]7() INTENSE HEAT — TIIUNUER. 



ciiAr. XVI. San Fernando is celebrated for the excessive heat 

 — wliich prevails there during the greater part of the year. 



^.xctssi\ ,^,j^^ travellers found the white sand of the shores, 

 wherever it was exposed to the sun, to have a tempera- 

 ture of 120*5°, at two in the afternoon. The thermo- 

 meter, raised eighteen inclies above the sand, indicated 

 109' ; and at six feet, 101-7°. The temperature of the 

 air in the shade was 97°. These observations were 

 made during a dead calm, and when the wind began to 

 blow the heat increased five degrees. 



Tliunder. 0" the 28th .March, Humboldt and his companion 



being on the shore at sunrise, heard the thunder rolling 

 all around, although as yet there were only scattered 

 clouds, advancing in opposite directions toward the 

 zenitli. Deluc's hygrometer was at SS'', the thermo- 

 meter stood at 7-4-7°, and the electrometer gave no par- 

 ticular indication. As the clouds mustered, the blue of 

 the sky changLd to deep azure, and then to gray ; and 

 when it was completely overcast the thermometer rose 



Meteorologi- several degrees. Although a heavy rain fell, the tra- 



tnena.'^"'*' vellers remained on tlie shore to observe the electrometer. 

 When it was held at the height of six feet from the 

 ground, the pith-balls genei-ally separated only a few 

 seconds before the lightning was seen. The separation 

 was four lines. The electric charge remained the same 

 for several minutes, and there were repeated oscillations 

 from positive to negative. Toward the end of the storm 

 the west wind blew with great impetuosity, and when 

 the clouds dispersed the thermometer fell to 71*6°. 



oi.iect of Humboldt states, that he enters into these details 



'''"^'''^^"'""' because Europeans usually confine themselves to a 

 description of the impressions made on their minds by 

 the solemn spectacle of a tropical thunder-storm ; and 

 because, m a country wliere tlie year is divided into two 

 great seasons of drought and rain, it is interesting to 

 trace the transition from the one to the other. In the 

 valleys of Aragua, he had from the 18th of February 

 observed clouds forming in the evening, and in the 

 beginning of March the accumulation of vesicular va- 



