Section 76. The Influence of Temperature and Continuous Pressure 



Temperature has a considerable effect on the ability of ice to undergo all sorts of deforma- 

 tions. This property is shown very clearly in relation to the hardness of ice. 



Andrews computed the relative hardness of ice by comparing the depth of penetration of a 

 polished rod into ice at different temperatures with the depth of penetration of the same rod into ice, 

 the temperature of which equals 0°. 



The same experiments were conducted by Royen with a solid, transparent sea ice in which the 

 pressure in all the experiments was applied parallel to the plane of freezing. As a result of his 

 experiments, Royen presented the formula 



El = 



k^ 



l — t' 



(1) 



where e is the relative compression, 



fr is the constant coefficient for a given sample, 

 t is the temperature of the ice. 



Table 59 was computed according to formula (1) . 



TABLE 59. THE PENETRABILITY OF ICE AT DIFFERENT TEMPERATURES EXPRESSED 

 IN PERCENTAGES PENETRATION AT 0° 



Temperature in °C . . . 1 2 3 4 5 6 7 8 9 10 15 20 30 

 Percentage 100 50 33 25 20 17 14 12 11 10 9 7 5 3 



Komarovskii, who compared the results of Andrew's experiments (solid curve) figure 61 and 

 the computations according to Royen's formula (dashed curve) notes there is almost complete 

 agreement. 



ui 



m 

 a. 



o 



u 



-15' -20' 

 TEMPERATURE 



-25' 



-30° 



Figure 61. The compression of ice of different 

 temperatures under the effect of con- 

 stant pressure during identical per- 

 iods of time according to the experi- 

 ments of Andrew ( — ) and according 

 to Royen's formula ( — ). 



186 



