particles to act
on each other through straight lines, whatever other particles may be
between them, is more analogous to that of a series of magnetic needles, or
to the condition of the particles considered as forming the whole of a
straight or a curved magnet. So that in whatever way I view it, and with
great suspicion of the influence of favourite notions over myself, I cannot
perceive how the ordinary theory applied to explain induction can be a
correct representation of that great natural principle of electrical
action.

1232. I have had occasion in describing the precautions necessary in the
use of the inductive apparatus, to refer to one founded on induction in
curved lines (1203.); and after the experiments already described, it will
easily be seen how great an influence the shell-lac stem may exert upon the
charge of the carrier ball when applied to the apparatus (1218.), unless
that precaution be attended to.

1233. I think it expedient, next in the course of these experimental
researches, to describe some effects due to _conduction_, obtained with
such bodies as glass, lac, sulphur, &c., which had not been anticipated.
Being understood, they will make us acquainted with certain precautions
necessary in investigating the great question of specific inductive
capacity.

1234. One of the inductive apparatus already described (1187, &c.) had a
hemispherical cup of shell-lac introduced, which being in the interval
between the inner bull and the lower hemisphere, nearly occupied the space
there; consequently when the apparatus was charged, the lac was the
dielectric or insulating medium through which the induction took place in
that part. When this apparatus was first charged with electricity (1198.)
up to a certain intensity, as 400 deg., measured by the COULOMB'S electrometer
(1180.), it sank much faster from that degree than if it had been
previously charged to a higher point, and had gradually fallen to 400 deg.; or
than it would do if the charge were, by a second application, raised up
again to 400 deg.; all other things remaining the same. Again, if after having
been charged for some time, as fifteen or twenty minutes, it was suddenly
and perfectly discharged, even the stem having all electricity removed from
it (1203.), then the apparatus being left to itself, would gradually
recover a charge, which in nine or ten minutes would rise up to 50 deg. or 60 deg.,
and in one instance to 80 deg..

1235. The elec