CLIMATE. 



79 



The difference of climate on the east and west of 

 the Alleghanies is accompanied with two circum- 

 stances of great importance : the first is, that beyond 

 the latitude of 35 and 86 degrees, as you proceed 

 southwai^d, this difference ceases, and the tempera- 

 ture of the Floridas and the west part of Georgia, 

 from the Mississippi to the river Savannah and the 

 ocean, is subject to the same common law ; so that 

 the chain of the Alleghanies, and the turn of the 

 Apalachians, form the actual boundaries of the dif- 

 ference on this side, and thus show themselves to be 

 one of its efficient causes. 



The second circumstance is, that this excess, with 

 regard to temperature, ceases again almost suddenly 

 Ixitween the latitudes of 43 and 45 degrees north, 

 toward the great lakes. Scarcely have you passed 

 the south shore of lake Erie, wlien the climate grows 

 colder every minute in an astonishing proportion. 

 At fort Detroit it still resembles that of Niagara, its 

 parallel; but from lake St. Clair, the settlers find 

 the cold much more severe, and of longer duration^ 

 than at Detroit. This little lake remains frozen 

 over every year from November to February ; the 

 south and south-west winds, by which the tern* 

 perature at lake Erie is rendered more mild, are 

 here less frequent, and no fruits but Winter pears 

 and apples will ripen. 



At fort Michillimakkinak, two degrees and a half 

 farther north, observations made in 1797, under the 

 direction of the American general Wilkinson,* show, 



* See Med. Ilepos. of New York^ vol. i, where is a meteorological 

 table^ drawn up by major Swan, 



