32 



THE ROYAL SOCIETY OF CANADA 



After making his observations on reefs, Mr. Sawyer devoted 

 himself to a careful study of the expansion of ice. In this he con- 

 structed a trough the total length of which was 100 ft. This was made 



9'o' 





//moon + a/" . 

 £xpanj/c/t » / // 



/4-0 



Fig. 2. 



Sketches showing forms taken by ice reefs in 

 expansion cracks. (Sawyer). 



in 5-ft. sections connected together with a bellow-like construction 

 to allow for expansion and to maintain the whole apparatus water- 

 tight. The sections were constructed with a 2-inch by 8-inch plank 

 bottom with 1-inch by 10-inch sides. Rollers were placed under the 

 plank bottom, so that the sections would be free to move. The trough 

 was filled with water, and after it was frozen the sides of the box 

 were removed, so that the air would be in contact with as much of 

 the ice as possible. An indicator was made by fastening one end of 

 a swinging arm to one end of the ice box, the free end of the arm moving 



