6i4 



MOTONORI MATSUYAMA 



(c) parallel to the length of the bar. Since, as we will see later, 

 ice is affected by the phenomena of elastic fatigue, a new bar was 

 generally prepared for each experiment. These bars were not 

 always of the same magnitude; the bar la was made by cutting 

 bar I in half to see if we could get the same result. The results of 

 several observations are given in the following table : 



It will not be safe to consider the effect of temperature upon 

 Young's modulus in each case from these few determinations. 

 Since the range of temperature in these observations is not very 

 large, we may consider the mean values for each case not very far 

 from the truth. These mean values are: 



Here it is clearly shown that the specimens of orientation c 

 whose crystals are parallel to the long dimension of the bar have 

 the largest value of Young's modulus. We have already seen 

 that the modulus of rigidity seemed greater when shear is parallel 

 to the basal section of the constituent crystals than when per- 

 pendicular to it. These results have very important meaning in 

 considering the behavior of an aggregate of ice crystals. If the 

 gliding planes of an ice crystal parallel to the basal plane are the 

 main factor determining the behavior of an aggregation of ice crys- 

 tals under deforming forces, we must expect that ice will be deformed 



