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