William Whewell to Faraday   5 May 1834

Trinity Coll. Cambridge, May 5, 1834

My dear Sir,

I quite agree with you that stechion or stecheon ¹ is an awkward word both from its length and from the letters of which it is composed, and I am very desirous that you should have a better for your purpose. I think I can suggest one, but previous to doing this I would beg you to reconsider the suggestion of anode and cathode which I offered before. It is very obvious that these words are much simpler than those in your proof sheet², and the advantage of simplicity will be felt very strongly when the words are once firmly established as by your paper I do not in the least degree doubt that they will be. As to the objection to anode I do not think it is worth hesitating about. Anodos and cathodos do really mean in Greek a way up and a way down; and anodos does not mean, and cannot mean, according to the analogy of the Greek language no way. It is true that the prefix an put before adjectives beginning with a vowel, gives a negative signification, but not to substantives, except through the medium of adjectives. Anarchos means without government, and hence anarchia, anarchy, means the absence of government: but anodos does not and cannot mean the absence of way. And if it did mean this as well as a way up, it would not cease to mean the latter also; and when introduced in company with cathodos no body who has any tinge of Greek could fail to perceive the meaning at once. The notion of anodos meaning no way could only suggest itself to persons unfamiliar with Greek, and accidentally acquainted with some English words in which the negative particle is so employed; and those persons who have taken up this notion must have overlooked the very different meaning of negatives applied to substantives and adjectives. Prepositions are so very much the simplest and most decisive way of expressing opposition or other relations that it would require some very strong arguments to induce one to adopt any other way of conveying such relations as you want to indicate[.]

If you take anode and cathode I would propose for the two elements resulting from electrolysis the terms anion and cation ³ which are neuter participles signify‑ing that which goes up and that which goes down; and for the two together you might use the term ions ⁴ instead of zetodes or stechions. 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.

Your passages would then stand thus p.78

"We purpose calling that towards the east the anode<dagger>, and that towards the west the cathode<doublebar>...p.79⁵. I purpose to distinguish these bodies by calling those anions<sect> which go to the anode of the decomposing body, and those passing to the cathode, cations<para>. And when I have occasion to speak of these together I shall call them ions ⁶. <dagger><alphaac><nu><alphaac> upwards, <omicronac><delta><omicronac><sigma2>, a way; the way which the sun rises. <doublebar><kappa><alpha><tau><alphaac> downwards <omicronac><delta><omicronac><sigma2> a way; the way which the sun sets. <sect><alphaac><nu><iota><omicronac><nu>, that which goes up, (neuter participle). <para><kappa><alpha><tau><iota><omicronac><nu>, that which goes down⁷.["]

I am so fully persuaded that these terms are from their simplicity preferable to those you have printed that I shall think it a misfortune to science if you retain the latter. If however you still adhere to dexio and scaio I am puzzled to combine these with ion without so much coalition of vowels as will startle your readers. I put at the bottom of the page the explanation if you should persist in this.[*] I would only beg you to recollect that even violent philological anomalies are soon got over, if they are used to express important laws, as we see in the terms endosmose and exosmose⁸: and therefore there is little reason for shrinking from objections founded in ignorance against words which are really agreeable to the best analogies. The existing notation of Chemistry owes its wide adoption and long duration to its simplicity.

I am afraid you will think I am fond of playing the critic if I make any further objections, otherwise I would observe on your Article 666⁹, that if you are not sure that you will want such words as astechion, it is throwing away your authority to propose them. If what I have written does not answer your purpose pray let me hear from you again, and believe me

Yours very truly | W. Whewell

P.S. If, adopting the term ion for stechion you do want the negative astechion I do not think there will be any difficulty in devising a suitable word.

[+] You may easily take an adverb if you so please - but ought you to do so!

[*] <delta><epsilon><xi><iota><omicronac><sigma2>, on the right hand and hence, the east, <sigma1><kappa><alpha><iota><omicronac><sigma2>, on the left hand and hence, the west.

Address: M. Faraday Esq | Royal Institution | Albemarle Street | London