GREENLAND THE MOTHER OF ICEBERGS. 347 



ference of many thousands of yards ; when we reflect that 

 from one sixth to one eighth part of the ice only appears 

 above water, it conveys a still more wonderful idea of 

 the vastness of these floating" mountains of ice which 

 must weigh many millions of tons. The question of 

 the formation of icebergs is however still a mooted point 

 among scientific men, but according to the Encyclopedia 

 Britannica, the balance of probability seems to be 

 opposed to the idea of their forming upon the sea 

 itself. The thickness of ice formed by a winter's 

 frost, authorities seem generally to agree in saying, 

 does not exceed about seven feet in any one year, * 

 and though exact data upon these subjects are unattain- 

 able at present, it is supposed that the great bergs are 

 merely pieces broken off from the termination of 

 glaciers, where they move down from the interior of 

 the land, and reach the edge of the sea. f This of 

 course would account for their being fresh water ice. 

 According to the Encyclopedia Britannica 



" Greenland is the principal mother of icebergs " (in the 

 Northern Hemisphere). " The whole of the interior is believed 

 to be capped with an enormous glacier, always moving towards 

 the coasts, and at certain points reaching the sea, where 

 masses break off in the shape of icebergs." " Recent observa- 

 tions of one of the principal discharging glaciers of Greenland, 

 show it to be 920 feet thick, and 18,400 feet wide: and 

 that it advances at the rate of 47 feet a day during the 

 summer season." 



This ice would of course necessarily be fresh water 



* See Encycl. Brit., gth Edition. Vol. xix., p. 328. 



\ See The Great Ice Age, by Professor James Geikie, 3rd Edition, 

 1894, p. 47. 



Encycl. Brit., gth Edition., Vol. xix, p. 329. (Article " the Polar 

 Regions "). 



