234 IOWA ACADEMY OF SCIENCE 



may say that long annealing with the wire under a small load, 

 and at a comparatively high temperature, causes state III. On 

 the other hand long continued vibration causes state II. 



SUMMARY AND CONCLUSION. 



The. main points of this paper on the elastic properties of 

 phosphor-bronze wire, are: 



1. There are three states in which the wires appear. 



2. Drawing of the wires has a tendency to increase the ef- 

 fect of a varying period with the amplitude. 



3. The magnitude of the period of vibration and the load 

 supported by the wire have no appreciable effect upon the 

 period-amplitude curves. 



4. In a given sample of wire with a constant load and 

 period, the number of vibrations executed during a fall of a 

 given number of degrees in amplitude, varies inversely as the 

 length of the suspension. N*xL=K. 



5. The initial amplitude determines to a certain extent the 

 rate of loss of energy of the pendulum. 



6. In the larger amplitudes state II has a more rapid rate 

 of loss of energy than state III and their rates tend to become 

 equal in the smaller amplitudes. 



7. The amplitude-vibration number curve of state III is 

 gentler in slope than the one of state II but the two coincide in 

 the smaller amplitudes. 



8. In general, long continued annealing at a comparatively 

 high temperature brings about state III. 



9. Long continued vibration will, in general, bring aboirt 

 state II. 



In conclusion we must say that phosphor-bronze wires are 

 certainly not fit for use in delicate suspensions. The elastic 

 peculiarities are too complicated to be corrected for. 



While these elastic properties may be typical of this alloy 

 alone, it is reasonable to suspect that other alloys have their 

 distinct peculiarities just as platinum-iridium and these wires 

 were found to have. 



I wish to acknowledge my indebtedness to the staff of the 

 Department of Physics for their interest in the problem, and 

 especially to Dr. Sieg for suggesting it, and for his encourage- 

 ment and assistance during the progress of the work. 



State University of Iowa. 



University of Iowa. 



