Faraday to Benjamin Abbott   19 August 1812

Aug. 19th. 1812.

Dear Abbott,

Never do I feel so well able and so well inclined to answer a letter as at the time of receiving it or rather at the first reading[.] I have just reperused yours but having seen you since I received it I find that by far the greater part of it is answered[.] It is probable therefore that this letter will be a dull one for I have but few subjects and the heat of the weather has so enervated me that I am not able to treat those I have in a proper manner - But rouse up Michael and do not disgrace thyself in the opinion of thy Friend¹ -

I have again gone over your letter but am so blinded that I cannot see any subject except Chlorine to write on but before entering upon what I intend shall fill up the letter I will ask your pardon for having maintained an opinion against one who was so ready to give his own up - I suspect from that circumstance I am wrong - I am happy to find from the conclusion of your Epistle that your views are so comprehensive and indulge largely the pleasures of anticipation in expectation of a rich harvest (in the winter) of new and important information[.]

With respect to Chlorine if we intend to debate the question of its simple or compound nature we have begun at a wrong point or rather at no point at all[.] Conscious of this I will at this time answer your present objections but briefly & then give the best statement I can of the subject - The Muriate of Soda is a compound of Chlorine and Sodium and as Chlorine in this theory is esteemed a simple substance I conceive that the name Chlorate of Sodium is improper ate and ite are the terminations of the generic names of Salts, and convey to our minds an idea of the Acid that the base is combined with but Chlorine is not an acid it is a simple substance belonging to the same class as oxygen and therefore its binary compounds should I conceive be termed in imitation of Oxydes, Chlorides. The Muriate of Soda is therefore a Chloride of Sodium and the Oxymuriate of Soda is a compound of that Chloride with Oxygen.

I will not say more at present on your objections since you will now be able to answer them yourself in the same way that I should do but I will proceed to the more simple and elementary parts of the subject - In the present case I conceive that Experiments may be divided into three classes 1st Those which are for the old theory of Oxy-muriatic Acid and consequently oppose the new one 2ndly Those which are for the new one and oppose the old Theory and 3rdly Those which can be explained by both theories - apparently so only for in reality a false theory can never explain a fact - I am not aware of any belonging to the first class what appeared to be such at first have on consideration resolved themselves into the third class[.] Of the second class I will propose a few to you and of the third class is that we have already been engaged upon[.]

Be not surprised my dear Abbott at the ardour with which I have embraced this new theory - I have seen Davy himself support it[.] I have seen him exhibit experiments conclusive experiments explanatory of it and I have heard him apply those experiments to the theory & explain and enforce them in (to me) an irresistible manner[.] Conviction Sir struck me and I was forced to believe him and with that belief came admiration[.]

As you are already acquainted with the properties of Chlorine it will be improper to say anything about its particular characters[.] I shall therefore enter immediately upon such experiments as I am acquainted with that tend to prove it a simple body that is an undecomposed one - You well know that when a taper is immersed burning in Chlorine gas the combustion becomes very dim the flame appears of a dull red & a great quantity of smoke is emitted²[.] This smoke is the carbonaceous part of the taper[.] Now on the supposition that Chlorine or Oxy-muriatic Acid is a compound of the Muriatic Acid and Oxygen how happens it that <<the>> Hydrogen of the combustible burns and not the Ca<<rbon.>> Carbon is considered as having the strongest affinity <<for>> Oxygen of any combustible yet here Hydrogen will burn and Carbon will not[.] Carbon which has the strongest affinity cannot do what Hydrogen does[.] Several of the Metals will burn spontaneously in this gas a proof that the supporter of combustion is not held by so strong an affinity from them and tho Carbon will decompose the Oxides of those Metals it cannot combine with the Oxygen of the gas[.] The fact is no oxygen is present nothing but Chlorine a simple substance and with Chlorine Charcoal has no apparent affinity[.] Hydrogen possesses a strong attraction for it and therefore we see why that part of the combustible burns & not the Carbon. As a still more simple and decisive experiment I will relate the following of Davys[.] He had a glass globe filled with dry Chlorine gas and by means of a Voltaic Battery he ignited in this gas two points of charcoal but no change took place both the combustible and the gas remained unaltered³[.] Carbon at a white heat could abstract no oxygen from Chlorine gas whereas at the same time he made Gold a metal which has the least affinity for Oxygen burn in the same portion of gas & by the same power It combined with the Chlorine⁴.

When Chlorine gas is mixed with Hydrogen gas equal parts of each being put together and are submitted to the action of the Sun’s rays or electric sparks are passed through them it is affirmed that the Hydrogen combines with the Oxygen and both Muriatic Acid gas & Water are formed but this affirmation is false it is not so if the gases are both perfectly dry no condensation takes place no water is formed nothing but Muriatic Acid remains - This is a very decisive experiment and therefore particular attention has been paid to it it has been performed with every possible care both by French Chemists and by Davy⁵and the result has been as I have stated it no water was obtained nothing but pure Muriatic Acid gas and as Chlorine & Hydrogen were present it follows that Muriatic Acid is composed of these two bodies[.]

The experiment I last stated is a synthetical proof of the compound nature of Muriatic Acid[.] I shall now in order to complete the circumstances relate an analytical one - If a piece of Potassium is enclosed in a portion of dry Muriatic Acid gas and its temperature is somewhat raised it will inflame the Acid gas will disappear and Hydrogen will be found remaining⁶[.] The metal has united to the Chlorine forming a Muriate of Potash & the Hydrogen remains behind[.] The same effect may be produced by other metals but more slowly Tin Antimony Arsenic Copper &c. are all capable of decomposing the Muriatic Acid gas[.]

By Lavoisier’s Theory you would explain it thus[.] The metal say you decomposes a portion of water combined with the Oxygen and the Hydrogen remains - But no water is present - it is impossible that water sufficient to supply so much Hydrogen can be present & escape detection it cannot be the Hydrogen proceeds solely from the decomposition of the Muriatic gas.

I will before I conclude this long letter just notice another synthetical experiment using Muriatic Acid - When steam & Chlorine gas in proper proportions are passed through a red hot porcelain tube a decomposition of the water takes place⁷[.] Its Hydrogen combines with the Chlorine and forms Muriatic Acid and its oxygen comes over accordingly Muriatic Acid Gas & Oxygen gas comes over and nothing else[.] By Lavoisier’s Theory the fact would be explained thus[.] The steam caused a decomposition of the Oxy-Muriatic Acid and Muriatic Ad & Oxygen came over - but what becomes of the steam? no water in Davy’s experiment came over - none at all - but by Lavoisier’s theory the disappearance of that is unaccounted for - and for the decomposition of the Oxy-Muriatic Ad & it is very unaccountable when it does not combine with either of its parts - in fact it is not so the water is decomposed and thus it disappears and thus the Muriatic Acid composed -

Thus far dear Friend for the present in my next I will continue the subject and in the mean time transmit to me any objections you have to what I have already drawn[.]

I have not time, dear Ben at present to close my letter in a proper manner I shall be at Ranelagh⁸ tomorrow evening (if fate permits) & if we do not meet before will take my station exactly at nine under the orchestra[.]

Yours Truly | M. Faraday

PS. Give my respects to all at home[.]

Endorsed by Abbott: Received 8 Mo 20 1812 AM

Address: Mr. B. Abbott | Long Lane | Bermondsey