METEOKO LOGICAL OESEllVATIONS. 
435 
bees, which are peculiar to the JS T ew World, are destitute of 
all offensive weapons. Their sting is indeed comparatively 
feeble, and they use it seldom ; but a person, not fully con- 
vinced of the harmlessness of these angelitos, can scarcely 
divest himself of a sensation of fear. I must confess, that, 
■w hilst engaged in ltvy astronomical observations, I was’ often 
on the point of letting 1113; instruments fall, when I felt my 
hands and face covered with these hairy bees. Our guides 
assured us that they attempt to defend themselves only 
when irritated by being seized by their legs. I was not 
tempted to try the experiment on myself. 
Tho dip of the needle at tho Silla was one centesimal 
degree less than in the town of Caracas. In collecting tho 
observations which I made during calm weather and in 
very favourable circumstances, on the mountains as well as 
along tho coast, it would at first seem, that we discover, in 
that part of tho globe, a certain influence of the heights’ 011 
the dip of the needle, and the intensity of the magnetical 
forces; but we must remark-, that the dip at Caracas is much 
greater than could bo supposed, from the situation of tho 
town, and that the magnetical phenomena arc modified by 
the proximity of certain rocks, which constitute so many 
particular centres or little systems of attraction.* 
_ The temperature of the atmosphere varied on the summit 
of the Silla from eleven to fourteen degrees, according as 
the weather was calm or windy. Every one knows how 
difficult it is to verify, on the summit of a mountain, tho 
temperature, which is to serve for tho barometric calcida 
lion. The wind was east, which would seem to prove 
that the trade-winds, extend in this latitude much higher 
than fifteen hundred toises. Von Bueh had observed that, 
at the peak of Teneriffe, near the northern limit of the 
trade-winds, there exists generally at the elevation of one 
thousand nine hundred toises, a contrary current from the 
* 1 have seen fragments of quartz traversed by parallel bands of mag- 
nctic iron, carried into the valley of Caracas by the waters descending 
from the Galipano and the Cerro dc Avila. This banded magnetic iron- 
ore is found also in the Sierra Nevada of Merida* Between the two 
peaks of the Silla, angular fragments of cellular quartz are found, covered 
with red oxide ot iron. They do not act on the needle. This oxide is of 
a cinnabar-red colour. 
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