THEORY of RAIN. 63 



BUT the queftion is not, if, in any fituation upon the fur- 

 face of the earth, a judgment might be formed, a priori , of no 

 rain happening, during a certain courfe of time, which to us 

 feems endlefs ; the contrary is the refult of reafoning from the 

 theory of aqueous condenfation, and from the natural confti- 

 tution of the globe. But here are two little foots upon the 

 earth where it almoft never rains, contrary to a conclufion of a 

 generality in the phenomenon of rain. It muft, however, be con- 

 fidered, that this generality was not a thing abfolute in the 

 conclufion, and neceflary in the univerfal of the cafe. It was 

 only abfolutely neceflary in fome places ; and it was, from the 

 indefinite variety of cafe, in all probability, moft general. But 

 this generality will admit of fuch an exception as may be con- 

 fident with the theory. 



Now it is nowife inconfiftent with the theory to fuppofe, 

 that there fhould be, upon the globe, a few places, in which the 

 concurrence of the various conditions neceflary for producing 

 rain fhould not be found : That the greater part of the earth 

 fhould be found without rain, would certainly be inconfiftent 

 with the theory ; but that a particular fpot or two, containing 

 no diverfity of climate or of country, no variation of moun- 

 tain and of valley, fhould be found without rain, inftead of 

 tranfgrefling the neceflary conclufion of a generality with re- 

 gard to rain, confirms the theory, in prefuming the neceflity 

 for the concurrence of certain circumftances or conditions, 

 which are required in order to condenfe humidity in air. 



THE caufe of rain, though often exerted, will not be al- 

 ways fufEcient to produce the full efFecT: ; for a fcanty con- 

 denfation of aqueous vapour will not defcend in rain, but re- 

 main fufpended in a vifible form, and thus produce mift upon 

 the furface of the earth, and clouds in the atmofphere above. 

 There are alfo fome fituations in which the effecT; of the fum- 

 mer fun is, to form a certain haze, that diminifhes very much 



the 



