10 



MR. H. TOMLINSON ON THE INFLUENCE OF STRESS AND 

 Experiment VIII. 



The vibration-period of the wire was made 4 seconds ; the reversals synchronised 

 with the vibrations of the wire, and the magnetising circuit was opened immediately 

 after each reversal. 



The value of the logarithmic decrement when there was no magnetic stress acting 

 on the wire was '000782, or little less than when the reversals were made as the wire 

 passed its position of equilibrium and the magnetic stress was 1*135. Even with the 

 higher stress of 42775 the effect of reversing when the wire was at the end of each 

 swing is very considerably greater than when the reversals are made in the position of 

 equilibrium. 



In the next experiment an attempt was made to ascertain to what extent the 

 magnetic stress could be reduced before it ceased to have any sensible effect on the 

 internal friction. 



Experiment IX. 



The reversals were made to synchronise with the vibrations of the wire, and as 

 exactly as possible when the wire had reached its extreme position on either side. The 

 vibration-period of the wire was 4 seconds. 



