POLAR ICE. — FRAGILITY OF ICE-BERGS. 257 



All ice becomes exceedingly fragile towards the 

 close of the whale-fishing season, when the tem- 

 perate air thaws its surface, and changes its solid 

 structure into a brittle mass of imperfectly attached 

 columns. Bergs, in this state, on being struck by 

 an axe, for the purpose of placing a mooring anchor, 

 have been known to rend asunder, and precipitate 

 the careless seamen into the yawning chasm, whilst 

 occasionally the masses are hurled apart, and fall in 

 contrary directions with a prodigious crash, burying 

 boats and men in one common ruin. The awful 

 effect produced by a solid mass many thousands or 

 even millions of tons in weight, changing its situa- 

 tion with the velocity of a falling body, whereby its 

 aspiring summit is in a moment buried in the ocean, 

 can be more easily imagined than described. 



Though a blow with an edge-tool on brittle 

 iee does not sever the mass, still it is often succeed- 

 ed by a crackling noise, proving the mass to be ready 

 to burst from the force of internal expansion, or 

 from the destruction of its texture by a warm tem- 

 perature. 



It is common, when ships moor to icebergs, to lie 

 as remote from them as their ropes will allow, and 

 yet accidents sometimes happen, though the ship 

 ride at the distance of a hundred yards from the ice. 

 Thus, calves rising up with a velocity nearly equal 

 to that of the descent of a falling berg, have pro- 

 duced destructive pfFeets. In the year 1812, while 



VOL. I. R 



