across 

 the naked plains of the great desert, penetrating quite to the 

 Atlantic coast. 



We have reason to believe that the opinion of M. Volney, 

 respecting the comparative temperature of the regions east 

 and west of the Alleghany mountains, has been somewhat 

 too hastily adopted. Our limited observations have led us 

 to suspect that.at equal elevations, the aggregate temperature, 

 if any thing different, is by no means more mild or equable 

 on the western side of the mountains, in the valley of the 

 Mississippi, than on the Atlantic coast, and in confirmation 

 of this opinion we are happy to cite the authority of Mr. 

 Darby, whose opportunities for observation have been much 

 greater than ours, he having spent sixteen years in the val- 

 ley of the Mississippi. Some passages in the work of Baron 

 Humboldt seem at variance with the prevailing opinion which 

 he has adopted from Volney and Barton, of the greater mild- 

 ness of the climate of the western parts of the Mississippi 



