Currents in Wires subjected to Mechanical Strain. 34:5 



comes to its final state after the wire has been violently dis- 

 turbed, as in the last experiment, as also the fact of there being 

 a permanent as well as a temporary effect, seem to render this 

 hypothesis more probable than that the current is actually 

 produced by a change in the molecular state of the wire. 



The phenomena obtained in the last experiment will be ren- 

 dered more clear by a diagram. 



The intervals between taking off and putting on the weight 

 were approximately equal. These are therefore represented 

 by equal distances along the axis T; and the strength of the 

 current is set off along the axis C. Starting from the point 

 0, at the beginning of the experiment, with the weight attached 

 to the wire as it had been left, then at any time the broken line 



represents the permanent change in the current pro- 

 duced by taking off or putting on the weight ; 



represents the temporary change; 



represents the resultant strength of the current, being 



the sum of these two components. 



The curve A represents the change in the current when the 

 weight is left permanently attached; and the curve A / repre- 

 sents the change in the current when the weight is perma- 

 nently removed. 



At this stage in the experiments the method of measuring 

 the current-strength in terms of a standard current was adopted. 



The battery used as a standard was a " sawdust " Darnell's 

 (Menotti's) cell; and the strength of the current was approxi- 

 mately that produced by 1 volt through 10,000,000 ohms, or 



