THE OCEAN — A LECTURE. 63 



Should a barrier be interposed from pole to pole, dividing 

 the earth into two hemispheres, there would be, from this 

 cause alone, four oceanic currents, two in each hemisphere, 

 two North of the equator and two South. The present 

 configuration of land and ocean presents nearly such a 

 barrier, and we have consequently Jour great oceanic 

 currents, two South of the equator and two North, or the 

 two great currents of the Atlantic and the two of the 

 Pacific. Besides these we have a number of counter cur- 

 rents, or eddies, produced by local causes, and from which 

 causes the main currents are somewhat modified. 



It was shown that these main currents flowed westward 

 upon the equator with equal uniform velocity, and that 

 the return currents flowed eastward both North and South 

 of this line. 



He briefly alluded to the great Fucus Bank, or Sargasso 

 Sea. in the North Atlantic, which covers an area of 260,000 

 square miles, and forms the center of this great whirl- 

 pool. 



In the Pacific Ocean, the currents are somewhat impeded 

 by the numerous islands that occupy the equatorial regions, 

 and we hence find that the westward current spreads out 

 over about 22° of North and South latitude, or about 3000 

 miles in width. 



The efi"ect of these currents upon the climate in various 

 parts of the earth was noticed at some length, and in this 

 connection what are termed the drift currents, that convey 

 the icebergs from both the polar regions towards the 

 equator. 



The phenomena of difference in the level of the Atlantic 

 and Pacific Oceans, in the Bay of Panama and on the East 

 side of the Isthmus, were briefly considered. 



There appears to be an apparent anomaly in nature in 

 this case, for, according to the laws of inertia and motion. 



