same concussion to the living
system as the electrical machine, the voltaic battery, and the
thunderstorm being made known to us by various naturalists, it became
important to identify their electricity with the electricity produced by
man from dead matter. In the case of the _Torpedo_ [a fish belonging to
the family of Electric Rings] this identity has been fully proved, but
in the case of the _Gymnotus_ the proof has not been quite complete, and
I thought it well to obtain a specimen of the latter fish.

A gymnotus being obtained, I conducted a series of experiments. Besides
the hands two kinds of collectors of electricity were used--one with a
copper disc for contact with the fish, and the other with a plate of
copper bent into saddle shape, so that it might enclose a certain
extent of the back and sides of the fish. These conductors, being put
over the fish, collected power sufficient to produce many electric
effects.

SHOCK. The shock was very powerful when the hands were placed one near
the head and the other near the tail, and the nearer the hands were
together, within certain limits, the less powerful was the shock. The
disc conductors conveyed the shock very well when the hands were wetted.

GALVANOMETER. A galvanometer was readily affected by using the saddle
conductors, applied to the anterior and posterior parts of the gymnotus.
A powerful discharge of the fish caused a deflection of thirty or forty
degrees. The deflection was constantly in a given direction, the
electric current being always from the anterior part of the animal
through the galvanometer wire to the posterior parts. The former were,
therefore, for the time externally positive and the latter negative.

MAKING A MAGNET. When a little helix containing twenty-two feet of
silked wire wound on a quill was put into a circuit, and an annealed
steel needle placed in the helix, the needle became a magnet; and the
direction of its polarity in every cast indicated a current from the
anterior to the posterior parts of the gymnotus.

CHEMICAL DECOMPOSITION. Polar decomposition of a solution of iodide of
potassium was easily obtained.

EVOLUTION OF HEAT. Using a Harris' thermo-electrometer, we thought we
were able, in one instance, to observe a feeble elevation of
temperature.

SPARK. By suitable apparatus a spark was obtained four times.

Such were the general electric phenomena obtained from the gymnotus, and
on several occasions many of the phen