276 



WRITINGS OP JOSEPH HENRY. 



[1855- 



surface currents, particularly in the northern hemisphere. 

 By comparing the two figures, it will be seen that the systems 

 A, B, and C, of Fig. 5, correspond with the three zones of 

 arrows in Fig. 6. To supply the air which ascends in the 

 region near the equator, the current on each side, on account 



Surface Wiiids of the Globe. 



Fig. 6. 



of the rotation of the earth, takes an oblique direction, (as 

 we have seen,) flowing in the northern hemisphere from the 

 northeast, and in the southern from the southeast. It con- 

 tinues its westerly motion as it ascends until it reaches its 

 culminating point, and then flows backward in an opposite 

 direction curving as it goes, toward the east. 



The surface currents on either side of the equatorial 

 region, (called the trade winds,) as they pass over the ocean 

 constantly imbibe moisture, and deposit but little in the form 

 of rain, since there is no obstacle on the level surface of the 

 water to produce an upward current and the consequent 



