14 Depth of the Ocean. 



pleting the circuit of the world in the latitude of the Arctic 

 circle, subdivides itself into two parts, an eastern and a western 

 one — the former embracing Europe, Africa, Asia, and Australia, 

 the latter North and South America. In a similar manner the 

 different oceans combine into an area of depression, which, after 

 making the circuit of the world along the parallel of lat. 60" 

 South under the name of the Southern Ocean, divides itself into 

 three large basins, respectively designated as the Pacific, the 

 Atlantic, and the Indian Oceans. Thus the two elements, land 

 and water, starting from opposite hemispheres, extend their 

 arms across the Equator, holding each other in close embrace, 

 like two champions wrestling for the mastery of the world. 



Depth of the Ocean. — A comparison of the deep-sea 

 soundings obtained up to present date shows that, if we omit 

 the seas situated beyond the parallels of lat. 6o° N. and lat. 

 6o° S. — no depths exceeding 2000 fathoms having as yet 

 been ascertained beyond these latitudes — the average depth of 

 the ocean between these parallels may be estimated at about 

 2500 fathoms, or more roughly at three English miles, and the 

 average depth of all seas on the surface of the globe at probably 

 two miles. 



Contrary to the ideas formerly entertained of the enormous 

 depth of the ocean, the soundings of H.M.S. "Challenger," 

 S.M.S. " Gazelle," and of the U.S.S. " Tuscarora " and " Gettys- 

 burg," indicate that depths of five miles, or over 4000 fathoms, 

 are but seldom met with, and are as exceptional as heights of 

 the same amount on land. 



The greatest depth ascertained in the Atlantic was found by 

 H.M.S. " Challenger," in lat. 19 41' N., long. 65 7' W., about 

 eighty miles north of the island of St. Thomas, in the West 

 Indies. It is 3875 fathoms, or about four and a-half miles. In 

 May, 1876, the " Gettysburg" found 3593 fathoms in lat. 19 30' 

 N., long. 65 5' W., or only eleven nautical miles south of the 



