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47 



When we cast our eyes over the Atlantic, or 

 that deep valley which divides the western coasts 

 of Europe and Africa from the eastern coasts of 

 the new continent, we distinguish a contrary 

 direction in the motion of the waters. Between 

 the tropics, especially from the coasts of Senegal 

 to the Caribbean Sea, the general current, that 

 which Was earliest known to mariners, flows 

 constantly from east to west. This is called the 

 Equinoctial current. Its mean rapidity, corres- 

 ponding to different latitudes, is nearly the same 

 in the Atlantic and in the Southern Ocean, and 

 may be estimated at nine or ten miles in twenty- 

 four hours, consequently from 0*59 to 0*65 of a 

 foot every second # ! In those latitudes the wa- 

 ters run towards the west, with a velocity equal 

 tx> a fourth of the rapidity of the greater part of 

 the large rivers of Europe. The movement of 

 the ocean, in a direction contrary to that of the 

 rotation of the globe, is probably connected with 

 this last phenomenon, only as far as the rotation 

 changes the polar winds, which, in the low re- 

 gions of the atmosphere, bring back the cold air 

 of the high latitudes towards the equator, into 



* In comparing the observations which I had occasion to 

 make in the two hemispheres, with those which are laid down 

 in the voyages of Cook, La P6yrouse 5 d'Entrescasteaux,Van- 

 couver, Macartney, Krusenstern and Marchand, I found that 

 , *he swiftness of the general current of the tropics, varies 

 from 5 to 18 miles in twenty-four hours, or 0 3 to 1*2 feet 

 each second. 



