3 



Mr. T. E. Stanton on 



the condition for a maximum value of p being when 



Substituting this value for e in equation (2) we have, 

 taking C = 39-4, 



p — 22*45 tons P er square inch. 



This corresponds very closely with the mean maximum 

 stress of wrought-iron of this brand, experiments on rough 

 bars giving values of/ ranging from 2r8 to 2070 tons. 



Table I. 



Tests of nine specimens cut from a bar of wrought-iron. Brand 

 R.H., Croivn B.B.B. 



No. of 



Initial 



Final 



Permanent 



Stress on 



Value 



Specm. 



Area. 



Area. 



Strain. 



Reduced Section. 



of C 





sq. in. 



sq. in. 





Tons. 





Z. 1. 



7643 



7420 



•O307I 



16*480 



39*37 



Z. 2. 



759° 



7238 



•O5227 



18-873 



39'48 



z. 3. 



•7528 



•6999 



•08133 



20-977 



39'3 2 



Z. 4. 



•7648 



7378 



•O3978 



17*620 



39'46 



z. 5. 



•7605 



7158 



•06585 



i9'973 



39H2 



Z. 6. 



•7810 



7638 



•O233O 



i5'338 



39- 2 7 



Z. 7. 



•7600 



7412 



•O2689 



15-893 



39-25 



Z. 8. 



75 IQ 



•7178 



•O4668 



18-306 



39'38 



Z. 9. 



•7560 



7306 



•034.9O 



17-068 



39'49 



Test of one specimen cut from a bar of wrought-iron. Brand 

 R.H. Croivn B.B.B. Duration of stress 15 minutes. 



No. of 

 Specm. 



Initial 

 Area. 



Final 

 Area. 



Permanent 

 Strain. 



Stress on 

 Reduced Section. 



Value 

 ofC 





sq. in. 



sq. in. 





Tons. 





2. 



74IO 



















— 



— 



7238 



•O245O 



I5-888 



40-I7 











7163 



■03547 



I7-45I 



4O'20 











7066 



•O5OO5 



19-106 



40-40 



— 







•694O 



'07 159 



20-893 



40-40 











•6725 



•I0875 



23-050 



40'15 



