78 Mifiellanea Curiofa. 



as the Defarts of Lybia are ufually reported to be* 

 the Heat occafion'd by the Reflexion of the 

 Suns Beams, and the retention thereof in the 

 Sand, is incredible to thofe that have not felt it ; 

 whereby the Air being exceedingly rarified, it is 

 neceflary that the cooler and more denle Air 

 fhoudrun thitherwards to reftore /Equilibrium: 

 This I take to be the caufe, why near the Coaft 

 of Guinea the Wind always lets in upon the Land, 

 blowing Wefterly inftead of Eafterly, there be- 

 ing fufficient Reafbn to believe, that the Inland 

 Parts of Africa are prodigioufly hot, fince the 

 Northern Borders thereof were lb intemperate, as 

 to give the Ancients caufe to conclude, that all be- 

 yond the Tropic^ was made uninhabitable by excefs 

 of Heat : From the fame Caufe it happens, that 

 there are fb conftant Calms in that part of the O- 

 cean, called thefy*/«j, (defcribed in the 7th Remark 

 on the Atlantic^ Sea) for this Tradl: being placed 

 in the middle, between the Wefterly Winds blow- 

 ing on the^Coaft of Guinea^nd the Eafterly Trade- 

 winds, blowing to the Weftwards thereof, the 

 tendency of the Air here, is indifferent to either, 

 and (b Hands in /Equilibria between both ; and 

 the weight of the incumbent Atmofphere being 

 diminiflied by the continual contrary Winds 

 blowing from hence, is the realbn that the Air 

 here holds not the copious Vapour it receives, 

 but lets it fall into frequent Rains. 



But as the cool and denfe Air, by realbn of its 

 greater Gravity, preffes upon the hot and rarifi- 

 ed, 'tis demonftrative that this latter muft afcend 

 in a continued Stream as faft it rarifies ; and that 

 being afcended, it muft di/perfe it felf to preferve 

 the /Equilibrium : that is, by a contrary Current, 

 the upper Air muft move from thole Parts where 

 the greateft Heat is ; So by a kind of Circulation, 



thi 



