16 Dr. F. Auerbach on the Passage of 



as great. Fig. 1 (PL I.) gives a part of the observed and the 

 calculated curves. 



§ 5. Hand in hand with the experiments on the influence 

 of magnetization went experiments on the extra currents which 

 are generated by every current in iron. I forbear to communi- 

 cate these experiments in detail, since in their essential results 

 they agree with those of MM. Herwig and Streintz. Quanti- 

 tative statements, however, on the intensity of the extra cur- 

 rents, in any comparable measure, on the part of the latter 

 observer we have none ; and Herwig only states that once a 

 diminution of the resistance of O'OOll to 0*0014 would have 

 corresponded to the deflection of the galvanometer-needle ob- 

 tained, after the opening of the principal current, if the cur- 

 rent had persisted. As in general I took no account of an 

 agitation of the wires, I mostly obtained extra currents of 

 longer duration, by which I attained the possibility of some- 

 times carrying out very exact resistance-measurements of the 

 above sort. The values which I obtained are, in part, by no 

 means inconsiderably higher than Herwig' s above mentioned. 

 The signs of these values were, with few exceptions (to be 

 explained by extraneous influences) constantly such as to show 

 that on the closing of the principal current the standard resist- 

 ance must have been heightened, while on its opening that resist- 

 ance must have become less. Further, I find (as Herwig did) 

 the deflections with steel less than with iron; but if I follow up 

 the rate of each (which with iron, especially annealed wires, 

 is much quicker than with steel), I find for the integral cur- 

 rents corresponding to the deflections values not essentially 

 different. 



Now I obtained far more intense extra currents when I led 

 the current through magnetized iron or steel wires, although 

 their direction was constantly the same as if the wire had not 

 been magnetic. In those cases in which the definitive resist- 

 ance was increased by magnetizing, a still greater resistance 

 always corresponded to the extra current. This made itself 

 recognizable by a deflection towards the side of the greater 

 resistances, following after the bridge had been equalized for 

 the unmagnetic condition of the wire, which deflection was 

 greater than had corresponded to the permanent deviation of 

 the needle ; and this latter also, after the oscillations of the 

 needle had long ceased, diminished, in most cases slowly, a 

 little more, till it took the value given in the Tables of § 4. 

 But even in those cases in which the resistance in the mag- 

 netic state was less, the deflection constantly took place first 

 toward the side of the greater resistances. I do not give nu- 

 merical data, because a similar diversity prevails as in the 



