All your names I and my friend approve of or nearly all as to sense & expression, but I am frightened by their length & sound when compounded. As you will see I have taken deoxide and skaiode because they agree best with my natural standard East and West. I like Anode & Cathode better as to sound, but all to whom I have shewn them have supposed at first that by Anode I meant No way.

I have taken your advice, and the names used are anode cathode anions cations and ions; the last I shall have but little occasion for. I had some hot objections made to them here and found myself very much in the condition of the man with his son and ass who tried to please every body; but when I held up the shield of your authority, it was wonderful to observe how the tone of objection melted away.

I require a term to express those bodies which can pass to the electrodes, or, as they are usually called, the poles. Substances are frequently spoken of as being electro-negative, or electro-positive, according as they go under the supposed influence of a direct attraction to the positive or negative pole. But these terms are much too significant for the use to which I should have to put them; for though the meanings are perhaps right, they are only hypothetical, and may be wrong; and then, through a very imperceptible, but still very dangerous, because continual, influence, they do great injury to science, by contracting and limiting the habitual view of those engaged in pursuing it. I propose to distinguish these bodies by calling those anions which go to the anode of the decomposing body; and those passing to the cathode, cations; and when I have occasion to speak of these together, I shall call them ions.

I wanted some new names to express my facts in Electrical science without involving more theory than I could help & applied to a friend Dr Nicholl [his doctor], who has given me some that I intend to adopt for instance, a body decomposable by the passage of the Electric current, I call an 'electrolyte' and instead of saying that water is electro chemically decomposed I say it is 'electrolyzed'[.] The intensity above which a body is decomposed beneath which it conducts without decomposition I call the 'Electrolyte intensity' &c &c. What have been called: the poles of the battery I call the electrodes they are not merely surfaces of metal, but even of water & air, to which the term poles could hardly apply without receiving a new sense. Electrolytes must consist of two parts which during the electrolization, are determined the one in the one direction, and the other towards the poles where they are evolved; these evolved substances I call zetodes, which are therefore the direct constituents of electrolites.

The influence of electricity in producing decompositions, although of inestimable value as an instrument of discovery in chemical inquiries, can hardly be said to have been applied to the practical purposes of life, until the same powerful genius [Davy] which detected the principle, applied it, by a singular felicity of reasoning, to arrest the corrosion of the copper-sheathing of vessels. ... this was regarded as by Laplace as the greatest of Sit Humphry's discoveries.