376 



STRENGTH OF STEEL. 



The above figures, taken from a paper by Mr. Ricketts 

 in the American Society Civil Engineers, in 1887, are from 

 the results of a large number of tests of samples of steel 

 having various percentages of carbon. For each set the 

 figures higher up the list contain the smaller percentage 

 of carbon. It will again be noticed that the modulus is 

 in all cases higher in tension than in compression. 



198. Modulus of Rigidity for Steel. The following 

 table contains values of the modulus of direct elasticity 

 and the modulus of rigidity, taken from various sources : 



VALUES FOR THE MODULUS OF DIRECT ELASTICITY AND 

 MODULUS OF RIGIDITY. 



199. Determination of the Elastic Modulus by a 

 Committee of the British Association These tests were 

 primarily undertaken for the purpose of comparing the 

 behaviour of the different kinds of extensometers in use, 

 and have already been mentioned (p. 125). The results 

 of tests on six different bars of steel are given. The bars 

 tested were as follows : 



Flat bars, A and B, of ordinary mild steel. 



Cylindrical bars, E and F, of specially strong steel, 

 rolled for the committee by the Blaenavon Company. 



