60 TH E R T nf RA IN. 



are in the neighbourhood, proves, on the contrary, a caufe of 

 drought in other regions, where the fource of water, or evapo- 

 ration, is more fcanty, or at a diftance. A winter continent, 

 heated by the elevation of the fummer fun, mould be more dif- 

 pofed to have drought than rain, during the period of its heat, 

 unlefs fome tranfient ftreams of atmofphere, proper for the 

 purpofe, mould reach this place, and happen to meet : There 

 would thus be occafioned mowers of rain, of great importance 

 to the vegetation of the place, but not to be confidered as a ge- 

 neral feafon of rain. 



BUT the cafe is altered, upon the declining of the fummer 

 fun. The atmofphere, upon this continent, then becoming ei- 

 ther faturated to its degree of heat, or cooled to its degree of 

 faturation, is difpofed to produce rain, with every mixture 

 which is in a different temperature. Hence a fource of autum- 

 nal rains and winter fnows, which may fall with all the regu- 

 larity of the tropical rains ; and of this we alfo have informa- 

 tion, from the regular covering of thofe northern continental re- 

 gions, with a permanent fnow ; an event that happens with 

 great conftancy, and may be confidered as a regular periodical 

 rain. 



HAVING thus found rain as being properly caufed, upon two 

 oppofite principles, a vertical or highly elevated fun, and the 

 removal of that caufe of heat, no place mould be found, upon 

 the furface of this earth, where rain may not happen, more or 

 lefs, from the one or other of thofe caufes. But there are 

 places where it is faid never to rain : And now the queftion is, 

 how far thefe appearances may be confiflent with the theory of 

 general rain which has been given. 



3. Of apparent Exceptions from the Generality of Rain. 

 THE argument for the generality of rain has been founded 

 upon thefe two principles, firft, That mixed portions of the at- 

 mofphere are, by means of a certain law of nature, qualified 



for 



