﻿1 8 POPPLEWELL, Uniform Stress and Permanent Strain. 



results are obtained from surface measurements near the 

 middle of the bars than where obtained from end 

 measurements. In this respect they more nearly approach 

 the tension results, which would seem to indicate that 

 the correct way of making determinations of this kind on 

 compression specimens, is by means of surface measure- 

 ments. 



The experiments described were carried out in the 

 Engineering Laboratory of the Yorkshire College, Leeds, 

 and in the Materials Testing Laboratory of the Manchester 

 School of Technology. 



