Royal Institution, 23rd, Dec, 1855.
My dear Sir
From the interest you exhibited in the experiments on diamagnetic polarity during your visit to London1 I think it will not displease you to learn the further progress of the enquiry, an account of which I had the pleasure of giving to the Royal Society a few days ago.2 You know the disposition of the apparatus and you saw the experiments with bismuth and heavy glass. For the sake of clearing the subject of all doubt I thought it right to accept the conditions laid down by those who had opposed the notion, for the rigorous demonstration of diamagnetic polarity. One of these conditions, was that we must operate with insulated fragments of bismuth: Well I took a quantity of the powder of this metal, and exposed it to the air, it soon became so much tarnished as to be totally unable to conduct a voltaic current, but this powder enclosed in tubes gave me almost as great a deflection, and always in the same sense, as that of massive bismuth. Antimony is a better conductor than bismuth, but its diamagnetic power is feebler: the effect produced by this metal is less than that of bismuth, thus proving that it is upon its diamagnetic quality, and not upon its conductive quality, that the effect depends. Further, copper is perhaps fifty times a better conductor than bismuth, but its diamagnetic power is nearly nil: with this metal no sensible effect was obtained in my experiments; which, of course, could never be the case if the effect were due to induced currents. Passing on to positive insulators, I have added to the heavy glass; cylinders of sulphur, statuary marble, wax, calcareous spar, nitre and phosphorous; all these exhibit polarity equally distinct (though in a greatly diminished degree) to that of bismuth. A marble statue therefore, acted upon by the earth’s magnetism, has its feet a south pole and its head a north pole, being the reverse of that of an iron statue under the same circumstances: and there cannot be a shadow of doubt that each human being as he walks the earth’s surface is similarly polarized, for all the tissues of the his body are diamagnetic. I have extended the examination to liquids and find that solutions of muriate of cobalt, muriate of nickel and sulphate of iron enclosed in glass tubes and surrounded by an electric current, behave exactly as cores of soft iron would do, while distilled water, bisulphide of carbon and other diamagnetic liquids behave exactly as cylinders of bismuth. Were it necessary I should have no difficulty in increasing the number of bodies examined.
All the phenomena of magnecrystallic action can be deduced with the greatest ease à priori from the principle of polarity, and it is impossible to account for many of these phenomena in any other principle. It is surprising that this has not been more insisted on during the discussions which have taken place upon this subject. Some of the earlier experiments of Mr Faraday which he adduced to prove the notion he entertained at the time, that the magnecrystallic force was neither attractive nor repulsive are to my view perfectly demonstrative of the fact that the force must be both attractive and repulsive, or in other words must be polar. As this question has been already worked at by Professors Thomson and Plücker I do not think that I shall make it the subject of a special communication to the Royal Society, but I hope in an early number of the Philosophical Magazine to indicate in a brief and simple manner and from my own point of view the relation of the question of diamagnetic polarity to that of magnecrystallic action.
I have had a pleasing letter3 from M. Matteucci lately. Soon after the receipt of the Bakerian Lecture4 for the present year he occupied himself in repeating the experiments there described but found that he could not obtain my results. It was natural to suppose that I had made some grave mistake, and not wishing to expose my presumed errors publicly he wrote to Faraday and Grove upon the subject, asking their advice under circumstances which he considered embarrassing. M. Matteucci’s letters5 were placed in my hands by Faraday, but I had repeated my own experiments so often under such varied circumstances, and moreover in the presence of so many competent judges that I could not entertain a doubt of their accuracy. It was nevertheless pleasant to me to receive a few days ago from M. Matteucci himself a letter which concluded with the following words:– “En attendant j’ai envie de vous faire savoir que j’avais trouvé que vos expériences vont bien, et comme j’avais écrit à Faraday et à Grove que j’en doutais, je vous prie de leur dire de ma part, que je suis parvenu à une complete verification des experiences.”6 The indistinct words are equally indistinct in M. Matteucci’s communication.
In the next number of the philosophical Magazine you will find an interesting discussion7 carried on between Mr Faraday and Prof Riess of Berlin: it is very spirited but the spirit is also very good. Mr Faraday I am sorry to say is suffering a little from illness at present, but there is every prospect of its being very transitory. Next week he commences his course of juvenile lectures when I doubt not he will give the young people a great treat.
I saw with pleasure the 2nd volume of your great work on electricity8 in the library of the Royal Institution yesterday, but as yet I have not had time to look through it.
My compression experiments have lately led me to a physico-geological question which at present possesses great interest, and an article on which by Mr Sorby will appear in the next number of the Phil Mag.9 I mean the subject of slaty cleavage. It is a beautiful subject, and I hope ere long to be able to communicate to you some results connected with it. When you see Prof Wartmann would you kindly present my remembrance. I am also indebted to M. Soret10 for some interesting memoirs; should you see him pray be kind enough to thank him for me.
Believe me dear Sir | most sincerely Yours | John Tyndall
RI/JT/1/335
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during your visit to London: De la Rive had been in London in May and August 1855. Tyndall had joined him in experiments on 14 August 1855. See Journal RI MS JT/2/13c/781.
a few days ago: J. Tyndall, ‘Further researches on the polarity of the diamagnetic force’, Phil. Trans., 146 (1856), 237–259, read 20 December 1855.
a pleasing letter: see letter 1161.
Bakerian Lecture: 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.
Matteucci’s letters: This correspondence has not survived but is referred to in Faraday Correspondence, 5: 3033.
verification des experiences: The French quotation is the conclusion to letter 1161.
discussion: M. Faraday and P. Riess, ‘On the action of non-conducting bodies in electric induction’, Phil. Mag., 11 (1856), pp. 1–17.
your great work on electricity: A. de la Rive, Traité d’Électricité Théorique et Appliqué, 3 vols. (Paris, 1853–58). The 2nd volume appeared in 1855. An English translation by the electrician Charles V. Walker was published 1853–58.
Phil Mag: H. C. Sorby, ‘On Slaty Cleavage, as Exhibited in the Devonian Limestones of Devonshire’, Phil. Mag., 11 (1856), pp. 20–37.
M. Soret: Jacques-Louis Soret (1827–90), Swiss chemist, professor of medicine at the University of Geneva (Gèneve, Mém. Soc. Phys., 31 (1890–91), pp. xxviii-xxxv). No letters from Soret to Tyndall have been found for 1856; for later correspondence between 1866 and 1888, see the relevant volumes of Tyndall Correspondence.
Please cite as “Tyndall1172,” in Ɛpsilon: The John Tyndall Collection accessed on