THAT S IT : 



are frequently destroyed by firing 

 guns, 18, which, producing a dis- 



turbance of the air, checks the 

 whirling, and disperses the water- 

 spouts. The sea is also liable, 

 as in the Mediterranean, to dis- 

 turbances from vol- 

 canic eruptions, 19, 

 occurring under- 

 neath its bed, and 

 ! heaving up islands, 

 I which again dis- 

 j appear. [There is 

 in Central America 

 j a water volcano , 

 3 which, although 

 109. 12,600 feet above 

 the level of the sea, emits torrents 

 of water, and millions of stones, 

 but has never been known to 

 emit fire.~\ Earthquakes also 

 affect the sea by altering its bed, 

 or by swallowing up vast areas of 

 land, upon which the sea rushes 

 in. They also alter the channels 

 of rivers, and in this way aifect 

 the sea. 



Icebergs, 20, create consider- 

 able oceanic disturbances in seas 

 that approach the frigid zones. 

 In the arctic and antartic lati- 

 tudes, the cold is so intense that 

 the crests of waves freeze as they 

 rise, and k e accumulates until it 

 forms mountains, equal in weight 



to thousands of millions of tons. 

 These are driven by the winds 



and tides against each other with 

 terrible violence, and sometimes 

 entering warmer latitudes, ships 

 are overtaken by them and crushed 

 to pieces. 



Although the friction of the 

 wind upon the surface of the 

 ocean raises it into waves, 1, the 

 depths of the sea are calm, 2, and 



fishes swim, 3, and groves of ma- 

 rine plants, 4, nourish unaftected 



