. . . . 238
0 . . . . after discharge.
. . . . 0 after discharge.

Here app. ii. retained 238 deg., and gave up 150 deg. in communicating a charge of
237 deg. to app. i., and the capacity of the air apparatus is to that of the
sulphur apparatus as 1 to 1.58. These results are very near to each other,
and we may take the mean 1.62 as representing the specific inductive
capacity of the sulphur apparatus; in which case the specific inductive
capacity of sulphur itself as compared to air = 1 (1270.) will be about or
above 2.24.

1277. This result with sulphur I consider as one of the most
unexceptionable. The substance when fused was perfectly clear, pellucid,
and free from particles of dirt (1267.), so that no interference of small
conducting bodies confused the result. The substance when solid is an
excellent insulator, and by experiment was found to take up, with great
slowness, that state (1244. 1242.) which alone seemed likely to disturb the
conclusion. The experiments themselves, also, were free from any need of
correction. Yet notwithstanding these circumstances, so favourable to the
exclusion of error, the result is a higher specific inductive capacity for
sulphur than for any other body as yet tried; and though this may in part
be clue to the sulphur being in a better shape, i.e. filling up more
completely the space _o, o_, (fig. 104.) than the cups of shell-lac and
glass, still I feel satisfied that the experiments altogether fully prove
the existence of a difference between dielectrics as to their power of
favouring an inductive action through them; which difference may, for the
present, be expressed by the term _specific inductive capacity_.

1278. Having thus established the point in the most favourable cases that I
could anticipate, I proceeded to examine other bodies amongst solids,
liquids, and gases. These results I shall give with all convenient brevity.

* * * * *

1279. _Spermaceti._--A good hemisphere of spermaceti being tried as to
conducting power whilst its two surfaces were still in contact with the
tinfoil moulds used in forming it, was found to conduct sensibly even
whilst warm. On removing it from the moulds and using it in one of the
apparatus, it gave results indicating a specific inductive capacity between
1.3 and 1.6 for the apparatus containing it. But as the only mode of
operation was to charge the air apparatus, and then after a qui