It has long been supposed that the Stroke given by the Torpedo was the Effect of sudden violent muscular Motion. It is now suspected to be an Effect of the electric or some similar subtil Fluid, which that Fish has a Power of acting upon and agitating at Pleasure.

To discover whether it be the Effect of a subtil Fluid, or of muscular Motion, let the Fish be touch’d with the usual Conductors of Electricity, viz. Iron or other Metals; and with the known Non-conductors of Electricity, dry Wood, Glass, Wax, &c. If the Stroke be communicated thro’ the first and not thro’ the latter, there is so far a Similarity with the electric Fluid; and at the same time a Proof that the Stroke is not an Effect of mere muscular Motion.

Let it be observed whether the Stroke is sometimes given on the near Approach of a conducting Body without actual Contact; if so, that is another similar Circumstance. Then observe whether in that Case any Snap is heard; and in the Dark whether any Light or Spark is seen between the Fish and the approaching Body. If not, there the Fluids differ.

Let a Number of Persons standing on the Ground, join Hands, and let one touch the Fish so as to receive the Stroke. If all feel it, then let him be laid with his Belly on a Plate of Metal; let one of the Persons so joining Hands touch that Plate, while the farthest from the Plate with a Rod of Metal touches the Back of the Fish; and then observe whether the Force of the Stroke seems to be the same to all in the Circuit as it was before, or stronger.

Repeat the last Experiment with this Variation. Let two of the Persons in the Circuit hold each an uncharg’d electric Phial, the Knobs at the Ends of their Wires touching. After the Stroke, let it be observ’d whether those Wires will attract and repel light Bodies; and whether a Cork Ball suspended by a long silk String so as to hang between the Wires at a small Distance from the Knob of each, will be attracted and repell’d alternately to and from each Knob; if so, the Back and Belly of the Fish are at the Time of the Stroke in different States of Electricity.