etter show both the curved
lines or courses of the inductive action, disturbed as they are from their
rectilineal form by the shape, position, and condition of the metallic
hemisphere; and also a _lateral tension,_ so to speak, of these lines on
one another:--all depending, as I conceive, on induction being an action of
the contiguous particles of the dielectric, which being thrown into a state
of polarity and tension, are in mutual relation by their forces in all
directions.

1225. As another proof that the whole of these actions were inductive I may
state a result which was exactly what might be expected, namely, that if
uninsulated conducting matter was brought round and near to the excited
shell-lac stem, then the inductive force was directed towards it, and could
not be found on the top of the hemisphere. Removing this matter the lines
of force resumed their former direction. The experiment affords proofs of
the lateral tension of these lines, and supplies a warning to remove such
matter in repeating the above investigation.

1226. After these results on curved inductive action in air I extended the
experiments to other gases, using first carbonic acid and then hydrogen:
the phenomena were precisely those already described. In these experiments
I found that if the gases were confined in vessels they required to be very
large, for whether of glass or earthenware, the conducting power of such
materials is so great that the induction of the excited shell-lac cylinder
towards them is as much as if they were metal; and if the vessels be small,
so great a portion of the inductive force is determined towards them that
the lateral tension or mutual repulsion of the lines of force before spoken
of, (1224.) by which their inflexion is caused, is so much relieved in
other directions, that no inductive charge will be given to the carrier
ball in the positions _k, l, m, n, o, p_ (fig. 110.). A very good mode of
making the experiment is to let large currents of the gases ascend or
descend through the air, and carry on the experiments in these currents.

1227. These experiments were then varied by the substitution of a liquid
dielectric, namely, _oil of turpentine_, in place of air and gases. A dish
of thin glass well-covered with a film of shell-lac (1272.), which was
found by trial to insulate well, had some highly rectified oil of
turpentine put into it to the depth of half an inch, and being then placed
upon the top of the b