at one time thought they were due to an action continued during
the _whole time_ of the current, and expected that a steel magnet would
have an influence according to its position in the helix, comparable to
that of a soft iron bar, in assisting the effect. This, however, is not the
case; for hard steel, or a magnet in the helix, is not so effectual as soft
iron; nor does it make any difference how the magnet is placed in the
helix, and for very simple reasons, namely, that the effect does not depend
upon a permanent state of the core, but a _change of state_; and that the
magnet or hard steel cannot sink through such a difference of state as soft
iron, at the moment contact ceases, and therefore cannot produce an equal
effect in generating a current of electricity by induction (34. 37.).

* * * * *

1101. As an electric current acts by induction with equal energy at the
moment of its commencement as at the moment of its cessation (10. 26.), but
in a contrary direction, the reference of the effects under examination to
an inductive action, would lead to the conclusion that corresponding
effects of an opposite nature must occur in a long wire, a helix, or an
electro-magnet, every time that _contact is made with_ the electromotor.
These effects will tend to establish a resistance for the first moment in
the long conductor, producing a result equivalent to the reverse of a shock
or a spark. Now it is very difficult to devise means fit for the
recognition of such negative results; but as it is probable that some
positive effect is produced at the time, if we knew what to expect, I think
the few facts bearing upon this subject with which I am acquainted are
worth recording.

1102. The electro-magnet was arranged with an electrolyzing apparatus at
_x_, as before described (1084.), except that the intensity of the chemical
action at the electromotor was increased until the electric current was
just able to produce the feeblest signs of decomposition whilst contact was
continued at G and E (1079.); (the iodine of course appearing against the
end of the cross wire P;) the wire N was also separated from A at _r_, so
that contact there could be made or broken at pleasure. Under these
circumstances the following set of actions was repeated several times:
contact was broken at _r_, then broken at G, next made at _r_, and lastly
renewed at G; thus any current from N to P due to _breaking_ of contact wa