12 Dr. F. Auerbach on the Passage of 



19. Strong iron wire, annealed, / 6 . H = 1D; M = 4B ; 

 w = 212. Mean values. 



™ =0-5029 to = 0-5171 w =0*5078 



5 = 00240. 



Permanent increase A = 0*009 7. If we neglect this, we get 

 for the transient increase 



8=00281. 



These values are extraordinarily high. The permanent in- 

 crease of the resistance can also be inferred from the fact that 

 we have here to do with abnormal proportions. Of course 

 this conclusion must, to a certain extent, be extended to the 

 following series of experiments, based upon another wire. 



20. H and M as in 19. A thin iron wire, annealed, / 7 , 

 several times operated on galvanically; d=0'19. 



w = 6*3549 w = 6-4532 w = 6'3644 



S=+0'0147. 



Further, with the same signification as above, we get 



A = 0*0015 and S 1 = 00156. 



The disproportionately low value of A, compared with that 

 found in 19, can be accounted for from the circumstance that 

 the wire/ 7 had already, in consequence of having been fre- 

 quently passed through by the current, considerably neared 

 its stationary condition. 



21. H = 2D; M = 3B. A thin hard iron wire/ 8 ; d=0«15. 



No alteration of resistance, not even 0*0001, although here, 

 in spite of the very slight thickness, the extra currents corre- 

 sponded to a considerable increase of resistance for the moment 

 of the closing of the current. 



22. H = 2D; M=1D; n = 92. Hard iron wire f d ; Z=1670, 

 d=0'20. 



w = 7-3961 w= 7-3903 w = 7-3973 



S= -00009. 



The same wire, however, showed after longer working, after 

 8 had constantly approached nearer and nearer to zero, at last 

 small positive values of 8. In the meantime it was submitted 

 to experiment 23. 



23. H=1D; M=2D. Wire/ 9 . 



w =7*3991 w=7*3997 w =7*3993 

 8= -00002. 



