Proximate Causes of certain Winds and Stortns. 257 



north and west. Their course is generally opposite to that of the 

 trade winds. Tornados come from several points."''* 



(e.) " This is the wet season, but the rains by no means descend 

 from morning till night, as in some other tropical countries, but com- 

 mence generally every afternoon about four or five o'clock, with a 



thunderstorm. Formerly these diurnal rains came on with such 



regularity, that it was usual in forming parties of pleasure, to arrange 



whether they should take place before or after the storm. In the 



excursion made from Villa Rica to Labara, it will be seen that vio- 

 lent thunderstorms were experienced almost daily ; and I could not 

 help noticing the way these storms commenced. The sky was per- 

 fectly clear until about two or three o'clock, when some light white 

 clouds were seen approximating the sun with great rapidity. Some- 

 times they all passed, but if one lingered as if within its influence, 

 thunder was heard, and in a few minutes no remains of a blue sky 

 were visible. The storm commenced directly." Commencing in 

 the direction of the sun at two or three o'clock, these storms of 

 course begin in the west.f 



(/.) " Thunder and lightning are ten times more frequent than in 

 Spain, especially if a storm comes from the north-west. During my 

 residence in Paraguay, several persons fell victims to lightning, and 

 in the city of Buenos Ayres, in a storm on the 21st of January, 1793, 

 it fell in thirty-seven different places, and killed nineteen people. 

 These storms of \V\nd, thunder, rain, and lightning, cannot be attrib- 

 uted to the influence of mountains, as there are none within one 

 hundred leagues. J 



[g.) " Les vents de Nord N. de Nord-Ouest sont ceux que ame- 

 nent les gros temps et les ouragans dans les mois d'Avril, Mai, 

 Juin, Juillet et Aout ; mais ces ouragans, quelquefois furieux ne sont 

 pas frequens." The months speciSed, constitute the rainy season. 

 "La grele ne tombe guere que dans la saison pluvieuse: le tonnere 

 ne se fait aussi entendre que dans cette saison mais rarement ; on 

 ne voit les eclairs de chaleur que par un temps convert et jamais 

 par un temps chaud et serein comme il arrive ordinairement en Eu- 

 rope." De la Cailles' meteorological observations at the Cape of 



* Philosophy, Vol. ii, p. 458. It is hardly necessary to observe that a hurricane is 

 a violent thunderstorm. 



1 Caldcleugh's Observations in Brazil, in Brando's Journal, vol. xiv. 



t Azara's Travels in S. America, quoted in tlie Anti-Jacobin, vol. xxxiv. p. 456. 



