NEW NOMENCLATURE.
[Whewell to Faraday], May 5, 1834.
If you take anode and cathode, I would propose for the two elements resulting from electrolysis the terms anion and cation, which are neuter participles signifying that which goes up, and that which goes down; and for the two together you might use the term ions.... The word is not a substantive in Greek, but it may easily be so taken, and I am persuaded that the brevity and simplicity of the terms you will thus have will in a fortnight procure their universal acceptation. The anion is that which goes to the anode, the cation is that which goes to the cathode. The th in the latter word arises from the aspirate in hodos (way), and therefore is not to be introduced in cases where the second term has not an aspirate, as ion has not.
Fig. 12.
On May 15th Faraday replied as follows:—
[Faraday to Whewell.]
I have taken your advice and the names, and use 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 everybody; but when I held up the shield of your authority it was wonderful to observe how the tone of objection melted away. I am quite delighted with the facility of expression which the new terms give me, and shall ever be your debtor for the kind assistance you have given me.
As though to prepare the way for a still further cutting of himself adrift from the slavery of using terms that might be found misleading, he added the following note:—
It will be well understood that I am giving no opinion respecting the nature of the electric current now, beyond what I have done on former occasions; and that though I speak of the current as proceeding from the parts which are positive to those which are negative, it is merely in accordance with the conventional, though in some degree tacit, agreement entered into by scientific men, that they may have a constant, certain, and definite means of referring to the direction of the forces of that current.