IMMENSE PRECIPICE. 15S 
~ to the hollow separating the two peaks, where they 
| 
might pass the night. With this view they sent half 
of their attendants to procure a supply, not of olives 
but of salt beef. These arrangements were scarcely 
made when the east wind began to blow violently, 
and in less than two minutes the clouds disappeared. 
The obstacles presented by the vegetation gradually 
diminished as they approached the eastern summit, 
in order to attain which it was necessary to go close 
to the great precipice. Hitherto the gneiss had pre- 
served its lamellar structure ; but as they climbed 
the cone of the Silla they found it passing into 
granite, containing instead of garnets a few scatter- 
ed crystals of hornblende. In three quarters of an 
hour they reached the top of the pyramid, which 
was covered with grass, and for a few minutes en- 
joyed all the serenity of the sky. The elevation be- 
ing 8633 feet, the eye commanded a vast range of 
country. The slope, which extends nearly to the 
sea, had an angle of 53° 28’, though when viewed 
from the coast it seems perpendicular. Humboldt re- 
marks that a precipice of 6000 or 7000 feet is a phe- 
nomenon much rarer than is usually believed, and 
that a rock of 1600 feet of perpendicular height 
has in vain been sought for among the Swiss Alps. 
That of the Silla is partly covered with vegetation, 
tufts of befarie and andromede appearing as if sus- 
pended from the rock. 
Seven months had elapsed since they were on 
the summit of the Peak of Teneriffe, where the 
apparent horizon of the sea is six leagues farther 
distant than on the Silla; yet while the boundary- 
line was seen distinct in the former place, it was 
completely blended with the air in the latter. The 
