He then passed on to other substances; to oxides and chlorides, and iodides, and salts, and sulphurets, and found them all insulators when solid, and conductors when fused.

In all cases, moreover, except one--and this exception he thought might be apparent only--he found the passage of the current across the fused 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.