158 THE WEATHER, AND WEATHER PROPHETS. 



the intertropical region, and a little more, and which, 

 though differing as to north and south, conspire in theii 

 general easterly character, the surface of the equatorial 

 ocean is driven westward, and directed full against the 

 two great barriers (the west coasts of America and Asia), 

 and divided northward and southward into streams or 

 currents which in their progress, after issuing from 

 tropical latitudes, receive a direction, by reason of the 

 rotation of the earth, corresponding to that of the anti- 

 trade winds. These also, beginning about the same 

 latitudes to descend to the sea level and strike on the 

 ocean, aid their further progress, and carry them, or 

 portions of them, far northward and southward into the 

 Polar Seas, there to perform the work above assigned to 

 them of melting the ice, and so keeping up the total 

 amount of the ocean-water ; besides mitigating, to a 

 great extent, the severity of the cold on the coasts in 

 high latitudes on which they strike ; of which we have a 

 familiar example in the warming influence of the cele- 

 brated Gulf-stream. 



(21.) The steady and equalized agency by which the 

 great system of the permanent winds and oceanic cur- 

 rents is kept up, which we have just described, contrasts 

 itself strongly with the violent and, as it may almost in 

 comparison be called, impulsive action of the sun on 

 and around the point of the globe over which, for the 

 moment, it happens to be vertical ; and which corre- 

 sponds to that portion of the solar energy which is 

 directly employed in producing evaporation. The nature 

 of this process we have now to explain. 



