minates the
extent of the induction, by all the intermediate particles (1165, 1295.),
these becoming polarized exactly as the particles of a solid electrolyte do
when interposed between the two electrodes. Hence the conclusion regarding
the unity and identity of the current in the case of convection, jointly
with the former cases, is not so strange as it might at first appear.

* * * * *

1646. There is a very remarkable phenomenon or effect of the electrolytic
discharge, first pointed out, I believe, by Mr. Porrett, of the
accumulation of fluid under decomposing action in the current on one side
of an interposed diaphragm[A]. It is a mechanical result; and as the liquid
passes from the positive towards the negative electrode in all the known
cases, it seems to establish a relation to the polar condition of the
dielectric in which the current exists (1164. 1525.). It has not as yet
been sufficiently investigated by experiment; for De la Rive says[B], it
requires that the water should be a bad conductor, as, for instance,
distilled water, the effect not happening with strong solutions; whereas,
Dutrochet says[C] the contrary is the case, and that, the effect is not
directly due to the electric current.

[A] Annals of Philosophy, 1816. viii. p. 75.

[B] Annales de Chimie, 1835. xxviii. p. 196.

[C] Annales de Chimie, 1832, xlix. p. 423.

1647. Becquerel, in his Traite de l'Electricite, has brought together the
considerations which arise for and against the opinion, that the effect
generally is an electric effect[A]. Though I have no decisive fact to quote
at present, I cannot refrain from venturing an opinion, that the effect is
analogous both to combination and convection (1623.), being a case of
carrying due to the relation of the diaphragm and the fluid in contact with
it, through which the electric discharge is jointly effected; and further,
that the peculiar relation of positive and negative small and large
surfaces already referred to (1482. 1503. 1525.), may be the direct cause
of the fluid and the diaphragm travelling in contrary but determinate
directions. A very valuable experiment has been made by M. Becquerel with
particles of clay[B], which will probably bear importantly on this point.

[A] Vol. iv. p. 192, 197.

[B] Traite de l'Electricite, i. p. 285.

* * * * *

1648. _As long as_ the terms _current_ and _electro-dynamic_ are