ter. M. de la Rive has pointed this result out in
sulphurous acid[A], iodine and bromine[B]; the chloride of arsenic produces
the same effect. A far more striking case, however, is presented by that
very influential body sulphuric acid (681.): and probably phosphoric acid
also is in the same peculiar relation.

[A] Quarterly Journal, xxvii. 407. or Bibliotheque Universelle, xl.
205. Kemp says sulphurous acid is a very good conductor, Quarterly
Journal, 1831, p. 613.

[B] Quarterly Journal, xxiv, 465. or Annales de Chimie, xxxv. 161.

1356. It would seem in the cases of those bodies which suffer no change
themselves, as sulphuric acid (and perhaps in all), that they affect water
in its conducting power only as an electrolyte; for whether little or much
improved, the decomposition is proportionate to the quantity of electricity
passing (727. 730.), and the transfer is therefore due to electrolytic
discharge. This is in accordance with the fact already stated as regards
water (984.), that the conducting power is not improved for electricity of
force below the electrolytic intensity of the substance acting as the
dielectric; but both facts (and some others) are against the opinion which
I formerly gave, that the power of salts, &c. might depend upon their
assumption of the liquid state by solution in the water employed (410.). It
occurs to me that the effect may perhaps be related to, and have its
explanation in differences of specific inductive capacities.

1357. I have described in the last paper, cases, where shell-lac was
rendered a conductor by absorption of ammonia (1294.). The same effect
happens with muriatic acid; yet both these substances, when gaseous, are
non-conductors; and the ammonia, also when in strong solution (718.). Mr.
Harris has mentioned instances[A] in which the conducting power of metals
is seriously altered by a very little alloy. These may have no relation to
the former cases, but nevertheless should not be overlooked in the general
investigation which the whole question requires.

[A] Philosophical Transactions, 1827, p. 22.

1358. Nothing is perhaps more striking in that class of dielectrics which
we call electrolytes, than the extraordinary and almost complete suspension
of their peculiar mode of effecting discharge when they are rendered
_solid_ (380, &c.), even though the intensity of the induction acting
through them may be increased a hundredfold or more (419.). It not only
e