434 Proceedings of the Royal Society 
The western coasts of the continents are the weather shores of 
the oceans. Both the continents mentioned occupy positions 
which extend from the northern trade-wind region through the 
equatorial calms to the southern trade-wind region. The trade 
winds blow from the north-east and the south-east, and the result 
of their mechanical action is to drag away the water from their 
weather shores and drive it to leeward. As the wind acts at the 
surface it removes chiefly surface water, and it is the surface 
water which assumes the temperature due to the local climate. 
The water so removed must be supplied, and it is supplied from the 
readiest source. As the surface water is being removed by the 
wind, it draws on the deeper layers to supply the deficiency. 
But in low latitudes the deeper water in the ocean has always a 
very much lower temperature than that at the surface. Hence, 
at the weather shores of the oceans we have a constant removal 
of surface water to leeward and replacement of it by colder 
water from greater depth. The cold water found along the west 
coast of South America has always been considered evidence of 
the “ Humboldt current.” And so it is. But the Humboldt 
current, or at least the current which brings the cold water there, 
is not a horizontal current from higher latitudes, but a vertical one 
from greater depths. 
From Mogador a course was shaped for the Seine bank above 
referred to. It is indicated on the chart by two soundings of 
100 and 118 fathoms respectively, at a distance of 12 miles apart. 
The bank was struck on the position of the 118 fathom sounding, 
and a day was devoted to its exploration. A couple of “ balloon 
buoys ” were anchored in the noon position, namely, lat. 33° 47' N., 
long. 14° 1' W., the depth being 89 fathoms. Hempen swabs were 
attached to the end of the anchoring line. These balloon buoys 
are made of india-rubber and canvas, and when not in use occupy 
very little space. They are used for floating the shore end of a 
cable from the ship to the land, and they are then inflated with air 
by means of a small pump. They are much like footballs 3 
feet in diameter. The bank was crossed and recrossed in different 
directions, and found to occupy less surface than was expected. 
Its length in an approximately north and south direction is 6 
miles, and its breadth from east to west 3 miles. The depth of 
