130 THE WORLD. 



moved over in the same time. If therefore, a body, still retain- 

 ing the quantity of motion it had while upon A B, should sud- 

 denly be placed upon E E, it is evident that the excess of motion 

 at E E would leave it behind. This is actually the case with the 

 colder air rushing from the higher latitudes to fill the space vaca- 

 ted by the ascent of heated air Within the tropics. The air thus 

 transferred, does not acquire at once the motion of the equatorial 

 regions, and consequently lags behind, or-the earth moves uncfer 

 it, and thus since the earth moves from west to east upon its axis, 

 it gives the appearance of a wind coming from the opposite quar- 

 ter, i. e. from the eastward. But, as we have seen before, these 

 winds had a direction from the north, at all places uorth of the 

 equator, and from the south, at all places south of the equator, 

 'Combining the two therefore, we will have a constant north-east 

 wind one side of the equator, and south-east the other; these two 

 winds, meeting at the equator, will flow constantly eastward, or 

 destroy each other and produce a calm. Such is the character of 

 that general wind, which encircles the globe, flowing with slight 

 deviations, constantly from the east, and spreading over a zone of 

 more than 50 in breadth. It sweeps the Atlantic ocean from the 

 coast of Africa to Brazil, and the Pacific from Panama to the 

 Phillipine islands, and New Holland; and again over the Indian 

 sea partially, from Summatra to Zanguebar ; here however its 

 direction is curiously varied, owing to the peculiar locality of this 

 ocean. 



The course of the trade winds is changed or interrupted by high 

 lands, thus calms and variable winds prevail at the Cape Verd 

 islands, being under the the lee of the African shore, and an eddy, 

 or counter current of air from the south-west, is generated under 

 the coast of Guinea. The lofty barrier of the Andes shelters 

 the sea on the Peruvian shores from the trade winds, which are 

 not felt until a ship has sailed eighty leagues westward, but the 

 'intervening space is occupied by a wind from the south. The 

 heated air of the tropi$s after becoming somewhat cooler in its 

 passage towards the temperate regions, descends to the earth 

 still retaining in a great measure, its equatorial velocity, conse- 

 quently, it sweeps over the surface of the earth in the same di- 



