850 Sir W. Thomson—General Ocean Circulation. 
may be practically disregarded: and speaking in this sense it 
may be said that the trade-winds and their modifications and 
counter-currents are the cause of all movements in the stratum 
n the distribution of climate is sufficiently simple. Disre- 
garding minor details, the great equatorial current driven from 
east to west across the northerly extensions of the ocean by the 
trade-winds, impinges upon the eastern coasts of the continents. 
A branch turns northward and circles round the closed end of 
the Pacific, tending to curl back to the North American coast 
from its excess of initial velocity ; and in the Atlantic, follow- 
ing a corresponding course, the Gulf Stream bathes the shores 
of Northern Europe, and a branch of it forces its way into the 
Arctic basin, and battling against the paleocrystic ice, keeps 
imperfectly open the water-way by which Nordenskjéld hopes 
o work his course to Behring’s Strait. The southern deflec- 
tions are practically lost, being to a great extent, though not 
entirely dissipated in the great westerly current of the southern 
anti-trades. 
One of the most singular results of these later investigations 
is the establishment of the fact that all the vast mass of water, 
