Faraday to William Whewell   24 April 1834

Royal Institution | 24th April 1834

My dear Sir

I am in a trouble which when it occurs at Cambridge is I understand referred by every body in the University to you for removal and I am encouraged by the remembrance of your kindness and on Mr. Willis'¹ suggestion to apply to you also[.] But I should tell you how I stand in the matter.

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 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"² 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 "Electrolytic intensity" &c &c³[.] What have been called the poles of the battery I call the electrodes ⁴ they are not merely surfaces of metal but even of water & air ⁵, 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 one direction the other in the other towards the electrodes or poles where they are evolved[;] these evolved substances I call zetodes ⁶, which are therefore the direct constituents of electrolites[.]

All these terms I am satisfied with but not with two others which I have used thus far. It is essential to me to have the power of referring to the two surfaces of a decomposable body by which the current enters into & passes out of it, without at the same time referring to the electrodes[.] Thus let a be a decomposable body &

P & N the pos & neg poles which may or may not be in contact with a at the points b. c and shall yet transmit the electricity which passes through a[.] Admitting the usual mode of expression & talking of a current of Electricity proceeding from the positive pole P through a to the negative pole N my friend suggested & I have used the term eisode for c and exode ⁷ for b, the points where the zetodes are rendered and a zetode going to c I have called a zeteisode & another going to b, a zetexode ⁸[.]

But the idea of a current especially of one current is a very clumsy & hypo‑thetical view of the state of Electrical forces under the circumstances[.] The idea of two currents seems to me still more suspicious and I have little doubt that the present view of electric currents and the notions by which we try to conceive of them will soon pass away and I want therefore names by which I can refer to c & b without involving any theory of the nature of electricity[.] In searching for a reference on which to found these I can think of nothing but the globe as a magnetic body[.] If we admit the magnetism of the Globe as due to Electric currents running in lines of latitude their course must be according to our present modes of expression from East to West and if a portion of water under decomposition by an electric current be placed so that the current through it shall be parallel to that considered as circulating round the earth then the oxygen will be rendered towards the east or at c in the figure & the hydrogen towards the west or at b in the figure[.] I think therefore that if I were to call c the east-ode & b the west-ode I should express these parts by reference to a natural standard which whatever changes take place in our theories or knowledge of Electricity will still have the same relation[.] But Eastode & Westode or Oriode & Occiode are name[s] which a scholar could not suffer I understand for a moment and Anatolode and dysiode have been offered me instead[.]

Now can you help me out to two good names not depending upon the idea of a current in one direction only or upon Positive or negative and to which I may add the prefixes Zet or Zeto, so as to express the class to which any particular Zetode may belong.

I am making very free with you but if you feel inclined to help me I shall be very much obliged & if not may [sic] no ceremony in saying that you cannot assist me.

I am Dear Sir | Your faithful Servant | M. Faraday

Rev. W. Whewell | &c &c &c

Endorsed by Whewell: Ansd. Ap. 25. 1834

Address: Revd. W. Whewell | &c &c &c | Trinity College | Cambridge