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the impulsive loading, and in machines of the Buckton type, having a 

 beam weighing several thousands of pounds, the stress imposed may be 

 more than doubled owing to the inertia of the beam. Thus in a test 

 of a tension bar having a section of 208 by 0-4 inches, with an extenso- 

 meter of the Martens type attached, the following readings were 

 obtained when the length under test was 8 inches and the times of ap- 

 plication were estimated by stop-watoh: — 



TABLE VI. 



The observations made showed that the strain varied after the 

 manner shown in Figure 5, the second vibration being almost invari- 

 ably the greatest. If, however, a compression piece is set in an 



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Turner 



hydraulic press, and a load is applied as quickly as possible, no such 

 vibration appears, and the strain does not appear to differ from that 

 obtained when the load is applied gradually. 



In order to determine if thermal measurements will detect an in- 

 crease of stress due to an impulsive load, a number of experiments were 

 made on tension and compression specimens. 



In order to compare results for different times of application of 

 the load, it is easily seen that the correction factor to be applied for 



