HOT WINDS OF THE LLANOS. 
141 
mercury in the barometer, the waters of the Apure hare 
oiiiy a fall of thirty-four toises from San Fernando to the 
sea. The fall from the mouths of the Osage and the 
Missouri to the bar of the Mississippi is not more con- 
siderable. The savannahs of Lower Louisiana everywhere 
Remind us of the savannahs of the Lower Orinoco. 
During our stay of three days in the little town of San 
Fernando, we lodged with the Capuchin missionary, who 
hved much at liis ease. We were recommended to him by 
Die bishop of Caracas, and be showed us the most obliging 
attention. He consulted me on the works that had been 
'midertaken to prevent the flood from undermining the shore 
? n which the town was built. The flowing of the Portuguesa 
mto the Apure gives the latter an impulse towards south- 
ea st ; and, instead of procuring a freer course for the river, 
attempts were made to confine it by dykes and piers. It 
}'' as easy to predict that these would he rapidly destroyed 
iff the swell of the waters, the shore having been weakened 
py taking away the earth from behind the dyke to employ 
^ M these hydraulic constructions. 
San Fernando is celebrated for the excessive heat which 
prevails there the greater part of the year; and before I 
b ®gin the recital of our long navigation on the rivers, I 
shall relate some facts calculated to throw light on the 
meteorology of the tropics. We went, provided with ther- 
mometers, to the flat shores covered with white sand which 
border the river Apure. At two in the afternoon I found 
he sand, wherever it was exposed to the sun, at 52-5°. 
instrument, raised eighteen inches above the sand, 
marked 42-8°, and at six feet high 38'7°. The temperature 
"I the air under the shade of a ceiba was 3 6' 2°. These 
obi 
the 
ser vations were made dui'ing a dead calm. As soon as 
"ind began to blow, the temperature of the air rose 3° 
i§her, y e t we were not enveloped by a wind of sand, hut 
e strata of air had been in contact with a soil more 
fougly heated, or through which whirlwinds of sand had 
cessed. This western part of the Llanos is the hottest, 
tL C: \ USe ’t re ceives air that has already crossed the rest of 
P ® barren steppe. The same difference has been observed 
o. 'yeen the eastern and western parts of the deserts of 
nta > where the trade-winds blow. 
