into operation.

405. The following are bodies which acquired no conducting power upon
assuming the liquid state:--

Sulphur, phosphorus; iodide of sulphur, per-iodide of tin; orpiment,
realgar; glacial acetic acid, mixed margaric and oleic acids, artificial
camphor; caffeine, sugar, adipocire, stearine of cocoa-nut oil, spermaceti,
camphor, naphthaline, resin, gum sandarach, shell lac.

406. Perchloride of tin, chloride of arsenic, and the hydrated chloride of
arsenic, being liquids, had no sensible conducting power indicated by the
galvanometer, nor were they decomposed.

407. Some of the above substances are sufficiently remarkable as exceptions
to the general law governing the former cases. These are orpiment, realgar,
acetic acid, artificial camphor, per-iodide of tin, and the chlorides of
tin and arsenic. I shall have occasion to refer to these cases in the paper
on Electro-chemical Decomposition.

408. Boracic acid was raised to the highest possible temperature by an
oxy-hydrogen flame (401.), yet it gained no conducting powers sufficient to
affect the galvanometer, and underwent no apparent voltaic decomposition.
It seemed to be quite as bad a conductor as air. Green bottle-glass, heated
in the same manner, did not gain conducting power sensible to the
galvanometer. Flint glass, when highly heated, did conduct a little and
decompose; and as the proportion of potash or oxide of lead was increased
in the glass, the effects were more powerful. Those glasses, consisting of
boracic acid on the one hand, and oxide of lead or potassa on the other,
show the assumption of conducting power upon fusion and the accompanying
decomposition very well.

409. I was very anxious to try the general experiment with sulphuric acid,
of about specific gravity 1.783, containing that proportion of water which
gives it the power of crystallizing at 40 deg. Fahr.; but I found it impossible
to obtain it so that I could be sure the whole would congeal even at 0 deg.
Fahr. A ten-thousandth part of water, more or less than necessary, would,
upon cooling the whole, cause a portion of uncongealable liquid to
separate, and that remaining in the interstices of the solid mass, and
moistening the planes of division, would prevent the correct observation of
the phenomena due to entire solidification and subsequent liquefaction.

410. With regard to the substances on which conducting power is thus
conferred by liquidity, the degree of power so