Faraday to Benjamin Abbott   9 and 11 September 1812

Sept 9th. 1812.

“Read it through”

You wrong me, dear Abbott if you suppose I think you obstinate for not coinciding in my opinion immediately. On the contrary I conceive it to be but proper retention[.] I should be sorry indeed were you to give up your opinion without being convinced of error in it and should consider it as a mark of fickleness in you that I did not expect - It is not for me to affirm that I am right & you wrong - speaking impartially I can as well say that I am wrong and you right or that we both are wrong and a third right I so not so self opinionated as to suppose that my judgement & perceptions in this or other matters is better or clearer than that of other persons nor do I mean to affirm that this is the true theory in reality but only - that my judgement conceives it to be so[.] Judgements sometimes oppose each other as in this case and as there cannot be two opposing facts in nature so there cannot be two opposing truths in the intellectual world consequently when judgements oppose one must be wrong - one must be false - and mine may be so for aught I can tell - I am not of a superior nature to estimate exactly the strength & correctness of my own and other mens understanding and will assure you dear A_ that I am far from being convinced that my own is always right.

I have given you this theory not as the true one but as the one which appears true to me - and when I perceive errors in it I will immediately renounce it in part or wholly as my judgement may direct - From this dear Friend you will see that I am very open to conviction but from the manner in which I shall answer your Letter you will also perceive that I must be convinced before I renounce[.]

You have made a blunder in your letter Abbott. You say that you will first answer my experiments and then relate others but you have only noticed one of mine and therefore I suppose the answers to the others are to come - “With respect to the taper” do you mean to say that none of its Carbon is burnt in Atmospheric air or Oxygen gas[.] I understood Davy that none of it was burned in Chlorine gas and as for your Query of water being formed I do not believe there was any not the slightest condensation took place - I did not insist much on this experiment by itself but had connected it to another where charcoal would not burn you should have answered them both together.<qr>Wednesday Night 10.30.pm

I thank you dear A_ most heartily for the amusement and pleasure I have just experienced[.] I was instructed at the Lecture but expected to see (hear) more of the particular nature of the Alkalies the subject was copious enough[.] Order was not sufficiently attended to yours I have no doubt will abound in that respect.

You wish to alter the tenor of our arguments you conceive that if you prove oxygen to exist in Muriatic Acid you have done enough - not so - if you do that you will do wonders and I shall certainly pay that respect to it it deserves but the experiments I have related must also be answered before I change opinions[.] I understand it is possible to support a new theory of Chlorine namely that it is a compound of an unknown base and Oxygen but which have never yet been detected separate - but this will not alter our arguments since still MA is considered as the Chlorine and Hydrogen united and whilst this Chlorine is undecomposed we must consider it as simple -

I was considerably surprised to hear you charge me last night with having denied facts[.] I am not aware that I have denied any nor do I wish to do so - I have denied some which have been accounted facts but those cannot be what you alluded to - pray point them out to me[.]

I shall now answer all your conclusive experiments and must confess I do not see that difficulty I expected - Do you remember the first experiment you quoted the solution of a metal in Muriatic Acid in which experiment you consider the Metal as being oxidised at the expence of the Acid - By this means you have arrived at a discovery which has drawn the attention of all great chemists the decomposition of the Muriatic Acid - for by informing us what remains by the de-oxidation of the Acid by the Metal we shall have its other constituent part and thus our dispute - no not dispute - friendly controversy will end - I fear dear A_ you will find it hard to decompose MA by the solution of a metal in it[.] It has never knowingly been done by any of Lavoisier’s disciples yet or at least they have never allowed it[.] It has been done and I have before related the experiment to you - but to return to your experiment. When a metal is dissolved in MA I believe it is generally the case that Hydrogen is evolved - from whence is this Hydrogen but from decomposed water and in what manner is the Oxygen employed but by combining with the metal - the oxide is then dissolved - as very prominent instances of this kind I will notice the action of MA on Iron & Zinc - other metals are dissolved by this Acid but I have never noticed the phenomena attendant - If you say the metal obtains Oxygen from the Acid inform me what part of the Acid is left and in what state.

2nd. Oxygen I know may be obtained from the Oxy-muriates because they contain it they are formed by double combination first a Muriate is formed being a compound of Chlorine & the metallic base of the Alkalies and with this compound Oxygen combines - by applying heat the only operation that takes place is the driving off of Oxygen - but more of this when I have detailed farther to you Davy’s theory tho’ you must perceive the experiments are as easily explained thus as by Lavoisier’s opinion[.]

3rd. You can refer I presume to J Davy’s experiment¹ and therefore I shall give here only my opinion on it whether mechanical or chemical if the oxide is held mechanically in the Ferrane as he supposes it makes no part of the compound of Chlorine & Iron and of course does not affect the subject at all in my idea and if chemically which is not at all probable it does not make its appearance untill water is added and then it is easily accounted for but in order to estimate the experiment exactly it would be necessary to consider the manner in which the Ferrane is formed.

I come next to your remarks of which I own the propriety and tho I do not suppose that at any time I can make experiments with more exactness & precision than those I have quoted yet certainly the performance would give us a clearer idea[.] I accept of your offer to fight it out with joy and shall in the battle experience & cause not pain but I hope pleasure nevertheless I will if you will allow me give whilst I have time & opportunity & whilst my ideas are fresh & collected what little more I know of this theory not requiring your immediate answer but leaving it to your leisure consideration[.]

One circumstance amongst many others which makes the difference between Chlorine & the Acids is the change it causes in vegetable colours it does not turn them red as the Acids do but it destroys them entirely and makes the body white and the colour can be restored by neither Acids or Alkalies²[.] Pure Chlorine has no effect on vegetable colours at all as has been proved but when water is present it decomposes it and the oxygen causes the change of colour[.] Acids act by combining with the colour without decomposition but Chlorine by presenting oxygen to them having first liberated it from water by taking to itself the Hydrogen - Muriatic Ad is formed[.]

Sr. H. Davy I believe was first induced to make an experimental inquiry into the nature of MA by observing that it could never be obtained from Oxy-muriatic acid or the dry Muriates unless water or its constituent parts were present³ - having noticed that this phenomena never took place in his general experiments he made some directly to ascertain the point and found that he was incapable of obtaining that Ad from the dry Muriates or from what has been considered as a combination of it with oxygen[.] Neither Oxygen or MA can be obtained or at least has been obtained from the Oxy-muriatic Acid - This circumstance it was that first induced Davy to prosecute the inquiry and is a high stumbling block to the Lavoisierian theory of this Acid.

There is an experiment of the reciprocal decomposition of Ammonia & the Oxy-muriatic gas that appears directly opposite to this theory of Chlorine[.] So it appeared to Davy and of course he examined it in order to see what conclusions it would lead to[.] He found that it had generally been too loosely made and the opinion that water is formed too hastily adopted he found that when those gases pure & dry were mixed in the proportions of one of Chlorine to 3 of Alkali no water was formed but the product was dry & solid M of Ammonia with about 1/10 of nitrogen gas⁴[.] The Chlorine had decomposed a part of the Ammonia the nitrogen of which was liberated[.] The Hydrogen it united to forming MA & then a M of Ammonia was formed.

Chlorine forms binary compounds not only with Hydrogen Phosphorus & Sulphur but also with several of the metals amongst which are the bases of the Alkalies and Alkaline earths⁵ - When Tin is heated in Chlorine gas both the metal & gas disappear and a liquid being the liquor of Libavius or a Muriate of Tin is obtained[.] This substance is a binary compound only - if ammoniacal gas is added to it[,] no decomposition takes place but the gas & the Stannane (as Davy terms it⁶) combine & a solid volatile body is obtained - What is this Volatile body by the Lavoisierian theory?

Some of the combustibles (including metals) have a stronger affinity for Chlorine than for Oxygen[.] Others have a stronger affinity for Oxygen than for Chlorine - When the affinity of the Chlorine exceeds that of the Oxygen it can be employed to decompose the Oxides in which case it separates the Oxygen - When a piece of Potassium is inflamed in Chlorine gas it unites to the Chlorine and a dry M of P is formed[.] If an oxide of Potassium (not Potash that is an Hydrat) is used the Chlorine combines with the metal and the oxygen is liberated a Muriate is formed - If the Red Oxide of Mercury is heated in Chlorine gas the Metal & gas unite and the Oxygen is given out[;] Corrosive Sublimate is formed⁷[.] If Lime is heated in Chlorine gas the base or Metal Calcium unites to the Chlorine & the Oxygen is given out & in this way can the Alkalies & Alkaline earths be decomposed⁸[.] I know well your answer to this “O the Acid parts with Oxygen & then the simple MA & the base combine” but not too fast[;] if so then the same quantity of Oxygen should always be liberated from the same quantity of OMA gas but that is Not the case[.] The quantity of oxygen varies with an equal portion of Chlorine gas but is always in exact proportion to the quantity contained in the oxides a clear proof that it is given out by them and not by the Chlorine[.] Indeed it appears singular to say that the Oxygen is given out by a body (Chlorine) from which it has never yet been directly (or any other way) obtained when other bodies are present containing it in exactly similar proportions.

Amongst other experiments S H. Davy heated some dry Muriatic Acid gas in contact with the per-oxide of Manganese also very dry - water was rapidly formed & Chlorine gas was liberated - how do you explain this - I know well your theory but you cannot account for the production of the water - in reality the MA was decomposed[,] its Hydrogen united to the Oxygen of the Oxide & formed water & the Chlorine remained free - I should have observed that the black oxide was reduced to the brown oxide of Manganese.

I have before adverted to the peculiar action of Chlorine on vegetable colours but I shall now intimate that in reality it does not act on them at all⁹[.] S H. Davy made some experiments where the dry & pure gas produced no effect on litmus paper tho the contact was continued some time[.] His gas was freed from water by the Muriate of Lime and then it did not at all affect dry Litmus paper or other vegetable colours at the same time Litmus paper that had been dried & heated when exposed to gas not standing over the M of Lime was instantly rendered white & also paper not previously dried when immersed in the dry gas slowly underwent the change but when no water was present no bleaching powers were exhibited[.] This certainly proves Chlorine to be of a very different nature to the Acids since it in reality has no action on vegetable colours[.] It only destroys them by decomposing water & by liberating & giving to them Oxygen[.]

Davy in his Bakerian Lecture says that “most of the salts which have been called Muriates are not known to contain MA or any Oxygen[.] Thus Libavius Liquor tho converted “into a Muriate by water contains only Tin & Oxy-muriatic gas and horn silver seems incapable of being converted into a true muriate.”¹⁰

With respect to the affinity of the Metals & Inflammable bodies with Chlorine and Oxygen he says that Potassium Sodium, Calcium, Strontium, Barium, Zinc, Mercury Tin Lead and probably Silver Antimony & Gold seem to have a stronger affinity for Oxy-muriatic Gas than for Oxygen but Boron, Phosphorous Iron & Arsenic have apparently a stronger affinity for Oxygen than Chlorine.

It is now time to conclude dear A - which I do with best wishes to yourself & friends[.] In my next I will conclude the subject with Euchlorine¹¹ when I will again subscribe myself,

Your Sincere Friend, | M. Faraday

Dear Abbott

I have received yours of to day the perusal of which has raised in my mind a tumult of petty passions amongst which are predominant vexation Sorrow & regret[.] I write under the influence of them and shall inform you candidly of my feelings at this moment[.] You will see by the foregoing part of this letter that I have not acted in unison with your request by dropping the subject of chlorine and for not having done so I feel very considerable sorrow[.] I had at various short intervals as time would permit drawn it up & felt I will own gratified on reading it over but the reception of yours has made me most heartily regret it[.] Pity me dear Abbott in that I have not sufficiently the mastery of my feelings & passions - In the first part of this long Epistle you will see reasons I have given for continuing the subject but I fancy that I can now see the pride & self complacency that led me on & I am fearfull that I was influenced by thinking that I had a superior knowledge in this particular subject - being now aware of this passion I have made a candid confession of it to you in hopes to lessen it by mortifying it & humiliating it - You will of course understand that I shall not now enter on Euchlorine untill it is convenient for both of us when I hope to take up the subject uninfluenced by any of those humiliating & to a Philosopher disgraceful feelings.

I am heartily obliged to you for your Queries but have not time to consider them at present - the Philosophical adventures of your Friend were laughable & I hope the sentiment you express namely caution will also strike him least he should err in more important cases - I am glad you are pleased with Accum¹²[;] you must at some opportunity let me look into it - I wish to see you shortly (perhaps tomorrow at noon) when I will bring the MS Lecture & the P.M. - and thus having made my confession I subscribe myself with humility[.]

Yours Sincerely, | M. Faraday