Faraday on Electro- Magnetic Rotation. 289 



Dr. Wollaston was, I believe, the person who fust enter- 

 tained the possibility of electro-magnetic rotation ; and if I now 

 understand aright, had that opinion very early after repeating 

 Professor Oersted's experiments. It may have been about 

 August 1820, that Dr. Wollaston first conceived the possibility 

 of making a wire in the voltaic circuit revolve on its own axis. 

 There are circumstances which lead me to believe that I did 

 not hear of this idea till Noveri>ber following ; and it was at the 

 beginning of the following year that Dr. Wollaston, provided 

 with an apparatus he had had made for the purpose, came to the 

 Institution with Sir Humphry Davy, to make an experiment of 

 this kind. Iwas not present at the experiment, nor did I see 

 the apparatus, but I came in afterwards, and assisted in making 

 some further experiments on the rolling of wires on edges*. 

 I heard Dr. WoUaston's conversation at the time, and his 

 expectation of making a wire revolve on its own axis ; and I 

 suggested (hastily and uselessly) as a delicate method of sus- 

 pension, the hanging the needle from a magnet. I am not 

 able to recollect, nor can I excite the memory of otliers to the 

 recollection of the time when this took place. I believe it was 

 in the beginning of 1821. 



The paper which I first published was written, and the expe- 

 riments all made, in the beginning of September^ 1821. It 

 was published on the 1st of October ; a second paper was pub- 

 lished in the same volume on the last day of the same year. I 

 have been asked, why in those papers I made no reference to 

 Dr. WoUaston's opinions and intentions, inasmuch as I always 

 acknowledged the relation between them and my own expe- 

 riments ? To this I answer, that upon obtaining the results 

 described in the first paper, and which I shewed very readily to 

 all my friends, I went to Dr. WoUaston's house to communicate 

 them also to him, and to ask permission to refer to his views 

 and experiments. Dr. Wollaston was not in town, nor did he 

 return whilst I remained in town ; and, as I did not think I 

 had any right to refer to views not published, and as far as I 



* See Sir Humphry Davy's Letter to Dr.Wollaston. Pliil. Trans. 1821. p. 17. 

 U2 



