SECT. xni. J CURRENTS IN THE OCEAN. 113* 



peninsula past Madagascar to the most southern point of 

 the continent of Africa, where it mingles with the general 

 motion of the seas. Icebergs are sometimes drifted as far 

 as the Azores from the north pole, and from the south pole 

 they have come even to the Cape of Good Hope. But the 

 ice which encircles the south pole extends to lower latitudes 

 by 10 than that which surrounds the north. In conse- 

 quence of the polar Current Sir Edward Parry was obliged 

 to give up his attempt to reach the north pole in the year 

 1827, because the fields of ice were drifting to the south 

 faster than his party could travel over them to the north. 



The theory of under-current s setting from the poles to 

 the equator is proved to be erroneous by Kotzebue and Sir 

 James Ross, who found a stratum of constant temperature 

 in the ocean at a depth depending upon the latitude : at 

 the equator it is at the depth of 7200 feet, from whence it 

 gradually rises till it comes to the surface in both hemi- 

 spheres about the latitude of 56 26', where the water has 

 the same temperature at all depths ; it then descends to 

 4500 feet below the surface about the 70th parallel both in 

 the Arctic and Antarctic Seas. The temperature of that 

 aqueous zone is about 39 0- 5 of Fahrenheit. 



