From Carlo Matteucci 3 dec,18551
Pise. 3 déc,1855
Mon cher Mn Tyndall
Vous savez que j’ai écrit dernièrement au Prf [Professeur] M. Faraday pour qu’il vous comunique en douteux [adjective illeg ] que j’avai concue sur les conclusions tirées de vos dernieres experiences sur la polarité diamagnétique. La lettre que F[araday] m’a répondu me fait presque soupconner [?]2 que vous aviez interprété cette demarche d’une maniere inattendue pour moi et que vous n’en aviez pas été content. Mon intention n’etait pas celà : j’ai cru de faire dans cette circonstance ce que j’aurai fait très naturlment si j’avais été a Londres et j’avai causé de science avec vous – Moi comme tous vous aurai dit, étant dans mon cas[.]
Je travaille depuis longtemps sur ce sujet, je travaille de cette maniere je crains que votre maniere ne fut pas la meilleure – Réfléchissez, et si vous le croyez, repétez mes experiences ou les votres[.] –Voilà tout : j’espere de m’etre bien expliqué et que vous ne pouvez juger ma demarche que telle qu’elle est, tout à fait amicale. Par les même sentiment, je m’empresse maintenant de vous ecrire que j’ai répété avec tous les soins vos experiences, quant a la disposition generale, mais en les rendant du moins suivant ma manier [manière] de voir, indépendantes de toute critique. Ainsi – je n’ai employé que des spirales sans fer doux. Le corps diamagnetique était un cylindre de poudre de bismuth et de résine. Le fil de suspension était un fil d’argent et je mesurai les forces par la torsion. Bien. Ce resultat est conforme au votre et j’ose le dire, du moins dans ma tête, il est incontestable ce qui n’était pas avant.
[diagram]
Lorsque les extrémités a et b de deux spirales [repoussent]3 des poles de même nom le cylindre de quelque maniere qu’on opera, en fermant un circuit avant l’autre ou tous les deux en meme temps, le cylindre le porte et le fixe [fixé] sur a ou vers a. Cela veut-il dire que la polarité diamagnétique existe?
C’est autre chose. Je ne fais que vous apporter ici le résultat principal auquel j’etais parvenu et qui m’avait fait douter de vos experiences, pour vous prouver ce qui suivant moi est contraire a l’idée de la polarité diamagnétique.
[diagram]
Le cylindre diamagnétique qui est dans la spirale n’oscille pas dans ce cas autour de son centre, mais il se deplace le long de l’axe de la spirale.
Dans ce cas, si l’on met une seconde spirale b (bout à bout) contre la première, on trouve que le cylindre diamagnétique, quelque soit la direction du courant en a, est toujours repousse par l’autre spirale b et exactement de la même quantité quelque fut la direction du courant de a ou de b et cela en changeant les forces relatives des courants.
Notez que si le cylindre est magnétique, mais d’une matiere aussi faiblement magnetique qu’on peut la comparer au diamagnétisme du bismuth, la polarité magnetique dans les mêmes circonstances est trop marquée et avec des différences enormes.
Le sujet est bien [word illeg.]. Dans quelques jours ou un mois je ferais paraitre mon travail et vous le jugerez.
En attendant j’ai voulu vous faire savoir que j’avai trouvé que vos expériences vont bien et comme j’avai ecrit a Faraday et a Grove que j’en doutai, je vous prie de lui dir de ma part que je suis parvenu à une complete verification des experiences.
Agreez mon respect et attachement | C. Matteucci
Pisa December 3, 1855.
My dear Mr Tyndall,
You know that lately I wrote to Professor Faraday4 so that he could let you know about the [adjective illeg.] doubts I had conceived concerning the conclusions you drew from your last experiments on diamagnetic polarity.5 I suspect from the letter that F[araday] sent me back6 that you had interpreted my efforts in a manner I was not expecting and that it had upset you. That was not my intention: I believed that I was doing in this circumstance was what I would have done very naturally had I been in London and discussing science with you face to face. Like anyone else in my position, I would have told you.7
I have been working on this topic for a long time, I work in this manner. I fear that your method is not the best. Think about it, and if you believe it, repeat my experiments or yours. That’s all: I hope I explained myself clearly8 and that you will judge my initiative for what it is, absolutely friendly. It is with the same feelings that I rush to write to you today that I repeated your experiments faithfully with regard to the general disposition, but making them, in my opinion, independent of any criticism. Hence, I have only used helixes [spirales]9 without soft iron. The diamagnetic body was a cylinder of bismuth powder and resin. The suspended wire was a silver wire and I measured the forces by torsion.10 Good. This result is consistent with yours, and I dare say, at least in my mind, it is indisputable, unlike previously.
When the extremities a and b of two helices [word illegible] the same polarity by the same name, the cylinder, in whichever way it is operated, by closing a circuit before the other or one after the other, the cylinder is carrying it and fixing it on a or towards a.
Does that mean that diamagnetic polarity exists? That is something else [again]. I only intend to bring to you here the main result that I have achieved and which made me doubt your experiments, in order to prove to you what, according to me, is contrary to the idea of diamagnetic polarity.
The diamagnetic cylinder which is in the helix does not oscillate in this case around its centre but moves along the axis of the helix. In this case, if a second helix b is placed against the first one (end to end) we find that the diamagnetic cylinder, whatever the direction of the current in a, is always repelled by the other helix b and by exactly the same amount whatever the direction of the current in a or b and that by changing the relative forces of the currents [?]. Note that if the cylinder is magnetic, but made from a material that is as indistinctly magnetic that we can compare it to the diamagnetism of the bismuth, the magnetic polarity in the same circumstances is too pronounced and with enormous dissimilarities.
The subject is quite [word illeg. difficult?]. In a few days or a month, I will publish my work11 and you will be able to judge it.
In the meantime I’d like you to know that I’ve found your experiments are true and because I wrote to Faraday and to Grove that I had doubts, I beg you to tell him from me that I am sending a complete verification of the experiments
With respect and affection | C. Matteucci.
RI MS JT/1/M/58
Accents have not been restored and grammatical errors are ignored except where the sense demands.
soupçonner: writing unclear; could be ‘supposer’ or ‘frissonner’.
reposoussent: The verb is unclear and may be ‘repressentent’.
I wrote to Professor Faraday: letter missing.
doubts I had …experiments on diamagnetic polarity: Matteucci had expressed these orally in his lectures at the University of Pisa in June 1853. These lectures appeared in French as Cours spécial sur l’induction, le magnétisme de rotation, le diamagnétisme: et sur les relations entre la force magnétique et les actions moléculaires (Paris: Mallet-Bachelier, 1854), with the critique of Tyndall’s experiments, pp. 253-7. Matteucci presented a copy of this to Faraday, who passed the book to Tyndall in time for him to add ‘A Note on M. Matteucci’s objections’ to the Bakerian lecture as it went to press. J. Tyndall, ‘On the Nature of the Force by which Bodies are Repelled from the Poles of a Magnet’, Phil. Trans., 145 (1855), pp.1-51 at pp. 41-3. When Tyndall republished his papers on diamagnetism in 1870, he was rather cavalier concerning his dispute with Matteucci, writing: ‘Matteucci undertook to repeat the experiments recorded in my [Bakerian] lecture but failed to obtain the results. He considered the memoir a tissue of error from beginning to end, and thought my character as a scientific man so gravely compromised that he wrote to ask Faraday for advice as how he ought to act under the circumstances. Faraday showed me Matteucci’s letter, and the result of our conversation regarding it is stated by Faraday himself [Faraday Correspondence, 5: 3033]. Weeks, it may have been months, elapsed without my hearing anything further about the matter; when at length a terse, frank letter [letter 1161] reached me direct from Matteucci, the substance of which was this: “I have written to Faraday, to Grove, and to Wheatstone, stating that your experiments were wrong. I now wish to give you the opportunity of correcting them, and of saying to these gentlemen that I have repeated all your experiments and found them true to the letter”.’ J. Tyndall, Researches on Diamagnetism (London: /Longmans, Green, 1870), pp. 182-3.
the letter that Faraday sent me back: Faraday Correspondence, 5: 3033.
Moi comme tous …étant dans mon cas: This might also be rendered as ‘I did what everyone in my position would have done’.
I explained myself clearly: in the Cours (n. 5).
I have only used helixes: We have translated ‘spiral’ as ‘helix’ since this is the term used by Tyndall in the Bakerian lecture.
I measured … by torsion: by means of a torsion balance.
I will publish my work: no such publication has been traced.
Please cite as “Tyndall1161,” in Ɛpsilon: The John Tyndall Collection accessed on