DOVE ON THE ELECTRICITY OF INDUCTION. 14/ 



hypothesis, of an electric nature. Wherefore then is it not con- 

 nected with the power of conduction of the metals ? 



58. The inferences to be drawn from the experiments in this 

 memoir, when viewed without any preconceived hypothetical 

 notions, are, that when iron is electro-magnetized, two phseno- 

 mena result which are opposed to each other, namely, the exci- 

 tation of electric currents, and the production of magnetic 

 polarity. In the researches which have hitherto been made in 

 this field of inquiry, the effect of the magnetic polarization al- 

 ways overpowered the obstructing influence of the electric cur- 

 rents produced at the same time ; we obtained therefore, by pre- 

 venting more or less the formation of these latter, merely an 

 augmentation of the effect already produced by the magnetic 

 polarization. The experiments instituted with the aid of fric- 

 tional electricity showed, under the same circumstances, a com- 

 plete reversion of this action into that of an opposite nature. 

 This reversion, however, does not take place simultaneously for 

 the physiological action of the induced cuiTcnts, for their mag- 

 netizing properties and their calorific effects, so that the same 

 experimental arrangement which renders more powerful one of 

 these effects, exerts at the same time a weakening influence upon 

 another. Consequently all explanations which were advanced to 

 explain one of these actions in its different modifications alone 

 are set aside. Now, as it does not appear advisable to call by 

 the same name, and consider identical, two forces of nature, the 

 one of which begins to act under conditions in which the other 

 never occurs at all, and which, when they are both simultane- 

 ously active in the same body, so oppose each other, that some- 

 times one, sometimes the other predominates, I think it more 

 appropriate to consider the magnetic polarization as not only 

 an independent but as an opposing agency to the electric cur- 

 rents excited in iron. 



The explanation of the phenomena which have here been ob- 

 served would then be the following : — 



59. The primary active electric current traversing a spirally- 

 coiled wire which surrounds the iron, produces at the moment 

 in which it commences electric currents in the iron ; during its 

 continuance it causes magnetic polarity, which is more tardily 

 augmented than that current, and in the moment that it ceases 

 an electric current is again produced. The second electric 



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