Dr. Forry on the Climate of the United States, fyc. 33 



a greater inequality than Washington City, and Fort Gibson than 

 Fort Monroe. Fort Jesup cannot be fairly compared, by way of 

 contrast, with a position in the same latitude on the Atlantic, as 

 the warm atmospheric currents from the Gulf of Mexico exercise 

 there a very appreciable influence. 



The laws developed as respects the mean annual range of the 

 thermometer are also here corroborated. Washington City has a 

 mean annual range of 84°, while that of Jefferson Barracks is 89° ; 

 the ratio of Fort Monroe, on the one hand, is 73°, and that of 

 Fort Gibson, on the other, is 89° ; and lastly, the range at Fort 

 Johnston is 62°, while that of Augusta Arsenal is 73°. 



It is thus seen that the climate of the region of the great lakes 

 on our nothern frontier is not more contrasted in the opposite sea- 

 sons than that of Philadelphia — an inference long since deduced 

 from the fact that similar vegetable productions are found in each, 

 while the same plants will not flourish in the interior of New 

 York, Vermont, and New Hampshire. The region of Pennsyl- 

 vania, as though it were the battle-ground on which Boreas and 

 Auster struggle for mastery, experiences, indeed, the extremes of 

 heat and cold. But proceeding south along the Atlantic plain, 

 climate soon undergoes a striking modification, of which the Poto- 

 mac River forms the line of demarcation. Here the domain of 

 snow terminates. Beyond this point, the sledge is no more seen 

 in the farmer's barn-yard. The table-lands of Kentucky and 

 Tennessee, on the other hand, carry, several degrees farther south, 

 a mild and temperate clime. 



3. The Southern division, which is characterized by the pre- 

 dominance of high temperature remains to be considered. On 

 approaching our southern coast, climate undergoes a most remark- 

 able modification. The seasons glide imperceptibly into each 

 ot her, exhibiting no great extremes. This is strikingly illustrated 

 °n comparing the difference between the mean temperature of 

 summer and winter at Fort Snelling, Iowa, and at Key West, at 

 the southern point of Florida, the former being 56°-60, and the 

 latter only ll°-34. Compared with the other regions of the Uni- 

 ted States, the peninsula of Florida has a climate wholly peculiar. 

 The lime, the orange, and the fig, find there a genial tempera- 

 te j the course of vegetable life is unceasing ; culiuary vegeta- 

 bles are cultivated, and wild flowers spring up and flourish in the 

 month of January ; and so little is the temperature of the lakes 



V °l- xlvii, No. 1.— April-June, 1844. 5 ^ 



