17th Oct. 1853
My dear Tom
I return you a proof1 which I received this morning. I was about making some alterations in the portion referring to electricity but it will I think be better to tell you my thoughts and allow you to make the necessary alterations yourself. You have Riess on Electricity2 have you not? Look out for the chapter on the back stroke3 which Lord Mahon4 discovered and explained. This back stroke it was which caused the convulsions of the frog in Galvani’s first experiment.5 The frog was first electrified by induction, the – E drawn towards the conductor and the + E repelled or vise versa. The student placed his scapel upon the frog – the – E flowed through it or through him to the earth, but when the conductor was discharged the natural state of the frog was restored and the sudden recomposition of the fluids caused the convulsion. Of course you need not say all this but I think you can with advantage be a little more precise than you have been.
Next the account of the lady’s sickness6 is in all probability a fiction to which currency has been given by Arago.7 The truth seems to be that she was the first who saw the contraction of the dead animal and communicated the result to Galvani. In DuBois Book there is an Italian Sonnett8 celebrating her praises for being the discoverer.
At the end of page 14 you draw a parallel between magnetism and the ‘positive and negative electricities’ – You never mentioned posit & neg. el. up to this point – would it not make it clearer if you stated the law of electric action9 at its proper place in page 13.
I have now said all I intended to say – with these trivial exceptions the lecture has given me the greatest satisfaction – There is a serenity – a deep tranquility in its sentences – and withal a flush of life and hope which will commend it to everybody competent to judge of truly good writing.
Are you correct regarding the ignorance of our forefathers mentioned in page 13. They had thunder & lightning in those days had they not? Beware of keeping your glance on one sphere of electric action and founding a general statement upon that.
I should like to give a few copies of it among my great acquaintance here, for it is fit to be read by the first man of the land.10 but you have almost taken this power away from me by mentioning me as you have done. I would propose the omission of the last paragraph. The thing will end beautifully with the word ‘instructing.’
Yours affectionately | John
RI MS JT/1/T/574
RI MS JT 1/HTYP/274
a proof: likely the second part of Hirst’s introductory lecture at Queenwood. See letters 0808, nn. 2 and 3 and 0809, n. 5.
Riess on Electricity: see letter 0727, n. 14.
the chapter on the back stroke: refers to vol. 2, ch. 1 of Riess’s work, titled ‘Der Rückschlag und die Seitenentladung’, or ‘The Recoil and the Side Discharge’.
Lord Mahon: Charles Stanhope, or Charles Mahon, 3rd Earl Stanhope (1753–1816), a politician and inventor. He was a fellow of the Royal Society and notable for his work on electricity (ODNB). According to Stanhope, the ‘back stroke’ (which he termed the ‘returning stroke’) was a sudden discharge of electricity between oppositely charged clouds and earth, which allowed ‘fatal Effects’ to occur ‘at a vast Distance from the Place where the Lightning falls’ (C. Mahon, Principles of Electricity: Containing Divers New Theorems and Experiments, Together with An Analysis of the Superior Advantages of High and Pointed Conductors [London: P. Elmsly, 1779]).
Galvani’s first experiment: refers to physician and scientist Luigi Galvani’s (1737–98) chance viewing ‘of contractions at a distance, when he observed the movements of a frog’s leg coincident with a spark extracted from the electrical machine and with no material connection between the animal and the instrument’ (M. Piccolino and M. Bresadola, Shocking Frogs: Galvani, Volta, and the Electric Origins of Neuroscience, trans. N. Wade [Oxford: Oxford University Press, 2013], p. 71). Galvani discussed this experiment in his work on animal electricity, which was first published in Italian as De Viribus Electricitatis in Motu Musculari Commentarius (Bologna: Accademia delle Scienze, 1791).
the account of the lady’s sickness: when discussing Galvani’s first experiment in his biography of Alessandro Volta (1745–1827), an Italian physicist and chemist, Arago (see n. 7) wrote that the frogs were originally prescribed to make broth as a remedy for Madame Galvani’s illness (Arago, ‘Alexandre Volta’, Ouvres de François Arago, 2nd edn, 17 vols [Paris: Librairie des Sciences Naturelles, 1865], vol. 1, pp. 187–240, on p. 212).
Arago: Dominique François Jean Arago (1786–1853), a French physicist notable for his work on magnetism and optics (‘Arago, Domique François Jean’, The Encyclopedia Britannica: A Dictionary of Arts, Sciences, Literature and General Information, ed. H. Chisholm, 11th edn, 29 vols [Cambridge: Cambridge University Press, 1910], vol. 2, pp. 312–3, on p. 313).
Italian Sonnett: entitled, ‘Sonett auf die Entdeckung des Galvanismus’, in E. du Bois-Reymond, Untersuchungen Über Thierische Elektricität (Berlin: G. Reimer, 1848), p. 39.
the law of electric action: ‘The attraction or repulsion between two quantities, q and q1, of electricity supposed concentrated at two points at a distance d apart, is q q1/d2, and is in the line joining the two points’. The law was determined by the physicist Charles–Augustin de Coulomb (1736–1806) and the chemist and physicist Henry Cavendish (1731–1810). (R. Walmsley, The Electric Current: How Produced and How Used [London: Cassell and Company, 1894], p. 395.)
first man of the land: perhaps a reference to Faraday, otherwise not identified.
Please cite as “Tyndall0810,” in Ɛpsilon: The John Tyndall Collection accessed on