AUTOGRAPHIC DIAGRAMS. 



co-ordinates, it will be necessary to re-plot them on squared 

 paper. With regard to the diagrams themselves, it will be 

 seen that the elastic portion of the curves in all cases 

 coincides with the base line, the scale being such that the 



L Zero Line, 4 Magnifications. 

 M Zero Line, 347 Magnifications. 



FIG. 115. Riehle-Gray Autographic Diagrams from Tension Specimen 

 of Machinery Steel. 



-elastic extensions are inappreciable. The elastic limit is 

 well marked, but it will be noticed that the curve beyond 

 the limit follows a somewhat erratic course before settling 

 down to the semi-plastic extension ; after the limit load is 

 passed the extensions increase rapidly with the increase of 



Torsion Diagram . 



(9 



90 US ISO 225 270 313 060 405 45O 



of Torue 



FIG. 116.* 



load for some little time, and then, as the extension 

 increases, it will be noticed that the load diminishes 

 again slightly for a time, and then continues to increase, 



* Inafc. Mech. Eng. Proc., 18U8. 



