30 ROYAL SOCIETY OF CANADA 
collected in the opening, and it was observed that the temperature at the 
centre with the water standing in it was 1-10th of a degree below 
freezing. The temperature remained below the freezing point for a 
period of four days, during which time slow freezing continued, and the 
temperature gradually approached the freezing point. The block 
diminished in size by surface melting, and its temperature approached 
the freezing point by the conduction of heat from the outside. Fig. 1 
illustrates the gradual rise of the temperature towards the freezing 
point. 
The freezing point on the thermometer was determined by immers- 
ing in a carefully prepared mixture of clear snow and water, and in a 
mixture of finely cracked ice from a similar block, and tap water. 
Both determinations agreed as closely as the thermometer could be read. 
The interesting part of this experiment is the anomaly of having 
supercooled water existing apparently in equilibrium with ice. 
> TEMPERATURE 
= 
a 
