Christian Friedrich Schoenbein to Faraday   10 February 1854

Bâle Febr. 10th 1854.

My dear Faraday

At last I have seen again some lines from the Master of the Royal Institution¹ and I can assure you that the mere sight of his handwriting gave me infinite pleasure, as it yielded me a visible proof of his being still amongst the living, and able to handle the pen, for I will not conceal it from you that the long silence he kept this time, had already begun to cause feelings of uneasiness about the well-being of the dearest of my friends.

What you tell me of your late electrical experiments makes me very curious to learn the details of them, which I hope will soon be the case. It seems to me that we are as yet very far from having arrived at a standstill in electrical researches.

As to my little scientific doings I have continued to study the influence exerted by temperature upon the colors of substances and obtained some pretty results. You are perhaps aware that some time ago I tried to prove that a great number of oxycompounds being more or less colored at the common temperature, would turn colorless on being sufficiently cooled down each of such substances having its peculiar temperature at which its color entirely disappears. I think I have satisfactorily proved that even common Ink is in that case and you may easily convince yourself of the correctness of the statement. Color a weak solution of gallic acid by some drops of a dilute solution of perchloride of iron dark blue even to opaqueness; put the colored liquid into a frigorific mixture of muriatic acid and snow until frozen, and you will of course obtain a dark colored ice; cool it then down to about 40˚ below zero or somewhat less and you will have a colorless ice, which on increasing its temperature again will reassume its color before having arrived at its melting point. From some reasons I was led to conjecture that there must exist a series of bodies that exhibit the reverse behaving i.e. grow colored on their temperature being sufficiently lowered, and my conjectures proved to be correct. The coloring matter of a great number of red and blue flowers such as Dahlias, Roses &c. being associated to sulphurous acid, are at the common temperature nearly or entirely colorless; now aqueous solutions of those matters having been uncolored by aqueous sulphurous acid become beautifully and intensely recolored on being sufficiently cooled down to lose their color again on raising the temperature of the ice, and I must not omit to mention that the colorless state is reassumed before the melting of the ice.

I have particularly worked upon the coloring matter of a certain sort of dark brown Dahlia very common with us, which exhibits the change of color indicated in a most beautiful manner. On account of the easy mutability of that matter in its discolored state, I preserve it by the means of filtering paper, which I rub with the leaves of the flower and suffer it to dry. Such paper, of which I send you a little specimen, yields very easily the coloring matter to water coloring beautifully the latter. A fresh solution of that kind should always be employed on making the experiment and you will be successful, when you employ my paper for preparing the solution.

It is a fact worthy of remark that such a solution rendered colorless by SO² turns colored also by heating it to its boiling point.

In want of something better you might perhaps give the substance of my late researches on colors and the connexion with the chemical constitution of the matters exhibiting them in a friday Evening, for the effects are very striking³. Part of the results are described in the X volume of the proceedings of the Phil. Society of Bâle⁴, part in a memoir published in the proceedings of the Academy of Vienna⁵ which most likely will be republished in Liebigs Annals⁶ and some, notably those above mentioned are not yet made known at all.

You are most likely aware that Dr. Baumert⁷ has of late confirmed the results previously obtained by de la Rive, Marignac⁸, Berzelius⁹ and myself, as to the capability of the purest i.e. absolutely anhydrous Oxigen of being thrown into its ozonic state by the means of the electrical discharge and I am therefore inclined to think that we can no longer doubt of the important fact that oxigen may exist in two different states in an active and inactive one, in the ozonic condition and in the ordinary state.

Now such a fact cannot fail bearing upon a great number of chemical phenomena and I am just now drawing up a sort of memoir¹⁰ in which I try to embody the Ideas and Views on Electrolysis, Thermolysis and Photolysis (sit venia verbis¹¹) I have been carrying about in my head these many years, ideas so very strange and queer that they will meet with but very little favor.

To give you some notion about their singularity and heterodoxical character allow me to state some of them, but in doing so I must ask you the favor to consider them as mere Ideas and Views.

1. There are no other electrolytes (taken [sic] that term in the limited sense, you attach to it) than oxycompounds.

2. There are no compound Ions such as acids, and it is only the basic oxide of salts upon which the electrolysing power of the current is exerted.

3. The theory of Davy on the nature of Chlorine, Bromine, Iodine, the acids and salts is unfounded.

4. Electrolysation depends in the first place upon the capability of common oxigen to assume the ozonic state when put under the influence of electrical discharge and in the second place upon the power of the current to carry under given circumstances matters from the positive to the negative electrode i.e. in the direction of the current itself.

5. The transfer of the electrolytic fluid from the positive to the negative electrode as observed by Wiedemann¹² and others is closely connected with the travelling of the kation in the same direction.

6. The travelling of the anion, i.e. Oxigen is only apparent or relative being caused by the real travelling of the kation.

7. Chemical decomposition caused by electricity heat and light depends upon allotropic modifications of one or the other constituent part of the compounds decomposed.

8. Chemical synthesis caused by electricity, heat and light is closely connected with allotropic modifications of one or the other matter concerned in that chemical process.

9. The notions of chemical affinity such as they are entertained at present cannot be maintained any longer.

You see such assertions are bold enough, so bold indeed, that I am afraid even you, the boldest philosopher of our age, will shake your head; but I thi<<nk>> there is no harm in going a little too far, truth will make its way in spite o<<f it>> and if the feelings of our cook-like Chymists, who are brewing on and on their liquors and puddings without paying much attention to the conditions of the primary matters they are continually mixing together, should be roused even to wrath I would not only care very little about it but even take some pleasure in it, for I cannot deny that now and then I grow very angry about the narrow or little-mindedness of the generality of the tribe. Being now in a confessing mood of mind, I will openly tell you that Davy’s theoretical views are most particularly unpalatable to my scientific taste and I cannot help thinking that they have retarded rather than accelerated the progress of sound chemical science. As to some of his scientific doings they are certainly of a superior kind and nobody can value them more than I do. The heterodoxical memoir alluded to will not henceforth go forth to the world, for I shall try to work it out as well as I can¹³. In April next I think to fetch my eldest daughter¹⁴ back again from the “Welchland”¹⁵ to put the second¹⁶ there. Your imagination gives you a correct idea of Miss Schoenbein, for she is really in many respects a second edition of her Mother. Our phil. Society will take great pleasure in sending you the whole series of their proceedings and in receiving, what your Institution is publishing. As the crossing of the channel and coming over to Switzerland is a matter of a couple of days I will not give up the pleasing hopes of seeing you and Mrs. Faraday once more with us in Bâle, where you have more friends and admirers than you are aware of.

Pray present my most humble compliments to your Lady and believe me

Your | most affectionate friend | C.F. Schoenbein

NB. Mrs. Schoenbein and the Children charge me to remember them kindly to you.

As I have something to send to Southampton you will receive my letter from that town.

P.S. In reading over the preceding lines I feel I have written a very bad english letter but I will not write another for fear of making it still worse. Being entirely out of the habit of speaking, writing and I may say even reading in your native tongue, I must necessarily lose the knowledge of it. And that you must take for my excuse. S.

Address: Doctor M. Faraday | &c &c &c | Royal Institution | London