Currents in Wires subjected to Mechanical Strain. 347 



Experiment 8. — A similar wire. 33 measures left on for 

 about 40 hours. = 12°. Deflections read immediately after 

 removal of weight. Direction of current S.U. There was no 

 initial deflection. 



M. 



33 



30 



27 



28 



21 



18 



15 



12 



9 



6 



3 







c. 



•0095 

 •0046 

 •0035 

 •0039 

 •0049 

 •0060 

 •0067 

 •0074 

 •0084 

 •0091 

 •0098 

 •0105 



Experiment 9. — A similar wire. = 12°. No initial deflec- 

 tion. Deflections read immediately after application of weight, 



M. 



3 



6 



9 



12 



15 

 18 

 21 

 24 

 27 

 30 

 33 

 36 



O. 

 0025 

 0025 

 0021 

 0014 

 0014 

 0014 

 0014 

 0014 

 0011 

 0007 

 0004 

 0014 



Direction. 



U.S. 

 U.S. 



U.S. 

 U.S. 

 U.S. 

 U.S. 

 U.S. 

 U.S. 

 U.S. 

 U.S. 

 S.U. 

 S.U. 



Experiment 10. — A steel wire *47 millim. diameter. © = 12°. 

 Initial deflection 4 U.S. On attaching the empty can for 

 containing the shot to the end of the lever the deflection in- 

 creased to 20 U.S., falling to 14*5. The strain was gradually 

 increased by pouring shot into the can until the wire broke. 

 The deflection changed very little until the wire began to 

 stretch, when the deflection fell very rapidly, passed through 

 zero, and went up to about 40 S.U. 



The more rapid the stretching the stronger is the current 

 produced. When the strain was slightly lessened, so as to stop 

 the stretching, the deflection fell very quickly to 20 S.U. On 

 removing the strain the deflection fell rapidly, passed through 



