[BARNES] THE PHYSICAL CONSTANTS OF ICE S 



The question of a possible difference between new and old ice was 

 subjected to a careful study by Barnes and Cooke in 1901. They obtained 

 large blocks of clear ice forming the under-side of the surface sheet on 

 the St. Lawrence river. Such ice was obtained freshly formed and com- 

 pared with similar ice which had been in the cold-storage warehouse of 

 the City Ice Company, for one and two years. The method employed 

 was to weigh the ice directly in water at 0°C. No difference was 

 found due to age comparable with the values found by Nichols. The 

 fresh ice had a density of .91674, the ice one year old was .91660, and 

 the two-year-old ice was .91649. These values tend to show, as Hess 

 points out, a relaxing of the crystalline texture with time. The mean 

 of the various determinations give ,916611 for the St. Lawrence river 

 ice. 



In 1902 J. H. Vincent determined the density of ice by weighing 

 water in mercury. The water was weighed both as liquid at 0°C. and 

 as solid at several degrees below zero. The mean value found Nvas .9160. 



In 1906 A. Leduc undertook a new determination of the density. 

 The presence of air formed the basis of special study and it was found 

 that even boiled water contains a large quantity of dissolved air. As 

 much as 1 cc. per liter was extracted by a special method. Leduc dis- 

 covered that the density increases as the amount of dissolved air de- 

 creases, and he concludes that the density of gas-free ice is .9176. 

 The influence of dissolved air helps to explain the small differences in 

 the work of previous observers and shows that the variations observed 

 by Nichols may possibly be due to this cause. 



We may conclude that the most probable values for ice formed in 

 the usual way from boiled water, may be taken as follows : — 



TABLE I . 



Brunner 91685 



Zakrzevski .91666 



Nichols 91615 



Nichols .91772 



Vincent .91600 



Leduc 91720 



Mean 91676 



while for natural ice we have 



TABLE II. 



Nichols 91806 



Nichols 91644 



• Barnes and Cooke .91661 



Mean 91704 



