Efects on First Loading a Wire. 623 



Similar sets o£ curves have been obtained with copper 



Ffc. 2. 



wires. 



12 3 4-5 



(1) Normal behaviour of specimen. 



(2) After being on a cylinder of 6 cm. diameter. 



(3) „ „ „ 4*5 „ „ 



(5) „ „ „ 1*5 „ „ 



The amount of tension applied to the wire in the process 

 o£ winding it, at least if it remains within the elastic limit, 

 does not seem to affect the form of the curve very appreciably. 

 A very large number of specimens have been examined, and 

 if there is any effect, it is almost of the order of experimental 

 error and is in the direction of increasing extension with 

 increasing tension. 



That these effects are of the same nature as the apparent 

 elastic loss observed in the case of iron or steel rods after 

 overstrain is further shown by the fact that the effect dis- 

 appears slowly with lapse of time, if the wire is kept suspended 

 in a straight condition under very small tension. Fig. 3 

 (p. 624) illustrates this recovery. In two months' time, a 

 specimen had recovered half- way to its normal condition as 

 a straight wire, while even in a week considerable progress 

 had been made. Similar results have been obtained with 

 other sizes of cylinders as well. 



