206 On the Determination of the Limit of Elasticity in Metals. 



It has above been shown that the limit of elasticity can be dis- 

 placed ; that this is also the case with the point of maximum 

 curvature is clear from fig. 1. Hence it cannot well be considered 

 an absolute measure for the quality of the material ; but it may 

 be regarded as a relatively good one, provided the bars inves- 

 tigated have undergone exactly the same treatment. 



§ 10. On the Relation between the Loads at the Maximum Curva- 

 ture and on Tearing. 



For the sake of its simplicity, a remarkable relation may here 

 be adduced which is observed between the loads at the point of 

 maximum curvature and on tearing ; a knowledge of it may per- 

 haps be of practical use. 



If M is the load at the maximum curvature, 

 B the load on tearing, 

 n the number of the bars investigated, 



we obtain the values of ^ given in the following Table : — 



Table VII. 



Kinds 

 of ore. 



Iron. 



Soft steel. 



Steel of mean 

 hardness. 



Hard steel. 



B 

 M* 



n. 



B 



M' 



n. 



B 

 M' 



n. 



B 

 M' 



n. 



a 

 b 

 c 

 d 

 e 

 f 



1-65 

 1-54 

 1-63 

 1-54 

 159 

 1-60 



3 



2 

 3 

 3 

 4 

 2 



2-02 



1-88 

 1-90 

 209 

 1-80 

 200 



2 



2 

 3 

 3 

 2 

 3 



2-03 

 210 

 212 

 200 

 201 

 1-90 



3 

 3 

 3 

 2 

 3 

 1 



202 



207 

 203 

 2-05 

 200 



2 



2 

 3 

 3 

 2 



Mean. 



1-59 





1-96 





207 





204 





Holding to the mean value for the different kinds of ore, and 

 denoting by 10 the load of iron at the maximum curvature, 

 and expressing in proportional numbers the loads at the maxi- 

 mum curvature and on tearing for the various kinds of steel, we 

 get the following values : — 



* The hardest steel of the kind b has been excluded from the list because 

 in this, as in many other respects, it materially deviated from the ordinary 

 kind. 



