ndicating galvanometer, or helix, occurred as before. The induced
electricity could also pass through a voltaic trough (20.). When, however,
the quantity of interposed fluid was reduced to a drop, the galvanometer
gave no indication.

24. Attempts to obtain similar effects by the use of wires conveying
ordinary electricity were doubtful in the results. A compound helix similar
to that already described, containing eight elementary helices (6.), was
used. Four of the helices had their similar ends bound together by wire,
and the two general terminations thus produced connected with the small
magnetising helix containing an unmagnetised needle (13.). The other four
helices were similarly arranged, but their ends connected with a Leyden
jar. On passing the discharge, the needle was found to be a magnet; but it
appeared probable that a part of the electricity of the jar had passed off
to the small helix, and so magnetised the needle. There was indeed no
reason to expect that the electricity of a jar possessing as it does great
tension, would not diffuse itself through all the metallic matter
interposed between the coatings.

25. Still it does not follow that the discharge of ordinary electricity
through a wire does not produce analogous phenomena to those arising from
voltaic electricity; but as it appears impossible to separate the effects
produced at the moment when the discharge begins to pass, from the equal
and contrary effects produced when it ceases to pass (16.), inasmuch as
with ordinary electricity these periods are simultaneous, so there can be
scarcely any hope that in this form of the experiment they can be
perceived.

26. Hence it is evident that currents of voltaic electricity present
phenomena of induction somewhat analogous to those produced by electricity
of tension, although, as will be seen hereafter, many differences exist
between them. The result is the production of other currents, (but which
are only momentary,) parallel, or tending to parallelism, with the inducing
current. By reference to the poles of the needle formed in the indicating
helix (13. 14.) and to the deflections of the galvanometer-needle (11.), it
was found in all cases that the induced current, produced by the first
action of the inducing current, was in the contrary direction to the
latter, but that the current produced by the cessation of the inducing
current was in the same direction (19.). For the purpose of avoiding
periphrasi