TENSILE STRENGTH OF RIVET IRON. 



Table XXI. — Sectional area ='24850. 



m 



This bar tore into the shackle, so that the strain was not thrown properly 

 on It; the experiment was therefore discontinued, and another shackle sub- 

 stituted with the bearing-edges steeled. When the same bar was tried again 

 having been injured in the previous experiment, it broke with 19,285 lbs 

 Under these circumstances, we have taken the mean of the two experiments 



21,805 + 19,285 anPAf ii_ i i. 



2 ^0,54-5 as the breaking weight, as recorded in the Table. 



Table XXIJ. — Sectional area ='19635. 



74,153 



Bar defective : a large longitudinal 

 fissure, filled with scoria. 



=33104 tons. 



There IS a progressive increase in the strength of the bars as the temperature 

 ascends, lable XX. exhibiting an increase of 11,831 lbs., and Table XXII. 

 an increase of 3,308 lbs. over the breaking weight at 114°. Taking the 

 mean of the two last experiments, we have an increase of 7,569 lbs. over the 

 breaking weight in experiment XX. 



Table XXIII. — Sectional area ='24850. 



80,985 



= 36'I54 tons. 



This experiment being at the same temperature as the two last, viz. 212°, it 

 1856. 2 E 



