28 Permanent Molecular Torsion of Conducting Wires. [Mar. 31, 



fully brought the wire to zero, and then observed the first contact 

 only. I found, then, that the first contact gave a value of 40, but 

 the second and following only one or two. By bringing the wire 

 back to zero by a momentary touch with a magnet, a continued force 

 of 40, or if constant reversals were used instead of a simple contact, 

 there was constant proof of a similar great molecular change by the 

 passage of a current in steel as well as iron. 



I can find no trace of the reaction of the wire upon the magnetism 

 of the earth, as in all positions the same degree of force was obtained 

 if great care is take that the wire is absolutely free from longitudinal 

 magnetism. There is, however, a slight reaction upon its own return 

 wire if brought within 1 centim. distance of the wire, and this reduces 

 the twist some 10°. The maximum effects are obtained when the 

 return wire is not nearer than 25 centims. ; thus, the action is not 

 one produced by a reaction, but by direct action upon its internal 

 structure. 



Copper and silver wires so far show no trace of the action. I 

 believe, however, that a similar strain takes place in all conductors, 

 and I have obtained indirectly indications of this fact ; in order, how- 

 ever, to verify this, would require a different method of observation 

 from the one I have described, and I have not yet perfected the 

 apparatus required. 



It seemed probable that if I approached a strong permanent magnet 

 to the wire, I should perceive a twist similar to that produced by the 

 passage of a current ; but no such effects were observed, but it has 

 a most remarkable effect of instantly bringing to zero a strain pro- 

 duced by the current, and, no matter which pole, the effect was the 

 same. Thus, a strain of 50°, which remains a constant, instantly dis- 

 appears upon the production of longitudinal magnetism, and I have 

 found this method of reducing an iron wire to zero of strain far more 

 effective than any other method yet tried, such as vibrations, heat, 

 twisting, &c. 



It will be seen from this that the molecular arrangement set up 

 by magnetism is very different from that produced by the passage 

 of an electric current. It evidently has a structure of its own, else 

 it would not have instantly destroyed the spiral strain left by the 

 passage of electricity if it had not taken up a new form, as rendered 

 evident in the longitudinal magnetism, which we could at once per- 

 ceive on the wire. This question, however, belongs to a separate 

 investigation, and I hope the apparatus will aid me later in throwing 

 some new light upon this subject. 



Another method of reducing the wire to zero, after the passage of 

 a current, is to keep the wire in a constant state of vibration. It 

 requires in time about one minute to bring it to zero, but if, on the 

 contrary, I set the wire vibrating during the passage of the current, 



