2 THE OCEAN WORLD. 
3,500 fathoms. It is true that a great number of deep-sea soundings 
fall short of that limit; but, on the other hand, many others reach 
7,000 or 8,000. Admitting that 3,000 fathoms represent the mean 
depth of the ocean, Sir John Herschel finds that the volume of its 
waters would exceed 3,279,000,000 cubic yards. 
This vast volume of water is divided by geographers into five 
great oceans: the Arctic, the Atlantic, Indian, Pacific, and Antarctic 
Oceans. 
The Arctic Ocean extends from the Pole to the Polar Circle ; it 
is situated between Asia, Europe, and America. 
The Atlantic Ocean commences at the Polar Circle, and reaches 
Cape Horn. It is situated between America, Europe, and Africa, a 
length of about 9,000 miles, with a mean breadth of 2,700, covering 
a surface of about 25,000,000 square miles, placed between the Old 
World andthe New. Beyond the Cape of Storms, as Cape Horn may 
be truly called, it is only separated by an imaginary line from the vast 
seas of the south, in which the waves, which are the principal source 
of tides, have their birth. Here, according to Maury, the young tidal 
wave, rising in the circumpolar seas of the south, and obedient to the 
sun and moon, rolls on to the Atlantic, and in twelve hours after passing 
the parallel of Cape Horn is found pouring its flood into the Bay of 
Fundy, whence it is prejected in great waves across the Atlantic and 
round the globe, sweeping along its shores and penetrating its gulfs 
and estuaries, rising and falling in the open sea two or three feet, but 
along the shore having a range of ten or twelve feet; sometimes, as 
at Fundy on the American coast, at Brest on the French coast, and 
Milford Haven and the mouth of the Severn in the Bristol Channel, 
“rising and falling thirty or forty feet, “impetuously rushing against 
the shores, but gently stopping at a given line, and flowing back to 
its place when the word goes forth, ‘Thus far shalt thou go and no 
farther.’ That which no human power could repel returns at its 
appointed time so regularly and surely, that the hour of its approach 
and the measure of its mass may be predicted with unerring certainty 
centuries beforehand.” 
The Indian Ocean is bounded on the north by Asia, on the west 
by Africa, on the east by the peninsula of Molucca, the Sunda Isles, 
and Australia. 
The Pacific, or Great Ocean, stretches from north to south, from 
the Arctic to the Antarctic Circle; being bounded on one side by 
Asia, the island of Sunda, and Australia, on the other by the west 
coast of America. This ocean contrasts in a striking manner with ; 
the Atlantic: the one has its greatest length from north to south, the | 
