a small electrometer at _c_ or at _d_, uninsulated, will
give signs of electricity, opposite in its nature to that of A, and
therefore caused by induction, although the influencing and influenced
bodies cannot be joined by a right line passing through the air. Or if, the
electrometers being removed, a point be fixed at the back of the ball in
its uninsulated state as at C, this point will become luminous and
discharge the conductor A. The latter experiment is described by
Nicholson[A], who, however, reasons erroneously upon it. As to its
introduction here, though it is a case of discharge, the discharge is
preceded by induction, and that induction must be in curved lines.

[A] Encyclopaedia Britannica, vol. vi. p. 504.

1231. As argument against the received theory of induction and in favour of
that which I have ventured to put forth, I cannot see how the preceding
results can be avoided. The effects are clearly inductive effects produced
by electricity, not in currents but in its statical state, and this
induction is exerted in lines of force which, though in many experiments
they may be straight, are here curved more or less according to
circumstances. I use the term _line of inductive force_ merely as a
temporary conventional mode of expressing the direction of the power in
cases of induction; and in the experiments with the hemisphere (1224.), it
is curious to see how, when certain lines have terminated on the under
surface and edge of the metal, those which were before lateral to them
_expand and open out from each other_, some bending round and terminating
their action on the upper surface of the hemisphere, and others meeting, as
it were, above in their progress outwards, uniting their forces to give an
increased charge to the carrier ball, at an _increased distance_ from the
source of power, and influencing each other so as to cause a second flexure
in the contrary direction from the first one. All this appears to me to
prove that the whole action is one of contiguous particles, related to each
other, not merely in the lines which they may be conceived to form through
the dielectric, between the _inductric_ and the _inducteous_ surfaces
(1483.), but in other lateral directions also. It is this which gives an
effect equivalent to a lateral repulsion or expansion in the lines of force
I have spoken of, and enables induction to turn a corner (1304.). The
power, instead of being like that of gravity, which causes