[91] This letter is translated from the French edition of Dr.
Franklin's works, as are also all that follow, to the Appendix, the
one to Miss Stephenson excepted. _Editor._
_Mode of ascertaining, whether the Power, giving a Shock to those
who touch either the Surinam Eel, or the Torpedo, be electrical._
1. Touch the fish with a stick of dry sealing-wax, or a glass rod,
and observe if the shock be communicated by means of those bodies.
Touch the same fish with an iron, or other metalline rod.
If the shock be communicated by the latter body, and not by the
others, it is probably not the mechanical effect, as has been
supposed, of some muscular action in the fish, but of a subtile
fluid, in this respect analogous at least to the electric fluid.
2. Observe farther, whether the shock can be conveyed without the
metal being actually in contact with the fish, and if it can,
whether, in the space between, any light appear, and a slight noise
or crackling be heard.
If so, these also are properties common to the electric fluid.
3. Lastly, touch the fish with the wire of a small Leyden bottle, and
if the shock can be received across, observe whether the wire will
attract and repel light bodies, and you feel a shock, while holding
the bottle in one hand, and touching the wire with the other.
If so, the fluid, capable of producing such effects seems to have all
the known properties of the electric fluid.