68 A VOYAGE TO BookVIL 



to check their courfc, there is not time fufficient for 

 the mitts to colled themlelves, and, by an increafe 

 of gravity to defcend in the manner of rain. Others 

 Bave attributed it to the natural cold brought by 

 the fouth wiad, which continue the atmofphere in a 

 certain degree of heat during the whole year, and thus 

 increafe the inagnitude of the particles of the air,,, 

 which with the nitrous effluvia acqiiircd in its paf- 

 fage over the furface of the fea, together with 

 thofe of the feveral minerals with which this coun- 

 try abounds, lelTen its velocity, and confequently its 

 power of uniting the vapours fo as to form drops^ 

 whofe gravity is greater than that of the air. To 

 this v/e may add, that the rays of the fvin not exert- 

 ing a force fuPncient for uniung and putting them 

 in motion, the heat being greatly leflened by the 

 coldnefs of the wind, the fog cannot be converted 

 into drops of rain. For while the weight of the 

 cloud does not exceed that of the air, by which it 

 is fupported, it cannot precipitate. 



I SHALL not cenfure this, or any other hypothefis, 

 formed for explaining the above phsenomenon, not 

 being certain that I have myfelf difcovered the true 

 caufe j I fhall however give the reader my thoughts^ 

 and leave them to the difcufnon of philofophers. In 

 order to this I fliali lay down fome preliminary prin- 

 ciples, which may ferve as a foundation to thofe who 

 fbaii apply themfelves to difcover the true caufe of 

 this phiEnomenon, with fome infcrudlions for judg- 

 ing of the feveral hypothefis that have been formed 

 on this extraordinary fubjed* 



I, It is to be fuppofed, that throughout the whole 

 country of Vailes, no other winds are known 

 during the whole year, than the foutherly, that is, 

 between the S. and S. E. and this not only on the land, 

 but alfo to a certain diftance at fea it evidently ap- 

 pearing that the winds are limited between the S. 

 ami S. E. It is therefore very ftrange that fome 



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