GREENLAND OR POLAR ICE. 275 



breaking surface. These crystals soon unite, and 

 would form a continuous sheet, but, by the motion 

 of the waves, they are broken into very small 

 pieces, scarcely three inches in diameter. As they 

 strengthen, many of them coalesce, and form a 

 larger mass. The undulations of the sea still con- 

 tinuing, these enlarged pieces strike each other on 

 every side, whereby they become rounded, and 

 their edges turned up, whence they obtain the 

 name of pancakes : several of these again unite, 

 and thereby continue to increase, forming larger 

 pancakes^ until they become perhaps a foot in 

 thickness, and many yards in circumference. 



Freezing of the Sea in sheltered situations. 



When the sea is perfectly smooth, the freezing 

 process goes on more regularly, and perhaps more 

 rapidly. The commencement is similar to that 

 just described ; it is afterwards continued by con- 

 stant additions, to its under surface. During 

 twenty- four hours keen frost, it will have become 

 two or three inches thick, and in less than forty- 

 eight hours time, capable of sustaining the weight 

 of a man. This is termed hay -ice ^ whilst that of 

 older formation is distinguished into light and 

 heavy ice ; the former being from a foot to about 

 a yard in thickness, and the latter from about a 

 yard upwards. 



