432 
ENOEMOUS PEECIPICB- 
was the sea, and to the south, the fertile valley of Caracas 
The barometer was at 20 inches 7'6 lines; the thermo- 
meter at 13‘7°. We were at thirteen hundred and fifty 
toises of elevation. We gazed on an extent of sea, the 
radius of which was thirty-six leagues. Persons who are 
affected by looking downward from a considerable height 
should remain at the centre of the small flat which crowns 
the eastern summit of the Silla. The mountain is not very 
remarkable for height : it is nearly eighty toises lower than 
the Canigou; but it is distinguished among all the moun- 
tains I have visited by an enormous precipice on the side 
next the sea. The coast forms only a narrow border ; and 
looking from the summit of the pyramid on the houses oi 
Caravalleda, this wall of rocks seems, by an optical illusion, 
to be nearly perpendicular. The real slope of the declivity 
appeared to me, according to an exact calculation, 53° 28'. # 
The mean slope of the peak of Teneriffe is scarcely 12° 30'. 
A precipice of six or seven thousand feet, like that of the 
Silla of Caracas, is a phenomenon far more rare than is 
generally believed by those who cross mountains without 
measuring their height, their bulk, and their slope. Since 
the experiments on the fall of bodies, and on their deviation 
to the south-east, have been resumed in several parts of 
Europe, a rock of two hundred and fifty toises of perpen- 
dicular elevation has been in vain sought for among all the 
Alps of Switzerland. The declivity of Mont Blanc towards 
the Allee Blanche does not even reach an angle of 4*5° ; 
though in the greater number of geological works, Mont 
Blanc is described as perpendicular on the south side. 
At the Silla of Caracas, the enormous northern cliff is 
partly covered with vegetation, notwithstanding the extreme 
steepness of its slope. Tufts of befaria and andromedas 
appear as if suspended from the rock. The little valley 
which, separates the domes towards the south, stretches in 
the direction of the sea. Alpine plants fill this hollow; 
and, not confined to the ridge of the mountain, they follow 
the sinuosities of the ravine. It. would seem as if torrents 
* Observations of the latitude give for the horizontal distance between 
the foot of the mountain near Caravalleda, and the vertical line passing 
through its simnit, scarcely 1000 toises. 
