M 



THE ROYAL SOCIETY OF CANADA 



They all show a gradual increase in thickness. The difference 

 in the initial thickness is due to the position of the ice with respect 

 to the openings through which the cold air gained admittance. This 

 illustrates very well the protective action of a cover under whicht the 

 heat of the water is more easily conserved. 



Melting of the Ice. 



The melting of the ice with the advent of warm weather was a 

 problem of some difficulty. The roof prevented the rotting action 

 of the sun which is the most powerful agent in nature for getting 



TABLE III. 



Table of Ice Thickness — Filter Bed No. 16. 



February and March, 1914. 



A. Thickness near south or open end of chamber. 



B. " " centre of chamber. 



C. " north or closed end of chamber. 



D. A channel in the ice was made down the centre of the chamber and covered 



with blocks of ice early in the winter. Measurements were taken near 

 the north end through these blocks where it was found that ice had formed 

 downwards on these blocks, into the channel giving a greater thickness 

 as indicated. 

 D. = total thickness. 



E. = Depth of ice extending below general surface. 



F. = Height of block above general surface. 



