30(5 



mi:. MS OF TEST BARS. 



the case of the first bar. The tests showed the breaking 

 strength of the parallel specimen to be 35 '87 tons per 

 square inch, and for the nicked specimen 53'25 tons 

 per square inch. These results show very well the effect 

 of the suppressing of the drawing out in increasing the 

 tensile stress. 



In the discussion on Mr. Hackney's* paper, Mr. 

 Stromeyer gives the results of some tests he made on 

 test pieces of the forms shown on Fig. 156. Of these 

 there was one made of the form A, four of B, with 

 varying ratios of b to d, and there were eight bars marked 

 C, also with varying ratios of b to d. The following 

 table contains the chief results obtained, the measure- 

 ments being reduced to British units : 



1 60. Cracks in the Edges of Bars. Experiments in 

 this direction have been made by Mr. (now Sir) Benjamin 

 Baker, and the results are given in the discussion on 

 Mr. Stromeyer's paper read before the Institution of 

 Civil Engineers. f 



The forms of the bars tested are shown on Fig. 157. 

 Of these A is an ordinary flat test bar of the original 



* Min. Proc. lust. C.E., vol. Ixxvi. 

 t Min. Proc. Inst. C.E., vol. Ixxxiv. 



