Looking for a “Simple Case”: Faraday and Electromagnetic Rotation

Examples appear as early as in Hacking I. , Representing and intervening (Cambridge, 1983). Since then the number of studies of historical, philosophical, and sociological aspects of experimentation has greatly increased. Bibliographies are to be found, for example, in Batens D. v. Bendegem J. P. (eds), Theory and experiment: Recent insights and new perspectives on their relation (Dordrecht, 1988); Gooding D. Pinch T. Schaffer S. (eds), The uses of experiment: Studies in the natural sciences (Cambridge, 1989); and Le Grand H. E. (ed.), Experimental inquiries: Historical, philosophical and social studies of experimentation in science (Dordrecht, 1990).

The formulation is David Gooding's in his Experiment and the making of meaning (Dordrecht, 1990), p. xiv. For an analogous distinction, see Nickles T. , “Justification and experiment”, in Gooding Pinch Schaffer (eds), op. cit. (ref. 1), 299–333.

A good survey of those studies is given by A. Pickering in the first chapter of his recently edited volume, Science as practice and culture (Chicago, 1992).

Gooding , Experiment (ref. 2). Of particular importance are his concepts of ‘construals’ and of ‘convergence’. See also his numerous previous studies on this problem, e.g. “‘In Nature's School’: Faraday as an experimentalist”, in Gooding D. James F. A. J. L. (eds), Faraday rediscovered: Essays on the life and work of Michael Faraday, 1791–1867 (London, 1985), 105–35; and “How do scientists reach agreement about novel observations?”, Studies in the history and philosophy of science , xvii (1986), 205–30. For another approach to cognitive questions, see Pickering A. , “Living in the material world”, in Gooding Pinch Schaffer (eds), op. cit. (ref. 1), 275–97.

For an analogous diagnosis, as well as for a call for further historical studies concerning this problem, see Holmes F. L. : “Do we understand historically how experimental knowledge is acquired?”, History of science, xxx (1992), 119–36.

Nickles , op. cit. (ref. 2).

Besides Faraday's being one of the greatest experimenters, my supposition is based on the unique availability of sources which give insights in his actual practice.

There is a great scope in the use of the term ‘theory’. I shall use it here in the quite narrow sense of those theories that aim at explaining phenomena by microscopic causes, mostly by means of postulated entities such as electric fluids or magnetic molecules. Characteristic examples are Ampère's theory of magnetism considered as a result of molecular currents, the one- and two-fluid theories of electricity, the wave and corpuscular theories of light, and so on. In Faraday uses the term ‘theory’ mostly in this narrow sense, quite common in his time. Faraday himself has a cautious relation to such theories; see, e.g., Faraday's Experimental researches in electricity , ii (London, 1844; hereafter ERE, ii), 145.

My frequent use of the term ‘phenomenon’ is not to imply any position regarding a realistic or a constructivistic interpretation of it; the same holds for my using of the term ‘discovery’. As Gooding has convincingly argued (Experiment (ref. 2), ch. 8.5), the very study of experimentation reveals both of these interpretations as problematic. I shall not discuss these topics in this paper.

For example (besides those already mentioned in refs 1 and 4), Crawford E. , “Learning from experience”, in Gooding James (eds), op. cit. (ref. 4), 211–27; Tweney R. , “Faraday's discovery of induction: A cognitive approach”, ibid. , 189–209; idem, “Stopping time: Faraday and the scientific creation of perceptual order”, Physis , xxix (1992), 149–64; Gooding D. , “Mathematics and method in Faraday's experiments”, ibid., 121–47.

Gooding , Experiment (ref. 2), ch. 9.

Gooding , “Mathematics…” (ref. 10).

Ibid., 146.

Ibid., 145.

See Williams L. P. , Michael Faraday: A biography (New York, 1965), 167–8, and “Faraday and Ampère: A critical dialogue”, in Gooding James (eds), op. cit. (ref. 4), 83–104, in particular pp. 95–96.

Williams , Biography (ref. 15), sect. 4.2; Cantor G. , Michael Faraday: Sandemanian and scientist (Basingstoke, 1991), sect. 9.1.2; Gooding , Experiment (ref. 2), chs 5 and 6. In his recent paper, “Different experimental lives: Michael Faraday and William Sturgeon”, History of science, xxx (1992), 1–28, Iwan Morus deals with sociological aspects of Faraday's behaviour in this period.

Faraday M. , “Historical sketch of electro-magnetism”, Annals of philosophy, ii (1821), 195–200 and 274–90; iii (1822), 107–21. The editor of the Annals, Phillips R. , had received Faraday's manuscript on 4 September, as he says in a letter to Faraday of this day; cf. The correspondence of Michael Faraday , ed. by James F. A. J. L. , i (London, 1991), 220–1. For the background of the “Historical sketch”, see Williams , Biography (ref. 15), 151–6, or Cantor , Faraday (ref. 16), 226–9.

Faraday , “Historical sketch” (ref. 17), 197–9.

Faraday Michael , “Historical statement regarding electro-magnetic rotation”, Quarterly journal of science, xv (1823), 288–92; reprinted in ERE, ii, 159–62; quotation on p. 162.

My following account of these experiments is based on Faraday's entries in his laboratory diary: Faraday's diary. Being the various philosophical notes of experimental investigation made by Michael Faraday…, ed. by Martin Thomas , i (London, 1932), 49–57, of which the relevant page is reproduced in Figure 1.

Cantor regards this early episode, like Faraday's later discovery of electromagnetic induction and his search for a gravelectric effect, as mainly driven by metaphysical beliefs ( Cantor , Faraday (ref. 16), 257). Although in the two latter cases I fully agree with this claim, I disagree with regard to electromagnetic rotation. I do not see any specific metaphysical beliefs — Concerning the mutual convertibility of all forces of nature, for example — As playing a directive role for his experimental activity. His attempt to look for rules is, of course, based on a sort of ‘metaphysical’ principle, namely on the belief that there are such rules in nature, and that they can be grasped by investigators. This is, however, a very general belief, broadly accepted in Faraday's period among researchers with very different metaphysical backgrounds.

Cantor , Faraday (ref. 16), 208.

See §6 on my Figure 1; my emphasis.

This can be drawn from the completion date given by Faraday at the end of the published paper. The date appears plausible since Faraday on 12 September writes an enthusiastic letter to his friend and colleague C. G. de la Rive, in which he summarizes some of his results; see Faraday , Correspondence, i (ref. 17), 221–3.

Cf. Faraday , Diary, i (ref. 20), 49–57. The numbers in the text refer to the numbers of entries. Faraday stopped this numbering after entry no. 54.

This is not to say that he is unaware of the necessity of such efforts: Only a little later he will strongly engage in such activity (see below).

The paper ( Faraday Michael , “On some new electro-magnetical motions, and on the theory of magnetism”, Quarterly journal of science, xii (1821), 74–96) was originally published in October 1821 and has been reprinted in ERE, ii, 127–47, to which I refer. The numbers in parentheses refer to the page-numbers in that reprint.

This survey may explicate the title of the paper in which a twofold aim is announced (see above): In what I call Sections I to V, Faraday deals with new phenomena and, in particular, with their interrelations, while in Section VI he is intensely concerned with the only theory of magnetism that he regards as deserving the name of a theory, namely with Ampère's; cf. his remark in the “Historical sketch” (op. cit. (ref. 17), Third Part, 111).

This point is not recognized by Williams in his analysis of the argument between Faraday Ampère : Biography (ref. 15), 161–8, and “Faraday and Ampère” (ref. 15).

Cantor , Faraday (ref. 16), 231. For a detailed account see, e.g, Williams , Biography (ref. 15), 158–60.

For what can be regarded as the ‘community’ for Faraday, see Morus , op. cit. (ref. 16).

Faraday Michael , “New electro-magnetic apparatus”, Quarterly journal of science, xii (1821), 186–7, reprinted in ERE, ii, 147–8.

Letter of 18 October to Hachette (inferred from Hachette's answering letter of 30 October; Correspondence, i (ref. 17), 234), and letter of 16 November to de la Rive (ibid., 236).

Faraday Michael , “Description of an electro-magnetical apparatus for the exhibition of rotatory motion”, Quarterly journal of science, xii (1822), 283–5; reprinted in ERE, ii, 148–51. See my Figure 3. I. Morus claims that it was Faraday's strategy “… to draw attention away from the apparatus through which the fact made itself visible” (op. cit. (ref. 16), 8). Faraday's distribution of his apparatus, as well as his publication of experimental details, make this thesis appear problematic.

Faraday Michael , “Note on new electro-magnetical motions”, Quarterly journal of science, xii (1822), 416–21, reprinted in ERE, ii, 151–8.

Faraday , Diary, i (ref. 20), 61–63.

Ibid. , entries 361–71 and 49–50 on pp. 54–55, see my survey given above; and his “On some new electro-magnetical motions…”, op. cit. (ref. 27), 146–7.

The formulation is Morus's , op. cit. (ref. 16), 22.

Op. cit. (ref. 16).

Op. cit. (ref. 16), 8.

This underlines Holmes's call for dealing not only with the way in which experimenters “secure assent” within the community, but for analysing also the “processes that lead an experimenter to believe that he or she has something to communicate to the ‘experimental community’”, op. cit. (ref. 5), 126.

In what follows I refer to ERE, ii, 132–3 and 138–40. The connection of these two passages is made explicit by Faraday on p. 139. For the sake of a concise presentation I have combined the two parts. The illustrations are mine, since Faraday gives few in his publication.

I use the term ‘current’ simply as a shorthand device. Like many of his contemporaries, and in order to avoid any commitments to theories of what happens within the wire, Faraday prefers to speak of “the connecting wire of the battery”.

ERE , ii, 132f. Faraday emphasizes this point in the letter of 12 September to de la Rive , Correspondence (ref. 17), i, 222.

ERE, ii, 138.

Ibid., 139f.

Ibid., 140.

Ibid. , 146f; for his own reproduction of the experiment see entries no. 36^l and 37^l of 6 September: Diary, i, 54.

Op. cit. (ref. 35), see ERE, ii, 151–3.

Ibid., 153.

By “deduction” Faraday has in mind the reverse procedure of “reduction”. I shall analyse both concepts in Section 6.

For details, see the letters of Ampère to Faraday of 23 January 1822 and of Hachette to Faraday of 27 January; see also Faraday's response of 2 February, in Correspondence (ref. 17), i, 245–52.

Faraday's use of the term ‘reduction’ is found in some of his contemporaries as well. Peter Barlow, for example, after having obtained some new and inexplicable experimental results in electromagnetism, felt “desirous of undertaking a regular set of experiments, in order to reduce the several apparently anomalous results to some certain law of action” (my emphasis): “On the magnetic effect induced in iron bodies in rotation”, Philosophical transactions, cxv (1825), 317–27, p. 319.

As to concepts of ‘simplicity’, their importance has often been emphasized by philosophers of science as well as by scientists themselves. In most cases ‘simplicity’ refers to mathematical formulations of theories and is thought to play a decisive role in the choice between competing theories. Much less attention has been paid, however, to cases in which ‘simplicity’ refers to phenomena, and in which such a concept plays a directive role in the experimental activity itself.

He uses the terms ‘compound’ and ‘complicated’ interchangeably as contrasting with ‘simple’; see, for example, ERE, ii, 129 and 132 respectively.

For this term see, e.g., ERE, ii, 135.

Faraday to Ampère on 3 Sept 1822: Correspondence (ref. 17), i, 287, emphasis mine.

This is, of course, not to say that Faraday has no interest in such questions. But he decidedly defers them to another stage of the investigation.

Gooding introduces this distinction in Experiment (ref. 2), Sect. 3.5 and 3.6.

Correspondence (ref. 17), i, 222; emphasis mine. This quite characteristic passage is taken from the above-mentioned letter of 12 September 1821.

ERE , ii, 138, emphasis mine. For an analogous formulation, see again the letter of 12 September, Correspondence (ref. 17), i, 223.

Gooding , Experiment (ref. 2), 250, and cf. Nickles , op. cit. (ref. 1), 299.

I shall not deal here with the problem of the relation that Faraday finds between this ordered system of phenomena and theories. I discuss some aspects of this relation in Steinle F. , “Experiment, speculation and law: Faraday's analysis of Arago's wheel”, PSA 1994, i, 293–303. For Faraday's general view of the role of speculations and theories, see Cantor , Faraday (ref. 16), ch. 8, in particular Sect. 8.3.

Studies of Faraday's investigation of electromagnetic induction in 1831/32 reveal a quite analogous procedure, although Faraday's terminology changes in some way; see Steinle , op. cit. (ref. 63). Even the examples given by Gooding in “Mathematics…” (ref. 10), 134–8, appear to bear strong resemblances to what I have called Faraday's establishing of chains of mutually related phenomena.