THE AECTIC SEAS. Ill 



same process again going on in summer, of water 

 percolating through the porous ciystals, which in its 

 turn was refrozen, soon changed the lowest stratum 

 into a mass of dense and transparent ice. Centuries 

 of alternate winters and summers have thus produced 

 aggregations of enormous hulk. Scoresby mentions 

 one of eleven miles in length, and four hundred feet 

 in height at the seaward edge, whence it slopes up- 

 ward and backward till it attains the height of six- 

 teen hundred feet; an inclined plane of smooth 

 unsullied snow, the beauty and magnitude of which 

 render it a very conspicuous landmark on that inhos- 

 pitable shore. The upper surface of a land iceberg is 

 usually somewhat hollow, and during the summer the 

 concavities are filled with pools or lakes of the purest 

 water, which often wears channels for itself throuch 

 the substance, or is precipitated in the form of a 

 cataract over the edge. The water freezing in fissures 

 thus produced, and expanding with irresistible force, 

 tears off large fragments from the outer edge, wliich 

 are precipitated into the ocean ; and high spring 

 tides, lashed by storms, undermine portions of the 

 base, and produce the same effect. The masses thus 

 dislodged float away, and form ice-islands. When 

 newly broken, the fracture is said to present a glis- 

 tening surface of a clear greenish blue, approaching 

 an emerald green ; but of such as I have myself had 

 an opportunity of examining in Newfoundland, the 

 hollows were of the purest azure. 



" On an excursion to one of the Seven Icebercrs," 

 says Mr. Scoresby, "in July, 1818, I was particularly 

 fortunate in witnessing one of the grandest effects 



