[barnes-hayward- EXPANSIVE FORCE OF ICE 49 



MCLEOD] 



(2) An ice block will yield under pressure at approximately 

 200 pounds per square inch, which is probably due to the slipping of 

 the crystals. 



(3) An ice sheet will form cracks on the upper and under surface 

 due to unequal strain. 



(4) That a permanent expansion may result if the cracks be- 

 come filled and frozen. 



(5) According to the most trustworthy results of other observers, 

 the ice frozen to concrete develops its full crushing strength, and the 

 tensile strength of ice is under 200 lbs. pensquare inch. 



Sec. Ill, 1914—4 



