240 



AUTOGRAPHIC DIAGRAMS. 



compression test of mild steel, and D is from a similar test 

 of Muntz metal. Owing to the fact that the load ordinate 

 depends on the movement of the poise, the tension diagram 

 terminates at the maximum load. 



A diagram produced by the Richly-Gray apparatus is 

 represented in Fig. 115. Here two curves are shown, that 

 marked A being the elastic curve, in which the stretch is 

 magnified 347 times, and B the curve for the whole test, in 

 which the stretch is magnified four times. In this latter 



120 



360 



330 



270 



FIG. 118. Torsion Diagram for Cast-iron Specimen. 



case the diagram gives true indications up to the actual 

 point of rupture. The material tested was a specimen of 

 machinery steel. 



On Fig. 116 is an autographic diagram taken on a Deeley 

 torsion machine. The material tested was a piece of 

 crank axle steel. 



Two spiral torsion diagrams taken by the writer on a 

 Buckton torsion machine are shown in Figs. 117 and 118, 

 the former being for a specimen of mild steel 5 in. long and 

 0'473 in. diameter, and the latter is for a bar of cast iron 



