274 LOCALIZED ELECTRIZATION. 



§ III. — Explanation of the peincipal properties op the 

 Double-current Magneto-faradic Apparatus and the 

 different combinations which have governed its con- 

 struction, 



Although double induction had not previously been applied 

 to magneto-faradic instruments, I had no doubt of the possibility 

 of obtaining it. I have described how, and by what series of 

 researches, I was led to its realization. 



The MM. Becquerel, however, physicists of great scientific 

 authority, have disputed the possibility of producing double in- 

 duction with my magneto-faradic instrument. I may be per- 

 mitted to endeavour to show, by experiment, that I am not, on 

 this point, under an error. 



I must repeat, that, in my volta-faradic instrument, the initial 

 force is mixed, that the induction of the primary coil results from 

 the modification produced : first, by the battery current circulating 

 through the coils of its helix in an intermittent manner ; secondly, 

 by the influence of the temporary magnet. 



I have already stated (Chap. I., Part III. § 1, page 30) that M. 

 E. Becquerel attributes the special physiological phenomena of 

 the current of the secondary coil to the direct influence of the 

 temporary magnet. It will be remembered that, in order to prove 

 how unfounded was this hypothesis, I made experiments without 

 placing the soft iron core in the centre of the inductive helix ; 

 and that the phenomena peculiar to the current of the secondary 

 helix were, none the less, very powerfully produced (see experi- 

 ment, page 29). 



A physicist, celebrated for his discoveries, and of no less scien- 

 tific authority than MM. Becquerel — M. de la Rive — has thus 

 written, with reference to this experiment, which I repeated in his 

 presence : — • 



" I must admit, with M. DucJienne, that the current which circu- 

 lates through the primary coil must certainly act upon the ivire of the 

 secondary, since ive hnow that, even when there is no soft iron core, 

 induction is produced." But he is careful to add, " The presence 

 of the soft iron increases the induction in an enormous degree, and 

 the two actions, coinciding to produce the same effects, greatly 

 increase them. The current induced in the second wire is there- 

 fore ])recisely like that tchich induces the direct action of the magnet, 

 and hence I am unable to discover in this anytliiug but a current 

 of the first kind, and not a current of the second kind, as believed by 

 M. Duchenne." " 



De la Eive, loo, cit. t. iii., p. 581. 



