r 495 1 



they proceed fortlier, this different eledrical flate muft either ceafe 

 or be diminifhed. When the coafts are mountainous, thefe moun- 

 tains quickly abforb the eledric matter contained in the weflern. 

 blafls, and by collifion, condenfe the vapours they contain, firft 

 into clouds, and finally into rain. Hence it often happens that 

 Wefterly winds, pairticularly in fummer, produce no rain, either 

 becaufe they introduce no clouds^ or meet with none differently 

 tefeflrified. 



8^. That in fome cotintries it fcarce ever rains. — This arifes 

 from local circumftances, as is apparent in the following inftances : 

 I**. It never rains on the plains of Peru from the gulf of Guyaquil, 

 nearly under the equator, up to latitude 23'^ fouth, nor is thunder 

 ever heard there, though thefe plains border on the Pacific Ocean, 

 but they receive a flight dew every night. Bouguer, fig. de la 

 Terre XXIIi. a Ulloa's Mem. p. 157. 2 Phil. Tranf. Abr. 132. 

 Plainly from the following reafons : Thefe plains are entirely fandy, 

 and, Gonfequently, emit very little vapour, being foon parched by 

 the heat that there prevails ; confequently, the intermixture of 

 marine vapours can produce no effe£t. Again, the clouds in thefe 

 tra£ls are elevated to a great height, and are attraded by the elec- 

 trical agency of the Cordellierres that border on thefe plains, to 

 their lofty fummits, and there produce copious rains; hence alfo 

 ;the fandy and extenfive defarts of Arabia and Africa are feldom re- 



3 Q_ « freflied 



