[ 492 J 



but in fa6l this inteVmixtufe'dannot talce place, except with the 

 fuperior and unmoved ftrata of the atmofphere, and thefe alone 

 could not produce numerous clouds, much lefs copious rains ; 

 for the air of the countries into which thefe foutherly winds flow, 

 muft itfelf have flown northwards, before the more fouthern air 

 could enter upon them, as Ihewn p. 397. 



Moreover, foutherly winds retain much warmth, and north- 

 erly winds are fo much colder in th-e countries into which they 

 are introduced, that their temperature caimot be fuppofed fuffi- 

 cientlv altered to depofit much vapour in the one cafe, or diflx)lve 

 much of that already condenfed in the other; on the contrary 

 the warm foutherly wind fhould diflblve the clouds already 

 formed, and the northerly, by their encreafed cold, fhould produce 

 many more. 



Hence elefirical agency muft of necefllty be recurred to, 

 though I do not doubt but it may be more corredlly applied by 

 perfons better verfed in eledrical knowledge than I can pretend 

 to be. Currents of air flowing in different diredions at different 

 heights in the atmofphere, muft undoubtedly be intimately con- 

 ncdled with thefe effeiis, but with thefe we are at prefent too 

 little acquainted. 



4*^. That a difpofition to rain is generally connecfled with 

 a diminution of the weight of the atmofphere, as is a difpofition 



to 



I 



