378 Prof. Harrison and Mr. S. K. Chakravarti on the 



fig. 4 (1), and the numerical results will be found in 

 Table I. 



Fig. 4. 



24 



23 

 §22 



| 20 

 518 



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20 



40 



60 80 100 



Temperature 



120 



140 



160 



Experiment 2. 



A new portion of wire was mounted in the apparatus and 

 stretched at 27°, first for 32 hours under a tension of 

 26 kilos / sq. mm. ; subsequently for 24 hours under 

 38 kilos/ sq. mm.*. The wire was straightened by this 

 treatment, bat remained hardened by the slight permanent 

 strain produced. The specimen was then tested in the same 

 way as the annealed wire, except that measurements were 

 begun at laboratory temperature and were carried on with 

 successively rising temperatures up to 140° 0. Points marked 

 with crosses on the graphs represent a series of measurements 

 taken with continuously falling temperature after the main 

 series was finished f. 



As in experiment 1, in all cases load elongation graphs are 

 seen to be straight lines within the limits of experiment. 

 The corresponding Young's modulus temperature curve is 

 given in fig. 4 (2), and the numerical results in Table II. It 

 is not considered necessary to show specimens of the load 

 elongation graphs in this experiment, as they are of precisely 

 the same type as those in fig. 3. 



The dotted curve in fig. 4 represents, on the same scale as 



* Half the breaking stress Is about 28 kilos/sq. mm. 



t One or two values, both in experiments 1 and 2, lie off the curve. 

 They are inserted as the discrepancy cannot be accounted for, and there 

 is no justification for excluding them. 



