90 



THE ROYAL SOCIETY OF CANADA 



Log of Test. 



5,000 lbs. Slight crack. 

 9,700 lbs. Vertical crack — top to bottom. 

 13,200 lbs. Block rotation about vertical axis; the load was 



released, and plates were readjusted. 

 19,400 lbs. Ultimate load. Block failed by splitting up verti- 

 cally. 



19 400 



Ultimate strength ^ =108 lbs. per sq. inch. 



12 X 15 



F 



