ifies and even requires them.

App. i. Air. App. ii. Lac.
Balls 200 deg..

. . . . 0 deg..
286 deg. . . . .
283 . . . .
Charge divided.
. . . . 110
109 . . . .
. . . . 0.25 after discharge.
Trace . . . . after discharge.

Here app. i. retained 109 deg., having lost 174 deg. in communicating 110 deg. to app.
ii.; and the capacity of the air app. is to the lac app., therefore, as 1
to 1.58. If the divided charge be corrected for an assumed loss of only 3 deg.,
being the amount of previous loss in the same time, it will make the
capacity of the shell-lac app. 1.55 only.

1265. Then app. ii. was charged, and the charge divided thus:

App. i. Air. App. ii. Lac,
0 deg. . . . .
. . . . 250 deg.
. . . . 251
Charge divided.
146 . . . .
. . . . 149
a little . . . . after discharge.
. . . . a little after discharge.

Here app. i. acquired a charge of 146 deg., while app. ii. lost only 102 deg. in
communicating that amount of force; the capacities being, therefore, to
each other as 1 to 1.43. If the whole transferable charge be corrected for
a loss of 4 deg. previous to division, it gives the expression of l.49 for the
capacity of the shell-lac apparatus.

1266. These four expressions of 1.47, 1.50, 1.55, and 1.49 for the power of
the shell-lac apparatus, through the different variations of the
experiment, are very near to each other; the average is close upon 1.5,
which may hereafter be used as the expression of the result. It is a very
important result; and, showing for this particular piece of shell-lac a
decided superiority over air in allowing or causing the act of induction,
it proved the growing necessity of a more close and rigid examination of
the whole question.

1267. The shell-lac was of the best quality, and had been carefully
selected and cleaned; but as the action of any conducting particles in it
would tend, virtually, to diminish the quantity or thickness of the
dielectric used, and produce effects as if the two inducing surfaces of the
conductors in that apparatus were nearer together than in the one with air
only, I prepared another shell-lac hemisphere, of which the material had
been dissolved in strong spirit of wine, the solution filtered, and then
carefully evaporated. This is not an easy operation, for it is difficult to
drive off the last portions of alcoho