XVII 
CHATHAM ISLAND 
399 
surrounding water, brought here by the great southern Polar 
current. Excepting during one short season very little rain 
falls, and even then it is irregular ; but the clouds generally 
hang low. Hence, whilst the lower parts of the islands are very 
sterile, the upper parts, at a height of a thousand feet and 
upwards, possess a damp climate and a tolerably luxuriant 
vegetation. This is especially the case on the windward sides 
of the islands, which first receive and condense the moisture 
from the atmosphere. 
In the morning (17th) we landed on Chatham Island, which, 
like the others, rises with a tame and rounded outline, broken 
here and there by scattered hillocks, the remains of former 
craters. Nothing could be less inviting than the first appear¬ 
ance. A broken field of black basaltic lava, thrown into the 
most rugged waves, and crossed by great fissures, is everywhere 
covered by stunted, sunburnt brushwood, which shows little 
signs of life. The dry and parched surface, being heated by 
the noonday sun, gave to the air a close and sultry feeling, 
like that from a stove : we fancied even that the bushes smelt 
unpleasantly. Although I diligently tried to collect as many 
plants as possible, I succeeded in getting very few ; and such 
wretched-looking little weeds would have better become an 
arctic than an equatorial Flora. The brushwood appears, from 
a short distance, as leafless as our trees during winter ; and it 
was some time before I discovered that not only almost every 
plant was now in full leaf, but that the greater number were in 
flower. The commonest bush is one of the Euphorbiacese : an 
acacia and a great odd-looking cactus are the only trees which 
afford any shade. After the season of heavy rains, the islands are 
said to appear for a short time partially green. The volcanic 
island of Fernando Noronha, placed in many respects under 
nearly similar conditions, is the only other country where I 
have seen a vegetation at all like this of the Galapagos islands. 
The Beagle sailed round Chatham Island, and anchored in 
several bays. One night I slept on shore on a part of the 
island where black truncated cones were extraordinarily 
numerous : from one small eminence I counted sixty of them, 
all surmounted by craters more or less perfect. The greater 
number consisted merely of a ring of red scoriae or slags 
cemented together : and their height above the plain of lava 
