OF THE PHYSICAL SCIENCES. 7 



the vision of modern times you cast your eyes, you will find 

 marks of superiority and improvement ; and the results of in- 

 tellectual labour, or of scientific genius, are permanent, and 

 incapable of being lost. Monarchs change their plans ; ( io- 

 vernments their objects ; but a piece of steel touched by the 

 magnet preserves its character for ever, and secures to man 

 the dominion of the trackless ocean. A new period of society 

 may send armies from the shores of the Baltic to those of the 

 Euxine, and the empire of the followers of Mahomet may be 

 broken in pieces by a northern people, and the dominion of 

 the Britons in Asia may share the fate of that of Tamerlane 



not be familiar with subjects of this kind, as well as for the consideration of 

 those whose interest in the discussions of science is founded on the know- 

 ledge of their objects and importance, I have thought it right to give the 

 explanation with which this note commences, lest Sir H. Davy's allusion to 

 artificial instruments stated to possess some of the powers of lining animals, 

 should be misunderstood, or appear a Promethean flight, unwarranted by H 

 just appreciation of the limits of human power. The subject of animal 

 electricity is one of great interest in a scientific point of view, and on that 

 account the above remarks have been extended beyond the length required 

 by the object now explained. It is right to mention, in conclusion, that the 

 first suggestion of determining the nature of Animal Electricity, by ascer- 

 taining its relations to magnetism, was made by Professor Cumming, of 

 Cambridge, in a notice published in the Annals of Philosophy, several 

 years prior to the date of Sir Humphry Davy's researches on that subject. 

 See Phil. Trans. 1829, p. 15 ; or Phil. Mag. & Annals, N.S. vol. vi. p. 81 ; 

 and Ann. of Phil. N.S. vol. x. p. 161. 



The preceding allusion to Professor Cumming's suggestion was written 

 from memory ; but the subsequent perusal of it in the Annals of Philoso- 

 phy, as above, has rendered it expedient to add a further remark on the 

 subject. 



" If this animal electricity be similar to common electricity," Professor 

 Cumming observes, " it is to be expected that it will be capable of magne- 

 tizing a needle inclosed in a spiral, but not of causing deviation in the gal- 

 vanoscope ; if it resemble galvanism, we may expect both effects ; " and 

 after mentioning Mr. Cavendish's experiments, he subjoins, " I should, 

 therefore, anticipate from the Torpedo, magnetic action resembling that 

 from galvanism." 



The experiment with a needle inclosed in a spiral does not appear to have 

 been made; but we have seen that the electricity of the Torpedo is inca- 

 pable of affecting the galvanoscope (or magnetic electrometer), and so far, 

 therefore, contrary to Professor Cumming's inference from Mr. Cavendish's 

 experiments, but in agreement with what he expected would be the case on 

 one view of the subject, animal electricity has been found to resemble, not 

 galvanic, but common electricity. From the foregoing summary it is clear 

 that new researches are required on this subject, which is equally interest- 

 ing and important to the electrician and the physiologist. The properties 

 and relations of both common and voltaic electricity of low tension, are at 

 present involved in considerable obscurity ; and in the actual condition of 

 this inquiry, it may not be unphilosophical to suppose that the provisional 

 opinion above given, in agreement with that of Volta, that the electricity 

 of the Torpedo is similar to that of certain forms of the Voltaic Pile, may 

 be compatible with Sir H. Davy's view that animal electricity will be 

 found of a distinctive and peculiar kind." 



