POLAR ICE. — DESCRIPTION OF ICE-BERGS. 255 



of chalk, or of white or grey marble. The sun's 

 rays reflected from them, sometimes give a glisten- 

 ing appearance to their surfaces. Different shades 

 of colour occur in the precipitous parts, accordingly 

 as the ice is more or less solid, and accordingly as it 

 contains strata of earth, gravel, or sand, or is free 

 from any impurity. In the fresh fracture, greenish- 

 grey, approaching to emerald-green, is the prevail- 

 ing colour. 



In the night, ice-bergs are readily distinguished, 

 even at a distance, by their natural effulgence ; and, 

 in foggy weather, by a peculiar blackness in the at- 

 mosphere, by which the danger to the navigator is di- 

 minished. As, however, they occur far from land, and 

 often in unexpected situations, navigators crossing 

 the Atlantic in tlie gloom of night, between the pa- 

 rallels of 50° and 60° of latitude, or even farther to the 

 south, require to be always on the watch for them. 

 In some places, near Cape Farewell, or towards the 

 mouth of Davis' Strait, they sometimes occur in ex- 

 tensive chains ; in which case, fatal accidents have 

 occurred, by vessels getting involved among them 

 in the night, during storms. But ice-bergs occur- 

 ring singly, have rarely been productive of any se- 

 rious mischief. 



Ice-bergs, though often dangerous neighbours, oc- 

 casionally prove useful auxiliaries to the whale- fish- 

 ers. Their situation, in a smooth sea, is very little 

 affected by the wind : under the strongest gale, they 

 arc not perceptibly moved ; ])ut, on tlie contrary, have 



