284? Mr. Faraday on Magneto-electric Induction ; 



have always admired M. Arago's prudence and philosophic 

 reserve, in resisting the temptation to give a theory of the 

 effect which he had discovered until he could offer one per- 

 fectly applicable, and in refusing his assent to the imperfect 

 theories of others. Admiring him I adopted his reserve in 

 this respect, and for that reason, perhaps, had my eyes open 

 to recognise the truth as soon as it was presented. 



We now arrive at that part of the subject which relates to 

 the philosophy of my memoirs. The fourth part of my me- 

 moir of the 24-th of November, 1831, contains my opinion 

 on the cause of the phenomenon discovered by M. Arago, 

 an opinion that even now I see no reason to alter. Messrs. 

 Nobili and Antinori, in their papers of the 31st of January 

 and 24th of March, 1832, animadvert upon certain errors 

 which they attriLute to me, and enter upon extended deve- 

 lopments of magneto-electric phenomena. I cannot, how- 

 ever, discern that they have added a single fact to those con- 

 tained in my memoirs, unless it be the obtaining of a spark 

 with a common magnet, a result that I had myself previously 

 obtained, but only with the electro-magnet. On the other 

 hand, these gentlemen's memoirs appear to me to contain 

 erroneous ideas upon the nature of magneto-electric currents ; 

 they exhibit also mistaken views as to the action and direction 

 of those currents in Arago's revolving disc. They say, 

 " We have recently verified, extended, and perhaps corrected in 

 some particidars the results of the English philosopher" &c. 

 {Annates, vol. 1. p. 281.) And again at page 298, comment- 

 ing on what they suppose to be my ideas (for though my 

 papers had been read, and were published, they had not 

 thought proper to consult them), they say, "We have al- 

 ready given our opinion upon this idea, but if at the com- 

 mencement of our researches it were difficult to reconcile it 

 with the nature of the currents discovered by M. Faraday, what 

 can we say after all the new observations that we have made 

 during the progress of our investigations ? We say that we 

 have a competent judge in the galvanometer, and that by its 

 means the question must be decided." 



With the most sincere desire to be set right when I am in 

 error, I yet find it impossible to discover any corrections in 

 the memoirs of these gentlemen by which I can profit; but 

 I fully admit the competency of the galvanometer, and shall 

 proceed as briefly as possible to submit our different ideas to 

 its decision, in all that relates to Arago's phenomenon : and 

 I am at the present time so satisfied with the facts and results 

 stated in my published memoirs (though were I to rewrite 



