136 



On Ice and Brines 



water to that found in the brine. The difference between the 

 weight so found and that of the original water is the weight 

 of the ice formed. In Table II the results of this calculation 

 are given for Experiment III on pure sea-water from the 

 Clyde, and for Experiment IV on the same water diluted 

 with an equal weight of distilled water. 



TABLE II. Calculation of Ice formed, on the basis of the 

 Salinity of the Original Water and of the Residual Brine. 



Sea-water, like other saline solutions, is easily cooled 

 several degrees below its freezing-point before crystals begin 

 to form. While cooling down to and below what was known 

 to be its freezing-point, simultaneous observations of the 

 temperature of the sea-water and the freezing-bath were 

 made from half-minute to half-minute. From these observa- 

 tions, the rate of abstraction of heat for different differences 

 of temperature of sea-water and bath was found. At a given 

 moment a minute splinter of ice (weighing much less than a 

 drop of water) was introduced. Crystals immediately began 

 to form, and the temperature rose in from ten to fifteen 

 seconds to the freezing-point. During the freezing the tem- 

 peratures of bath and sea-water were observed at regular 

 intervals. The heat removed is thus made up of that 

 eliminated during the few seconds when freezing began and 

 the temperature rose to the freezing-point, which is found by 

 multiplying the rise of temperature by the weight of the water 

 in the liquid, and that removed during the subsequent cooling, 

 which is found from the duration of the operation and the rate 

 of loss of heat, deduced from observations made during the 



