f the dielectric
contiguous to them, are entirely engaged to each other by induction through
the glass; and a carrier ball (1181.) applied either to the inside or
outside of the jar will show no signs of electricity. But if the jar be
insulated, and the charging ball and rod, in an uncharged state and
suspended by an insulating thread of white silk, be restored to their
place, then the part projecting above the jar will give electrical
indications and charge the carrier, and at the same time the _outside_
coating of the jar will be found in the opposite state and inductric
towards external surrounding objects.

1683. These are simple consequences of the theory. Whilst the charge of the
inner coating could induce only through the glass towards the outer
coating, and the latter contained no more of the contrary force than was
equivalent to it, no induction external to the jar could be perceived; but
when the inner coating was extended by the rod and ball so that it could
induce through the air towards external objects, then the tension of the
polarized glass molecules would, by their tendency to return to the normal
state, fall a little, and a portion of the charge passing to the surface of
this new part of the inner conductor, would produce inductive action
through the air towards distant objects, whilst at the same time a part of
the force in the outer coating previously directed inwards would now be at
liberty, and indeed be constrained to induct outwards through the air,
producing in that outer coating what is sometimes called, though I think
very improperly, free charge. If a small Leyden jar be converted into that
form of apparatus usually known by the name of the electric well, it will
illustrate this action very completely.

1684. The terms _free charge_ and _dissimulated electricity_ convey
therefore erroneous notions if they are meant to imply any difference as to
the mode or kind of action. The charge upon an insulated conductor in the
middle of a room is in the same relation to the walls of that room as the
charge upon the inner coating of a Leyden jar is to the outer coating of
the same jar. The one is not more _free_ or more _dissimulated_ than the
other; and when sometimes we make electricity appear where it was not
evident before, as upon the outside of a charged jar, when, after
insulating it, we touch the inner coating, it is only because we divert
more or less of the inductive force from one direction i