230 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H Ser. 
lower parts of the islands than in the middle and upper regions. 
The weather is often practically clear at sea level, while a few 
hundred feet up it may be dark and gloomy, the clouds being 
arrested as they strike the mountains and thus hanging as fog- 
banks around the sides. Owing to the generally more open 
arrangement of the vegetation, there is not the same intense 
struggle among plants to get to the light that was noted in the 
rain-forests of Cocos Island, some three hundred and fifty 
miles northeast of the Galapagos. 
The most marked effect of light on vegetation is seen among 
some of the species of the Cactaceae, which seldom grow in 
shaded places, and, when they do so, are much stunted in 
growth. Specimens of Plumbago scandens usually have a deep 
red color when they grow in direct sunlight, a character that 
is usually not developed on specimens in the shade. 
Winds . 
The prevailing winds blow from the southeast, east-south- 
east, and south-southeast, and are the regular trade winds of 
this part of the Pacific Ocean. They blow quite regularly 
from June until January, but during the remainder of the year 
are very uncertain, and the waters surrounding the islands are 
subject to long periods of calm. Our vessel had to depend 
entirely on sail, and at one time it required from May 3rd until 
June 23rd to go from Villamil, on the south side of Albemarle 
Island, to Hood Island, a distance of about eighty-five miles. 
We spent two weeks of this time anchored at Charles Island 
waiting for wind, so that we were actually under way thirty- 
six days. The calm was so complete at one time during this 
trip that a flour tin, which was thrown overboard and which 
happened to light right side up, was still in sight forty-eight 
hours afterward. There are often light winds during the day 
in the calm season, but they usually go down, in the 
evening, and unfortunately do not always come up again on 
the following morning. It is very seldom that the winds come 
from a northerly direction, and when they do they are usually 
of short duration. Storms are very rare, but short squalls 
sometimes occurred several times a day at Tagus Cove on 
Albemarle Island during the months of March and April. 
Wolf, in his paper on the Galapagos Islands, mentions similar 
