the Island of Tristan da Cunha, &c. 403 
maguitude in the whole island, is one which gushes out at the 
base of the mountain immediately behind the cantonment. Ex- 
cepting this brook, you meet with nothing from one end of the 
plain to the other but the dry beds of mountain torrents, impe- 
tuous, indeed, while they flow, but ceasing with the shower to 
Which they owe their existence. 
This singular deficiency of spriugs may, perhaps, be attributed 
to the nature of the rocky mass of which the island is formed. 
Though regularly stratified, the rock is cracked and split in all 
directions, and the rain transmitted through the spongy, absorbent 
soil, penetrates easily through its fissures, and sinks down at once 
to the level of the sea, where it may be seen along the shore gush- 
ing out through the sand on the reflux of every tide. 
Notwithstanding the frequency of the rains, the climate appears 
to be abundantly healthy. Nota symptom of sickness appeared 
among the soldiers during the four months I remained on the 
island. ; 
The spot pitched upon for the cantonment is at the northern 
extremity of the plain; ile- landing-place, 
and within range of cannon-shot from the anchorage. It is plen- 
tifully supplied with excellent water from the stream alread y men- 
tioned, which runs close by it, and which, even during the hottest 
days of summer, maintains the low temperature of 50° degrees. 
This stream, after running its course for about half a mile, preci- 
pitates itself in a cascade over the face of the rock into a small 
sandy cove, where boats can easily put in to supply shipping with 
wood and water. 
The prevailing winds off Tristan da Cunha blow from the west- 
ward and southward. Strong gales are frequent, but rarely con- 
tinue above twenty-four hours. They never blow quite home on 
the island, but incline upwards at some distance from the shore, 
: 3s2 and 
