Faraday's Researches

increased distances from the poles, he states that in a circuit
of ten inches of water, solution of sulphate of potassa placed
four inches from the positive pole did not decompose; whereas
when only two inches from that pole, it did render up its
elements .1

220. When in 1826 Sir Humphry Davy wrote again on this
subject, he stated that he found nothing to alter in the funda-
mental theory laid down in the original communication,2 and
uses the terms attraction and repulsion apparently in the same
sense as before.3

221. Messrs. Riffault and Chompre experimented on this
subject in 1807. They came to the conclusion that the voltaic
current caused decompositions throughout its whole course in
the humid conductor, not merely as preliminary to the recom-
ppsitions spoken of by Grotthuss and Davy, but producing final
separation of the elements in the course of the current, and
€lsewhere than at the poles. They considered the negative
current as collecting and carrying the acids, etc., to the positive
pole, and the positive current as doing the same duty with the
bases, and collecting them at the negative pole. They likewise
consider the currents as more powerful the nearer they are to
their respective poles, and state that the positive current is
superior in power to the negative current.4

222. M. Biot is very cautious in expressing an opinion as to
the cause of the separation of the elements of a compound
body.5 But as far as the effects can be understood, he refers
them to the opposite electrical states of the portions of the
decomposing substance in the neighbourhood of the two poles.
The fluid is most positive at the positive pole; that state
gradually diminishes to the middle distance, where the fluid is
neutral or not electrical; but from thence to the negative pole
it becomes more and more negative.6 When a particle of
salt is decomposed at the negative pole, the acid particle is
considered as acquiring a negative electrical state from the pole,
stronger than that of the surrounding undecomposed particles,
and is. therefore repelled from amongst them, and from out of
that portion of the liquid towards the positive pole, towards
which also it is drawn by the attraction of the pole itself and
the particles of positive undecomposed fluid around it.7

1 Philosophical Transactions, 1807, p. 42.

2 Ibid. 1826, p. 383. 8 Ibid. pp. 389, 407, 415.
4 Annales de CMmie,-i8o7, torn. Ixiii. p. 83, etc.

6 Precis Elcmentaire de Physique, 31110 Edition, 1824, torn. i. p. 641.
0 Ibid. p. 637. 7 Ibid. pp. 6.11, 642.i. p. 64.s the former.