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IOWA ACADEMY OF SCIENCE 



lum was set into vibration without any preliminary vibrations. 

 The results of this test are shown in curve III. We see that the 

 wire had changed from state II to state III in supporting its 

 load during the summer. 



ZLO 



2.5.0 



o 





S 10 



Amplitude 0*r 



Fig 31. 



'A 



Prom the coordinates it is readily seen that the maximum 

 variation from a constant period, between the two curves, is 

 about 3.85 seconds. Considering this variation with the maxi- 

 mum period of the two curves, it is found to be in the neighbor- 

 hood of 16 per cent. 



Curve I shows the identical sample of wire when in state I. 

 It is seen that the variation from a constant period is not so 

 marked in this type. 



This phenomenon is found to be less marked as the diameter 

 of the suspension becomes larger. In other words the draw- 

 ing of the wires has a tendency to increase the effect. Figure 

 30 shows the results of experiments with seven successive 

 drawings when the wires were in state I. Figure 31 shows the 

 results of the four smallest of the above seven wires when in 

 state III. The curves of each figure are reduced essentially, 

 to a common period at a given amplitude. The diameter of the 

 wires are given in figure 30. This result is similar to that 

 found in platinum-iridium wires by Sieg 6 . 



e L. P. Sieg, Phys. Rev., Vol. 35, 1912, p. 347. 



