1826.] Royal Society. 67 



labours and the discoveries of various philosophers belonging to 

 this and the other learned Societies of Europe, and which have 

 established, within the last five years, a perfectly nevv order of 

 facts, not less brilliant from their striking and unexpected results, 

 than important in their relations and theoretical applications to 

 other phsenomena of nature." 



" I cannot, however, quit this part of my subject without call- 

 ing your attention to the manner in which these discoveries 

 have originated and been pursued, as it affords the most remark- 

 able instance upon record of the unity of the laws of nature — of 

 the mode in which remote phgenomena are connected together, 

 and the happy consequence of close attention to unexpected or 

 uncommon results." 



" A fact discovered by Galvani, and by him believed to be 

 strictly physiological, investigated by the genius of Volta, was 

 the origin of his wonderful pile, or battery ; and this instrument, 

 after its powers had been apparently exhausted in demonstrating 

 new laws in electricity, and affording us new creations in 

 chemistry — altering our arrangements and systems, — became, in 

 the hands of the Danish philosopher, a source of novel and per- 

 fectly unexpected combinations, throwing a light upon parts of 

 the corpuscular philosophy vvhich were before in absolute 

 darkness." 



" Though the labours of M. Arago, which have been the 

 object of the vote of your Council, cannot be considered as 

 immediate consequences of M. (Ersted's discovery, it is proba- 

 ble they never would have been undertaken had not this 

 discovery immediately excited the attention of their excellent 

 author, who was one of the first philosophers that endeavoured 

 to investigate, confirm, and illustrate the facts of electro-magne- 

 tism." Sir Humphry Davy next alluded to the idea of Coulomb 

 (who was probably deceived by the presence of minute portions 

 of iron in the substances he operated on) that all bodies in 

 nature are capable of magnetic attractions; and the various 

 experiments which were made, after the discovery that magne- 

 tism is a consequence of electrical action, to produce magnetic 

 effects in other metals besides those long known to be capable 

 of them, the results of which proved that the effects were tran- 

 sient, and disappeared with the electrical cause. 



"Till M. Arago's inquiries, iron, nickel, cobalt, and their 

 combinations, were the only species of matter apparently 

 affected by magnets. His experiments extend this property 

 under certain modifications to all metallic substances ; and it is 

 said, though as yet we have no distinct details, to various other 

 bodies." 



" M. Arago found that the extent of the vibrations of a magne- 

 tized needle was greatly diujinished by holding over it a plate 

 of copper ; and by causing a plate of copper to revolve below it. 



