Superphysics Superphysics

NOTES on De Magnete

by Gilbert
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During the work of revising and editing the English translation of De Magnete, many points came up for discussion.

There were discrepancies between the 3 known editions:

  1. The London folio of 1600
  2. The 2 Stettin quartos of 1628 and 1633

Passages relating to astrology, to pharmacy, to alchemy, to geography, and to navigation, required to be referred to persons acquainted with the early literature of those branches.

Phrases of non-classical Latin presented some obscurity. They needed explanation by scholars of mediæval writings.

Descriptions of magnetical experiments needed to be interpreted by persons whose knowledge of magnetism enabled them to infer the correct meaning to be assigned to the words in the text.

In this wise a large amount of miscellaneous criticism has been brought to bear, and forms the basis for the following notes.

To make them available to all students of Gilbert, the references are given to page and line both of the Latin folio of 1600 and of the English edition of 1900. S. P. T.


Gilbert’s glossary introduces new Latin words such as nouns:

  • terrella
  • versorium
  • verticitas

and the adjectival noun magneticum, which either did not exist in classical Latin or had not the technical meaning which he now assigns to them.

His terrella, or μικρόγη, is a little magnetic model of the earth in page 13. But in the glossary he simply defines it as magnes globosus.

Neither terrella nor versorium appears in any Latin dictionary.

No older writer had used either word. Peter Peregrinus (De Magnete, Augsburg, 1558) had described experiments with globular loadstones, and pivotted magnetic needles suitable for use in a compass had been known for nearly three centuries.

Yet the pivotted needle was not denominated versorium. Blondo (De Ventis, Venice, 1546) does not use the term.

Norman (The Newe Attractiue, London, 1581) speaks of the “needle or compasse,” and of the “wyre.”

Barlowe (The Navigators Supply, London, 1597) speaks of {2}the “flie,” or the “wier.” The term versorium (literally, the turn-about) is Gilbert’s own invention.

It was at once adopted into the science, and appears in the treatises of Cabeus, Philosophia Magnetica (Ferrara, 1629), and of Kircher, Magnes sive de Arte Magnetica (Coloniæ, 1643), and other writers of the 17th century.

Curiously enough, its adoption to denote the pivotted magnetic needle led to the growth of an erroneous suggestion that the mariners’ compass was known to the ancients because of the occurrence in the writings of Plautus of the term versoriam, or vorsoriam.

This appears twice as the accusative case of a feminine noun versoria, or vorsoria, which was used to denote part of the gear of a ship used in tacking-about. Forcellini defines versoria as “funiculus quo extremus veli angulus religatur”; while versoriam capere is equivalent to “reverti,” or (metaphorically) “sententiam mutare.”

The two passages in Plautus are:

Eut. Si huc item properes, ut istuc properas, facias rectius,
Huc secundus ventus nunc est; cape modo vorsoriam;
Hic Favonius serenu'st, istic Auster imbricus:
Hic facit tranquillitatem, iste omnes fluctus conciet.
(in Mercat. Act. V., sc. 2.)

Charm. Stasime, fac te propere celerem recipe te ad dominum domum;
. . . . . . . . . . . . . . . . Cape vorsoriam
Recipe te ad herum.
(in Trinum. Act. IV., sc. 3.)

The noun magneticum is also of Gilbert’s own coinage.

As an adjective, it had been certainly used before, at least in its English form, magneticall, which appears on the title-page of William Borough’s Discourse of the Variation of the Compasse (London, 1596).

Gilbert does not use anywhere the noun magnetismus, magnetism.

The first use of that noun occurs in William Barlowe’s Magneticall Aduertisements (1616), in the Epistle Dedicatorie, wherein, when speaking of Dr. Gilbert, he says “vnto whom I communicated what I had obserued of my selfe, and what I had built vpon his foundation of the Magnetisme of the earth.”

Gilbert speaks of the virtus magnetica, or vis magnetica; indeed, he has a rich vocabulary of terms, using, beside virtus and vis, vires, robur, potestas, potentia, efficientia, and vigor for that which we should now call magnetism or the magnetic forces.

Nor does he use the verb magnetisare, or its participle, magnetisatus: he speaks of ferrum tactum, or of ferrum excitatum a magnete. In spite of certain obscurities which occur in places in his work, he certainly shows a nice appreciation of words and their use, and a knowledge of style.

One finds occasionally direct quotations from, and overt references to, the classic authors, as in the references to Plato and Aristotle on page 1, and in the passage from the Georgics of Vergil on p. 21.

But here and there one finds other traces of unmistakable scholarship, as in the reference to goat’s wool on p. 35, or in the use, on p. 210, of the word perplacet, which occurs in the letter of Cicero ad Atticum, or in that of commonstrabit, occurring on p. 203, and found only in Cicero, Terence and Plautus; whilst the phrase on p. 3, in which Gilbert rallies the smatterers on having lost both their oil and their pains, has a delightfully classical echo. {3}

The term orbis virtutis, defined by Gilbert in the glossary, and illustrated by the cuts on pages 76, 77, and 96, might be effectively translated by sphere of influence, or orbit within which there is sensible attraction.

It has been preferred, however, to translate it literally as the orbe of virtue, or orbe of magnetick virtue. This choice has been determined by the desire to adopt such an English phrase as Gilbert would himself have used had he been writing English. T. Hood, writing in 1592 in his book The Vse of both the Globes, in using the word orbe, says that the word globe signifies a solid body, while a sphere is hollow, like two “dishes joyned by the brimme”; “The Latines properly call Orbis an Orbe”;

“Moreouer the word Sphaera signifieth that instrument made of brasen hoopes (wee call it commonly a ringed Sphere) wherewith the Astronomers deliuer unto the nouices of that Science the vnderstanding of things which they imagine in the heauen.” Further, Dr. Marke Ridley in his Treatise of Magneticall Bodies and Motions (1613), has a chapter (XIIII) “Of the distance and Orbe of the Magnets vertue,” throughout which the term Orbe is retained. Sir Thomas Browne also writes of “the orb of their activities.”

The word Coitio, used by Gilbert for the mutual force between magnet and iron, has been retained in its English form, coition. Gilbert evidently adopted this term after much thought. The Newtonian conception of action and reaction being necessarily equal had not dawned upon the mediæval philosophers.

The term attraction had been used in a limited sense to connote an action in which a force was conceived of as being exerted on one side only. Diogenes of Apollonia, Alexander Aphrodiseus, Democritus, and others, conceived the magnet to draw at the iron without the iron in any way contributing to that action. Saint Basil specially affirms that the magnet is not drawn by iron.

On the other hand, Albertus Magnus had conceived the idea that the iron sought the magnet by a one-sided effort in which the magnet took no part. Gilbert had the wit to discern that the action was mutual, and to mark the new conception he adopted the new term, and defined it as it stands in his glossary. It is “a concourse or concordancy of both,” and to emphasize his meaning he adds, “not as if there were an ἑλκτικὴ δύναμις but a συνδρομή” not a tractile power, but a running together.

The adjective ἑλκτικὴ is obviously related to the verb ἕλκω, I draw: but its meaning puzzled the subsequent editors of the text, for in the two Stettin editions of 1628 and 1633, the phrase appears in the respective forms of ἑλητικὴ δύναμις and ἑλκυστικὴ δύναμις. In Creech’s English version of Lucretius (edition of 1722, p. 72a, in the footnote) is the commentary “Galen, disputing against Epicurus, uses the term ἑλκεῖν, which seems likewise too violent.”

It may be noted that the same verb occurs in the passage from the Io of Plato quoted below. The term συνδρομή applied by Gilbert to explain his term Coitio is used by Diodorus for the mutual onset of two hostile forces.

A picturesque sentence from Sir Thomas Browne’s Pseudodoxia Epidemica (London, 1650, p. 51) sets the matter succinctly forth. “If in two skiffs of cork, a Loadstone and Steel be placed within the orb of their activities, the one doth not move the other standing still, but both hoist sayle and steer unto each other; so that if the Loadstone attract, the Steel hath also its attraction; for in this action the Alliency is reciprocall, which jointly felt, they mutually approach and run into each others arms.” {4}The page and line references given in these notes are in all cases first to the Latin edition of 1600, and secondly to the English edition of 1900.

[2] Page 1, line 28. Page 1, line 28. Plato in Ione

The passage in the Io of Plato is in chap. v. Socrates addressing the poet Io tells him that his facility in reciting Homer is not really an art: θεία δὲ δύναμις, ἥ σε κινεῖ ὥσπερ ἐν τῇ λίθῳ, ἥν Εὐριπίδης μὲν Μαγνῆτιν ὠνόμασεν, οἱ δὲ πολλοὶ Ἡράκλειαν. καὶ γὰρ ἄυτη ἡ λίθος οὐ μόνον αὐτοὺς τοὺς δακτυλίους ἄγει τοὺς σιδηροῦς, ἀλλὰ καὶ δύναμιν ἐντίθησι τοῖς δακτυλίοις, ὤστ ἄυ δύνασθαι ταυτὸυ τοῦτο ποιεῖν, ὅπερ ἡ λίθος, ἄλλους ἄγειν δακτυλίους, ὥστ’ ἐνίοθ’ ὁρμαθὸς μακρὸς πάνυ σιδηρίων καὶ δακτυλίων ἐξ ἀλλήλων ἤρτηται πᾶσι δὲ τούτοις ἐξ ἐκείνης τῆς λίθου ἡ δύναμις ἀνήρτηται. The idea is that as the loadstone in attracting an iron ring will make it into a magnet, which can in turn act magnetically on another ring, and this on yet another, so the inspiration of the Muse is transferred to the poet, who in turn hands on the inspiration through the reciter to the listener. After further expanding the same idea of the transference of influence, Socrates again mentions the magnet (chap. vii.): Ὄισθ’ ὄυν ὅτι οὐτός ἐστιν ὁ θεατὴς τῶν δακτυλίων ὁ ἔσχατος, ὥν ἐγὼ ἔλεγον ὑπὸ τῆς Ἡρακλειώτιδος λίθου ἀπ’ ἀλλήλων τὴν δύναμιν λαμβάνειν, ὁ δὲ μέσος σὺ ὁ ῥαψωδὸς καὶ ὑποκριτής, ὁ δὲ πρῶτος αὐτὸς ὁ ποιητής; ὁ δὲ θεὸς διὰ πάντων τούτων ἕλκει τὴν ψυχὴν ὅποι ἂν βούληται τῶν ἀνθρώπων, κ.τ.λ. (Edition Didot of 1856, vol. i., p. 391; or Stephanus, p. 533 D).

There is another reference in Plato to the magnet, namely, in the Timæus (p. 240, vol. ii., Edit. citat.). See the Note to p. 61.

The reference by Euripides to the magnet occurs in the lost play of Œneus, in a fragment preserved by Suidas. See Fragmenta Euripidis (Ed. Didot, 1846, p. 757, or Nauck’s edition, No. 567).

ὡς Εὐριπίδης ἐν Οἰνεῖ· τὰς βροτῶν γνώμας σκοπῶν, ὥστε Μαγνῆτις λίθος τὴν δόξαν ἕλκει καὶ μεθίστησιν πάλιν.

[3] Page 1, line 28. Page 1, line 29. The brief passage from Aristotle’s De Anima referring to Thales is quoted by Gilbert himself at the bottom of p. 11.

[4] Page 2, line 1. Page 1, line 29. The edition of 1628 inserts commas between Theophrastus and Lesbius, and between Julius and Solinus, as though these were four persons instead of two.

[5] Page 2, line 8. Page 2, line 5. si allio magnes illitus fuerit, aut si adamas fuerit. An excellent version of this myth is to be found in Julius Solinus, Polyhistor, De Memorabilibus, chap. lxiv., of which the English version of 1587, by A. Golding, runs thus: “The Diamonde will not suffer the Lodestone to drawe yron unto him: or if ye Lodestone haue alreadie drawne a peece of yron to it, the Diamond snatcheth and pulleth away as hys bootye whatsoever the Lodestone hath taken hold of.” Saint Augustine repeats the diamond myth in his De Civitate Dei, lib. xxi. Baptista Porta says (p. 211 of the English version of 1658): “It is a common Opinion amongst Sea-men, That Onyons and Garlick are at odds with the Loadstone: and Steers-men, and such as tend the Mariners Card are forbid to eat Onyons or Garlick, lest they make the Index of the Poles drunk. But when I tried all these things, found them to be false: for not onely breathing and belching upon the Loadstone after eating of Garlick, did not stop its vertues: but when it was all anoynted over with the juice of Garlick, it did perform its office as well as if it had never been touched with it: and I could observe almost not the least difference, lest I should make void the endeavours of the Ancients. {5}And again, When I enquired of Marines, whether it were so, that they were forbid to eat Onyons and Garlick for that reason; they said, they were old Wives fables, and things ridiculous; and that Sea-men would sooner lose their lives, then abstain from eating Onyons and Garlick.”

The fables respecting the antipathy of garlick and of the diamond to the operation of the magnet, although already discredited by Ruellius and by Porta, died hard. In spite of the exposure and denunciations of Gilbert—compare p. 32—these tales were oft repeated during the succeeding century. In the appendix to Sir Hugh Plat’s Jewel House of Art and Nature, in the edition of 1653, by D. B. Gent, it is stated there (p. 218): “The Loadstone which … hath an admirable vertue not onely to draw Iron to it self, but also to make any Iron upon which it is rubbed to draw iron also, it is written notwithstanding, that being rubbed with the juyce of Garlick, it loseth that vertue, and cannot then draw iron, as likewise if a Diamond be layed close unto it.”

Pliny wrote of the alleged antipathy between diamond and goat’s blood. The passage as quoted from the English version of Pliny’s Natural Historie of the World, translated by Philemon Holland (London, 1601, p. 610, chap, iv.), runs: “But I would gladly know whose invention this might be to soake the Diamond in Goats bloud, whose head devised it first, or rather by what chance was it found out and knowne? What conjecture should lead a man to make an experiment of such a singular and admirable secret, especially in a goat, the filthiest beast … in the whole world? Certes I must ascribe both this invention and all such like to the might and beneficence together of the divine powers: neither are we to argue and reason how and why Nature hath done this or that? Sufficient is it that her will was so, and thus she would have it.”

[6] Page 2, line 22. Page 2, line 22. Machometis sacellum. Gilbert credits Matthiolus (the well-known herbalist and commentator on Dioscorides) with producing the fable as to Mahomet’s coffin being suspended in the air by a magnet. Sir Richard Burton, in his famous pilgrimage to El Medïnah in 1855, effectually disposed of this myth. The reputed sarcophagus rests simply on bricks on the floor. But it had long been known that aerial suspension, even of the lightest iron object, in the air, without contact above or below, was impossible by any magnetic agency.

In Barlowe’s Magneticall Aduertisements (London, 1616, p. 45) is the following: “As for the Turkes Mahomet, hanging in the ayer with his yron chest it is a most grosse untruth, and utterly impossible it is for any thing to hange in the ayer by any magneticall power, but that either it must touch the stone it selfe, or else some intermediate body, that hindreth it from comming to the stone (like as before I haue shewed) or else some stay below to keepe it from ascending, as some small wier that may scantly bee seene or perceived.”

[7] Page 2, line 26. Page 2, line 26. Arsinoes templum.—The account in Pliny of the magnetic suspension of the statue of Arsinoe in the temple built by Chinocrates is given as follows in the English version (London, 1601) of Philemon Holland (p. 515): “And here I cannot chuse but acquaint you with the singular invention of that great architect and master deviser, of Alexandria in Ægypt Dinocrates, who began to make the arched roufe of the temple of Arsinoe all of Magnet or this Loadstone, to the end, that within that temple the statue of the said princesse made of yron, might seeme to hang in the aire by nothing. But prevented he was by death {6}before hee could finish his worke, like as king Ptolomæe also, who ordained that temple to be built in the honour of the said Arsinoe his sister.”

There are a number of similar myths in Ausonius, Claudian, and Cassiodorus, and in the writings of later ecclesiastical historians, such as Rusinus and Prosper Aquitanus. The very meagre accounts they have left, and the scattered references to the reputed magical powers of the loadstone, suggest that there existed amongst the primitive religions of mankind a magnet-worship, of which these records are traces.

[8] Page 2, line 37. Page 2, line 41. Brasevolus [or Brasavola].—The list of authorities here cited consists mostly of well-known mediæval writers on materia medica or on minerals: the last on the list, Hannibal Rosetius Calaber, has not been identified.

The following are the references in the order named by Gilbert:

Antonio Musa Brasavola. Examen omnium simplicium medicamentorum, Section 447 (Lugdun., 1537).

Joannes Baptista Montanus. Metaphrasis summaria eorum quæ ad medicamentorum doctrinà attinet (Augustæ Rheticæ, 1551).

Amatus Lusitanus. Amati Lusitani in Dioscoridis Anazarbei de materia medica libros quinque (Venet., 1557, p. 507).

Oribasius. Oribasii Sardiani ad Eunapium libri 4 quibus … facultates simplicium … continentur (Venet., 1558).

Aetius Amidenus. Aetii Amideni Librorum medicinalium … libri octo nunc primum in lucem editi (Greek text, Aldine edition, Venet., 1534). A Latin edition appeared in Basel, 1535. See also his tetrabiblos ex veteribus medicinæ (Basil., 1542).

Avicenna (Ibn Sinâ). Canona Medicinæ (Venice, 1486), liber ii., cap. 474.

Serapio Mauritanus (Yuhanná Ibn Sarapion). In hoc volumine continentur … Ioan. Sarapionis Arabis de Simplicibus Medicinis opus præclarum et ingens … (edited by Brunfels, Argentorati, 1531, p. 260).

Hali Abbas (’Alí Ibn Al ’Abbās). Liber totius medicinæ necessaria cōtinens … quem Haly filius Abbas edidit … et a Stephano ex arabica lingua reductus (Lugd., 1523, p. 176 verso).

Santes de Ardoniis (or Ardoynis). Incipit liber de venenis quem magister santes de ardoynis … edere cepit venetiis die octauo nouēbris, 1424 (Venet., 1492).

Petrus Apponensis (or Petrus de Abano). The loadstone is referred to in two works by this author.

(1) Conciliator differentiarum philosophorum: et precipue medicorum clarissimi viri Petri de Abano Patauini feliciter incipit (Venet., 1496, p. 72, verso, Quæstio LI.).

(2) Tractatus de Venenis (Roma, 1490, cap. xi.).

Marcellus (called Marcellus Empiricus). De Medicamentis, in the volume Medici antiqui omnes (Venet., 1547, p. 89).

Arnaldus (Arnaldus de Villa Nova). Incipit Tractatus de virtutibus herbarum (Venet., 1499). See also Arnaldi Villanovani Opera omnia (Basil., 1585).

Marbodeus Gallus. Marbodei Galli poetae vetustissimi de lapidibus pretiosis Enchiridion (Friburgi, 1530 [1531], p. 41).

Albertus Magnus. De Mineralibus et rebus metallicis (Venet., 1542, lib. ii., de lapidibus preciosis, p. 192). There is a reference to the loadstone {7}also in a work attributed falsely to Albertus, but now ascribed to Henricus de Saxonia, De virtutibus herbarum, de virtutibus lapidum, etc. (Rouen, 1500, and subsequent editions). An English version, The Secrets of Albertus Magnus of the vertues of hearbs stones and certaine beasts was publisht in London in 1617.

Matthæus Silvaticus. Pandectæ Medicinæ (Lugduni, 1541, cap. 446).

Hermolaus Barbarus. His work, Hermolai Barbari Patritii Veneti et Aqvileiensis patriarchæ Corollarii Libri quinque … Venet., 1516, is an early herbal. On p. 103 are to be found descriptions of lapis gagatis and lapis magnes. The latter is mostly taken from Pliny, and mentions the alleged theamedes, and the myth of the floating statue.

Camillus Leonardus. Speculum Lapidum (Venet., 1502, fol. xxxviii.). An English translation, The Mirror of Stones, appeared in London in 1750.

Cornelius Agrippa. Henrici Cor. Agrippæ ab Nettesheym … De Occulta Philosophia Libri Tres (Antv., 1531). The English version Of the Vanitie and uncertaintie of Artes was publisht in London, 1569, and again later.

Fallopius (Gabriellus). G. F. de simplicibus medicamentis purgantibus tractatus (Venet., 1566). See also his Tractatus de compositione medicamentorum (Venet., 1570).

Johannes Langius. Epistolarum medicinalium volumen tripartitum (Paris, 1589, p. 792).

Cardinalis Cusanus (Nicolas Khrypffs, Cardinal de Cusa). Nicolai Cusani de staticis experimentis dialogus (Argentorati, 1550). The English edition, entitled The Idiot in four books, is dated London, 1650.

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