250 Dr. Faraday on the Magnetic Affection of Light. 



in the manner that had been employed for the heavy glass, 

 that the magnetic poles might be brought as close as possible; 

 still no evidence ot any magnetic action on the ray could be 

 observed. 



A natural six-sided prism of rock-crystal, 2*3 inches in 

 length, was polished and silvered at the ends : no magnetic 

 effect upon the light could be observed with this crystal with 

 either the first, second or third image. 



M. E. Becquerel thinks that he has observed an effect pro- 

 duced in doubly refracting crystalline bodies ; and it is pro- 

 bable that his apparatus is far more delicate for the observance 

 of optical changes than mine. In that case, if combined with 

 the procedure founded on repeated transits of the ray, it per- 

 haps would produce very distinct results : but the latter pro- 

 cess alone has not as yet given any evidence of the action sought 

 after. 



Certain indications led me to look with interest for any 

 possible effect which the crossing of the reflected rays might 

 produce in the arrangement of reflectors and glass represented 

 in fig. 1 ; but I could find no difference of action between it 

 and the other arrangement, fig. 2, in which no such crossing 

 occurred. 



Near the close of last year I sent to the Royal Society 

 two papers On the Magnetic Condition of all Matter*, in 

 which 1 believed that I had established the existence of a 

 magnetic action new to our knowledge; antithetical in its na- 

 ture to the magnetism manifested by iron in any of its forms 

 or conditions, strong or weak, or to that magnetism which iron 

 could, in any quantity or under any circumstances, produce. 

 Further, that all bodies not magnetic as iron, were magnetic 

 according to this new mode of action; and that as attraction 

 by the magnet marked the magnetic condition of iron, however 

 small its quantity, or whatever its state might be, so repulsion 

 was the distinctive characteristic of all those bodies which were 

 naturally fitted to acquire the new state, and develope this 

 new form of power. 



M. Becquerel has sent a note to the Academy of Sciences f, 

 in which he states certain results of his own much anterior to 

 mine, due to ordinary magnetic action, and in which the po- 

 sition of the substances was across the magnetic axis. I need 

 not quote the whole, but will select the following words at the 

 end : — " From these facts it results that the magnetic effects 



* Philosophical Transactions, 1846, p. 21, or Phil, Mag., vol. xxviii. 1846. 

 t Comptes. Renins, 1846, p. 147. 



