Exp. 



ON THE MECHANICAL PROPERTIES OF STEEL. 123 



SECOND SERIES OF EXPERIMENTS. 



TENSILE STRAIN. 



I. (June 1867). — Bar of Steel from the Barrow Haematite Steel and 

 Iron Company. Elongations taken on 8 inches length. Mark on bar, 

 "HI." Diameter of specimen -744 inch. Area -4347 square inch. 

 Eeduced diameter after fracture -744 inch. Area '4347 square inch. 



Besults. — Here the breaking-strain (P,) per square inch of section is 

 93,383 lbs., or 41-7 tons, and the corresponding elongation (?^) is -0406. By 

 formula (13). — The work (t() expended in producing rupture = 1895. 



Exp. 



II. — Bar of Steel from the Barrow Haematite Steel and Iron Company. 

 Elongations taken on 8 inches length. Mark on bar, " H 2." Dia- 

 meter of specimen -69 inch. Area -3754 square inches. Eeduced 

 diameter after fracture ^66 inch. Area •3401 square inch. 



Results.- — Here the breaking- strain (Pj) per square inch of section is 

 80,724 lbs., or 36^03 tons, and the corresponding elongation (ZJ is ^0866. 

 By formula (13). — The work (i<) expended in producing rupture = 3495. 



