THE ANTARCTIC REGIONS. 283 



dall, ' vaster masses sail which spring from a totally 

 different source. These are the icebergs of the polar 

 seas. They rise sometimes to an elevation of hundreds 

 of feet above the water, while the height of ice sub- 

 merged is about seven times that seen above.' ' What 

 is their origin ? ' he proceeds, speaking of those met 

 with in the northern seas. ' The Arctic glaciers. 

 From the mountains in the interior the indurated 

 snows slide into the valleys, and fill them with ice 

 The glaciers thus formed move, like the Swiss ones, 

 incessantly downwards. But the Arctic glaciers reach 

 the sea, and enter it, often ploughing up its bottom into 

 submarine moraines. Undermined by the lapping of 

 the waves, and unable to resist the strain imposed by 

 their own weight, they break across, and discharge vast 

 masses into the ocean. Some of these run aground on 

 the adjacent shores, and often maintain themselves for 

 years. Others escape, to be finally dissolved in the 

 warm waters of the ocean.' 



Now, it is important to notice that the Antarctic 

 icebergs are vaster and more numerous than those 

 formed in Arctic seas. How large these last are will 

 be understood from the instance referred to by Tyndall, 

 who, citing Sir Leopold McClintock, describes an Arctic 

 iceberg 250 feet high, and aground in 500 feet of water. 

 But Captain Maury speaks of Antarctic icebergs in the 

 open sea, hundreds of feet high and c miles in extent.' 

 'The belt of ocean that encircles this globe on the 

 polar side of fifty-five degrees south latitude is never 

 free from icebergs,' he adds ; ' they are formed in all 



