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ROYAL SOCIETY OF CANADA 



The relation of thermal change to compression stress and to strain 

 was determined in precisely the same manner as in the case of the 

 tension experiments, except that a strain measuring instrument of the 



I 



3 ToTTte nrturxLuCes 



Qoo E-xtonscmxeXe^ KecLcU/rujs 





Ewing type was employed as being more convenient. Its calibration 

 value was one -unit^l/SSOjOOO of an inch, and before using it was re- 

 calibrated, using a Whitworth measuring machine as a standard. 



