PROPERTIES OF PHOSPHOR-BRONZE WIRES 229 



wires from No. 1 to No. 7, inclusive, to be in state I. After that, 

 however, this state became exceptional. To illustrate how com- 

 plicated the changes of stales are, the following paragraphs 

 are given. 



It has already been stated how wire No. 1 changed from state 

 II into state III during the summer without any treatment. 

 The wire was then vibrated artificially by means of the ap- 

 paratus shown in figure 27, for 20 minutes at the rate of about 

 40 complete vibrations per minute. (During this process the 

 pendulum was fixed.) The state was now I and the curve 

 is shown in figure 29 (curve I). After another 30 minutes of 

 rotation the wire was in state III again. Another hour of vibra- 

 tion had no appreciable effect. 



The wire was then annealed by 1.2 amperes current in a ves- 

 sel exhausted to about 3 cm. pressure and under a load of 27 

 grams. The first condition above was simply a precaution to 

 prevent oxidation. The temperature became so high that the 

 wire softened and allowed its load to fall about 1 cm. to the 

 bottom of the annealing tube. A test now showed the wire to 

 be in state II again. At other times the same process yielded 

 state III. 



The same inconsistencies were found in all the wires. There 

 was never any doubt as to the state of the wires because of the 

 magnitude of the effects. 



Kates of loss of energy in states II and III. If A 1: I . .1 , be 

 the successive amplitudes of vibration, Ave may say that 



The Potential Energy at A x = j^_*A x 



2 



where & = Aj A 



or P. E. at A x KA\ 



L 



and P. E. at A« = KAl 



their dirTerence is 



and the rate of loss of energy is 



A%) 



The rates of loss of energy were calculated for several of each 

 type of curves. Two of each of types II and III are shown in 



