Chapter 2

As the "generans" of terrestrial change moves what is light and heavy to another place by implanting a new form in a substance, so the magnet moves the iron by impressing upon it the quality by which it is moved. By virtue of the new quality, the iron is not in its natural place and moves accordingly. St. Thomas proved that the loadstone acts as a secondary "generans" in three ways: (1) the loadstone produces an effect not from any distance but only from a nearby position (showing that this motion is due to more than place alone), (2) rubbing the loadstone with garlic acts as if it impedes or alters the "virtus magnetis," and (3) the iron must be properly aligned with respect to the loadstone in order to be moved, especially if the loadstone is small. Thus the iron is moved by the magnet not only to a place, but also by changing and altering it: one has not only the change of locomotion but that of alteration. Moreover the source of this alteration in the iron is not the heavens but the loadstone. Accordingly the loadstone could cause change in another substance because it could influence the nature of the other substance.

[22] St. Thomas Aquinas, _op. cit._ (footnote 19), vol 7, _Scriptum in quartum librum sententiarum magistri Petri Lombardi_, lib. 4, disq. 33 (De diversis coniugii legibus), art. 1 (Utrum habere plures uxores sit contra legem naturae), p. 168. The same statement occurs in one of his most mature works, _op. cit._ vol. 20, _Summa theologica_, pars 3 (supplementum), quaestio 65 (De pluralitate uxorum in quinque articulos divisa), art. 1 (Utrum habere plures uxores sit contra legem naturae), p. 107.

[23] St. Thomas Aquinas, _op. cit._ (footnote 19), vol. 8, _Quaestio unica: de spiritualibus creaturis_, art. 2 (Utrum substantia spiritualis possit uniri corpori), p. 404. See also vol. 9, _Summa contra gentiles_, lib. 3, cap. 92 (Quomodo dicitur aliquis bene fortunatus, et quomodo adjuvatur homo ex superioribus causis), p. 344; and vol. 17, _Opuscula, De operationibus occultis naturae ad queindam militem ultramontem_, pp. 213-214.

[24] St. Thomas Aquinas, _op. cit._ (footnote 19), vol. 8, _Quaestio unica: de anima_, art. 1 (Utrum anima humana possit esse forma et hoc aliquid), p. 437. See also vol. 8, _Quaestio: De veritate_, quaestio 5 (De providentia), art. 10 (Utrum humani actus a divina providentia gubernentur mediis corporibus coelestibus), p. 678.

[25] St. Thomas Aquinas, _op. cit._ (footnote 19), vol. 2, _Physicorum Aristotelis expositio_, lib. 7, lect. 3, cap. g (Probatur in motu locali quod movens et motum oportet esse simul), p. 97 (quoted in Gilbert, M: p. 104).

About the time that St. Thomas was writing his letter _De operationibus occultis naturae_ to a certain knight, Petrus Peregrinus was writing from a military camp a letter in which he showed how certain relatively new effects could be produced by the loadstone. He was more interested in what he could do with the magnet than in explaining these effects. However, he discussed it at sufficient length for one to find that his explanation of magnetic phenomena was basically similar to that of his contemporary, St. Thomas.

Peregrinus based his discussion of the loadstone upon its nature and analyzed magnetic phenomena in terms of the change of alteration. In magnetic attraction, the nature of the iron is altered by having a new quality impressed upon it,[26] and the loadstone is the agent that makes the iron the same species as the stone.[27]

... Oportet enim quod illud quod iam conversum est ex duobus in unum, sit in eadem specie cum agente; quod non esset, si natura istud impossible eligeret.

This impressed similarity to the agent, Peregrinus realized, is not a pole of the same polarity but one opposite to that of the inducing pole. To produce this effect, the virtue of the stronger agent dominates the weaker patient and impresses the virtue of the stronger on the weaker so that they are made similar.[28]

... In cuius attractione, lapis fortioris virtutis agens est; debilioris vero patiens.

A further instance of alteration occurs in the reversal of polarity of magnetized iron when one brings two similar poles together. Again, the stronger agent dominates the weaker patient and the iron is left with a similarity to the last agent.[29]

... Causa huis est impressio ultimi agentis, confundentis et alterantis virtutem primi.

In this assimilation of the agent to the patient, another effect is produced: the agent not only desires to assimilate the patient to itself, but to unite with it to become one and the same. Speaking of the motion to come together, he says:[30]

Huius autem rei causam per hanc viam fieri existimo: agens enim intendit suum patiens non solum sibi assimilare, sed unire, ut ex agente et patiente fiat unum, per numerum. Et hoc potes experiri in isto lapide mirabili in hunc modum.... Agens ergo, ut vides experimento, intendit suum paciens sibi unire; hoc autem fit ratione similitudinis inter ea. Oportet ergo ... virtute attractionis, fiat una linea, ex agente et patiente, secundum hunc ordinem ...

The nature of the magnet, as an active cause, tends to enact, and since it acts in the best manner in which it is able, it acts so as to preserve the similarities of opposite poles.[31]

Natura autem, que tendet ad esse, agit meliori modo quo potest, eligit primum ordinem actionis, in quo melius salvatur idemptitas, quam in secundo ...

Thus unlike poles tend to come together when a dissected magnet is reassembled.

Like St. Thomas, Peregrinus argued that the magnet receives its powers from the heavens. But he further specified this by declaring that different virtues from the different parts of the heavens flow into their counterpart in the loadstone--from the poles of the heavens the virtue flows into the poles of the magnet,[32]

Praeterea cum ferrum, vel lapis, vertatur tarn ad partem meridionalem quam ad partem septemtrionalem ... existima cogimur, non solum a partem septemtrionali, verum etiam a meridionali virtutem influi in polos lapidis, magis quam a locis minere ... Omnes autem orbes meridiani in polis mundi concurrent; quare, a polis mundi, poli magnetis virtutem recipiunt. Et ex hoc apparet manifeste quod non ad stellam nauticam movetur, cum ibi non concurrant orbes meridiani, sed in polis; stella enim nautica, extra orbem meridianum cuiuslibet regionis semper invenitur, nisi bis, in completa firmanenti revolutione. Ex hiis ergo manifestum est quod a partibus celi, partes magnetis virtutem recipiunt.

and similarly for the other parts of the heavens and the other parts of the loadstone.[33]

Ceteras autem partes lapidis merito estimare potes, influentiam a reliquis celi partibus retinere, ut non sic solum polos lapidis a polis mundi, sed totum lapidem a toto celo, recipere influentiam et virtutem, estimes.

Physical proof for such influences was adduced by Peregrinus from the motions of the loadstone. That the poles of the loadstone receive their virtue from the poles of the heavens follows experimentally from north-south alignment of a loadstone. That not only the poles but the entire loadstone receives power from corresponding portions of the heavens follows from the fact that a spherical loadstone, when "properly balanced," would follow the motion of the heavens.[34]

Quod tibi tali modo consulo experire: ... Et si tunc lapis moveatur secundum celi motum, gaudeas te esse assecutum secretum mirabile; si vero non, imperitie tue, potiusquam nature, defectus imputetur. In hoc autem situ, seu modo positionis, virtutes lapidis huius estimo conservari proprie, et in reliquis sitibus celi virtutem eius obsecari, seu ebetari, potiusquam conservari puto. Per hoc autem instrumentum excusaberis ab omni horologio; nam per ipsum scire poteris Ascensus in quacumque hora volueris, et omnes alias celi dispositiones, quas querunt Astrologi.

As the heavens move eternally, so the spherical loadstone must be a "perpetuum mobile".

Another of the scholars whose explanation of the loadstone Gilbert noted with approval was Cardinal Nicholas of Cusa.[35] The latter's references to it were not as direct as those of St. Thomas, but he did use it as an image several times to provide a microcosmic example of the relation of God to his creation. From this one can infer that he explained the preternatural motion of the magnet and the iron by impressed qualities, the heavens being the agent for the loadstone, and the loadstone, the agent for iron.

[26] Hellmann, _op. cit._ (footnote 6), Peregrinus, pt. 1, ch. 8. The magnet attracts the iron "secundum naturalem appetitum lapidis ... sine resistentia." There is no natural resistence to this motion since it is no longer contrary to the nature of the iron. The nature of the iron has changed.

[27] _Ibid._, pt. 1, ch. 9.

[28] _Ibid._, pt. 1, ch. 9.

[29] _Ibid._, pt. 1, ch. 8.

[30] _Ibid._, pt. 1, ch. 9.

[31] _Ibid._, pt. 1, ch. 9. See also footnote 27.

[32] _Ibid._, pt. 1, ch. 10. See also ch. 4.

[33] _Ibid._, pt. 1, ch. 10. See also ch. 4.

[34] _Ibid._, pt. 1, ch. 10.

[35] However, he may not always have approved of him. See M:74; "Overinquisitive theologians, too, seek to light up God's mysteries and things beyond man's understanding by means of the loadstone and amber."

In the _Idiota de sapientia_ the Cardinal used the image of the magnet and the iron to provide a concrete instance of his "coincidentia oppositorum," to illustrate how eternal wisdom, in the Neoplatonic sense, could, at the same time, be principle or cause of being, its complement and also its goal.[36]

Si igitur in omni desiderio vitae intellectualis attenderes, a quo est intellectus, per quod movetur et ad quod, in te comperires dulcedinem sapientiae aeternae illam esse, quae tibi facit desiderium tuum ita dulce et delectabile, ut in inerrabili affectu feraris ad eius comprehensionem tanquam ad immortalitatem vitae tue, quasi ad ferrum et magnetem attendas. Habet enim ferrum in magnete quoddam sui effluxus principium; et dum magnes per sui praesentiam excitat ferrum grave et ponderosum, ferrum mirabili desiderio fertur etiam supra motum naturae, quo secundum gravitatem deorsum tendere debet, et sursum movetur se in suo principio uniendo. Nisi enim in ferro esset quaedam praegustatio naturalis ipsius magnetis, non moveretur plus ad magnetem quam ad alium lapidem; et nisi in lapide esset major inclinatio ad ferrum quam cuprum, non esset illa attractio. Habet igitur spiritus noster intellectualis ab aeterna sapientia principium sic intellectualiter essendi, quod esse est conformius sapientae quam aliud non intellectuale. Hinc irraditio seu immissio in sanctam animam est motus desideriosus in excitatione.

By virtue of the principle that flows from the magnet to the iron--which principle is potentially in the iron, for the iron already has a foretaste for it--the excited iron could transcend its gravid nature and be preternaturally moved to unite with its principle. Reciprocally, the loadstone has a greater attraction to the iron than to other things. Just as the power of attraction comes from the loadstone, so the Deity is the source of our life. Just as the principle implanted in the magnet moves the iron against its heavy nature, so the Deity raises us above our brutish nature so that we may fulfill our life. As the iron moves to the loadstone, so we move to the Deity as to the goal and end of our life.

In _De pace fidei_, Cusa[37] again used the iron and magnet as an example of motion contrary to and transcending nature. He explained this supernatural motion as being due to the similarity between the nature of the iron and the magnet, and this in turn is analogous to the similarity between human spiritual nature and divine spiritual nature. As the iron can move upward to the loadstone because both have similar natures, so man can transcend his own nature and move towards God when his potential similitude to God is realized. Another image used by Cusa was the comparison of Christ to the magnetic needle that takes its power from the heavens and shows man his way.[38]

[36] Nicholas of Cusa (Nicolaus Cusaneus), _Nicolaus von Cues, Texte seiner philosophischen Schriften_, ed. A. Petzelt, Stuttgart, 1949, bk. 1, _Idiota de sapientia_, p. 306 (quoted in Gilbert, M:104). It is interesting that Cusa held that the loadstone has an inclination to iron, as well as the converse!

[37] Cusa, _Cusa Schriften_, vol. 8, _De pace fidei_, translated by L. Mohler, Leipzig, 1943, ch. 12, p. 127.

[38] Cusa, _Exercitationes_, ch. 7, 563 and 566, quoted in, F. A. Scharpff, _Des Cardinals und Bischofs Nicolaus Von Cusa Wichtigste Schriften in Deutscher Uebersetzung_, Freiburg, 1862, p. 435. See also Martin Billinger, _Das Philosophische in Den Excitationen Des Nicolaus Von Cues_, Heidelberg, 1938, and _Cusa Schriften_ (see footnote 37), vol. 8, p. 209, note 105. Gilbert (M: p. 223) called the compass "the finger of God."

The Elizabethan Englishman Robert Norman also turned to the Deity to explain the wonderful effects of the loadstone.[39]

Now therefore ... divers have whetted their wits, yea, and dulled them, as I have mine, and yet in the end have been constrained to fly to the cornerstone: I mean God: who ... hath given Virtue and power to this Stone ... to show one certain point, by his own nature and appetite ... and by the same vertue, the Needle is turned upon his own Center, I mean the Center of his Circular and invisible Vertue ... And surely I am of opinion, that if this would be found in a Sphericall form, extending round about the Stone in Great Compass, and the dead body Stone in the middle therof: Whose center is the center of his aforesaid Vertue. And this I have partly proved, and made visible to be seen in the same manner, and God sparing me life, I will herein make further Experience.

Again, one can infer that the heavens impart a guiding principle to the iron which acts under the influence of this Superior Cause.

One of the points made in St. Thomas' argument on motion due to the loadstone was that there is a limit to the "virtus" of the loadstone, but he did not specify the nature of it. Norman refined the Thomist concept of a bound by making it spherical in form, foreshadowing Gilbert's "orbis virtutis."

Gilbert's philosophy of nature does not move far from scholastic philosophy, except away from it in logical consistency. As the concern of Aristotle and of St. Thomas was to understand being and change by determining the nature of things, so Gilbert sought to write a logos of the physis, or nature, of the loadstone--a physiology.[40] This physiology was not formally arranged into definitions obtained by induction from experience, but nevertheless there was the same search for the quiddity of the loadstone. Once one knew this nature then all the properties of the loadstone could be understood.

[39] Hellmann, _op. cit._ (footnote 6), Norman, bk. 1, ch. 8.

[40] M: p. 14.

Gilbert described the nature of the loadstone in the terms of being that were current with his scholarly contemporaries. This was the same ontology that scholasticism had taught for centuries--the doctrine of form and matter that we have already found in St. Thomas and Nicholas of Cusa. Thus we find Richard Hooker[41] remarking that form gives being and that "form in other creatures is a thing proportionable unto the soul in living creatures." Francis Bacon,[42] in speaking of the relations between causes and the kinds of philosophy, said: "Physics is the science that deals with efficient and material causes while Metaphysics deals with formal and final causes." John Donne[43] expressed the problem of scholastic philosophy succinctly:

This twilight of two yeares, not past or next, Some embleme is of me, ... ... of stuffe and forme perplext, Whose _what_ and _where_, in disputation is ...

As we shall see, Gilbert continued in the same tradition, but his interpretation of form and formal cause was much more anthropomorphic than that of his predecessors.

Gilbert began his _De magnete_ by expounding the natural history of that portion of the earth with which we are familiar.[44]

Having declared the origin and nature of the loadstone, we hold it needful first to give the history of iron also ... before we come to the explication of difficulties connected with the loadstone ... we shall better understand what iron is when we shall have developed ... what are the causes and the matter of metals ...

His treatment of the origin of minerals and rocks agreed in the main with that of Aristotle,[45] but he departed somewhat from the peripatetic doctrine of the four elements of fire, air, water, and earth.[46] Instead, he replaced them by a pair of elements.[47] (If the rejection of the four Aristotelian elements were clearer, one might consider this a part of his rejection of the geocentric universe but he did not define his position sufficiently.)[48]

[41] Richard Hooker. _Of the laws of ecclesiastical polity_, bk. 1, ch. 3, sect. 4 (_Works_, Oxford, Clarendon Press, 1865, vol. 1, p. 157)

[42] Francis Bacon, _De augmentis scientiarum_, bk. 3, ch. 4, in _Works_, ed. J. Spedding, R. L. Ellis, and D. D. Heath, Boston, n.d. (1900?), vol. 2, p. 267.

[43] _The poems of John Donne_, ed. H. J. C. Grierson, London, Oxford University Press, 1933, p. 175 ("To the Countesse of Bedford, On New Yeares Day").

[44] M: pp. 33, 34.

[45] M: pp. 34, 35. Aristotle, _Works_, ed. W. D. Ross, Oxford, 1908--1952, vol. 2, _De generatione et corruptione_, translated by H. H. Joachim, 1930, vol. 3, _Meteorologica_, translated by E. W. Webster, 1931.

[46] M: pp. 34, 35, 64, 65, 69, 81. Dr. H. Guerlac has kindly brought to my attention the similarity between the explanation given in Gilbert and that given in the _Meteorologica_, bk. 3, ch. 6. p. 378.

[47] M: p. 83.

[48] A statement of the relation between Aristotle's four elements and place can be found in Maier, _op. cit._ (footnote 17), pp. 143-182.

According to Gilbert the primary source of matter is the interior of the earth, where exhalations and "spiritus" arise from the bowels of the earth and condense in the earth's veins.[49] If the condensations, or humors, are homogeneous, they constitute the "materia prima" of metals.[50] From this "materia prima," various metals may be produced,[51] according to the particular humor and the specificating nature of the place of condensation.[52] The purest condensation is iron: "In iron is earth in its true and genuine nature."[53] In other metals, we have instead of earth, "condensed and fixed salts, which are efflorescences of the earth."[54] If the condensed exhalation is mixed in the vein with foreign earths already present, it forms ores that must be smelted to free the original metal from dross by fire.[55] If these exhalations should happen to pass into the open air, instead of being condensed in the earth, they may return to the earth in a (meteoric) shower of iron.[56]

[49] M: pp. 21, 34, 35, 36, 45.

[50] M: pp. 35, 36, 38, 69; see, however, pp. 42-43: "Iron ore, therefore, as also manufactured iron, is a metal slightly different from the homogenic telluric body because of the metallic humor it has imbibed ..."

[51] M: pp. 19, 34, 36, 37, 42, 69.

[52] M: pp. 35, 36, 37, 38.

[53] M: pp. 38, 63, 69, 84; on p. 34 he says that iron is "more truly the child of the earth than any other metal"; it is the hardest because of "the strong concretion of the more earthy substance."

[54] M: pp. 21, 35, 37, 38.

[55] M: pp. 35, 63.

[56] M: pp. 45, 46.

Gilbert was indeed writing a new physiology, both in the ancient sense of the word and the modern. The process of the formation of metals had many biological overtones, for it was a kind of metallic epigenesis.[57] "Within the globe are hidden the principles of metals and stones, as at the earth's surface are hidden the principles of herbs and plants."[58] In all cases, the "spiritus" acts as semen and blood that inform and feed the proper womb in the generation of animals.[59] "The brother uterine of iron,"[60] the loadstone, is formed in this manner. As the embryo of a certain species is the result of the specificating nature of the womb in which the generic seed has been placed, so the kind of metal is the result of a certain humor condensing in a particular vein in the body of the earth.

[57] Gilbert's terminology strongly suggests that he was familiar with alchemical literature, as well as that of medical chemistry. He has been credited as being highly skilled in chemistry. See Sir Walter Langdon-Brown, "William Gilbert: his place in the medical world," _Nature_, vol. 154, pp. 136-139, 1944.

[58] _Ibid._, p. 37.

[59] M: pp. 35, 36, 53, 59. See also Galen, _op. cit._ (footnote 15) bk. 2, ch. 3.

[60] M: pp. 16, 59.

Gilbert developed this biological analogy further by ascribing to metals a process of decay after reaching maturity. Once these solid materials have been formed, they will degenerate unless protected, forming earths of various kinds as a result.[61] The "rind of the earth"[62] is produced by this process of growth and decay. If these earths are soaked with humors, transparent materials are formed.[63]

[61] M: pp. 20, 21, 32, 61, 63, 66, 70.

[62] M: p. 59.

[63] M: p. 84.

As we shall see below, the ultimate cause of this internal and superficial life is the motion of the earth, which animation is the expression of the magnetic soul of this sphere.[64] As the life of animals results from the constant working of the heart and arteries,[65] so the daily motion of the earth results in a constant generation of mineral life within the earth. In contrast to Aristotle's[66] making the motion of the heavens the cause of continuous change, Gilbert made that of the earth the remote cause.[67] However, unlike the constant cyclical transmutation of substances in Aristotle, there is only generation and decay.

[64] M: pp. 310, 311, 312.

[65] M: p. 338. A somewhat different opinion, although not necessarily inconsistent is expressed on p. 66, where he says the surface is due to the action of the atmosphere, the waters, and the radiations and other influences of heavenly bodies.

[66] Aristotle, _op. cit._ (footnote 45), _De generatione et corruptione_, bk. 2, ch. 10.

[67] M: pp. 311, 334, 338.