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On the change of CLIMATE 



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when they fall obliquely; therefore, the nearer the direc- 

 tion of the Sun's rays is to a perpendicular with the fur- 

 face of the earth, the greater, altera paribus^ will the heat 

 be. Hence, countries fhould be colder the nearer they 

 are to the poles. But, 



We obferve that the air may be heated to a very differ- 

 ent degree in different countries, which are in the fame 

 latitude, according as they abound in rough mountains, 

 fertile plains, or fandy deferts; as they are furrounded by 

 land or by fea, or according to the different wind, which 

 prevail in thofe countries. The temperature of Pennfyl- 

 vania is very different from that of Portugal; and the tem- 

 perature of England is different from that of Saxony, on 

 the neighbouring continent, though they be under the fame 

 parallels. In order then that we may be enabled to form 

 aneftimate of the heat of any country, we muflnot only 

 confider the latitude of the place, but alfo the face and 

 fituation of the country, and the winds which generally 

 prevail there, if any of thefe fhould alter, the climate muft 

 alfo be changed. The face of a country may be altered 

 by cultivation, and a tranfient view of the general caufe 

 of winds will convince us, that their courfe may alfo be 



changed. 



It is generally believed that moft winds are occafioned 

 by the heat of the Sun. Were the Sun to ftand flill over 



ajiy particular part of the furface of the earth, the wind 

 would conftantly blow to that place from all diredions. For 

 the air in that part being rarificd by the heat of the fun, 

 would be expanded and thus become lighter, whence it 

 would afcend, and the heavier air in the neighbouring 

 parts would rufli in, to occupy it's place; this too being 

 heated both by the fun's rays, and by the warm furface of 

 the earth, would inflantly afcend to give place to that which 

 was colder. But as the fun moves, or feems to move, be- 

 tween the tropics, from Eafl to Wefl, there fhould be a 

 conftant current of air fetting towards the fun from the 



North, South, and Eaflward, while the current, which 



would 



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