162 HEAL STUKSS DIAGRAMS. 



But 



Real stress 



Apparent stress 



. A_ 

 a 



G_B 

 " GC 



BF 



P, E. 



The defect in using this construction is due to the fact 

 that, after the first few loads beyond the elastic limit have 

 been passed, the parallel form leaves the specimen, and it, 

 becomes more and more barrel-shaped. 



