M 



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in' N O R T 11 - a M E R I c a. 



:i! 



342 



As we might have conjectured from eftabliflied prui- 

 ciples of philofophy, that clearing and fmoothiiig the 

 face of a country, would promote the heat of the atmof« 

 phere, and in many cafes would prevent or mitigate thofe 

 winter blafts, which are the general origin of cold, v/hence 

 tlie winters mud become more temperate^ and as fads ap- 

 pear to fupport and confirm our reafoning on this fubjedl, 

 we may rationally conclude, that in a feries of years, when 

 the virtuous induftry of poflerity fhall have cultivated the 

 interior part of this country, we fliall feldom be vifited by 

 frofts or fnows, but may enjoy fuch a temperature in the 

 midft of winter, as fliall hard^ 



r 



plants. 



Perhaps it may be apprehended, that as clearing the 

 country, will mitigate the cold of our winters, it will alfo 

 increafe the heat of our fummers; but I apprehend, that 



deftroy the mod tender 



iTt' 



on a careful attention to this fubjed we fhall find, that the 

 fame caufe will in thofe feafons appear to produce different 

 effeds, and that inftead of more heat, we fliall prefently 

 have lefs in fummer than ufual. 



It is well known, that during the grcateli fammer heats 

 of this or any other country, the extraordinary heat of 

 the atmofphere does not rife to any confiderable height. 

 In the upper regions it is perpetually cold, both becaufe 

 the air in thofe parts is too flir from the earth, to be 



warmed by the heat of its furface, and becaufe the air in 

 thofe regions not being preffed by fuch a weight of incum- 

 bent atmofphere is too rare to be fufceptible of a great de- 

 gree of heat; for the heat of the air, as of every other 

 body, that is warmed by the Sun, depends not only upon 

 the fimple adion of the particles of light upon thofe of 

 the air, but alfo upon the mutual adioa of the particles of 

 air upon one another, which, by their elaflScityj propagate 

 or continue that motion, called heat, which was originally 

 excited by the Sun's rays. Therefore, the rarer the at- 

 mofphere is, the lefs heat will be produced therein by the 

 Sun, 6' vice ver/a* Hence we obferve, that in the warmeft 



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Vol. I. 



Xx 



countries 



