468 Dr. Faraday's Researches in Electricity. 



electro-conducting power, which permits the formation of cur- 

 rents in it by inductive forces, that cannot produce the same 

 in a corresponding degree in bismuth, and of course not at all 

 in heavy glass. 



2340. Any ordinary magnetism due to metals by virtue of 

 their inherent power, or the presence of small portions of the 

 magnetic metals in them, must oppose the development of the 

 results I have been describing : and hence metals not of abso- 

 lute purity cannot be compared with each other in this respect. 

 I have, nevertheless, observed the same phaenomena in other 

 metals; and as far as regards the sluggishness of rotatory mo- 

 tion, traced it even into bismuth. The following are the 

 metals which have presented the phasnomena in a greater or 

 smaller degree : — 



Copper. 



Silver. 



Gold. 



Zinc. 



Cadmium. 



Tin. 



Mercury. 



Platinum. 



Palladium. 



Lead. 



Antimony. 



Bismuth. 



2341. The accordance of these phenomena with the 

 beautiful discovery of Arago*, with the results of the experi- 

 ments of Herschel and Babbagef, and with my own former 

 inquiries (81.)J, are very evident. Whether the effect ob- 

 tained by Ampere, with his copper cylinder and a helix§, was 

 of this nature, I cannot judge, inasmuch as the circumstances 

 of the experiment and the energy of the apparatus are not 

 sufficiently stated ; but it probably may have been. 



2342. As, because of other duties, three or four weeks may 

 elapse before I shall be able to complete the verification of 

 certain experiments and conclusions, I submit at once these 

 results to the attention of the Royal Society, and will shortly 

 embody the account of the action of magnets on magnetic 

 metals, their action on gases and vapours, and the general 

 considerations in another series of these Researches. 



Royal Institution, Nov. 27, 1845. 



* Annates de Chimie, xxvii. 363; xxviii. 325; xxxii. 213. I am very 

 glad to refer here to the Comj)tcs Iiendus of June 9, 1845, where it appears 

 that it was M. Arago who first obtained his peculiar results by the use of 

 electro- as well as common magnets. 



t Philosophical Transactions, 1825, p. 467. f Ibid. 1832. p. 146. 



§ Bibliolheque Universale, xxi. p. 48. 



