ANNOTATIONS AND ADDITIONS. 133 



confluence of the river St. Peter's with the Mississipi, the 

 mean winter temperature of Fort Snelling is 7.2 Reaumur, 

 or 15. 9 Fahrenheit (see Samuel Ferry's excellent Memoir 

 on "the Climate of the United States/' 1842, p. 37, 39, 

 and 102.) At this distance from the Canadian Lakes, 

 (whose surface is from 500 to 600530 to 640 English- 

 feet above the level of the sea, whilst the bottom of the 

 lakes Michigan and Huron is about five hundred feet below 

 it), recent observations have 'shewn the climate of the 

 country to possess a proper continental character, i. e. y 

 hotter summers and colder winters. " It is proved/' says 

 Forry, " by our thermometrical data, that the climate west 

 of the AUeghany Chain is more excessive than that of the 

 Atlantic side." At Fort Gibson, on the Arkansas Biver 

 which falls into the Mississipi in lat. 35 47', with a mean 

 annual temperature hardly equal to that of Gibraltar, the 

 thermometer in the shade, and without any reflected heat 

 from the ground, has been seen, in August 1834, to rise 

 to 37.7 Reaumur, or 117 Fahrenheit. 



The statement so often repeated, although unsupported 

 by any thermometric measurements, that since the first 

 European settlements in New England, Pennsylvania, and 

 Virginia, the eradication of many forests on both sides 

 of the Alleghanies had rendered the climate more equable, 

 (i. e., milder in winter and cooler in summer), is now gene- 

 rally doubted or disbelieved. Series of trustworthy thermo- 

 metric observations in the United States hardly extend so far 

 back as 78 years. We see in the Philadelphia observations, 



