420 ICE PHENOMENA. 



This phenomenon seemed as if it would baffle investigation, and it 

 was only by careful observation of all the circumstances attending the 

 formation and movements of the ice that I could deduce a theory to 

 my satisfaction. It would perhaps be well to describe that portion of 

 Rice Lake which came within my observation. The railway bridge 

 crosses the lake at its widest part. An island, containing some three 

 acres of land, is situated on the line of the bridge, about three-fourths 

 of a mile from the south shore. The bridge is formed of pile bents, 

 with the exception of that portion immediately to the north of Tie 

 Island, which is a continuous truss for half a mile. To the east is a 

 wide and unobstructed expanse of water ; at the distance of perhaps 

 four miles from the bridge, the lake is narrowed by two promontories 

 to a mile in width. Less than a mile to the westward a succession of 

 beautiful islands rise from the lake. The Otonabee River, a large 

 sluggish stream, enters the lake opposite those islands from the north. 

 "We have .then at this particular part of the lake some twelve square 

 miles of water-way. When this large space is therefore covered with 

 glare ice, and is swept by warm winds after a previous low temperature, 

 the amount and force of its expansion is somewhat surprising. 



An instance of expansion from the centre of this large field may 

 be cited: — In December, 1857, the lake was covered with dense glare 

 ice five inches in thickness. The temperature was extremely low 

 (ranging from minus 10^ to minus 30*) for some time after the ice 

 formed, it suddenly rose to plus 30° previous to rain. The expansion 

 that followed was of the most violent description. The truss bridge 

 superstructure moved two feet six inches on to Tic Island ; the pile 

 bridge south of the island was forced four feet and a half on to the 

 south shore. The bridge was slightly shoved to the north, but was 

 mainly preserved by the parallel channels that happened to be open 

 for the purpose of isolating it in that direction. The centre of the 

 bridge was not afPected in the slightest, it being the neutral point. 

 The ice was piled on to Tic Island from the north, east and west, but 

 on the south side it was toi-n away from the shore, exhibiting a fissure 

 or opening some twenty inches in width. 



Instances of the ice shoving on to the north and south shores of the 

 lake, and also on to the shores of islands at the same time, are frequent. 

 In fact, when the ice is equally dense and glare, and being fairly 

 acted upon by a warm atmosphere, it must naturally expand from its 

 centre to its circumference. But ice, owing to the peculiar circum- 



