compound to be accompanied by its decomposition. Is
then the act of decomposition essential to the act of conduction in
these bodies? Even recently this question was warmly contested. Faraday
was very cautious latterly in expressing himself upon this subject;
but as a matter of fact he held that an infinitesimal quantity of
electricity might pass through a compound liquid without producing its
decomposition. De la Rive, who has been a great worker on the chemical
phenomena of the pile, is very emphatic on the other side. Experiment,
according to him and others, establishes in the most conclusive manner
that no trace of electricity can pass through a liquid compound without
producing its equivalent decomposition.[2]

Faraday has now got fairly entangled amid the chemical phenomena of the
pile, and here his previous training under Davy must have been of the
most important service to him. Why, he asks, should decomposition thus
take place?--what force is it that wrenches the locked constituents
of these compounds asunder? On the 20th of June, 1833, he read a paper
before the Royal Society 'On Electro-chemical Decomposition,' in which
he seeks to answer these questions. The notion had been entertained
that the poles, as they are called, of the decomposing cell, or in other
words the surfaces by which the current enters and quits the liquid,
exercised electric attractions upon the constituents of the liquid and
tore them asunder. Faraday combats this notion with extreme vigour.
Litmus reveals, as you know, the action of an acid by turning red,
turmeric reveals the action of an alkali by turning brown. Sulphate of
soda, you know, is a salt compounded of the alkali soda and sulphuric
acid. The voltaic current passing through a solution of this salt
so decomposes it, that sulphuric acid appears at one pole of the
decomposing cell and alkali at the other. Faraday steeped a piece of
litmus paper and a piece of turmeric paper in a solution of sulphate of
soda: placing each of them upon a separate plate of glass, he connected
them together by means of a string moistened with the same solution.
He then attached one of them to the positive conductor of an electric
machine, and the other to the gas-pipes of this building. These he
called his 'discharging train.' On turning the machine the electricity
passed from paper to paper through the string, which might be varied in
length from a few inches to seventy feet without changing the re