immediately after discharge.

1211. The transferable charge being 148 deg. - 5 deg., its half is 71 deg..5, which is
not far removed from 70 deg., the half charge of i.; or from 73 deg., the half
charge of ii.: these half charges again making up the sum of 143 deg., or just
the amount of the whole transferable charge. Considering the errors of
experiment, therefore, these results may again be received as showing that
the apparatus were equal in inductive capacity, or in their powers of
receiving charges.

1212. The experiments were repeated with charges of negative electricity
with the same general results.

1213. That I might be sure of the sensibility and action of the apparatus,
I made such a change in one as ought upon principle to increase its
inductive force, i.e. I put a metallic lining into the lower hemisphere of
app. i., so as to diminish the thickness of the intervening air in that
part, from 0.62 to 0.435 of an inch: this lining was carefully shaped and
rounded so that it should not present a sudden projection within at its
edge, but a gradual transition from the reduced interval in the lower part
of the sphere to the larger one in the upper.

1214. This change immediately caused app. i. to produce effects indicating
that it had a greater aptness or capacity for induction than app. ii. Thus,
when a transferable charge in app. ii. of 469 deg. was divided with app. i.,
the former retained a charge of 225 deg., whilst the latter showed one of 227 deg.,
i.e. the former had lost 244 deg. in communicating 227 deg. to the latter: on the
other hand, when app. i. had a transferable charge in it of 381 deg. divided by
contact with app. ii., it lost 181 deg. only, whilst it gave to app. ii. as
many as 194:--the sum of the divided forces being in the first instance
_less_, and in the second instance _greater_ than the original undivided
charge. These results are the more striking, as only one-half of the
interior of app. i. was modified, and they show that the instruments are
capable of bringing out differences in inductive force from amongst the
errors of experiment, when these differences are much less than that
produced by the alteration made in the present instance.

P iv. _Induction in curved lines._

1215. Amongst those results deduced from the molecular view of induction
(1166.), which, being of a peculiar nature, are the best tests of the truth
or error of the theory, the expected action in curved lines is