SOME EXPERIMENTS ON THE TORPEDO. 17 



wetted in salt and water, and keeping the wire connected with the electrometer 

 in the other wet hand ; the shocks which passed through the reduplications of 

 the electrometer were sufficiently powerful to be felt in both elbows, and once 

 even in the shoulders. 



These negative results may be explained by supposing that the motion of 

 the electricity in the torpedinal organ is in no measurable time, and that a 

 current of some continuance is necessary to produce the deviation of the mag- 

 netic needle ; and I found that the magnetic electrometer was equally insen- 

 sible to the weak discharge of a Leyden jar as to that of the torpedinal organ ; 

 though whenever there was a continuous current from the smallest surfeces in 

 Voltaic combinations of the weakest power, but in which some chemical action 

 was going on, it was instantly and powerfully affected. Two series of zinc and 

 silver, and paper moistened in salt and water, caused the permanent deviation 

 of the needle several degrees, though the plates of zinc -were only |th of an 

 inch in diameter. 



It would be desireable to pursue these inquiries with the electricity of the 

 Gymnotus, which is so much more powerful than that of the Torpedo : but if 

 they are now to be reasoned upon, they seem to show a stronger analogy 

 between common and animal electricity, than between voltaic and animal elec- 

 tricity : it is however I think more probable that animal electricity will be 

 found of a distinctive and peculiar kind. 



Common electricity is excited upon non-conductors, and is readily carried 

 off by conductors and imperfect conductors. Voltaic electricity is excited 

 upon combinations of perfect and imperfect conductors, and is only transmitted 

 by perfect conductors or imperfect conductors of the best kind. 



Magnetism, if it be a form of electricity, belongs only to perfect conductors ; 

 and, in its modifications, to a peculiar class of them. 



The animal electricity resides only in the imperfect conductors forming the *i 



organs of living animals, and its object in the oeconomy of nature is to act on -P 



living animals. 



Distinctions might be established in pursuing the various modifications or 

 properties of electricity in these different forms ; but it is scarcely possible to 

 avoid being struck by another relation of this subject. The torpedinal organ 

 depends for its powers upon the will of the animal. John Hunter has shown 



MDCCCXXIX. D 



