ds were
moistened in salt and water, and good contact between them and the wires
retained, no shock could be felt upon _making_ contact at the electromotor,
but a powerful one on _breaking_ contact.

1061. When the _helix_ i or iii (1053, &c.) was used as the connecting
conductor, there was also a good spark on breaking contact, but none
(sensibly) on making contact. On trying to obtain the shock from these
helices, I could not succeed at first. By joining the similar ends of i and
ii so as to make the two helices equivalent to one helix, having wire of
double thickness, I could just obtain the sensation. Using the helix of
thick wire (1055.) the shock was distinctly obtained. On placing the tongue
between two plates of silver connected by wires with the parts which the
hands had heretofore touched (1064.), there was a powerful shock on
_breaking_ contact, but none on _making_ contact.

1062. The power of producing these phenomena exists therefore in the simple
helix, as in the electro-magnet, although by no means in the same high
degree.

1063. On putting a bar of soft iron into the helix, it became an
electro-magnet (1057.), and its power was instantly and greatly raised. On
putting a bar of copper into the helix, no change was produced, the action
being that of the helix alone. The two helices i and ii, made into one
helix of twofold length of wire, produced a greater effect than either i or
ii alone.

1064. On descending from the helix to the mere _long wire_, the following
effects were obtained, A copper wire, 0.18 of an inch in diameter, and 132
feet in length, was laid out upon the floor of the laboratory, and used as
the connecting conductor (1059.); it gave no sensible spark on making
contact, but produced a bright one on breaking contact, yet not so bright
as that from the helix (1061.) On endeavouring to obtain the electric shock
at the moment contact was broken, I could not succeed so as to make it pass
through the hands; but by using two silver plates fastened by small wires
to the extremity of the principal wire used, and introducing the tongue
between those plates, I succeeded in obtaining powerful shocks upon the
tongue and gums, and could easily convulse a flounder, an eel, or a frog.
None of these effects could be obtained directly from the electromotor,
i.e. when the tongue, frog, or fish was in a similar, and therefore
comparative manner, interposed in the course of the communication between
the