ICE PHENOMENA. 421 



stances nnder wliicli it sometimes forms, is not found to be equally- 

 pure or dense, neither is it of uniform thickness. This ice irregularly- 

 acted upon by warm winds, or by the slanting rays of the sun at 

 different altitudes, shoves or expands from various directions other 

 than from the centre of the lake. During the early part of the last 

 ■vdnter the ice shoves were entirely from the east, in the vicinity of the 

 bridge. Upon an examination of the ice, I found that to the eastward 

 glare and dense, the ice to the west of the bridge was not so pure but 

 was seemingly thicker and more porous. This difference in its char- 

 acter was owing to snow having fallen during its formation ; the bridge 

 had retained the snow to the westward, and it became incorporated 

 with the new ice. The large open expanse to the east was constantly 

 swept by the wind. The glare ice became the most dense during cold 

 weather, and of course the m.ost susceptible of expansion by heat. Con- 

 sequently the shoving was (until subsequent rains had changed the 

 relative character of the ice) from the stronger and most susceptible 

 ice towards the weaker and less expansive. 



Ice on any large and irregular sheet of water studded with islands, 

 like Rice Lake, must naturally be of unequal thickness and density. 

 I have therefore no doubt whatever, that the phenomenon of ice ex- 

 panding and shoving from various directions is caused by the unequal 

 thickness, density and glareness of the ice, and like"wise by the 

 manner in which the heated atmosphere strikes it. 



The fact that channels opened in the lake (no matter whether trans- 

 versely or longitudinally) always close up on the ice exhibiting the 

 slightest tendency to expansion, is another proof that ice invariably 

 expands and shoves to the line of such least resistance, and under 

 peculiar circumstances from a general centre of the field. 



On mentioning these circumstances to a friend from Kingston he 

 asked : " If ice moves from the centre of the mass, why is it, that it 

 does not do so between Kingston and Wolf Island ?" and stated, that 

 on the contrary a longitudinal shove and fracture are generally vdt- 

 nessed in the middle of the stream. I replied that the centre of the 

 stream was generally the last to take, and being consequently the 

 weaker ice, was sure to be crushed and fractured by the stronger ice 

 on each side while expanding. I heard a seaman state, that he dis- 

 covered the channel of a harbour (formed by the entrance of a river 

 into the Black Sea) by the appearance of an irregular line of fracture 

 in the ice. 



