To Benjamin Franklin from John Walsh, 27 August 1772
From John Walsh
ALS: American Philosophical Society
Paris, 27th. Augt. 1772.
Dear Sir
I will not let this Post slip without making to You my hearty congratulations on your being elected by the French Academy of Sciences to be one of it’s eight foreign Members, a truely illustrious Society; and I will freely say it, even to You, because I think it, that Your Election does honour to the Judgement of the Academy.3
On my Arrival here the 21st. I found your favour of the 28th. July, having order’d my Letters to be detained at Paris during my Journey from La Rochelle; to which I was engaged by Circumstances, that agreably arose, to give more time than I at first proposed: Among the Rest that of seeing my Nephew well settled at the Academy of Angers.4 The hope of seeing you soon in England, which I always entertained, and do now, is the reason you have not had a full account by Letter of my further Experiments on that wonderfull Animal the Torpedo.
I spent a compleat week at the Isle de Ré in my Experiments and had every convenience there for prosecuting them, except that I was something restricted by the Jealousy of the Governour from making them where the Animal was caught. At my Return to La Rochelle, I communicated to the Gentlemen of the Rochelle Academy and to many of the principal Inhabitants all that I had observed concerning the Torpedo, in the Intention of stirring up a Spirit of Enquiry both as to it’s Electricity and general Oeconomy, and I shall be glad to find that this has produced other effects than meer Surprize. I did hope that three days of very general Exhibition in this manner would have left me nothing more to do in France, but finding by an absurd Paragraph in the french Papers that those present are not very capable of relating of what they heard saw and felt;5 and being a good deal pressed by your Confreres of the Academy to communicate a Fact so interesting and singular, I shall endeavour to conquer my Indolence and Aversion to stepping forth on the publick Stage because indeed I feel that it will be ridiculous in me if I do not. You must therefore allow me to address a short Letter to You on this Subject. As the Coasts of France abound with this Animal and as it is denied to us,6 with your Leave I will publish the Letter here with a french Context, by either your friend LeRoy or Du Bourg. This cannot be affected entirely during my Stay here, especially as a plate must accompany the publication, therefore I shall probably be able to converse with you on this Matter, however I hope that will not prevent my hearing from you first. It is now high time for me to acquaint You with the Result of my Experiments on the Isle de Ré and I must do it in a Word if I mean to use this post. The Vigour of the fresh-taken Torpedos there was not able to force the Torpedinal Fluid across the most minute Tract of Air, not from one Link of a small Chain to another, not even thro’ a Separation made by the Edge of a Knife in a Slip of Tinfoil pasted on Sealing Wax. The Spark therefore and snapping noise attending it were denied to all our Attempts, either in the Light or compleat Darkness.7 I observed to you in my Last the Singularity of the Torpedo being able when insulated to give to an insulated Person a great number of successive Shocks: In this Circumstance I have taken no less than fifty Shocks from him in the Space of a Minute and half. All our Experiments confirmed that the Torpedinal fluid was concentrated in the very instant of it’s Explosion by a sudden Energy of the Animal; and as there was no gradual accumulation and Retention of this elastick fluid as in the Case of charged Glass, it is not surprizing that there should be no effect on Canton’s Balls of Attraction or Repulsion.8 In short the Torpedinal Shock appears to arise from a compressed elastick fluid restoring itself to it’s former State by the same Conductors as the elastick fluid compressed in charged Glass. The Skin of the Animal, bad conductor as it is, appears to be a better conductor of the Torpedinal elastick fluid than the least Tract of the likewise elastick fluid Air. Notwithstanding the weak Spring of the Torpedinal fluid I was able to convey it in the publick Exhibitions at La Rochelle thro’ two Brass Wires of twelve feet each and thro’ 4 to 8 Persons, at different times, the Wires and Persons communicating with each other by the medium of Water, in Basins placed between each. The Torpedo laid on a wet Napkin was placed on a Table six feet distant from the Table on which the Basins stood. One End of One of the Wires was wrapt in the Wet Napkin and the other End went into the first Basin in which the first Gentleman put a finger of one hand, with a finger of the other hand in the next Basin. The Circuit was in this manner continued to the last Basin. One End of the other Wire was put into this last Basin and with the other End I just touched the Back of the Fish, when all the Persons in the Circuit were affected, but I, the toucher, being out of it felt nothing.9 The effect in Air, on many repeated Experiments, is about four times as strong as it is in Water.1 I have only Room to wish you a Return of Health2 and to assure you that I am with the greatest Esteem and Respect Dear Sir Your obedient humble Servant
John Walsh
3. For the choice of BF as a foreign associate of the Academy see his letters below, to de la Vrillière, Sept. 4, and to the Academy, Nov. 16.
4. The nephew was Arthur Fowke (c. 1756–75), the son of Walsh’s sister Elizabeth and Joseph Fowke, who like Walsh had been in the service of the East India Company. After Elizabeth’s death and Joseph’s return to India in 1771, Walsh took charge of their children. Arthur lived with him in London, met BF there and pronounced him agreeable, and then went to France with his uncle and shared in his experiments. In mid-August Walsh, apparently on the spur of the moment, enrolled him for a few months in the famous Académie d’équitation at Angers. The young man returned to England the following February; in 1774 he followed his father into the Company’s service in India, where he soon died. George R. Kaye and Edward H. Johnston, eds., Minor Collections and Miscellaneous Manuscripts (India Office Library, Catalogue of Manuscripts in European Languages, II, part 2; London, 1937), pp. 64–5, 68, 71–2, 80–3.
5. For the trip to Rhé see Walsh’s letter above of July 12. The experiments before the La Rochelle Academy were reported in the Gaz. de France of Aug. 14. The secretary of the Academy, it seems, agreed with Walsh’s view of the report, for two months later he sent the newspaper a lengthy description of what had happened. An extract of that description is included in Walsh’s letter to BF below, July 1, 1773; see also Jean Torlais, “L’Académie de la Rochelle et la diffusion des sciences au XVIIIe siècle,” Revue d’histoire des sciences …, XII (1959), 119–20.
6. It was not denied, Walsh later discovered; he found torpedoes off the English coast, and reported to the Royal Society on his experience with them: Phil. Trans., LXIV (1774), 464–73.
7. The spark and noise were proof of an electrical discharge, and their absence raised doubt about Walsh’s analogy between the torpedo and the Leyden jar; see BF to Ingenhousz below, Sept. 30, 1773. Walsh later demonstrated that an electric eel could make sparks: John Nichols, Illustrations of the Literary History of the Eighteenth Century … (8 vols., London, 1817–48), 1, 156. The full solution to the problem came not from Walsh but from Henry Cavendish, who showed that an electrical discharge might occur without spark or noise: “An Account of Some Attempts to Imitate the Effects of the Torpedo by Electricity,” Phil. Trans., LXVI (1776), 200–4, 216–23; Arthur J. Berry, Henry Cavendish: His Life and Scientific Work (London, [1960]), pp. 113–14.
8. For Canton’s balls, a form of electrometer, see above, IX, 351 n. Cavendish’s experiment, just cited, modified Walsh’s conclusion by showing that the discharge was too rapid and complete to make the balls separate; see Berry, op. cit., p. 114.
9. This experiment was similar to one that BF suggested in his instructions above, Aug. 12; for a more detailed discussion of it see Walsh to BF below, July 1, 1773.
1. Walsh later elaborated this sentence into several paragraphs: ibid. The principle involved, the same as that of Henly’s experiment with different circuits the previous October (above, XVIII, 229–31), was that most but not all of the charge passes through the circuit that has the greatest conducting power.
2. From his severe attack of gout, which he must have mentioned in his missing letter of July 28, and did mention to Stiles on the 22nd and DF on Aug. 22.