THE THERMO-ELECTRIC EFFECTS OF LONGITUDINAL STRESS IN IRON. 5 I 



§ 28. Next I tried a few experiments on iron wires hardened 

 by stretching them beyond their limits of elasticity. Pieces cut from 

 the same bundle as the foregoing, after being carefully annealed, were 

 drawn with about 15 kilos., and coupled with each other. When 

 tested, they showed nothing worthy of notice ; the thermo-electric 

 curves obtained were in every respect of Prof. Ewing's type. It is 

 evident, as it is from other points of view, that by the operation of 

 wire drawing metals are subjected to far more complex combinations 

 of stresses and strains than when they are simply stretched. 



