l without injuring the lac by the heat
applied; and unless they be dissipated, the substance left conducts too
well to be used in these experiments. I prepared two hemispheres this way,
one of them unexceptionable; and with it I repeated the former experiments
with all precautions. The results were exactly of the same kind; the
following expressions for the capacity of the shell-lac apparatus, whether
it were app. i. or ii., being given directly by the experiments, 1.46,
1.50, 1.52, 1.51; the average of these and several others being very nearly
1.5.

1268. As a final check upon the general conclusion, I then actually brought
the surfaces of the air apparatus, corresponding to the place of the
shell-lac in its apparatus, nearer together, by putting a metallic lining
into the lower hemisphere of the one not containing the lac (1213.). The
distance of the metal surface from the carrier ball was in this way
diminished from 0.62 of an inch to 0.435 of an inch, whilst the interval
occupied by the lac in the other apparatus remained O.62 of an inch as
before. Notwithstanding this change, the lac apparatus showed its former
superiority; and whether it or the air apparatus was charged first, the
capacity of the lac apparatus to the air apparatus was by the experimental
results as 1.45 to 1.

1269. From all the experiments I have made, and their constant results, I
cannot resist the conclusion that shell-lac does exhibit a case of
_specific inductive capacity_. I have tried to check the trials in every
way, and if not remove, at least estimate, every source of error. That the
final result is not due to common conduction is shown by the capability of
the apparatus to retain the communicated charge; that it is not due to the
conductive power of inclosed small particles, by which they could acquire a
polarized condition as conductors, is shown by the effects of the shell-lac
purified by alcohol; and, that it is not due to any influence of the
charged state, formerly described (1250.), first absorbing and then
evolving electricity, is indicated by the _instantaneous_ assumption and
discharge of those portions of the power which are concerned in the
phenomena, that instantaneous effect occurring in these cases, as in all
others of ordinary induction, by charged conductors. The latter argument is
the more striking in the case where the air apparatus is employed to divide
the charge with the lac apparatus, for it obtains its portion of