TESTING MACHINE FOR EQUAL ALTERNATING STRESSES. CXXIX. 



A TESTING MACHINE FOR EQUAL ALTERNATING 



STRESSES. 

 By Prop. W. H. Warren, m. i»st. c.e., wh. so. 



[Read be/ore the Engineering Section of the Royal Society of N. S. Wales, 

 December 21, 1898.] 



This machine was designed and constructed in the Engineering 

 School of the University for the purpose of subjecting test 

 specimens to equal alternating stresses, and thus determining the 

 vibrating strength of the material. 



Fit*. 1. 



As will be seen from the diagram (Fig. 2), three specimens are 

 tested at the same time ; and spare test pieces are kept in stock 

 to replace those that are the first to fail, so that all the spindles 

 may be maintained in continuous rotation. The three pedestals 

 on one side of the base plate can be moved transversely, to 

 allow of different lengths oftest pieces being used. For example, 



