Precursors to Peregrinus: The early history of magnetism and the mariner's compass in Europe

Precursors to Peregrinus: The early history of magnetism and the mariner’s compass in Europe Julian A. Smith Institutefor the History and Philosoply of Science and Tecfmo!ogy, Toronto, Ont., Canada

Histories of magnetism and tfle mariner’s compass flave usualb been restricted to a jw brief descriptions by Alexander JVeckam, Guyot de Provins and Jacques de Vi@ followed by tfte important Epistola de Magnctc of Peter Peregrinus (1269). But by reviewing the many other ear& European references to the man’ner’s compass, we jnd that there is little in Peregrinus tflat was not already wideb known; and tflat hir importance lies more in organizing, rather than originating, knowledge of tire compass.

Though the magnetic compass has had an enormous influence on the history of carto
Civr~sl,onde~c /oxJA Smith, Institutr for the History and Philosophy oT Sricncc and ‘I’crhnology, Room 316, Victoria Collcgc. Toronto, Ont. M!X IK7, Canada. ~~I.I.\s SMI is a doctoral candidate at thr Institute for the History and Philosophy or Scicncc and ‘I’crhnology, Univctrity of Toronto, Canada.

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Pctcr Pcrcbq-inus, I$is/n/n de AJqne!e; translated by Joseph Charlcs Mcrtens or ‘Brother Arnold as 77~ /r//e~ of fe/t7~~ J+wgrh~.r on /he wogne/ A.D. 12G!) (N cw York, 1904); we also H.D. Harrandon, ‘Some early contrihudons IO the history of gcomamxtism, I ,’ Terre.sfrial MqweG.vn aad Ahnos/heric /hrtCip, 43 (l943), 3 17. SW, for cxamplc, Alfred Hint, hfognehc cmnJ~m.~~sand magn&nwhr~ (Toronto, 1968), 1 2, Hcrbcrt Mcycr, A I,~/~J~ uf e/ec/riri!v and tnagne/zh (Cambridge, I97 I), 6 7, and Jean Gimpcl,ne medieval yachine: 7lre Jndushal Heuohlion of /Ire AJi!die Ages (New York, 1976), 193 195. A. Rupcrt Hall, 7%e s&n/& reuohhon (London, 1967), 6.

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Journal of Medieval History I8 (1992) 21-74 Elscvicr Science 0304-4 I8 I /92/SO5.00 0 1992

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1269 that a reasoned account of the properties of the magnet is anywhere to be found.“4 The thirteen-chapter EFidola, written by a military engineer during a siege at Lucera in Apulia, Italy, proposes two magnetic poles, gives a remarkably detailed theory of magnetic attraction, considers a magnetic ‘perpetual motion machine’, and explains in detail the construction of two different types of mariner’s compass. Lynn White calls the work ‘epochal’, and remarks that “ 1269 is a great date in the history of science”.” Paul Flcury Mottclay goes cvcn further and claims this as “the earliest known work of experimental science”,” an opinion shared by more recent authors.’ While there is no denying the importance of this treatise, a closer examination of the available magnetic theory in the century before Pcregrinus prcscnts us with a somewhat differing picture. The many available prior rcfcrences to the magnetic compass in Europe are scattered in dozens of sources, which arc often either inaccessible or untranslated. This paper will relicw those accounts, clearing up errors of interpretation and dating that have hampered previous researchers. It will include and discuss the lesser known citations of the ma
Wliam kVrightman, 771~grow//~ uf srk@ic i&a.%(NW Haven, 19.531, 206.

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Lynn ;Bcrkclcy, Paul 7 See,

\Vhitc, ‘Pumps and pcndula: Galileo and technology*, in: .IfedipI*a/ Rrhjjon and T+hrro/og~ 1978). 125. Mottclay ~lcury, Riblio_qaphirnl his/oy oJ ~l~c~rici~ wd Alagm4.wt (London, I922), 45. for example, Ronald ‘I’. Uwill, and Michael \V. McElhinny. 77~ IGzrtlri ntagwtic jekd. its histoop on@ and plane!ay pmpertiue (London, I9?3), .5. Among the bw htstorical stud& or thr manner’s compass are J. Klaproth’s II//W ri ‘\I. IP Bnron A. de Humboldt SW l’inuention de la boussole(Paris, 1834); Albwt Schuck’s IItv hktrpam (Hamburg, 19 1.5); klcury’s Bibliographical hisloty, George &mm’s Inlrotfuclim lo the hislon cf.~ritwre, vol. 2 (Baltimore, 192i- 1931) [hercaftcr IHS], and A. Chrichton Mitchell’s ‘Chaptcn in thr histoty or twrrstrial magnetism,’ Tmeskial rMgnt/im and &nosph& fTl&ici!r, 37 1932). I0.i 146: 42 I937), 24 I 280; 44 (1939), 77-80. All, regrettably, arc incotnplrtc, as well as being tuo old to take aclvantage or thr substantial rcccnt research in this area. ‘I Lynn \Vhitc, ‘The medieval roots or modern technology and scicncc,’ in: \Vhitc (1978), 88.

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particularly in the case of the adamant, which, as we shal! see, can sometimes mean all of the above. The Oxford EnglishDictionay considers the Mariner’s Compass as “an instrument for determining the magnetic meridian, or one’s direction or position with respert to it, consisting of a magnetized needle turning freely on a pivot; notably employed in a ship’s course at sea”.tO Its origin is unknown, but the term ‘compass’ may be derived from the Latin word compassare, meaning ‘to pass or step together’. It has come into our European magnetic sources in the following forms: compas (French/Spanish), compasso (Italian), kompas (Dutch/Norwegian), Kompass (German), and compass (English/German). It is worth noting that Germanic languages use this word to refer more to the mariner’s compass; Romance languages typically use it to refer to dividing or drawing compasses. I’ This distinction must constantly be kept in mind when examining texts. This O.E.D. definition is probably the one most readers have in mind when they set the words ‘magnetic compass’, and indeed this conception of the device has been common for hundreds of years. However, as we shall set, it is clearly insufficient for our purposes. Even the earliest European sources describe a marincr’s compass composed of a magnetized needle, placed inside a hollow straw for buoyancy, floating in a bowl of water. For ease of nomenclature, therefore, we will call this device the ‘wet compass’, and the mom common definition the ‘dry compass’. ‘Magnet’, meaning ‘a piece of lodcstonc’, comes from the Latin and Greek word magles, meaning ‘Magnesian (stone)‘,” after the mythical origin of the lodcstonc in Ancient Greccc, whcrc a shcphcrd of that name tending his flock on Mount Ida was held fast to the ground by the iron nails in his shoes. There arc also fables that claim the word comes from Magnesia, a city in Asia Minor, which provided lodcstoncs to the Greeks in 1000 B.C.‘” ‘Lodcstonc’ or ‘toadstonc’, a naturally magnetic iron arc, is a lustrous, black mineral, occurring as crystals, masses, and sands. The word appears to come from the Old English words ‘lad’, meaning course, way or path, and ‘Stan’, meaning stone, or rock. It appears in Old Norse and Icelandic as ‘leidarstcin’, German as ‘lcitstcin’.t4 ‘Adamant’ occurs continually in the mcdicval writers, and is often used in

OLD., vol. 2, 102”(p. 28 29). S. Mnlin, ‘Historical introduction I (London,

I987),

B; WC also Benjamin

in: J.A. Jacobs, cd., Geomgtetim, vol. Hcydnk dic/imo,m~ ?f d&s and r~s@tlit@ntu/io~~ (New

IO geomagnctism’, Vincent,

York, 1883), 431. This is a useful sow-c for magnetic ‘myths’ to the late nineteenth century. See also John B. Krmncr, ‘Thr early history of magnetism,’ in ‘Tinnsnc/ioas the &wcme~~ Sotie&, I4

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-34): 183 200. O.E.D., vol. I, 1625 (pa 370).

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contradictory and mutually exclusive ways. It appears to come from the Greek adamas, originally meaning ‘invincible’, but later applied to the hardest metal (probably steel). In Latin the word is adumus, meaning adamant, steel, or diamond. Early medieval authors, incorrectly deriving the word from the Latin ndumare, or ‘having attraction for’, took the lapidem adamanhn to be the ‘attracting stone’ or ‘magnet’; in this way, the word became incorrectly associated with the lodestone, magnet and compass. Later medieval writers, as we shall set below, use the term to refer to a fabulous, mythical mineral, whose properties show a confusion of ideas between the diamond, other gemstones, the lodestone, and the magnet. It passed into the Romance languages as the word for magnet or lodestone in these forms: aimanl (French), ndiman, azjman, aymnn (Portuguese), iman (Spanish), and cahmitu (Italian).‘j With these caveats in mind, we may begin to look at the earliest accounts of the magnetic compass in Europe. Many scholars claim that the compass was originally invented in China, and then was transmitted to the Latin West in the twelfth century, either overland or on Arabian ships;lG these arguments have lately been the subject of much research by Lynn White” and Joseph Needham.‘” However, the link has not yet been established, and indeed thcrc is some evidence against it. To begin with, the Arabic word for compass, al-kunbas, appears to derive from Italian roots. Furthermore, the earliest references to the compass in Arabic sources occur later than those of Europe; to bc precise, the compass is mentioned in the Jami al-Hikuyut, a PersiaI, collection of anecdotes of about 1232, and in the Kant ul-7;jur, a 1282 lapidary of Bailak al-Qabaji, the author mentions seeing a ‘wet’ compass in 1242. I9 As WC shall see, the carlicst European sources predate these by almost a century. The overland route remains possible, but again, dccisivc evidence is lacking. Consequently, until the link is cstablishcd, I will adopt the provisional hypothesis that the two compasses of China and Europe were invented and evolved independently. This paper, of course, is concerned only with devclopments in the West, and should be read with that restriction in mind whcncvcr questions of priority, discovery or invention arise. Those intcrcstcd in the dcvcl-

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If1 $ience

O.E.D., vol. I, 25 (p. 99). Merrill and %Elhinny, Earthi and society in lksf

.\lagne/irJeM 3: SW alsoJosrph Nt*rdllanl. 77~ grmd /i/ration: llb.v/ (Toronto, 1969). 114. /rrlrno/~~gr and .coria/ rhqe (Oxford, IYG], I32 I33. &we and rivilisntion in China (Glmhridgc, I962), vol. 4, lx~, I, 229 334;

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Lynn \Vhitc, Mdiwa/

‘” Joseph Nccdham, $SO vol. 4, prt. 3, (197 I), 3% 58.5.

Nerdham, 24

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vol. 4, pt. I.

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opment of the compass in the East, they may refer to Joseph Needham’s magnificent account of Scienceand ciuihalion in China. 2o It is very difficult to date precisely the first appearance of the magnetic compass in Europe. The literature of this topic abounds with errors, mistaken translations and unsubstantiated claims. Some of the most persistent legends have been reviewed by A. Chrichton Mitchell and Timoteo Bertelli.21 Mitchell has documented the erroneous attribution of the magnetic compass to the following figures: Salome Irene0 Pacifico, Gerbert d’Aurillac or Pope Sylvester II, the anonymous sailors of Amalfi in the eleventh century, Flavio Gioja, also of Amalfi, William the Clerk, and Marco Polo. We shall look at these arguments now. The first ascribes the discovery to Salomone Ircneo Pacific0 (778-846) of Verona. This claim, which was popularized in 1904?* was based upon an incorrect reading of an inscription on Pacifico’s tomb in the Verona Cathedral. Bertelli demonstrated in the same year that the claim could not stand.2” A more persistent error has given priority to the French mathematician and monk Gerbert d’Aurillac, or Pope Sylvester II (circa 945 1003).*” This is based upon an unusual passage in an early chronicle by Bishop Ditmarus (also known as Thietmarus) of Mcrseburg (circa 976- 10 18) which claims that around 994-995 ‘in Magdeburg, he [Gerbert] made a clock, and making it rightly, examined through a certain tube a star, the guide [leader] of the mariners’.*j Some authors

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have assumed this sentcncc refers to an early tclescopc, hut it is more likely a sighting tube,‘6 an astrolahe, or possibly an elaborate sundial. The belief that it represents a compass is based on a highly unlikely interpretation of the last two words, nautarum duce;27 but a letter from Gcrbcrt to the monk Constantine shows that this interpretation cannot possibly he sustained. 1HEarly mariners could easily have used astrolabes or dials, and the ‘guide of the mariners’ probably modifies the words ‘certain star’, that is to say? the pole star. Consequently, the ‘magnetic compass’ interpretation of this passage seems unlikely. A common argument in the secondary litcraturc ascribes the Wcstcrn ‘invcntion’ of the magnetic compass to the sailors of the small port of Amalfi, in southern Italy.29 Silvio Bedini, for example, says the compass is “bclicvcd to have been invented in the Mcditcrranean region, probably at the Italian port of Amalfi”.“0 Thcrc arc two strands to this claim; the first is due to a rcfcrcncc in a historical poem of \Villiam of Apulia (B. I IOO), composed bctwccn about 1085- 1 I 11, entitled the Gesta Roberti lVikardi (it is also somctimcs called the Poema de Rebus Normnnnorum).The text in question sl~ows internal cvidcncc of having been written somctimc after July 1099, and it describes navigational tcchniqucs at Amalh; ‘no more the wealth of your silver or gold; of parts innumcrablc. Of many cities, the sailors lingered here, though cxpcricnccd in uncowring the route in the seas and in the hcavens’.si It is important to note, however, that the passage does not mention the compass at all; most scholars bclicvc it rcfcrs to navigation hy the stars,32 but its citation by the famous English historian Edward Gibbon (1737-1794) helped to promote AmaWs longstanding claim to priority.“” The second strand of the Amalfi claim”’ gives the honour of inventing the

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mariner’s compass to a Flavio Gioja in 1302. 35 The history of this thesis begins with the Italian historian Flavio Blond0 (circa 1388-1463), who wrote (around 1450) that Amalfian navigators invented the marine compass, and used it for the first time;3” this claim was repeated in 1511 by Giovanni Baptista Pio (died circa 1540).“’ The sixteenth century writer Lillio Grcgorio Giraldi (1479- 1552), drawing on Pio’s account, incorrectly attributed the invention to ‘Fiavio’, the author of the original history,38 and in 1586 Scipione Mazzclla gave the surname ‘Gioja’ (possibly drawn from Guyot dc Provinsj to the inventor.“” The error was repeated for over three hundred years, by authors so widely read as Girolamo Cardano (1501-1576)“” and Voltairc (1694-1778),Ji and was then exploded by Timotco Bcrtclli;*l unfortunately, however, it has persisted in histories until the prcscnt day. Mitchell, who has documcntcd the transmission of this mistake quite thoroughly, has pointed out that it has caused a statue to be erected in Naples to the mythical Gioja, and has led to cclcbrations in Amalfi on the 600th amtivcrsary of his invention in 190 1.t9 Alongside the plausible explanation for the dcvclopmcnt of this error, there arc other grounds for rejecting it: historians looking at this issue have been able to trace only one Gioja family, and have found no one called Flavio among its mcmbersaa Another common belief ascribes the compass to William the Clerk, also known as \Villiam the Norman (6. twclfih century). This claim is based on an anonymous

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poem which, upon its publication in the 1835 Lnb hidits of Francisque Michel,aS was ascribed by historian Paulin Paris to William and dated 1 160.4G However, the poem does not refer to its author, it bears a close resemblance to the later poem of Guyot de Provins (set below), and other scholars have concluded that the more likely date of composition was bctwcen the thirteenth and fourteenth centuries, which clearly makes it too late to have been written by \Villiam.47 A final frequently quoted ‘myth’ attributes the origin of the marine compass to Marco Polo (circa 1254-1324), who was supposed to have brought the compass back to ktaly from China; this story was popularized by English magnetic scientist \Villiam Gilbert (1540- 1603), who wrote in 1600 that ‘knowledge of the mariner’s compass appears to have been brought into Italy by the Vcnctian Paolo who about the year 1260 learned the art of the compass in China’.)s This claim, despite its long&y, may be rcjcctcd on two
Francisque Michel, In6 inidih do .YIk PI .\‘lllu Gih (his. 1836). iii: Pour bisc nc pour autrc &irc/Ne laist sen dotttc scnisc i f;lirc/I,c trcstnontaignr clcrc ct puw;/Iss maronicrs par son rclaire/Jctc souwnt hors dr contraire/Et de chrmin Its arsiwrc;/l:t quand la nuis est crop oscurc/S’cst ele encore de tcl naturcK’8 I’aimant hit Ir far trairc,/Si quc par forchc et par droiturc/Et par ruille qui tous jours durc/Smcnt Ir liu dr son rcpairc./Son rcpaire srvent Irautc/quant Ii tans n’a de clart6 gout~/‘I’out chil hwi lbnt WSIC maitriw./Qui une aguille dr Lr boutc/Si qu’clr pert presque toutc/En un poi de litigc ct I’atise/A la pirrrc d’aimant bise,/S’en tm wssel plain d’yauc cst: misc,/Si que nus hots dc la dehoutr/Si tost corn l’iauc s’aserisr;/Car dons qucl part la point vise/L tresmontaigne cst 1~1sans doutr. (Because the north wind dors not for othrr things/lcavc without doubt much still to do./‘l’hr north star clear and purc/l’hc mariners for its clarity, /Often s&c on it without opposition,/and of the course it assures thcm./And whm the night is too obscure,/Still in such conditions,/‘l‘hr magnurt can attract iron,/lf that lbr strength and for uprightncss,/And for the things that cndttrc cvcry day,/‘l’hcy know the finding or its position./They know its position for their route,/\Vhcn tltr wathcr is complctcly witltout light,/NI those who employ this contrivancr;/\Vhorvcr thrusts a nrrdlc of iron,/So that it remains almost compltwly outside,/In a bit of cork, and rubs it/On the brown lodrstonr:/lf it lx put in a vrsscl full of watcr,/So that nobody push it out,/As soot, as thr wncr brcomcs quict,/‘l’o whatrvcr sidr thr point tums,/‘I’herc is certainly thr pole star.)‘l’hcrc is an incomplctc translation in Thomas jpght, Alqmdt-r:AMam De .Ahfwi~ Rtyt~ libm Duo (London, 1863). xxxvii. Pauhn Pans. Btdietin du Biblio@-, (Srptrmhcr, 1836). 47 Wright, xxxvii, considers it by ‘an anonymous port, who swms to IX contrmporary with Guiot * Provins.’ \\‘illiam Gilbwt. Lk ~\f~~efe (London. Pants Short, IO: translawd New York rrprintrd 19.58) 7. Ii

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his statement. Second, as we shall see below, the compass was popular in Italy long before Polo returned from the East to Venice (1295).4g With these false assertions examined and rejected, it is possible to look at more definitive evidence for the earliest mentions of the compass. Late clevcnth- and early twelfth-century sources that discuss magnets and lodestones in considerable detail, such as the lapidaries of Bishop of Rennes Marbode (1035-l 122)50 and German abbess, mystic and naturalist Hildegard of Bingen (1098-l 179),5’ do not mention the magnetic compass. Marbode’s Liber de Gemmarum, which was composed sometime between 10671 10 1, dcscribcs both the ‘adamant’ and the ‘magnet’. The ‘adamant’, which can bc used to counteract the magnet, is said to be incredibly hard, but it can be cracked by being steeped in goat’s blood. 52 It makes its bearer invincible, can bc used in magic, prevents nightmares, heals quarrels, cures the insane and repels encmics. The ‘magnet’ has two important propcrtics; a wife’s chastity can be tested by applying it to her head as she sleeps (if she is unfaithful, she will fall out of bed), and it can bc used to help thieves steal property from houses (by placing it on hot coals, all the occupants can bc driven out).53 Many of these beliefs are derived from the Hzhria Jvaturalis of the Roman naturalist Pliny (23-79 A.D.):” and arc repeated by Latin grammarian Caius Julius Solinus (2nd-3rd century

Joseph Ncedham, vol. 4,245, says further that Polo’s ow accounts do not mention the compass. II is widely believed that they do, but this is based on a mistranslation of the word ‘conpass’. Charles Raymond Bcazley, 77~ ~~zc~tr(!f modem geogm/@ (NW York, 1949), vol. 3, 150, paraphrases Polo as saying: As to the rest of the Indian Islrs, although they reached the rormidable total of 12,700, according to the writings and compass-reckoning of experienced scamrn who navigated that sea, they wcrc mostly suhjrct and altogcthcr inferior to those already described. Hemy Yule ar.d Henry Cordicr, 77~ book q[Ser Aforro A/o (London, Murray, 1903 1920, vol. 2, 424, translates the phrase “according IO the charts and documrnts of cxperienccd mariners who navigate that Indian sea”, which is a more plausible interprrtation of the original: sclonc qe moister le conpas ct la scriture dr sajcs mariner qc uzrnt cn ccl mcr de Yndie. (Bcazlcy, vol. 3, 150). Ruggcro M. Ruggieri’s modern critical edition, Afnrro PO/O:I/ Aliliotw (Fircnec, 1986), 282, has: sccondo chc dicono gli savi marinai rhr vanno per I’lndia e serondo rhc si truova iscritto. A similar problem of translation accounts for thr intcrcsting phrase ‘they fctchcd a compass’ in book 3 of Polo’s work (Yule and Cordicr, ;;A. 2, 2.58; Ruggieri, 246). AIarbodc, fiber & C~nm7~7mt InfGhwqae I4tfioson1m AmtL .J%~~IO~~S Af911eWbtcs (Cologne, 1539) rcprintcd in J.P. Mignc, cd., I’a/rulog~nInlirm, vol. I7 [Ilcrcafier abbreviated as PL]. For biography, SW Sarton, IHS, vol. I 764 765, and Lynn ‘I’horndikc, A Itir/ov 0J nmqi> nnd ex/xrinten/n/ seiertce, (,v York, lY29). vol. 1, 778 780. Hildcgard ol’Bingcn, 1la.s IM WI dm &i~~n (Salzburg, I979), Chapter 18, ‘Das Magnetstein’, p. 66. For more on Hildrgard, see \\‘altcr Pagcl, ‘Hildcgard of Bingcn’, in: D.S.B., vol. 6, 396-398; @wn, IHS, vol. 2. 386 388; and ‘l’horndikc, vol. 2 (l923), :24 154. *. For mow on this unusual story, SW below under Isidorc, Ncckam and Map. i Marbodr, 1639 40, scrtion I, ‘De Adamante’, and 1655 1656, section 19, ‘De hlagnctc’. il Pliny, Hishia.n’n/rtra/is, Book 37, XV. 53-61; a parallel Latin/English edition is that of D&E. I:.ichhols, Hiyc .Mhral ltis/oy zoi/h an IGghh /ran.da/ion in /en uohe.s (London, 19G2). Book 36, I27 gives Pliny’s v&on ot”thr ~~1oun1 Ida Wlr ol‘ the origins ol’ thr magnet’s name. Also SW Kramer, I83 200.

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.4.D.),“” Church fathers Augustine (354-430)“” and Isidore of Seville (c.560-636),s7 and many other medieval writers. Hildegard’s lapidary appears to be more original than Marbode’s, but when the magnet is discussed, similar legends and flights of fancy arc reported. ‘The magnet’, she writes, ‘is hot and originates out of the frothy saliva of certain poisonous worms.j8 Although it gives much detail about the propertics of the lodestone, its application to the mariner’s compass is not mentioned. Another possible source to locate early records of the magnetic compass appears in the works of the mythical Christian king and priest Prcstcr John, who was

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For Solinus’ \irws on magwtism, we his Coktclanw Rwunr .\fttnora6i/~wn: translated by hrthurolding as 77~ e.xce//een/and /hunt uwrkv (London, 1587; reprinted and cditcd by George Ksh \($aincsAle, Florida, Scholars’ Facsimiles and Reprints, 19%). 1871). vol. II, Bk. 21. De Civirnk Det (77~ City ofGod), trans. bv .\larcus Dods, (Edinbur&, Ch. 4. In this work, Augustinehoes not just claim to bc repeating earl& sources; he goes further, and reports some magnnrtic experiments he has sren himself. A he pms it, ‘\Ve know that the lodestone picks up iron in a marvellous way. \\‘hm I first saw it I was utterly aghast. For I actually saw an iron ring drawn up by a stone and held suspmded; thrn, as if the SIOIW had communicatrd its own power to the iron lirst caught up, this ring was brought near to another ring and it hrld it up: a the lint rung chmg IO the second, so the second clung to the fink. In the same way u third ring was added, then a rourth. ‘;‘hus a chain, as it wcrc. had brrn formed oT rings, each one not linked with the rest, but rather clinging by thrir outer surlicc.’ (I‘hc original wads: Magnctem lapidem novimus mirabilcm fiirri rsw raptorrm. Quod cum primum lidi, vrhemrntct inhorrui. Quippc wrncbam a lapide r&cum anuhtm raptum atqur suspensum, deindr tanquam fcrro quod rapuerat vim dedissct warn commtmrmqtte liccissct, idrm ~IUI~US dtrri admotus cst cundemque suspcndit, atquc ut ilk prior lapidi, sic alter anulus priori anulo coharr&at; acccssit rodcm mod0 1mius, accessit cl quartus. lamquc sibi per mutua circulis nesis non implicatowm intrinsccus, scd cxtrinsccus adhaercntium quasi catcna prpcndrrat anulorum.) Though this may well haw occurred as Augustinr desctibcd, in actual Tart, the obsmation is not nrw. h simiku stoty ran be found in the I)e Rmrnr .Ah/~m of thr Roman pnct Titus Lucrrtius Carus (circa 9.5 55 B.C.). SW Lucrctius, II& Kerw~ .h’nbr, \al. VI., trans. by ‘l’homas Busby. (Inndnn, 181 S), 1~. 1045 -IO59. ii Isidtrrc of Scvillc, @rrrrolo+wnr Siw Or&nwn libri .YS; in: /‘I, \ol. 8 I 84. ‘l‘his cnormnus work was probably compnscd bctwc~~~G!!! 633; his thoughts on thr UIU.~M arc in Book 16, chaptws 253 4 (fX, vol. 82, .564), and his beliefs about the ndamnn/ arc in book 16. chapter 276 (IX, vol. hcrc and also folk~ws Solinus and Pliny quite closely. 82, 577 578). lsidore cites Augustinr Concerning the blood of the gnat. for rsamplc, hr says in book 16, chaptrr 276 (PI,, vol. 82, 577): ‘BUI while [the udamant) dclics both iron and fire, it citn bc brokrn up bv bring stccprd in firrsh and warm gnat’s blood, and in this way many bfnws will shattrr it.’ (‘ll~s is almost idrntical to Auystinr. The original wads: Sed dum sit invictus l&i. igniquc contcmpttw. hircino rumpitur sz;nguinc rcccnti CI calido muccr;ltus, sicquc muhis ictibua l&i pcrliiingitur.) Hildcgard of Bingcn, Mysira: /.i/wr II; f)P hpidih, c‘ap. ‘Dr ~lag~wtr’, in 1X. vol. 197, I262 The original wads: Magtws cididus cst VI dc spume qunrund;un wncnusorum vcrmittm nascitur. SW Ao Pctcr Rirhr, Hildtgwd w, fhgm Ih flush I’ONdm Skintn (SaMurg. I979), Chi1ptcr 18, ‘Dus Xlagnctstcin’, p. 66 ‘lltr German edition tritnslatt*s this ns &IC IO SI~WS: Drr Magnrt ist warm tmd cntsteht uus drm Spcichcl giliigw ScMq~w.

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18.

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reputed to live in the early twelfth century. 5g Early legends (circa 1122) placed him in India; by 1145, however, the chronicle of Bishop Otto of Freising described him as a Nestorian Christian king who had attempted to reach Palestine to take part in the Crusades. The legends were amplified as time passed, and in a spurious letter of circa 1165 to Byzantine emperor Manuel I (1143-l 180), he outlined the marvels and riches of his empire, which by then supposedly stretched from India to the Babylonian desert. However, what is significant to us is his brief mention of the adamant stone. Prester’s fabulous kingdom includes a talc of a miraculous rnilltio which could apparently be operated indefinitely without water-power; as hc put it, ‘not long ago a citizen our Bibric had us make a mill-house without water [power], with a bakehouse, according to our majesty. In this way; namely four great and very high columns, of purest gold we made, of which inside them lcvcl surfaces wcrc arranged in a square, the distance between them more than 20 fCCt.‘e’ Prcster continues with more details of the mill’s construction, and then explains the mechanism underneath it: brlow the building arc IWO great mill-stones, cxcellcndy arranged for grinding, made of [and powered by] the adamant stone, which is a stone that cannot be destroyed by other stones or lirc or iron. Below the building under the columns is a great wheel from which Rows most yellow gold, lbrmcd and arranged just as it is in the mill-house.‘” A truly marvelous mill indeed! Although the rcfcrencc is quite brief, it seems that Prester John is describing a mill that can power itself indefinitely by the occult virtue of the adamant stone; in cffcct, an adamantinc pcrpctual motion machine, probably before that of

i’l

Klaprom, Mottclay, and AIitchell all overlook this rcfcrcnce. Par more on Prcstcr John, SW I~phraim Isaac, ‘Prcstcr John’, DNA., vol. IO. I I8 I 19, and Pranrisco Alvarez, ne Pres/erJokn ef Ih hdk A Trw relation oJlh~ lands (~//IF Presh-rJohw being a narrative oJthe Portuqe~e Embasg IO Ethiopia L $ikd

!I,

1520

tvrilleo

4P Alhrr

Iiran&

.4lvarr:.

771~ translalion

of Inrd

Slanlg

~Alderlg

(1881),

revtied and

zuidi additional

makrial kv Cl< I~eckinghatn and G. 1V.B. Hun/ing/iwd, vols. I 2 (Cambridge 1961). Prrstrr John, fA/er OJfre.s/er John; SW Thorndike, vol. 2, 243. Prcsrcr John, IA/er oJI+e~/er John; reprinted in Pricdrich %arnckc, ‘Dcr Pricstcr Johannes,

1

A bhondh:rrr~~eo der I’hiloh~~~srh- Hi~lorkchen Cla~ue der hk@ch S’khsi~chen C;Psell~chaJ der Vis~enxhaJen, 7 (I 87!)), ($27 1030; 8 (I RR3), I 186. Zarnckc collated and analyzed approximately one hundred Latin manuscripts in this work; wc quote liiom a ‘Fourth interpolation In]‘. ‘Ihc original (vol. 7, 918) reads: non longs a civitarr nostra Bibric fccimus ficri molcndinum sine aqua cum Turno, convcnicns nostrac maicsu~ti. Hoc modo. Quamor ncmpc columpnas magnas et praccclsas de auro purissimo licri liicimus, quac in quadam planicic in quadrum sum dispositac, distantcs inter se plus quam 5X pedcs. Zarnrkc, vol. 7, 918. ‘I’hc original wads: Infra domum sum duac magnac molac, optimc ad molendum dispositac, Factac de adamantc lapidc, qucm namquc lapidcm ncqur lapis nequc @is nrquc fcrrum po~cst confiingcrc. Subtus vcro domum infra columpnas cst magna rota cum Ioni Tuso de auro lulvissimo hrIIW ct disposila, vclud cst in aliis molendinis.

31

Peregrinus,63 a point to which we shall return later. There is, regrettably, no more; we see no mention of the magnetic needle or the lodestone in navigation here. Well-documented references to the mariner’s compass finally begin to appear in the last quarter of the twelfth century, and continue throughout the thirteenth century until well beyond the Epirlola of Peregrinus. Regrettably, however, most historians have made two significant errors in handling these sources. The first is their unwillingness to take account of the inherent uncertainties in dating the relevant texts, leading to unsubstantiated and misleading claims of absolute pri~rity.~~ The second is their habit of ignoring the contexts in which these references occur; even such thorough scholars as George Sartonti5 cite and tran_.;.!e only small fragments of the available materials, resulting in a tendency to minimize the considerable developments in magnetic sciences before 1269. Consequently, many secondary sources begin their history of magnetism in Europe with Pcregrinus, and are literally amazed at his scope, breadth, and originality.GG Yet it is clear that, had they been acquainted with the magnetic literature before 1269, Peregrinus’ work, though impressive, would by no means bc considered the only empirical magnetic research of this period. Of the almost 20 authenticated writers on the compass bcforc 1269, only three are sufficiently early to be considered as possible contenders for the ‘first mention’ of the magnetic compass in Europe. These arc Alexander Neckam (1157- 12 17), Guyot de Provins (6 I 184-12 10) and Jacq ues dc Vitry (circa I 165- 1240). The inability of previous scholars tu date their contributions more prcciscly has led to much confusion. G.J. Marcus has credited Ncckam definitively with the ‘earliest extant description of the magnetic compass’;c7 but Sarton is more cautious (indeed, somewhat contradictory!), saying that Ncckam’s claim is ‘the carlicst European mention’68 and ‘probably the earliest of all’@’ in some places, but conceding that the ‘other mentions, by Guiot of Provins and James of Vitry (first half of the

,,Y

Zarnckc, vol. 7, 897, considers this text to Ix of ~hc thirtwnth ccnrury; ‘I’horndikc, vol. 2, 243, agrees wide this asscssmrnt. Howewr, it srems only lilir IO admit hcrc that thr datings of virtually all of PrcsterJohn’s trxts are hotly disputrd; For mow rcwm criticism, XT Edward Ullcndotf and C.F. Beckingham, 77/e Hebrew /e//en of hkrJu6n (Oxford, l9W). ‘I‘hrir analysis ol‘ Zarnckr’s $nrts appears on pages I3 15. SW, for cxamplc, Mcrril and SlcElhint~y, 3. ‘I’hc ciatcs of thr carlicst Europran rcfbcncrs {between II75 1225) arc highly uncertain, Ixwusc so littlc is known al>uut thrir authors. ,I Sarton, vol. 2. (i(, For another rxample, see A. Rupcrt Hall, and hIa& Boas Hall, A brips lri.r/oy CJJscience (Toronto, 1964). 83: “the wry short III/~-~ art C Afqw/ of Pierre dr Naricourt (1269) is worthy of memory, for he described for thr first time, and accurately, all 111~simple propcrtirs oTmagncts”. $s we shall sec. this claim ignores many of Pcrcgrintts’ fiorgollcn prcdrccssors. ’ GJ. Marcus, “l’lw marinrr’s compass: Its influrncc upon na\igation in thr kttcr middle ages’, Hi&g, ns. 41 (1956). 19. Ml Sarton, vol. 2, 385. H8 Sarton, vol. 2, 510.

32

thirteenth century) may bc as early (or almost) as Alexander’s’.‘O Klaproth says the first explicit citation is that of Guyot, followed by Jacques de Viny; Neckam is ignored. ‘I Mottelay’s chronologically arranged bibliographical history lists Guyot de Provins first (1190-1210), Jacques de Vitry second (1204-1220), and Neckam third (1207). ‘* Others, like George Kimble for example, simply refuse to give exact dates, saying only that ‘the earliest references to [the compass]...occur in the early twelfth century works of Alexander Neckam and Jacques de Vitry’.rs The evidence presented here will place priority in the following order: Alexander Neckam, Guyot de Provins, and then Jacques de Vitry. When carefully examined, the secondary sources most often credit the English monk and scholar Alexander Neckam (1157-l 2 17) with the first mention of the magnetic compass in European sources. 74 He was born in 1157 in St. Alban’s in Hcrtfordshire, was educated at the Benedictine Abbey of St. Albans, and probably taught in the schools of Dunstable before a trip to France about 11 75.75 Neckam studied and lectured in the Petit Point Paris between 1175 and approximately 1 183.7G Upon his return to Dunstable, he became master of the Dunstable school, and in 1185 he became the St. Alban’s school master. Around 1190 he gave lectures in theology at Oxford University, and also decided to enter monastic orders. He may have joined the abbey of St. Alban’s, although there is some evidence hc hccamc an Augustinian canon in the monastery at Cirencester after 1197. After being appointed to a papal commission in 1203, he was consulted on all the major business of the monastery. WC do know hc was elected abbot of Circnccstcr on 1 August, 1213; and we also know that he died in 12 17 at Kcmscy in Worccstcrshire, and was buried at Worcester.” Ncckam wrote many works on grammar, literature, theology, philosophy and natural science. Only two of them, however, discuss the magnetic compass; the

70

Sarton, vol. 2, 385. KlaDrorh. 40 44. Moitclay, 30 3 I. 7, Ccorgc Kimblc, Geogr~~~~it, /ice AliMe AgeA (NW York, 1968), 222. 7, See, for cxamplc, Brown, 127, and IMarcus, 19. 7% Urban ‘I‘. Holmes, Dni& liviq itr /ire hut-@/~ce~lrc~ (Madison, WI 1952), 16, ‘chooses’ the ~~proximatc date as 1178. Gcorgc Francis Wcdrrc. ‘A Chronolorrv of Alexander’s Life and \Vorks’. in: rl/e.~~tfder.,Vecl;nnl’s De .htz/urk &run~: rl S/ut$l t~eosetlw twiih Hepre.&a~ive Passages in Translation (Ph.& Thesis, University of Southern California, 1967). 45-46; also see the articles on Alexander Ncckam in IV. Wistanlcy, 77/e lim cfl’L nmsl fanm.t English pods (London, I 687), T. \Vright, Biographia Britannia litteraria (London, I846), C. Knight. nre IGgM I~nqclopedia (London, 1856); and John R. Strayer, ‘Ncckam, Alexander’, I$“l.A., vol. 9, 92. Wcdgc, 45-46. il

I?

33

early grammatical work De AhminibuslJttm.dium78(written during his stay in Paris, circa I 175-I 183) and the treatise on natural philosophy, DeJhtuti Rerum, (written between 1197-l 204). The De &minibus Ukwsilum refers to an early form of a pivoted compass needle. 79 Neckam says that in the supplies of a ship, there should be ‘a needle mounted on a pivot, which will oscillate until the point looks to the east, and the sailors will know how to direct their course when the northern constellation the Little Bear is obscured by the troubled [state of the] atmosphere; for it never disappears below the horizon, bccausc of its small circIc’.s” This passage has caused trouble for many scholars. To begin with, thcrc is the problem of the word orientem.Thomas \Vright, a nineteenth-century editor ofNeckam’s writings, dcspitc valiant but unsatisfactor; cohorts to solve the apparent paradox, incorrectly translated orientem as ‘north’ instead of ‘cast’.st C.N. Bromehead also read ‘north’ in 1940,“’ as did Joseph Nccdham, following his translation in 1962.s3 Urban T. Holmes grappled with the issue, suggesting that ‘it may have been the compass deviation was such as to make the nccdlc point east’.8’t Looking at British palacomagnctic data, WC find that this suspicion is in fact correct, but the value is too minute to be of much USC. The magnetic declination in the twelfth century fell (almost linearly) from a high of 21 dcgrccs cast in 1100 to 13 degrees cast in 1200, and was approximately 15 dcgrccs cast in 1175.s” We cannot conclude from this that Ncckam was awAre of the declination of the needle; this value is in fact fairly smail and difficult to observe, given the crude instruments of the pcric.l, and it is more likely he is just reporting what

ill

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(Oxford, Clarcndon PWSS, 1981). 32. AliIn) writers (including kl~ltd+', 31, imd SiIrI(III. VOI. 2. 385) add IO hr confusion by shorwning this IiItr PO Ilr 1 ~~NMJw. ~lcrrill and .\l&ll~inn~. 3. $wrcctty datr this as 1190. ‘l’liis is fully sr\rlll)YCiIN

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I. I 14.‘l‘tworiginal passageis: circum\r~tvrIur drhmt \;roptcr II b/944), 111

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34

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he has heard or read elsewhere. Moreover, as we shall see, the other early writers do not mention it, nor does his second refcrence.86 There is also the minor issue of Wright’s incorrectly translating cynosura as ‘Pole Star’;*’ this translation has also been adopted by Mottelay.** The word actually means ‘the northern constellation Ursa Minor’, or the ‘Little Bear’, which contains the pole star in its tail. This is significant because the former reading implies a much more precise mcasuremcnt of the celestial sphcrc than the latter. The ‘small circle’ of diurnal stellar motion requires just a few degrees of arc for the pole star rather than 40 degrees for the Little Bear, and, given relatively primitive instruments, claiming the latter for mariners at sea in a constantly moving boat seems much more reasonable.*” Finally, it is worth noting the rcfercncc to the ‘pivot’ in the passage; clearly Ncckam is referring to a ‘dry’ compass, whet-c a nccdlc is balanced upon a point, rather than a ‘wet’ compass, whet-c the needle floated on water (as wc xc both in early Chincsc records, and in subscqucnt European accounts). This is important because many scholars have so far wrongly assumed that ‘the first form of compass was a lodestone resting on a wooden float in a bowl of watcr’;sO that is, they have bclicvcd that in Europe the ‘wet’ model preceded the dry. As we can see, Ncckam’s cvidcncc strongly argues this is not the case; the second rcfcrcncc, unfortunately, does not tell us what type of compass is being used, which prevents us concluding the convcrsc as well. It is more rcasonablc to suppose both models of magnetic compass appeared around the same time. Ncckam’s srcond (and more commonly quoted) rcfcrcncc to the magnetic compass occurs in his important work on natural philosophy, De .k~uris Rerum (written bctwccn I 197 and 1204); hcrc, hc dcvotcs scvcral short chapters to magnetism and the lodcstonc.!” Hc begins by giving a rather involved theory of attraction and repulsion, intcndcd to explain why the lodcstonc appears to behave in its strange manner. This passage is both thcorctically bold and very dctailcd:

Brrr m;lgu&rd

Hall (privarr urrdlrs

1991) has sprrulatrd hat early ‘dry’ compasscs wcrc communir;lrit,n, or lodrstonrs mom~wd on llat woodcu disks. ‘I’l~csc disks would contain

ri~s~-\vcs~ ascs(ronsistrm wirh ;I ‘pious geography, foruscd ou Jcrusalrm’, for in mcdicval T-0 maps. I:.;IsIwason thr rap and .Jcrusalcm thr ccmcr of tlw known world), dnw a~~swering Nrcknm’s o~itn/rt~t rrliwurc~ and solving thr x&us practical ;md tcclmical polhm of pivoting ;I nwdlr. ;\ simihr solution uwurs in China iIh>III I 1.50;SW Nrrdhn, vol. 4, pt. I, 2.57. pruminrur

Iii ,!,I

\\‘riglil,

sssviii. 31. Norton. .\i~~v~~~ J/W n/h (I:.diul~urgl~, 1978), star maps I 2. Him,. 2. hliluy ;IIIIIW~ ha\c tn;ldr thr saner assunqion: they iucludc H.T. Plcdgc, Srhrt I:WO (NW York. 1959). 33, and O.A.\\‘. Dilkc, “lh Culmhuion of Greek Cartography in

Mollrlay, ,111Arthur I’.

00

ciw

P~olrmy’. in: .J.K Hilrtlry, i\ud David \Yoodward, 771~ /ris/u!~ ?I rnrh,,r~/Jy (Chicago, I987), $rouc. IO, r~xrhrs IIW smnccourlusiou by ignoring Ncckem’s wl~tin~~alloglhcr! :\h;mdt~r Nrckam, I& .ib/sri.v Rerwn. ch. 88 !bt, in: ‘I’lm~~as Wright, cd., I78 18-t.

184.

35

the lodestone attracts on account of a similar part, and repels on account of a type of dissimilar part. And so appetitive power attracts by sympathetic similarity, and repels by antipathetic dissimilarity. Yet it should be observed that in addition, providing that attraction takes place, the attracting thing must be stronger in power than the thing being attracted. If their attracting power wcrc equal, no attraction would happen, because of equal opposition. Therefore, the lodestone draws iron, but not another lodestone, even though it has a greater similarity to it; since lodestone opposes lodestone, through equal and mutual opposition. And iron, since it is of a weaker power, yields [to lodestone].‘Y

Clearly Neckam is trying to account for the disturbing fact that the lodestone always attracts iron from any direction, but attracts other lodestones only in certain Gcntations.93 Yet it is clearly an early theory of magnetic force, well before Peregrinus. Neckam then uses his theory to explain the old legend of the free suspension of Mohammed’s iron statue in mid-air, without chains or supports: ‘there are in the walls of the temple many concealed adamantine stones, equal in size and strength, which through their equal strength in like properties support the iron which has been set up in the center. It cannot move towards the right side because of the power of the adamant on its left, attracting the iron towards it; nor can it fall down, because of the adamant in the cciling’.94 The reference to the compass appears just after these passages, and it is in this context that it must be viewed. One notes the simple and uncritical reporting

w

Alexander Neckam, De &~uris Rerum, ch. 93, in: Thomas \\‘right, cd., I82 3. The original passage is: Sic et magnes ex parre similitudinis trahit, cx partc quadam dissimilitudinis repellit. Sic et virtus appetitiva similitudine amica trahit; expulsiva, dissimilitudinr inimica repellit. Notandum est tamen, quod ad hoc ut fiat attractio, opportct rem agentem violcntiorcm cssc in attrahendo rc attrahenda. Nam si aequalis in attrahendo corum cssc potentia, arquali contradictionc mtlla tieret attractio. lnde est quod magnes trahit ferrum, et non alium magnetem, licct cum co majorem habeat similitudincm, quia magnes magneti mutua et acquali contradictione contradicit. Ferrum ;fro, cum sit debilioris virtutis, ipsi credit. That is, when its north pole attracts the south pole oT a second lodcstonc, or vice versa; ji the north poles of two lodestones are placed together, they will repel. Alexander Neckam, De Jlrahric Rerum. Ch. 93, in: Thomas \\‘right, cd., 183. The original reads: Sunt enim in paricntinis templi plums lapides adamantini, acquales in quantitatc et virtutc, reconditi, qui acquali vi proportionis frrum in mcdio collocatum sustinent. Non enim vcrgcrc potcst in dextram pattern propter vim adamantis in sinistra regione repositi, ferrum ad SC attrahentis. Ima petere non potcqt, propter adamantrm in superiori regionc constitutem.

36

of the Mohammed legend as fact (such a result is almost impossible to attain!);95 consequently, this story somewhat weakens the assumption that Neckam is reporting personal, first-hand information in these chapters. With this in mind, let us examine his second reference to the magnetic compass, which immediately follows: So sailors crossing the sea, when because of overcast skies they lose the sun’s light, or when the world is wrapped in the darkness of night, and they do not know what cardinal point the ship is headed toward, put a needle above the lodestone; and the needle revolves until, after its motion has stopped, its point faces due north. So should a prelate guide his subjects in the sea of life, so that his reason may set them facing that North of which it is written, From the North is all evil spread.“”

As one can easily see, the passage is somewhat garbled; the compass needle would, when free to move, poin: north of its own accord, and would not need a lodestone to guide it. This suggests Neckam is not reporting first-hand knowledge of the magnetic compass, but is rather repeating the confused accounts of others. The lodestone would be needed on a sea voyage to periodically re-magnetize a compass needle; but once mounted upon its pivot, the lodestone could then be put away. Also worth noting, in both of these passages, is the matter of fact way in which the mariner’s compass is described. This is clearly not a new phenomenon; it appears to be a common occurrence, and WC have only the paucity of surviving The story of Mohammed’s statue is probably derived from lsidore of Scviille’s E~n~~logiorum, vol. 16, 4). Similar talcs of ma.gnets holdin! up statues appear in Pliny (ffis[oria ~frrrah, Bk. 34, Ch. 14) and Ausonius, also known as Dcctmus Magnus (309-393 AD.) (1240&z, vv. 314-320). Neckam also recoutlts the common myths about adamants being broken by goat’s blood, their application in determining adultcry, and so on. See De .A+~lunlu,C Rer~tm, chapters 92-98. The goat’s blood tale appears in another treatise of this era, the De .A$+ Cutiulium (nle /r#Kng of of English ccclcsiastic, author and satirist Walter Map (circa 140-1209). This text, which was written between 182 192, uses almost the same words as Pliny in discussing the ‘adamant’. Map writes (dist. ch. 7): Quis hyrci sanguinibus adamantem subici compcrit? quis silicem conflauit in uitrum? Crrtc non nos; non comprehendit huiusmodi septuaginta curriculum annorum. Sed qui septingcntis aut octingcntis uacare potucrunt sapicncie, prospcritate rerum et persone fclices, abissum rimari phisis et in htccm profunds produccre ualucrunt. (‘\Vho was it that found out that the adamant would yield to the blood of hc-goat? \Vho melted flint into glass? Not we, assuredly. A course of’ seventy years leaves no room For such discoveries. On the other hand, men who could spend scvcn or eight hundred years in the acquisition of wisdom, and were blessed with health and riches, they could well plumb the abyss of’ nature and bring deep things to light.‘) For more on Map, SW Mary Jo Am, ‘Map, \Valtcr’, in &IU..%, vol. 8, 120; also Thomas Wright, cd., ‘l7~e @in porn~s co~~t~ott!rn//ril,rr/ed lo V?er Mopes (Lon+n, I841 rep: 1968). Ncsandcr Ncckam, IIe.A’nlttns Rerw, Ch. 93, m: Thomas \Vnght, cd., 863), 183. The original passage reads: Nautae ctiam marr Icgentes, cum bencficium claritatis solis in tcmporc nubile non scntiunt, aut ctiam cum caliginc nocturnarum tcnrbrarum mtmdus obvolvitur, et ignorant in quem mundi cardincm prom trndat, acum super magnctcm ponunt, quae circulariter rircumvolvitur usqur dum, ejus motu ccssantc, cuspis ipsius scptentrionalcm plagam rcspiciat. Sic et praclatus in hoc mari suos subditos dirigcrc dcbct, ut ratio cjus Aguilionc illi scsc obvial, dc quo sctiptutn cst, ‘Ab Aguilionc pdndctur omnc malum’. The verse being guotcd is from the Bible, Jeremiah 14. A porlion of this passage is also translated in Ncedham, vol. 4, pt. I, 246.

1,

I

courtiers)

I

I 1,

a

1

;

(I

I:

37

texts to blame for the fact that it appears so striking to us. Consequently, it would seem reasonable to date the introduction of the mariner’s compass into Europe at least a decade or two before the date of Neckam’s first reference (between 1175-l183), and assign a provisional date of about 1150 A.D. The discussions of the magnetic compass in the other two early claimants seem to support this interpretation. The next figure to mention the magnetic compass in European literature was the French poet and cleric, Guyot (or Guiot) de Provins (fi. 1184-l 210). Much of his life is shrouded in mystery. Some scholars have identified Guyot with the French poet Kyot, who inspired Wolfram von Eschenbath’s legend of Par$izl. Others have equated him with lyric poet and soldier Hugues de Ben& (circa 1150-l220).gi Legends aside, however, we do know that Hc Guyot was in Mainz (Mayence) in 1 184:8 and later on he was in Palestine. seems to have also been in the monasteries of Clairvaux and Cluny (where he was a cleric). In addition, he was a minstrel at the court of the Holy Roman Emperor Frederick I or Bcrbarossa (circa i 123 ! :%I&and had many other patrons (86 in all), including Richard the Lionheart (1157-l 199).“g Guyot is of interest to us primarily for a passage about the mariner’s compass in his La Bible, a satirical political poem of octosyllabic rhymed couplets that he wrote during his old age.‘O” 2691 lines long, the French poem was very popular because of its humorous criticism of medieval institutions, and went through many editions in the thirteenth century. It also inspired numerous other poems. The dating of La Bible is hotly cmtested among scholars. Thomas Wright assigns it a completion date 01 ‘alrout the year 1205’,101 and Mottclay dates it between 1190 and 1210;‘02 Lloyd Brown gives a date of 1190, probably from Mottelay.“‘” Needham, meanwhile, says ‘+ 1205’,‘OJ probably following Sarton;“‘” and A.

I-G,

MT. Le ,Moync des Essarts’s I& &ies liltiroiresde la fiance (Paris, 1800). vol. under the entry ‘Hugues de Bercy’, says he is ‘the lint one who has lcfi us a description of the compass, in the Poem entitled Bible Guy01(es1C premier qui nous ail laisskune desrnjhomde la boussole,dans la powe inhdi: Bible Guyol.); this claim is followed almost to the letter by F.X. de Fcllcr’s Bioqa/hie aniuersel/e (Paris, l85i), vol. i-8. The error, though detected by Mitchell, 12.5, has been rcpratcd even into the prcscnt. See Bcdini, D.M.A., vol. 3, 506. The confusion arose because Huguues also wrote a satirical poem of the same name lo Bible (about 1215 1220). which is fiiqurntly printed along with Guy&. For such an edition, we Eticnnc Barbazon, ‘la Bible au Seignor dc 8wr.r’ in: Fabhar et contesdts /m&s Francois (Paris, 1808), vol. 2, 394-420. ‘“’ John On; cd., Lcs Oemxes de Guyof de f+ooirts,pot/e ly$we e/ satiritpe (Alanchester, University of Manchester Publications, 1915), xiii. Sarton, (1931), vol. 2, 589, inadvcrtcntly transposes this !f 1148, which would make. Guyot oid.indccd by the time of In Bible! ,,“, John A. Gngsby, ‘Gmot de Prowts’, in D..Cl.A., vol. 6: 26. Grigsby, Ihid., vol. 6,26. There arc several rditions of thts work. SW, for cxampir, Barbaaon, $, 307-393; and OFT, Ibid. Wright, Alexander.hkchm De ~Wmis Rerum xxxv. ML! Motteiay, 30. 10’1 Brown, Lloyd, 77u S!oy of Maps (Boston, 1949), 127. III, Nccdham, 246. I,,; Sanon, vol. 2, 589, 591. ‘V

38

Chrichton Mitchell says ‘its date can be lixed as being later than 1204 and not later than 1209, most probably 1206. to6 Careful reading of the poem does support Mitchell’s argument, allowing a provisional dating for our purposes of 1205-i 206. The allusion to the compass in La &Ye is basically in the form of a critical comparison. It complains that the Pope is too indecisive and changeable, and suggests instead that he should remain constant and unmoving like the compass and the north star. Guyot says: ‘As to our father the Pope, I wish he resembled the star which remains unmoved. The mariners who might be there observe it well; by that star they come and go, and regulate their direction and route. They call it the ‘tresmontainne’. It is tixed and unmoveable; all the others move, change place and turn, but this star remains fixed. to7 This discussion of the north star leads Guyot to give us more information about mariners’ navigational techniques: They employ an art which cannot deceive; by the property of the lodestone, an ugly brown stone to which iron spontaneously joins itself, they pay attention to where it points. Afler they have applied the needle to it, and have laid the latter in a straw, and put it in the water, the straw makes it stay alloat. Then the point turns directly to that star, with such certainty that no one will ever doubt it, and it will never go wrong. When the sea is dark and hazy, so one cannot see either star nor moon, then they put a light by the needle, and have no fear of losing their way. The point turns towards the star, and the mariners are taught to follow the right day. !t is an art that -- _ cannot fail.t’tH

There are several things to note about this passage. To begin with, it is immediately apparent that Guyot is referring to a ‘wet’ compass, in which the needle is floated rather than pivoted, as in Neckam. As this reference, however, is only a few decades later than Neckam, it is clearly foolish to argue for any priority of design, either for the ‘wet’ or the ‘dry’ model; too much depends on the survival of easily lost texts. As noted above, it is much more reasonable to conclude that both are contemporaries. Secondly, the sailors (and Guyot) do not appear to be aware of the small circular Nxi

Mitchell, 125. Guyot de Provins, Ln Bible, lines 62 l-63 in Orr, Ibid., 29. The original text reads: De nostre peirc I’apostole volisse qu’il semblaist la stole qui ne SC muet. Molt bien la voient Ii marenier, qui s’i avoient; per selle estoille vont ct vienncnt et lor sens et lor voie tienent. II I’appellent la tresmontainne. Cclle est atachie et certaine; tout les autres SC muent, mais celle estoile ne se muet. A French edition with partial English translation appears in Needham, vol. 4, prt. I, 246-247; Klaproth, 40-43, has a complete French version; Wright’s edition of Neckam’s works, xxx&xxxvii, include complete French and English versions of Guyot; and Mottelay, 30, has a plate of an early CGtyot manuscript and a partial French edition. Guyot de Provins, Ibid., lines 632-652, in John Orr, 29-30. The original reads: Un art font qui mcntir ne peut par la vertu de la manatc; une piere laide et brunetc ou Ii fers volentiers se joint ont, si csgardent lor droit point; puea c’une agulle Fait touch% et en un festu Font fichie, en I’auguc la mcttent sens plus et Ii fcstuz la tient desus. Puis se torne la pointe toute contrc l’estoillc, si scn doutc quc ja por rien n’i faucerait ne mareniers ne douterait. Quant Ii nuis est tenebre et brune, c’on ne voit estoille ne lune, lor font a I’aguille alumer pub ne pueent il assarreir; contre I’cstoile va la pointe, por ce’sont Ii marenicr cointe de la droite voie tenir. C’est uns ars qui ne puet mcntir. 110

1,

39

motion of the north star; to them, the pole star is ‘fixed’. This gives further support to the interpretation of Ncckam’s ‘Cynosura’ above. Nor do they appear to be aware of any declination of the needle, making Ncckam’s earlier apparent allusion to it less credible. Finally, there is the apparent confusion of the word ‘tresmontainne’. This word is probably from the Latin transmontane, which means ‘over the mountains’. It simply refers to the high visual altitude of the North Star, implying the mariners arc observing in voyages near coastlines whcrc mountains are visible (Perhaps southern France or the northern Italian coast). The third early claimant for the first ‘mention’ of the mariner’s compass in Europe is the French preacher, historian and churchman Jacques de Vitry (circa 1 165- 1240). Littlr is known of his life as well; howcvcr, WC do know he was a student in Paris in 1187, and received an MA. there in 1193. Hc took orders in 1210, and upon becoming an Augustinian canon regular hc cntcrcd the monastery of St. Nicholas in Oignies. \Vhilc thcrc (121 I- 12 16) hc became attached to the lay religious group of Mary of Oignics, an early Bcguinc lcadcr. In 12 13 he was ordered to preach against the Albigcnsians, and in 12 14, he preached a new crusade to the Holy Land. In 1216 hc was elcctcd Bishop of Acre, and joined the Fifth Crusade army at Damictta horn 12 18m122 1. After watching the situation in the Holy Land dcgcncratc, hc returned to Europe in 1225, and became the cardinal bishop of Tusculum three years later. Hc died in 1240; by this time his charismatic preaching and voluminious writings had made him quite famous. WI Jacques de Vitry refers to the magnetic compass in his Hiroria Orietitalis seu Hierosobmituna, a history of the Holy Land to about 12 18, based largely upon the Latin prclatc William of Tyrc (circa 1130- 1185). Jacques composed much of his work while in the East, during the period 1218-1225, but portions of it may be carlier (but clearly not so early as Neckam, as Sarton hints). The passage dealing with the compass, for instance, appears to date to 1204.’ I” This is probably the cause of the misunderstandings over priority; Jacques’ 1204 early description of the compass was put aside for many years, until the rest of the trcatisc was complctcd and finally published around 1225. By that time, Guyot’s work (1205-1206) had already been long written. With this in mind, the confusion of Sarton (and others) over all thcsc dates is undcrstandablc.’ I’ Jacques dc Vitry’s discussion of the lodcstonc and compass occurs in his chapters on precious and unusual stones. It adds little to already available knowlcdgc of ,w

Phillip Funk, J&J/I LW 171~; f&n I& ll>r/s (I_++, 1909). SW also Klaproth, 43 4+ Xlottclay, 30 31; S.C. Fcrruolo, jarqucs dc Wry’. in D.M.A.. vol. 7. 37 38; Snrton, (1931), vol. 2, 67 I 672; and Monica Sandor, ‘Jacqurs dr Vitly and the Spirituality of thr Xlulirrcs Sanc~ac’, 1b.x &wf;c/b, 3 (I 988), 288 300. ,111 Mitchell, I2 6. III SarIon, vol. 2, 385, 671.

40

the mariner’s compass, but it does give us some interesting insights on some of the magnetic ‘legends’ of the time, and highlights twelfth-century confusion over the ‘adamant’. He writes: there arc, moreover, in eastern regions precious stones of admirable virtue and incredible rarity. ‘The adamant is found in farthest India, and is of a clear and reddish colour; its size does not exceed that OF the kernel of a hazelnut. It is so hard that it resists all other metals, but it can be broken down by the fresh and warm blood of a goat. Fire does not cause it IO grow warm; it attracts iron unto itself through some hidden power. After an iron needle touchpq the adamant it always turns towards the North Star, which, as though it were the axis of the firmament, is not moved, but the other bodies revolve around it.“’

Jacques de Vitry continues by referring obliquely to the mariner’s compass: Whrrcfmr it [thr adamant] is truly necessary for those navigating in the sea. When placed next to a magnet it does not allow the latter to attract iron. And if a magnet should attract iron, an appmaching adamant siezes the iron away, causing the magnet to surrender its prey. It is said, ‘lowever, that the adamant repels poison, rcsisrs evil arts, and repels the fantasies and dreams of thr night. Contact with the adamant is also highly beneficial for the insane.“3

He concludes by discussing ‘another’ stone of similar properties: ‘The magnet is likewise an Indian stone, rusty in colour, and attracts iron to such a degree that it can crcatc a chain out of rings. It is used by magicians in sleight of hand tricks. It is also useful against dropsy, and burns.“la What is one to make of all this? To begin with, Jacques de Vitry is clearly using the word ‘adamant’ in many difliircnt senses; in some places it seems to refer to lodestones, in others compass needles, and in others diamonds. It is clearly a garbled account, derived from many different sources. Most can easily be rccognizcd; the principal ones arc Pliny,“” AugustinellG and Isidore.“7 Both

“’ Jarqurs dr Viny, Hirhia Orhalis seu Hieroso~mitana, Ch. 91, in Jac. Bongats, Gesfa Dcipa fianrm, (I61 I), vol. I, 194. The original reads: Sunt practcrca in partibus orientis lapides prctiosi admirabilis virtutis CI inrrcdibilis inexpertis. Mamas in ultima India rcpcritur, lucidi coloris et fcrruginei; quantitatcm nuclei nucis avellanc non cxccdit, duritia sua omnibus mctallis resistit, hircino tamcn sanguine reccnti ct calido rompitur: igne non calescit, fcrrum occulta quadam natura ad sc trahit. hcus Lrrca postquam adamantcm contigcrit ad stellam septcmtrionalem que velut y,;is firmamrnti, aliis ;.ergcntibus, non movctur, scmpcr convcrtimr. Jacques dr Vitry, 194. For rxccrpts, see Klaproth, I4 (incomplete Latin text); Wright edition OF Ncckdm, xxxv (incomplctc Latin/English text); and Mottclay, 30-31 (incomplete English text). ‘I’hr original reads: Undc valdc ncccssarisu CSI naviganlibus in mari. Iuxta magnctcm positus non sinit cum raprrc fcrrum. Quod si magnles rerntm traxcrit, accedcntc adamantc fcrrum rapit, aul’rcndo praedam magneti. Dicitur autcm quod Fugat vcnena, artibus maleftcis resistit, noctis $tasmata cl somnia vana rcpcllit: Insanis autrm multum prodest contactus adamantis. Jacques dc Vitty, 195. The original reads: Magncs similitcr lapis cst Indicus, fcrrugcnei coloris, adco apprchcndens licrrum ut cathenam l’aciat annulorum: In magicis praestigiis utuntur y; magi. Valet contra Hydropisin CI contra ignis adultiones. Pliny, Book 37, xv. 55 61. II,, Augustine, vol. II, Bk. 21, CII. 4. II, lsidorc ol’ Seville, vol. 16, chapters 253 254, 276.

41

Augustine’ t8 and Isidoreiig include the ‘parlour game’ of using a magnet concealed under a table to move pieces of iron placed on a silver dish; these are probably the sources for Jacques’ ‘sleight of hand tricks’. As for the rcfcrencc to the compass, it is quite brief and sketchy; Jacques apparently had little interest in navigation, for he does not even tell us what type of compass is in use! He is, however, aware of the lodestone’s ability to magnetize needles, and, like Ncckam, has recognized that it can ‘interfere’ with the magnet’s attractive powers over pieces of iron. Looking at the works of Ncckam, Guyot and de Viny, we can conclude that by the beginning of the thirteenth century, the French, English and Italians wcrc well aware of the directive power of the magnet, and had begun to formulate some elaborate theories to explain it. Moreover, they had begun to apply it to navigation, and had designed primitive variants ofboth the ‘wet’ and ‘dry’ compass to aid them in that task. They were clearly quite experienced in using the compass, for they knew how to recharge ‘tired’ compass needles with lodestones, which were kept aboard ships for precisely this purpose. Knowledge of the magnetic compass quickly moved northwards to Scandinavia. Some historians, in fact, consider the compass to have been invented first by Norse explorers in the ninth or tenth centuries, and spread much later through the rest of Europe; these claims are based largely upon the apparent difficulty of ocean navigation without it. tzo Unfortunately, detailed searches of Norse sagas fail to reveal any allusion to the marLer’s compass. The sagas do, howcvcr, contain extended descriptions of deep-sea navigation, including ‘dead reckoning’, ‘latitude sailing’, the ‘sun shadow board’ (used to find latitudes from the sun’s azimuth), and releasing birds to find the direction of nearby land.‘*’

II”

Augustine, vol. 2, Bk. 21, Ch. 4. He says that Batharius (an African Count) ‘produced a magnet and held it under a silver plate on which hc placed a bit of iron; then as he moved his hand with the magnet undcmcath the plate, the iron upon the plate moved about accordingly. The intcrvcning silver was not alhcctcd at all’. (The original reads: protulrrit lapidcm et tenucrit sub argcnto fcrrumquc super argcntum posucrit. Heindr sicut subtcr movcbat manum qua lapidcm tencbat, ita hxrum dcsupcr movcbatur, atquc argcnto mcdio nihilquc paticntc concitatissimo cursu pi rccursu inha lapis ab hominc, supra &rum rapiebatur a lttpidc.) Isidorc closely follows Augustme’s dcscriptton of this event (/X, vol. 82, 564). ,218 Winter, 95-102. Winter’s conclusion that there is ‘a strong probability thaw it was the Vikings who introduced the pristine forms oT the compass’ @. lO2), depends upon very flimsy linguistic evidence; he too is forced IO concede Neckam’s priority (p. 97). See also Brown, 126-127, who flows Winter’s conclusions. Mitchell, 124; Samuel Eliot Morison, 77~ Ean$enn discowty oJ~ta&r, 7’lie nor/h uoynses AD. 500-1600 (New York, 1971), 34-35. Morison rcjccts the necessity of a compass, pointing out that the Polynesians navigated the much larger Pacific Ocean without it. It is also worth pointing out here that cvcn had the Norse cxplorcrs used the compass, the high wlucs of magnetic variation (also called declination) in northern regions would havc made navigation less reliable than traditional methods. See N.A. Miimcr, and C.A. Sylwan, ‘Drtailcd Palcomagnctic &cord for the last 6300 years from varvcd lake deposits in Northern Sweden’, in: Lowcs, 63-70, see G7.

’

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There are, however, two important later references to the mariner’s compass in Scandinavian records. The first is that of Norwegian priest and historian Frode Arius Polyhistor’s (circa 1067-l 148). Frode, called the Learned (or the Wise), was celebrated as the author of the Islenditgabdk,the first vernxular history of Iceland from its settlement to about 1120. He is also considered to have written much of the Islands Landncimabdk,a collection of family sagas. This work also contains Frode’s account of the discovery of Iceland by Floki Vilgerderson between 868-874, and it is here that an obliaue reference to the use of the lodestone in navigation is seen: l+&i Vilgcrdetson was the name of a great Viking. He set out from Roga-Land to seek the Snow-land. They lay in Smear-Sound. He made ready a great sacrifce, and hallowed three ravens, which wcrc to tell him his way; for in northern lands those who sailed the sea had not the lode-stone. They built a cairn where the sacrifice had been made, and called it Floki’s beacon or cairn.“’ As this passage presumably was written duriug Frode’s lifetime, it has been used to argue that the Norwegians knew of the compass well before the time of Neckaml;t2s however, it has been shown that this reference is a gloss of later date (about 1225).‘*’ That puts it immediately after de Vitry, but further supports the idea of the quick dissemination of this invention. Another early Scandinavian record of the compass is found in accounts of the life of Icelandic pact Snorri Sturluson (1178/l 179-1241). Sturluson was the author of a mythological and poetical handbook called the Prose Edda, and the Heihshhgla, a history of Norwegian kings. At age two, he was adopted and educated in law, poetry, history and saga telling under Iceland’s powerful chieftain Jon Loftsonn (died 1197); this led to his becoming ‘law speaker’ of the Icelandic Althing (judicial assembly) between 1215 and 1218 and between 1222 and 1231. Between 1218 and 1220 he travelled in Norway and Sweden, where he was lavishly honourcd for his work; upon his return he became the richest man in &land. Unfortunately, accumulating family and property disputes led to his flight

Pol yhistor

1700; I,

112 Frodc Arius Mands fmdnhtabcik (Copenhagen, chapter 2, section 7; English translation by Cudbrand Vi&sson and F. York Powell, Or&es Ishndicae (Oxford, 1905), vol. I, 17. The original reads: Ilbkc Vilgerdar son bet vikingr mikell: Hann biosk af Roga-landc at lcita Snaclanne. Peir laogo f Smior-sunde. Hann Tcck at blotc miklo, ok blotade hrafna ptia, pa es hanom skylldo leid visa [pvi at pti hofdo hafsiglingar-mcnn engir Icidar-stein Fpann tlma i Nordr-laondom.] Peir hlodo par varda es bloted h&de verct, ok kaollodo Floki-varda. Incompletely quoted in Mottclay, 28, and Mitchell, 124; this passage about the compass is omitted from the version of &matm Palsson and Paul Edwards, -ne 6ok ofsehments: Lhdnamabok (Winnipeg, 1972). Christopher Hansteen, ~f~gaaritl.liir~fu~jdenskabeme Qris~iana, vol. I, 2. See also Kamtz, L.F., fc~wct$r’sJou&lJ?ir Cketnie und fiysfimKR., vol. 15, 61, and Kalproth, 38-40. This was shown by Walter Vogel in I91 I; see Winter, 100. Regrettably, Mottclay, 28, and Mitchell, 124, date this passage to the Fourteenth century, and thus do not realize how quickly the compass travelled north.

43

to Norway in 1237; by 1240 he was accused of treason and defiance of Ring HBkon Hakonarson (1204-l 263) led to his assassination in 1241 .125 Sturluson did not actually discuss the compass in his works; instead, he received one as a gift. Historian Thormodr Torhason (1636- 17 19) noted in 17 11 that Sturluson’s poem on the death of Swedish Count Byerges (12 13) earned the reward of a box containing a mariner’s compass. lz6 The context suggests this is a pivoted ‘dry’ model; at that early date, compasses would have been quite rare in Scandinavia, making them suitable tokens for a job well done. Though unusual in northern Europe, the magnetic compass was by now (1225) quite common in southern Europe; Scottish translator, magician and astrologer Michael Scot (circa 1195?-circa 1235) refers to it several times in his works, but each time as an object well known. Very little is known of Scot’s life.12’ In 12 17 he was in Toledo, learning Arabic and Hebrew, and translating the works of the Greek philosopher Aristotle (384-322 B.C.) and the Islamic scientist Al-Bitruji [Alpetragius] (fl. circa 1190); during his life he also translated the books of Arabic doctor and philosopher Ibn Rushd [Averroes] (1126-l 198). He was in Bologna around 1220-1221; by 1224 he had become a priest, and later obtained English benefices from Pope Honorius III (died 1227) and Gregory IX (circa 1170-1241). Around 1225 i,;- became associated with the court of Holy Roman Emperor Frederick II (1194-l 250); as the Emperor’s astrologer, he apparently predicted the result of his military campaigns, the fate of various Italian towns, and even Frederick’s own death. Court po;t Henry of Avranches’ verses to Frederick record Scot’s recent death early in 1236; it is often claimed that he died at mass from the falling of a stone.12s Scot’s Feferences to the compass occur in a trilogy of writings addressed to the Liber Parhulatis, Frederick after July 1228, consisting of the Liber Introduc&otius, and the physionomia. One of Scot’s rcfercnces occurs in his general theory of medicine. ‘There are as many ailments as there are medicines’, Scot writes, ‘and these clearly consist of the three virtues of words, plants and stones, which we

I

Marlene Ciklamini. ‘Snorri Sturluson’. in I).Atl.. vol. I. 355 358. For more on Sturlusun, Sigurour Nordal, Snoti Sfurluson (Rckjavik, l$70). Thormodr Torfaeus, H&win Return .~%~vg~munt (Hafinia, J. Schmitgcnii, I7 4, 345. TorGacus concludes that by 1266 Scandinavia was well acquainted with the compass (Mottelay, 44-5, follows this), but it is clear they had it as early as the 1213 date. Mitchell, 126, says that ‘in 1266 the pact Sturla was rewarded for his poem with the compass; but as Sturla died in 1241, ;tis is hard to ‘bclicvc. For the little biographical information that is available, we Lorcnzo Minio-Palucllo, ‘Michael Scot’, in: D.S.B., vol. 9, 361.-365; Elaine Golden Robison, ‘Michael Scot’, in DXA., vol. 8, 305; Haskins, C.H. ‘Michael Scot and Frederick II’, Isis, 4 (1922), 250-27.i; and C.H. Haskins, Studies in the histoy of medieval science (New York, 1924; 272 298, also 1.. Thomdikc, Michael Scot (London, 1965). 12R Haskins, Studies 276, records this, but adds there is some cvidcnce (From dates on Scot’s manuscipts) for a much later death, in tbc 1250s or beyond. 9

’

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I I),vol.

can see every day in the offering of the sacrifice above the altar, in the magnet and plants.12g and iron [needle] used by deep-sea sailors, and in plasters, powders That the magnet is seen ‘eve& day’ as an example is evidence of its popularity, at least in southern Europe. Scot also discusses the compass in an appendix to the fiber Particular& Again, there is little in Scot’s very brief descriptions to suggest the compass is a scarce device. He says ‘through the lodestone with a needle it is known where the north star is, and the knowledge of the lord of years comes to us; out of the tables of Eater on, he broadens his account Toledo we know what the future is in things ’.I30 of the lodestone’s use in finding the north, by considering another stone which points to the south: ‘likewise is the stone whose virtue attracts iron to it which is the lodestone and it shows the place of the north star. And it is another stone of the lodestone type which repels iron from itself and shows the place of the southern star’.131 Finally, hc notes the ability of the magnet to ensure marital harmony: ‘the lodestone’, he claims, ‘reconciles wives to their husbands’.t3* To Scot, the lodestone was useful in many applications, and frequently employed in them; it was not rare or difficult to find. Its frcqucnt USCled scholars to consider the invisible ‘virtue’ of the magnet in ever more diverse fields. Historians, theologians and encyclopaedists continued to refine their concepts of magnetism, sometimes discussing the compass and lodestone in unexpected areas. One of these was Paris philosopher and theologian Guillamc d’Auvergnc [also called William of Auvergne or William of Paris] (circa I 180-1249), who used the lodestone to explain the motion of the planets. Born at Aurillac, Wi!liam bccamc a professor at Paris around 1225, and the bishop of Paris from 1228 until his death in 1249. His chief work, Magisterium Dhiuale, attcmptcd to reconcile the writings of Aristotle and Islamic scientists Ibn Sina [Avicenna] (980-1037) and Avcrroes with orthodox Christianity; it was written between 1223- 1240. William referred to magnetism in his De Universo Creaturarem, which was com-

IP’I

Paraphrased in Thorndikc,

vol. 2,324 (folio 173r). The original reads: Nam tot sunt medicine

quot sunt infirmitatcs ct hae constant in trihus videlicet in vcrhis, hcrhis, et lapidihus, virtutes quorum quotidic videmus ut in hostia sacrata super altare, in ma@& et fcrro navi@ntes in alto mari, y;,,in emplastris, pulvcrihus, et conscrtis. Quoted by Haskins, Studies 270. and Haskins, ‘Michael Scot’ 294-295. The orifiinal reads: Per calatktm s&n ubi est tramonta cum acu, et cognito domino anni adequatione-tabularum $; Tolleto scimus qttod futurum est in rebus. (MS. Canon. Misc. 555, f. 48~). Quoted by Haskins, Studies 270-27 I, and Haskms, ‘Mtchael Scot’ 295. The original reads: km cst lapis quia sua virtute trahit ferrum ad SC ut calamita et ostendit locum tramontane septcntrionalis. Et est alius lapis 9encris calamite qui depellit ferrum a se et demonstrat partem t;~montanc austri. (MS..Canon. Misc. 555, f. 50). Quoted by Haskms, Studtes 271, and Haskins, ‘Michael Scot’, 295. The original reads: Calamita reconciliat uxorem ad mat-hum. (MS. Canon. Misc. 555, f. 50~).

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posed between 123 1- 1236. 133 In this work, he first discusses the power of the magnet to exert its force through successive needles, claiming he has actually tried this experiment with successful results: On that which concerns natural properties, you will fnd fir example the contact of iron and the lodestone. When a piece OF iron touches the lodestone, or the magnet, it attracts a new piece of iron; this one, in turn, attracts another, and perhaps this continues without end. If then a needle touches a similar stone, it gets from this contact the power of attracting another needle and, so to speak, to stick to the same; then the second needle acts the same way on a third, the third on a fourth, and the fourth on a fifih. One cantrot try this cxpcricnce, at least to my knowledge, of the action evermore to its end, if it is stopped at a certain number of needles. Of these successive needles, you will see the first fixed, suspended from the stone it touches, the second adhering to the first in a similar way, then the third, then the fourth, and then the othcn; the virtue through which the lodestone adheres the first needle transmits itself through all the others.‘“’

Having established ‘magnetic induction’, he then tries to explain the apparent ‘induction’ of the heavenly spheres that carry the stars, sun, moon and planets: Then what is so astonishing if the itself to the second, then the second which is the sphere of the moon? them, another connection between

virtue of life or of the soul of the first celestial sphere transmits to the third, and so forth until it reaches the last moving sphcrc, That cannot itself’ produce the same if there is not, between closeness and contact, as happens in the proposed example’“’

This passage is important for several reasons. In the first place, it is clear from this passage that some scholars, at least, wcrc conducting detailed experiments with the lodestone well before Peregrinus. Secondly, this reference demonstrates that scholars had also been toying with the ‘perpetual’ and ‘endless’ nature of magnetic force long before 1269. Finally, it demonstrates that the lodestone had become much mote than just an oddity used by sailors; by the early thirteenth century, it had become a metaphor to explain all types of invisible forces, powers and virtues, both in heaven and earth. About the same time, Flemish cncyclopacdist and hagiographer Thomas of Cantimpre [also called Brabantinus, or van Bellinghcn] (circa 120 1- 127011272) I 13 Lynn White, Medieval Technology, 132. William of Auvcrgne, De Uniuerro Crealurorem, Primac Partis, Pars III, cap. 29, in Opera Omnin (Paris, 1674), vol. I, 802. The original reads: In naturis autcm unum cxcmplum cst tactus ferri, & adamantis vel ctiam magnetis, qui cst longc minoris virtutis, quam adamas in partc ista. Cum enim ferrum testigit adamantem, vel etiam magnctam, attrahet aliud fcrrum, 8; illud aliud, & forsitan non habet istud finem. Unde & si arm testigit hujusmodi lapidem, rcripit ex ipso tactu hujusmodi virtutem attrahcndi, & quasi agglutinandi sibi scum aliam, 8-r secunda similiter htcict de alia, & tertia eodem mode operabitur in quartam, & quarta in quintam, ncc est cxpcricntia probatum adhuc apud me, an linem habcat hoc, an stet in al&o numcro acuum. Videbis enim acuutn primum sic ordinatantm pendere ex lapido isto quem tangit: deindc secundam scum adhacrerr uilli per tactum similem: & tcrtiam; & quartam; & ita de aliis. Quia igitur virtus adamantis, qua sibi farit $haercrc scum primam, transfunditur in omnes acus. William of Auvergne, vol. I, 802. Th c original reads: Quid mirum si virtus vivilira, vcl animalis ptimi coeli transhtnditur in sccundum, & a secundo in tcrtium, 8; ita doncc vcniatur ad ultimum coelorum mobilium, quod est coelum lunac, ctiam si non sit alia ligatura, vel ligatio inter eos, quam contiguitas, sivc contactus, quemadmodum apparet in exemplo proposito.

I‘4,

46

was collecting mat&al for his famous 20 volume Liber de Natura Rerum (circa 1228-1245).13” Thomas was probably born near Brussels, and after a Liege education he became a canon regular of St. Augustine at the Cantimpre monastery, near Cambrai, in 12 17. In 1232 he converted to the Dominicans at Louvain, who sent him to Cologne to study under Albertus Magnus (see below); he then (circa 1237) studied at the priory of St. Jacques in Paris. After 1240 he returned to teaching at Louvain as lector; in 1246 he became subprior. Later on in his life (circa 1256-l 261), he composed his second most important work, a popular guide to the monastic life entitled Ronum Universale de Api6us.13’ Thomas discusses the magnetic compass in book 14 of his Liber de Xztura Rerum, which deals with precious stones. t3s His main source appears to be Marbode, though Thomas makes liberal use of Aristotle, Pliny, Solinus, Isidore, Augustine and Jacques de Vitry (see above). There are two sections dealing with magnetism; the first is chapter 4, ‘De Adamante’,13g and the second is ‘De Magnete’ in chapter 45.t”O Chapter 4 begins by giving us the usual ‘magnetic legends’ about the adamant; its origin in India, its durability, its impenetrability by fire or iron, but its susceptibility to new and warm goat’s blood. However, Thomas continues by describing a new type of adamant, found in Arabia, Cyprus, and the iron mines of Phillipi. This type has weaker powers, and dots not need goat’s blood to break it; furthermore, it can attract iron away from the magnet. More importantly, however, it betrays the location of the star of the sea, which is called Maria [the North Star], from between obscure mists by day or by night. When sailors are not able to find their way to the port because of obscure mists, they take a needle, and, after rubbing its sharp point on the adamant stone, they fasten it tranversally to a little straw and they then place it into a vessel full of water. Then they carry the adamant stone around the vessel, and soon aficrwards the stone moves the needle point, which follows in a circle. While speedily being rotated likewise in a circle, the stone is suddenly drawn backwards, and soon afier that loss the needle is found to stand against the star of the sea,

I ,I,

For a recent edition of this work, see Thomas

ol‘ Cantimpre,

L&Y de Nafura

Reruns (Berlin,

1973). I’,,

Par more on Thomas of Cantimprt, set Ago Vandcjagt, ‘Thomas of Cantimpre,’ D.M.A., vol. I!?, 34-35; also Daunou, PC. Pierre ed., H&ire /iGraire de la France (Paris, 1838), vol. 19, I77 184, also vol. 30, 365-384; Alexander Kaufmann, 7Ioams UORChanhnpi (Cologne, 1899); and Herman Stadler, ‘Albertus Magnus, Thomas von Cantimprc und Vincent von Beauvais,’ &slur y;t$ A’flur, vol. 4 (190(j), 86-90; Thorndike, vol. 2, 372-398; Sarmn, vol. 2, 592-594. Mottclay, 34, notes the existence of this work, but somehow manages to overlook the $crcncc to the compass altogether; Klaproth totally ignores him. Thomas of Cantimpre, vol. I, 357. ,111 Thomas of Cantimprc, vol. I, 365.

47

which it points to without even moving a littlc bit. Shortly afier this is done, sailors truly find their way to the port.“”

This is clearly a ‘wet’ compass of the Guyot type (see above); some scholars have mistakenly considered Thomas to refer to a Neckam ‘dry’ modeL1@ Thomas then goes back to Marbodc, and says the adamant is useful for magic arts. It can also accomplish a host of marvcllous things: it can make its bearer brave against his enemics, can help to rcpcl nightmares, fantasies and poisons, and curt the insane.14” With that, the chapter is cndcd, and Thomas goes on to treat other stones. Thomas’ chapter on the magnet stone (‘DC Magnctc’) is similarly full of the ‘magnetic talcs’ WCarc already familiar with. The magnet has miraculous powers; it can be used to tell if a woman is committing adultery, and it can bc used by thieves to break into homes. It concludes with the magnetic beliefs of Augustine and Isidorc.‘M A similar approach to the magnet was adopted by French Dominican scholar and encyclopacdist Vincent of Beauvais (circa 1 I 90- 1264), who borrows quite l&rally from Thomas in his works. Vincent was a student at the University of Paris, and was among the first to join the new Parisian Dominican house of St. Jacques (circa 1220). Ten years later, hc was transferred to the new priory at Beauvais; and about 1250 Vincent bccamc the lcctor and chaplain to the court of French king St. Louis IX (1214- 1270). I45 Hc wrote the De EruditioneFiliondm Abbiiium, a treatise on the cduc-ttion of the royal children, bctwccn 1246. 1249, and a book on the moral duties of rulers, De Moruli PrincipisInstitutione(circa

I,

III Thomas of’ Cantimprk, vol. 357. ‘I‘hc original reads: Stclhun rtiam m;uis, quc Maria dicitur, hat artc inter obscuras nrbulas prr dirm vcl nuctcm prodit: niuttc rnim cum intrr obsruras nrbulas vias suas dir&c non talent ad portam, accipiunt acum ct acuminr eius ad adamantrm lapidcm fricato infigttnt per transvcrsum in rcstura pama inmittuntqur vasi plrno a!tta. I’unr circumducunt vasi adamantem lapidcm, moxque srcundutn motus lapidis scguitur tn rircuitu cacumcn acus. Rotatum ergo pcrinde citius per rircuitum lapidcm subito rctrahunt, mosque cacumen acus amisso durtorc acirm ditifit contra stcllam matis subsistitqur statim nrr per punrtum ;;)vctur. Ntnttc vcro sccundum dcmo&trationrm tkam vias ad port~m dirigunt. Sarton, vol. 2, 593, has it right. but Mitchrll, 126, says this is ‘a compass rcsrmbling IIXII of Ncckam’. Ncckam’s only spccilic rcfercncr to thr type of romp;tss b&g imploycd is thr ‘dry’ model (xc above). I,( Thomas of Cantimpre, vol. I, 357. I,, Thomas of Cantimprc, vol. I, 365. rkcording IO the anonymous work Gqr~@~ P/ /!,&gm/~/~inr Kri,m~n& (Bnnnni;ttb, Virtorij Bcwdtij, 1661; rcprintcd Venctiis, Ioannis IANOU, l672), vol. IO, chqtcr 18, it \vRS during this king’s reign (I 226 1270) that the use of the magnrtic compass brcnmc widrsprcad among I:rt*nrh mariners. The author claims they used thr ‘WI compass, ii nrrdlr llnating in a vxc o!’ w+tcr, which they supported with two small tubes IO keep it from sinking to the bottom. This work was attributed to Italian Jrsuit astronomer Giovanni Baptista Rircioli (I598 1671) by thr k’rcnch astronomer Joseph Lalattdc (I 732 1807). Klaproth, 54, and Mottclay, 54 55, both ttssutnr Riccioli is the author. For more on Riccioli, SW I&i Campcdelli, ‘Rircioli, Ciambattistia’, in: D.&B., vol. II, 411 412.

I,i

48

1260-1263). However, he is best known for his vast encyclopaedia of human knowledge, the Speculum Majw, which he wrote between 1220-1244, with final revisions around 1260. i4G Upon its completion, the S’eculum Ma@ was the greatest encyclopaedia then available, and it remained popular until the eighteenth century; in 80 books, it consisted of 9885 chapters (about 3 million words). 14’ It is divided into three parts, the Natwale, Historiale and Doctinale. It is in the 32-book Speculum A&ale that Vincent’s thoughts on the magnet are to be found, specifically in book 8, chapters 19-21 (the magnet), and 39-41 (the adamant).ta Vincent began his account of the magnet (chapter 19) by describing five types of magnet stone: the Sicilian, Ethiopian, Theban (Boetian), Trojan (Alexandrian) and Magnesian (Asian). He then excerpted (from Isidore) a description of the Indian magnet, describing its color, appearance and properties. Then Vincent quoted a passage from the pseudo-Aristotelian Liber de Lapidibus:‘4g Aristotle in his book of stones says the magnet stone attracts iron, and that iron is obedient to this stone through occult virtues; that is it moves itself without help through all solid bodies, just as through the air. Indeed one of its corners attracts iron, and the other comer repels it. Furthermore, thr comer whose virtue attracts the iron, it is attracted to Zaron, that is the north; the opposite corner attracts to Aphron, that is the south. And so this peculiarity the magnet has, that if bring iron to the corner of the magnet which is called Zaron, which looks to the north, the iron will turn to the north. And truly if you bring the iron to the opposite corner, that is Aphron, the iron will move itsehto the south. And iFa piece ofiron comes close to another drawn by the magnet, the adamant stone acts, and naturally overcomes the magnet.‘“”

you

I IC For more on Vincent de Bcauvais, see Daunou, vol. 18, 449-459; Gregory G. Gueman, ‘Vincent of Beauvais’, in: D.M.A., vol. 12,453m455, and WJ. Aerts, RR. Smits, and J.B. Voorbij, Knre ofupnuvais and Alexander /he C&eat: Studies iu the Specuh Maius and its lranshlion iufo medieval vernaculars (!886). See also the I&en/ vJBt+auvais .Ahs~ef/er (!976-). Vincent of Bcauvais, Spect&r Q~adrup1e.x Stve Specuh Maius (Douai, Baltazaris Belleri, 1624; mpr. Cm%, 1964). Marcus, 19, possibly Ibllowing Mottelay, 33, incorrectly dates this reference at circa 1250; \\,is probably anywhere Fmm IO IO 38 years carlicr. This work has an interesting htstoty. It IS supposed to be an Aristotelian book of stones translated bv Gerard (which is now lost); a portion of it was also translated from the Arabic by $$mstatttine’ol. Ahica ‘(circa 1015 1087j. Vincent of Beauvais, vol. 8, ch. 19, 502 -503. The original passage reads: Aristo. in lib. de lapidibus. lapis magncs Rrru trahit, et l&rum obcdiens est huic IaRidi p” virtutem occulta, quae in est illi, ipsu movct ad se per omnia corpora solida, sicut per aera, et uno quidem ipsius angulo trahit Ferrum, cx opposito aut angulo litgat ipsum. Angulus quidcm cius cui virtus cst attrahcndi fcrrum, cst ad Zarott, id est scptenttioncm. Angulus autem oppositus ad /Con, id est meridiem. Itaqttc proprietatcm habct magnes, quod si appmximes ei fcrrum ad angulum ipsius, qui Zaron, id est scptcntrionem rcspicit, ad scptcntrionem se convertit. Si vero ad angulum oppositum l’errum admovcris, ad Aron id cst meridiem se movcbit. Quod si huic Ferro ferrum aliud approximaris ipsum de magnete ad se trahit, hoc ct lapis Adamas facis, naturamquc condemnat magnetis. Klaproth, 13, 49 -50 gives an incomplete Latin text; Mottelay, 33-34 gives no text at all, but does (thankhtlly) include a plate oT chapters 19-21 From a 1473 edition.

’

49

As WC shatl WC t!iiz p$, j,; : I ‘:i ; ; ,-.r-,rclo,Aristr~!il. Y,iI! come up again (see below) in the work of’Albertus Xfagnus. What is intcrcsting for us is the choice of the words ‘Zaron’ and ‘Aphron’ for north and south, respectively. Klaproth says these words indicate an Arabic origin,‘S’ but in fact they suggest the translation was made from Hebrew, rather than direct from the Arabic.‘“2 Consequently, it is dangerous to use this passage to conclude Arab priority over Europe in the invention of the compass. There is another point worth noting about this passage. Although Vincent does concede the magnet’s properties as ‘peculiar’, he says nothing about them being ‘new’. Mitchell, for example, says that Vincent ‘refers to the polar and directive properties as if they wcrc novelties’;‘“” however, this is clearly erroneous. Leaving aside the fact that the test of Vincent’s text (see below) rcvcals his reading of the prior work of Thomas of Cantimpre, who gave exactly the same magnetic laws, it is evident just from his citation that Vincent believed this knowledge to bc of ancient Greek origin. Vincent’s next chapter (20) is devoted to Augustine’s reports of ‘magic tricks’ with magnets, specifically his talc of suspending a chain of iron rings from a magnet, which hc described at some length. Hc also included the ‘sleight-of-hand’ demonstration of using a magnet under a silver tray to move picccs of iron around ‘invisibly’.l~~ In chapter 21, Vincent added something unusual; the use of the magnet in medicine. None of this ma&al is new, for Vincent borrowed it from the Greek, Roman and Arabic physicians Dioscoridcs (circa 40-90 A.D.), Constantine the African (circa 1015-1087), Galcn (129-circa 199 A.D.), Avicenna, and many others. The general conccnsus of opinion is that the magnet is very beneficial in medicine; it can heal the sick, curt dropsy, and is particularly useful in diseases of the eye.‘“” From chapters 22-38 Vincent discussed other marvcllous stones, including asbestos, pyrites, amethysts, and many other gemstones; hc returns to our topic in chapters 39-4 1,whcrc he discusses the ‘adamant’ as opposed to the ‘magnet’. However, as there was much confusion over the precise meanings of thcsc words, much of the material already printed under the ‘magnet’ reappears under the adamas. tSG In chapter 39, Vincent summarized the opinions held by Isidore, Aristotle, Pliny

Ii, Klaproth, 49-54. 1% \Vyckof& Dorothy, note :,VyckolT (.Oxford, 19671, 148. Mltchcll, 126; his source ,i( Vincent of Bcauvais, vol. ,Ti Vincent of Bcauvais, vol. 1% Vincent of Bcauvais, vol.

50

10 in Albw~us XIagnus, IJ’oo~$ rtGmtd~. translated is Klaproth, 53 4. 8, ch. 20, 503. 8, ch. 21, 503 504. 8, ch. 22 -41, 504 515.

by Dorothy

(XC alove) and German encyclopaedist Arnold of Saxony (fl. 1225).‘j7 Isidore is recalled for his versions of the ‘goat’s blood’ tale, the origin of the words ‘adamas’ in the Greek ‘unconquerable force’, and its use in resisting poisons, dreams, and various evils. The material cited from Aristotle described the attraction between adamant stones and magnets for various pieces of iron; it is similar to the excerpts (described above) in chapter 19.:5R Concerning Pliny, he recalled that shattered adamant fragments are highly prized by jcwellers to make cutting and boring tools, and that the adamant repels magnets and snatches iron from magnets attracting it. His excerpts from Arnold described the adamant’s appearance, and explained its use against enemies, nightmares, fanta&s, poisons and insanity.r5s Chapter 40 gave Pliny’s beliefs about the adamant in more detail (see above); hc recognized and described six varieties in all (the In&au, Arabian, Greek ‘millet seed’, Maccdonian, Cyprian and ‘iron stone’). The first four types are very hard and durable, Vincent rcpcated, but the last two can be broken by hammers and other adamants. Hc continued by summarizing Thomas of Cantimpre’s views on the adamant, mentioning the mariner’s ‘trick’ of walking a lodestone around a magnetic ncedlc floating in a vessel ofwater, to make it rotate; then the lodestone would bc removed, and the needle would point north. Vincent’s words are almost an exact copy of Thomas’ reference to the compass (see above).‘“” Vincent concluded (chapter 41) with Solinus’ thoughts on the magnet (see above); these consist of his four types of adamant (they arc found in crystals, gold, veins of copper, and iron mines), the story of breaking the adamant by steeping it in warm, fresh goat’s blood, its USCin magic, and the various countries it comes from.‘“’ With that, Vincent closed his account of the ‘adamant’, and went on to treat other stones. Up to the period 1250, most sources for information on the magnetic compass arc scholastic in nature: cncyclopacdias, and scientific, historical or technical works (cxccpting Guyot, of course). This indicates the compass is still of fairly restricted USC;it is well known to scholars and mariners, but its influence among other classes of medieval society is less prominent. Howcvcr, by the middle of the thirteenth century, poetical references to the compass begin to multiply; they begin in France

li,

Almost nothing is known about this figure except his name, and the fact hc was a member of the minor clqy. His book, I)e finihs h’erm .&/rtroliun~ (7hpttr@es ofnnlrtral things) was composed brtwcen l220- 1230 and contains a lapidary of 8 I stones which is csscntially a summary of k4arbode translated (SW Dorothy WyckoK, ‘Appendix B-l,apidarics’, in Nbcrtus Magnus, Book of lriu,Dorothy WyckoF (Oxford, l967), 268). See also Sarton, vol. 2, 592. Vincent of Bcauvais, vol. 8, ch. 39, 513-514. Vincent oT Bcauvais, vol. 8, ch. 39, 513-514. Vincent of Bcauvais, vol. 8, ch. 40, 514. Vincent of Beduvais, vol. 8, ch. 41, 514-515.

Mine&

51

and Italy, but quickly turn up in Germany as well. By this time, we may conclude that knowledge of the compass was fairly well known in many walks of life. Not surprisingly, the earliest poetical references to the compass come from France. Among the first is to be found in the works of minstrel Gauthier d’Espinois @mid-thirteenth century),‘62 who compares the charms of his mistress to the powers of the lodestone: ‘All therefore, as the adamant turns .tway the little magnetic needle by the force of its virtue, to my lady is everybody detained, who knows and observes her beauty.lG3 Italian references also begin about this time. Guido dclla Collonc [or da Collona] (circa 1215c-circa 1290), a Sicilian poet and judge of Messina, also considers magnetic attraction in his works, although in a little more detail than Gauthier.16” Guido is most famous for his Hktoria DestructionisTroiae (1287), which was later used as a source by poets and playwrights such as Boccaccio (13 13- 1375), Chaucer (circa 1342- 1400) and Shakcspcare (1564- 16 16); however, his discussion of the magnet occurs in his poetical works (circa 1250). Guido notes the power of the lodestone to attract iron, and stems to feel that the atmosphere has the ability to conduct and amplify magnetic force: ‘The lcarncd relate that the lodestone could not attract iron by its power, were it not that the air between them aids; although the calamitc [magnet] is a stone, the other existing stones are not so powerful to attract, because they have not the influence’.lG” As WC shall see, this concept of attraction became quite widcsprcad among Italian writers. About the same time, the Bologncsc poet, priest and scholar Guido Guinicclli (circa 1230- 1276) referred to the lodestone and compass in his poetry. Guinicelli, along with Florentine poet Guido Cavalcanti, founded the Dolce StilNuovo (Sweet New Style) variety of courtly love poetry, which often described the fruitless torments of unrequited love using the imagery of natural science.‘“” Only a few of Guinicclli’s fine canzone and sonnets survive today; howcvcr, in his era he

Both Klaproth,

44, and Mottelay,

33, say he lived hcforc the middlr

ofthr

thirtrcnth

rrntuty;

P$,arcus, 19 dates him at circa 1240. For more on Gattthicr, SW Dattnou. vol. 23, 574 Cauthtcr d’Espinois, quoted in Daunou, vol. 23, 576: Klaproth, 44; and Mottelay,

’

original

is: Tout

autrt-si ]ainsi] corn I’aymant

dcqoit

]d~tournr]/l.‘;liFtill~tt~

577. 33. The

par rorcc dc vcrtu/A

y,a dame tot le mot [mondcj rrtenu/Qui sa Ixattte connoit cl apcrcoit. Both Klaproth and Yitchcll overlook this rcrcrencc ,,,i Gianfranco Contini, cd., Aef~ de/ D~uren~o (Milan Nap& 19GO), vol. I,

’

reads: La calamita contano i sacccnti/che trarc non poria/lo in mezzo lc ‘I consenti./Ancor chc calamita pctra sia,/l’altrc

;Laiairr perch6 non hano bailin. Mottclay, 44, has an English translation. Gcorgc Holmes, Dnntc (Oxford, 1980). 7 8. For more on Guido,

’

‘Guinizclli,

52

Guide’,

in DAM.,

vol. 6, 24 26.

I IO. The

original

fcrro prr marstria,/sc no chr I’airc pctrc nrcnti/non son cusi pott-nti/a SW Massimo

Ciavolclla,

was quite popular, and was later considered the father of Italian love poetry.“j7 Concerning the magnetic compass, he writes as follows: ‘In those parts under northern skies are mountains of lodestone, which give power to the air to attract iron; but, because distant, it requires help from similar stones, to bring it to use, and direct the magnetic needle towards the north star.‘168 GJ. Marcus dates this at about 1240, but it is almost certainly later than that, and probably after 1250.‘sg An early German reference to the compass comes from a source which has been overlooked by most magnetic writers. r70 Poet Heiurich von Krolewiz (fl. 1255)t7’ composed User V&r between 1252-l 255, and it speaks about maqetism at some length. His discussion begins with the old myth of lodestones drawing the nails out of ships, causing them to sink: ‘He also put many a noble magnet in the wall; the stone thus became known to me. And yet the stone drew iron unto itself, and caused grief to many out on the sea.‘172 Hcinrich later compares the power of the magnet to that of the writings of the patriarchs; when WC do not understand them, WC become spiritually lost, and fall into crror.ti3 Similarly, if WC do not study the magnet, wc will lose our way on the seas: Dante, for instance, considered him “a father to me, and to those my betters who had ever used the sweet and plrasa~lt rhymes of love”. See la i)il,inn Cmmcdia, ‘Purgatorio’, Canto 26, v. 92; translated by HP. Carv, in 7le~ fXeirte CUINP~V (NW York, 1901), 250. The original wads: II padro/Mio c dcgli altri mici miglior chc mai/Rimc d’amorc usar dolci e lcggiadre. Par more on p,antc and his rcfiircncc to the mariner’s compass, SW below. Original in Gianlianco Contini, vol. 2. 45.5. ‘I’hc Italian wads: In quclla partc sotto tramontana/sono Ii monti dr la calamita,/Chc dan virtud’ all’airc/di trar lo fcrro; ma perch’ II lontana,/volc di simil pctra aver aita/pcr Lr I’adopcrarc,/chc si dirizzi I’ago vcr la stella. Also rcprintcd in Picrrc Louis Gin~gucnc, cd., Hishire li/h+aired’l(nlie (Paris, I824), I, 398-399. .Mottelay, 44, provides an English version, but incorrectly rcfcrs the reader to p. 413; Mtchcll, Ibid., 145 (note 2.57) makrs the same error, and unhappily rcfcrs the rcadcr to an English translation of a diJ%enf Guido porn,. “l‘hc Nature oT Love’, wlucl~ appears in Hcmy Longfellow’s i7fe Poe/s aad Pm/y o~fkv/~r (Boston, I870), 5 I I. This poem dots not dcscribc the magnetic compass at all; the closest it comes to is a doubtful rcfcrcncc in lines I 14: ‘kindles in noble heart the fire of love/as hidden \irtuc in the precious stonc;/this virtue comes not from the stars above/till round it the ennobling sun has shone.’ (‘l’hc original or this is: I~uoco d’amorc in gcntil car s’apprcndc/Comc virtutc in pictra prrziosa/Chc da la stclla valor non discendr/ hnzi chc’l sol la I’accia gcntil cosa. $ Cingucnc, vol. I. 400 401.) hlarcus, 19. Lon~gfcllow, 5 I I, says Cuido ‘flourished about l250’, which is consistent with the later date. ,i,I Inclttding Klaproth and Mottclay, Tar rxatnplc. Ii, For more on this 8gurc, SW ‘Krolcwiz’, in Al!ep)lleiac De~ehe/~eBiogra/hie (Leipdg, 1883), vol. 17, 179. li” Hcinrick van Krolcwia. L~tner Ihkr, s. 65, lines 1222 1227; quoted in Albert Schtick, ‘~nvlhrmmg cincs Vorgangcrs dcs Kompasscs in Deutschland um die Mitte dcs I3 Jahrhtmdcrts’, M&ilrrr~et~ ;w ~;Psrl,ir/r~eder i\fediziucouddie .A~/~~rnJ;.~.~etrsclm, vol. I2(3) I9 l4), 334; see also Albert Schiick, Dcr Kompass (Hamburg, 1915), vol. 2, 50 51. ‘I’hc original reads: Dar nach vcrgaaa cr such niht drs:/manigcn cdelcn magncs/satztc cr ouch in die want;/dcr stein wart mir also hkant/dtrz cr daz iscn zu sich zfiet/undc manigcn irITe dem mer mutt. Hcinrick von Krolcwiz, Unrer her, s. 74, v. 1456-1465; guotcd in Shuck, (1914), 334.

’

I

’

(

53

So we should do that which is good for us; what the mariner does. When he himself goes astray, so that there is an opposing wind for him, and night is falling, and he does not have the stars, he cannot correct himself any better than this: he pours waler into a vessel, and then puts a needle therein. Then it exhibits the appearance of the magnet, rhe stone that attracts iron to itself. This is certainly very mandlous. When hr. pulls back the stone, so that the needle becomes aware of it, it is thereby turned around frequently, so then it rightly stands against the guiding star [points to the North star].lia

H&rich concludes by singing additional praises to the lodestone, and its peculiar ability to reveal the North star.’ ‘j As the compass spread east to Germany, it also moved west to Spain. Spanish accounts of the magnet, compass and lodestone begin around the middle of the thirteenth century.“” A lapidary prepared under Castilian king Alfonso X [Alfonso the Wise] (122 1- 1284) about 1250 I” discusses the lodestone in some detail; the author of this work is believed to have been Spanish physician, astronomer and translator Judah Ben Moses whuda Mosca] (fl. 1250- 1275). ’7H It deals with 360 stones (one for each zodiacal day of the year), and, in common with those lapidaries we have already seen, it tends to be concerned with the lodestone’s ‘magical’ qualities. 17, Heinrick van Krolewiz, Unser lb/t-r, s. 74, v. 1466 1482; quored in Schiick, (1914), 334. The original reads: So sule wir lun, das ist uns guut,/als der memere tut,/swanne d er sich verirt/unde daz sin wide&m im wirt/unde daz diu naht ant gWundc er dcr sterne niht n&%,/w kan sich niht bcrihten baz,/cr guizct wwzer in tin vas/undc wirfct tin nldlen drin/undc wisct ir des magnes schin:/der stein daz isen zuihct zu sich,/daz ist zwlr harte wunderlich:/swcn er enzucket den stein,/sij wirt diu nldle des inein./daz siu sich dicke ummc d&/undc dannc r&c ~,stWzugegin dem leitcsternc. Heinnck van Krolewix, Unser Ii&r, s. 74, v. 1483 1502; guored in Schiick, (1914), 334. 171, Although his work was published after Peregrinus, Spanish mystic, philosopher, poet and missionary Raymond Lull (circa I235 I3 16) also mcntioncd the compass. See Raymond Lull, ~\fngG Libri Contemplahnis in Dun, in: Raynwndus Llh Opera (Mainz. 1740; reprinted Prankfun/~Main, Minelva G.m.b.H., 1965), rolls 9-10. Lully says that the seamen ofl.is day made use of charts, various measuring instruments, and the mapetic needle; this could reasonably be any time alicr 1250. According lo Lull,vol. 9, 264 “we set mariners proceed in a straigh1 line towards the pole star.” (Chapter 127, note 13. Originally: Videmus marinarios sc dirigere per stellam polarem). Later on he says “the needle naturally turns through to the north provided that it is touched by the magnet” (Lull, vol. 9,296, Chapter 129, note 19. The original is: “Sicut acus per naturam vertitur ad septemtrioncm dum sic tacta a magnctc”). Further on, Lull writes “the nautical needle helps mariners proceed in their navigation.” (Lull, vol. IO, 237, Chapter 291, note 17. The original is: Sicut acus nautica dirigit marinarios in sua navigatione.) IGnally, Lull suggests that %rre is no man who can perceive and comprehend all die properties and relations of nature occuring in rhc magnet and needle.” (Lull, vol. 9, 401, Chapter 172, note 23. The original is: Non rst ullus home, Dominc, qui posset percipere et scire totam proprietatem et convcnientiam, quam magncs CI acus habcnt in natura.) Lull also described the compass in 1308, in his “treatise on navigation” in the .4r/e Cennal(Mallorca, 1643), part IO, chapter 14. article 96. See also Antonio de Capmany, Afeworinc Irihirnr sobre la mariha, comcrcio y arks (kladrid, 1792; reprinted Barcelona, Gmara Oficial de Emercio y Navcgacib?, 1961), vol. I, 644 -654. Nfonso X, ‘Lnpdario (Se&n el Alana.wi/o Ewnialtnse H.I.I:i), cd. Sagrario Rodriguw M. $ontalvo, (Madrid, Bibliotcca Rominica HispBnica, 1981). Montalvo, 15.

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After defining the lodestone in Latin and Spanish, its various types, colours and places of origin are described. I79 Moses then explains the ‘grand marvels’ of this stone, including the tale of how lodestones can draw the nails from ships, causing them to sink; t80 he also explains the effects of garlic,‘*’ onions and (not surprisingly) goat’s blood on the magnet, but this time with a twist: ‘And if you wish this stone to lost all its virtue, put it into water of garlic or onions and cover it for three days and three nights, and it loses it. And if you want recovery, put it another three days and three nights in the blood of a goat; while it is again totally covered, and recovering, change the blood each day.“** Moses then discusses the lodestone’s value to the doctor; ‘in the art of medicine it is very beneficial’,r8s and he describes the ways in which the lodestone can be used. Finally, Moses tries to determine the source of the lodestone’s power. He is clearly quite familiar with the idea of attraction between the magnet and the stars, but instead of applying it to navigation, as our earlier writers had done, instead he discusses its astrological significance. And if you and virtttc, it is onr at from these Torcc, and

want to know with which stars this stone is attracted, and from which it receives force know that it is those three following the knot of the edge of the figure of Pisces, and the end of the tail of the fish. It has the property ol’ fiercelyprojecting the virtue received stars. And when the middle OF this is above the horizon, the eastern part has more mom virtue is in all these parts as has been said.‘“’

A more famous Spanish reference is that of the L.ges de las Siete Partida.ri,‘85 one of the early landmarks of Spanish jurisprudence. It was also written under Alfonso X, somctimc bctwecn 1256- 1265,i8G and mentions the magnetic nccdlc as a very useful guide for mariners. The citation is set in the form of a simile, and compares the sailor’s rcliancc on the compass to the King’s use of wise counsel: kr/Arrio, ,111

M011talv0,

‘Drl Sign0 dc Arks’,

in Montalvo,

20.

20.

For mom on this b&f’, SW \\‘.E. May, ‘Garlic and the klagtwtic Compass’, Mariner’s Mirror, f.. (I 979), 231 234, who shows it. is bawd largely on a mjs!ranslation of Pliny. hlontalvo, 20 21. ‘I’hr ortgmal reads: Et si omttc qutstcrc que esta piedra pierda su ucrtud, tnrta la t-n agua dr aios o dc cebollas. de guisa que rstc cubirrta toda trcs dias et trcs nochcs, rt pcrder la a. Et si quisicrc quc la cobre, mcta la otros trcs dids ct trcs nochcs cn sangrc de cabron; : t;c rstc otrossi toda cubicrta, et cobrar la a, mudando la sangm cadadia. h I\lontalvo, 2 ‘I’hc ofighlal reads: Et en cl arte dc ftsica es muy prouechosa. ,111 Xlontalvo, 21. ‘I’hc ortgmal reads: bt cl quc quisicrc sabrr con qualcs cstrcllas a esta piedra su atatniento, et dc que rccibc la htw~a ct la ucrtud, scpa que son aquellas tres que estan cn a~ ct siqurn al nudo dcl lilo dcla Rhwra dc Pisces, ct la una dclhis es en cabo dela cola dcl un pea. Et la propricdat qttc ellas an dc trirar cl ficrro L’Spor la uertud quc reciben dcstas estrcllas. Et qttando la mcdiana dcllas sube cn cl o&on, de parte dc orycntc, aura mayor fuerca [Fucrca], ct ;;as uertud cn todas cstas obras quc auc mos dichas. Satnttcl Parsons Scott, cd., Ins sit/e /Midas (Chicago, 1931); for an carlicr edition, SW Ins ;,$ /lar/ida~s del Snhio HE,* don rl$L~nsncl .I’ (Madrid, 1829). C&arks Sumner Lobingux, ‘Introductton’ in: Scott, Ii, also suggests a terminal date of 1263. Other sources give wildly vatytng dates: Mottchty, 60 says ‘the ftrst half of the thirteenth century’. Mtchcll, I 19, is closer: ‘written about 1250- 1257’. Klaproth, ignores it completely.

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And just as sailors are guided in the darkness of the. night by the magnetic needle which shares the qualities of both the stones and the stars, and shows them where to go both in bad weather, and in good; so those who are to give counsel to the King, ought always to guide themselves by iustice, which is the connecting medium between God and the world at all times, to reward the good and punish the wicked; to each according to his dcsserts.‘s7

The idea of the stars and the magnet sharing some common ‘virtue’ or power is quite common by the 1260s; having noticed the magnetic needle’s attraction to the north star, scholars were increasingly speculating on the various forms of influence between the two. These theories were to prove surprisingly fruitful in the work of Belgian physician John of St. Amand (fl.126 l- 1298), who began his medical practice in Paris about this time.‘*s Very little is known of John of St. Amand’s life; he was born at Tournai in Hainaut, or at St. Amand en PGve near Valenciennes, probably studied at Paris, and was later canon of Tournai .181)Hc wrote over twenty works,ICJomost of them on medical topics, but is remembered chiefly for two: the Expotitio siveAdd&o Super Antidotariumhicolai, which is a commentary on the medical antidotary of Nicholas of Salerno, and the RevocativumMemoriae, a medical compendium. The ExposiiiosiveAddiho Super Antidotarium.Nicoai contains an important discussion of the magnet,‘“’ which foreshadows Gilbert’s 1600 thesis that the earth is a large magnet; this concept was critical to the formation of the modern scicncc of magnetism. It also dcscribcs both north and south magnetic poles, and possibly even the idea of a magnetic ‘flux’ or current. John begins by trying to explain magnetic attraction by positing a magnetic force which excites the active power which exists incomplctc in iron, which is born to br complctcd by the form of the magnet, nay is moved towards it. \Vhercfore I say that in the magnet is a trace of the world, wherefore there is in it one part having in itself the property of the west, another of the east, another of the south, another of the north. And I say in the direction north and south it attracts most strongly,

Ins sielc ,bar/ida.b, Partida 2, Tit. 9, law 28; in Scott, 329. AII earlirr translation is that of Robert Southey, and Samuel Taylor Coleridge, 108. ‘l’hr Needle’, in Ot~tninw~ or Horar Ohiorc~ (Fontwell, Sussex, 1969), 121 122. The origi~xd text reads: E bien assi coma 10s marincros se guian en la no&c cscura por et agtja qur k-s es medianera cntre la piedra e la rstrrlla, c Ies tnurstra por de vayan, tambien en 10s males tiempos. romo en 10s buenos; otrosi 10s qur ban dr consejar al Rev, se drvcn sicmpre wiar par la iusticia, clue cs medianera wwc Die, c cl mtmdo, en todo $mpo, para dar gualardon a 10s hucnos, c prna it 10s m&s, a cada UIW sr~wncl SII mcrcscimicnto. H. \Vcltcr, cd., His/uiw /i/G&e C /a Franrr (Paris, 1895). vol. 2 I, 254 266. See also Il~orndikr, ;!I. 2, 510 513. Sarton, vol. 2, 1089 1091. 1’111 For a complete bibliography, see Lrnest \\‘ickcrshrimrr, fX&ntmire I,iqra/driqctr de.\ .If6dih1 y, France au Uym Age (Paris, 1936), 476 478. This has been totally igttorcd by most of the magnetic witcn, including Khtproth, Slotrelay and Mitcheli. It is, however, sutnmati~ed in AC. Crotnhie , .~lri~us~rrslitrr lo Galilcn: Ilrc lrblon ?I s&we, A.D. 400 100 (New York, 19.52), 90; and AC. Cromhic, Alcdhal aud car!v nodm .wicm (Garden City, N.Y., l959), 122.

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.I

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little in the direction east and west. Wherefore the virtues of the poles are stronger in it, which is recognized by sailors, because it attracts, that they have a north or south wind.“92

John then tells his readers how the north and south magnetic poles can be distinguished. After taking an eggshell full of water and placing it- in motion, the magnet is placed on the shell as it moves violently and the south part will be moved southward and the north northward. And sometimes it happens that the southern part attracts that which has the property and nature of the north, albeit they have the same specific form, and this is not except by some property existing more complete in the southern part which the northern has potentially and thereby its potentiality is completed. Wherefore I say that the southern part never attracts the southern part or the northern the northern, because there is not in the one anything that the other needs on account of which motion should be made, since they are of the same form and property.‘!”

This, *John claims, ‘exposes the ignorance of some who say that sometimes the magnet drives away the magnet and the southern part the southern part, because this is false.lg4 They may seem to repel, John admits, yet one of them attracts the northern part existing in one section of the magnet. And because in the opposite direction was the propc’rty as it were of L..~ ‘.,. ---.th, Juu therefore in attracting the northern part to itself it seems to repel the southern part. For instance, take a magnet of which one part has the property of the south and the other of the north and put a needle above that stone so that it lies on the stone. Then one end of the needic touches one end of the magnet and the other the other, and there flows into the end of the needle the virtue of that part which it touches, so that, if it touches the southern, the southern virtue iIows in. Then let the needle bc raised higher. Then, since there is a current from the magnet through the entire needle placed directly above it, that part of the needic in which at first there was southern virtue wilt become northern, as the current from the magnet flows through the whole necdic. So that if we should suppose a dish full of water to be piaccd directly underneath the needle, the current would How into the bottom of the dish. Similarly that part of the nccdic which first touched the southern part when it was rubbed against or lay on it, when that part is rubbed on that part directly, that part which at first possessed the southern ,‘)l

.John of St. Amand, fu/,osi/io sive Addilio Super An/idokwim .Nicolai; translated in Lynn Thorndike, :John of St. Amand on the Magncr’, Isis, 36(1945 -i946), 156-157. The original reads: Dice quod facit hoc muitipiicando suam simiiitudinem et sine cvaporatione aiiqua, excitando potcntiam acti\am incompictam cuistentcm in ferro, que nata cst compicri per formam addmantis, immo movetur ad ipsutn. Undo dice quod in adamante cts vestigium orbis, unde est in co aiiqua pats habcns in sc proprietatcm occidentis, aiia orientis, aiia meridiei, alia septcntrionis. Et dice quod in partc pro mcridie et scptcntrionr cxistente maximc attrahit, parum a partc orientis et occidcntis. Undr sunt in eo fortiores virlutcs poiorum, quod co.gnoscitur a nautis quia attrahit quod $bcnt vcntum scptcntrionalcm aut mcriodionaicm. -John of St. Amand, in Thorndikc, (I 945 194(i), 157. The original passage is: ponetur adamas in trsta fortitcr Mona, ~unc pars mcridionaiis ad meridiem movebitur et scptentrionaiis ad scptcntrionrm. EI aiiquando accidit quod illa pars quc est mcridionaiis attrahit iiiam quc cst habcns proprirtatcm ct naturam scptcntrionis, licct sint sub cadem forma spccifca, et hoc non est nici per aiiquatn proprirtatmm magis rompictam cxistentcm in partc mcridionali, ad quam cst pars scptcntrionaiis in potcntia et compirtur sua potentia per ipsam. Undc dice quod nunquam pars mcridionaiis attrahit partcm mcridionaiem ncc septcntrionaiis septentrionaicm, quia ncquc cst in :;a aiiquid quo iniqcat alia proptrr quid fiat motus, cum sint ciusdcm forme et proprictatis. John of St. Amand, in Thorndikc, (i945- i946), 157. The original passage is: Un?c propter hoc patct i~norantia quorundam diccntium quod aiiquando adamas fugat adamantcm, et pars mcriodionahs mcriodionaicm, quia hoc cst faisum.

57

property now has thr northcm property. And then that whir h was first southern, since it is now northern, is attracted by the southern part of thr magnet, since it dots not attract the southern, as has been said. And by the l&t that onr is attracted thr other seems :o be repelled.‘“’

This is an extraordinarily dctailcd description of the properties of the magnet; and given John’s anticipation of Gilbert, it is interesting that this passage has been neglected so long. If Gilbert knew ofJohn, he did not cite him in his work, though hc had high praise for both Peregrinus and St. Thomas Aquinas (circa 1225:271>.“36 However, before we can look at thcsc figures, WC should cxaminc the magnetic writings of Aquinas’ mentor, German scholastic philosopher, theologian and scientist Albertus Magnus (circa 1200-! 280). Albertus entered the Dominican order in 1223; hc taught at various German schools, at Paris (1245-l248), and at Cologne (1248- 1254, 1257- 1259), where he had Aquinas as his student. He was appointed Provincial of the German Dominicans in 1254, became the bishop of Rcgcnsburg (1260-l262), and was chosen papal legate in 1263- 1264 by Pope Urban IV (circa 1200- 1264). Upon his retirement to Cologne, hc continued his scientific and scholastic pursuits, writing commentaries on Aristotle and arbitrating complex litigations. He died on 15 November 1280.‘“’ Albertus discussed the compass in his work on stones, De A4iueralibus.‘!‘” It is not known exactly when this text was written, but it appears to bc approximately 1263.‘“” There is onr rcfcrcnce to the compass, and scvcral to magnetism in general. The first tries to accotmt for the propcrtics of the adamas, this time clearly “” John of St. Amand, in ‘I’homdikc, (194.5 19-S), 1.57. ‘I’hr original passage is: licct \idcatur fugare, non tamcn lkgat scd attrahit partcm scptcntrionalcm csistcntcm in una partc adamantis. Et quia in opposita parte wit proprictas quasi mcridici, idco attrahrndo partcm scptcntrionalcm ad se videtur fugarc partcm mcridionalem. Vcrbi Lgratia,ponctur hit adamas cuius una paIs IXIIW~I proprictatcm mcridici ct alia scptcntrionis, ct punatur acus super illum IapidcIn ita cpmd iaccat supra lapidcm. ‘I’unc tangit una cxtrcmitas acus cstrrmitatrm unam adamantis ct alia aliam. ct cxtrcmitati influcntur acus virtus illius partis rpam tangct, UI si tangat mrridionalrm inllurtur cius \irtus m~ridionalis. Tune elcvetur acus supcrius. Tune cum inlluatur ah adanxntc t,~~’to~atn awn dircctc positam, illa pars acus in qua prima virtus mcridionalis wit scptcntrionalis cum toti acui influatur virtus ah adamantc. Ut si intclligcrcmus quad UIXIscutrlla plcna aqua acui supposita dircctr influcretur tirtus fundi scutclle. lb similitrr rst hit quod illa pars iIcII$ quc priIno tang&at partcm mcridionalcm cum liicabatur vcl iacchat super cam, quando kicatur pars illa ad partcm illam dircctc, lrahct illa pars cpw habcbat prima proprictatcm mcridionalcIn proprictatcm scpwntrionalcm. Et IUIICilla quc prima crat Inrridionalis, rum sit scptcntrionalis, attrahitur a partc mrriclionali adamantis, quia non attrahit mcridionalcm, ut dictum est. Et per hoc cpmd attmhit illam vidctut l$arc aliam. Gilbert, 5 9. ,w For more on Alhcrtus, see \Villiam A. \\‘allacc, ‘Allwrtus ~Iagnus’, in: D.S.B., vol. I. 99 103: @mcs A. \\‘cishcipl. ‘Albertus Magnus’ in DAIA., vol. I. I26 130; ‘l‘horndikc, (192X), vol. 2, 3 I7 59!!. 692 750, and James A. \\‘cishcipl. .M~er/u~ .\l~gw.\ nrrn I/W.triewr.\: ~~~~~I~IIPI~I~~~~~I~~~ wnr.\ ~&oronto, Pontifical lnstitutc of Mcdicval StudicsT 1980). Alhcrtus Magnus, De Mneralhrs, in AugIstl Rorgnrt. cd., 11. It/w/i .\l@ O/ma Ownirr(Paris, IWO), \ni. 5. ‘I’ranslatcd by Dorothy \\‘ycknlT as 77rr book o/‘n~b~erals (Oslbrd, 1967). I’“, Motlclay, 35, datrs this ilS 12.i4. and Mlchcll, l2ti. claims it lo hr ‘about 12.50’.

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referring to the diamond. The adamas has watcrincss advanced towards earthiness, so it is dark and hard, and can scratch all metals excepting steel, because steel’s ‘wateriness’ is completely dried out. Consequently, the sharpened adamas can cut and divide virtually all metals. PO0The second reference, however, contrasts both the adamas and thr magnet, and it seems likely here the adamas means the lodestone: ‘WC see that the magnet attracts iron and that the adamas restricts that power in the magnct.20’ Albertus then devotes a chapter of the De Mineralibus exclusively to the adamas. He begins by describing its properties, and, as we expect, it is said to be ‘an extremely hard stone, a little darker coloured than rock crystal, but nevertheless of a bright, shining colour, and so solid that ncithcr fire nor iron can soften and destroy it. But it is destroyed and softened by the blood and flesh of a goat.*O* Then, following the lapidary of pseudo-Aristotle (see abovcj, he says that the ‘adamas is also dcstroycd - and this srcms even more marvellous - by lead, due to the great amount of quicksilver in lead. And the stone pierces iron and all other gems, but not steel, to which it sticks fast ‘.*03He then tells his readers where the stone may be seen: ‘The largcqt stonr of this sort thus far discovered is the size of a filbert. It occurs in Arabia and Cyprus mostly’.204 He concludes the chapter by describing more of the adamant’s magic properties: when this stone is placed on a magnet, it restrains the magnet and prevents it from attracting iron. But its pow-r is grcatcr iT mounted in gold, silver or steel. And the magicians say that, bound on thr left arm, it is good against encmirs and insanity and wild beasts and szwagc men, and against

1,111

Albertus, DP ,1lirrtw/~6rr.c,Book I, Tractate

40. ?I,,

2, chapter

2; in Opra Omia, vol. 5,

I5 16; \VyckolT,

1;

Albcrtus, 11~Alir~etnl i/m, Book 2, ‘I‘ractatc I, chapter in Opera Omia, vol. 5, 24; \Vyckoff, 56. ‘I’hr original reads: magnrtam videmus fcrttm attrahcre, rt adamantcm illam virtutem in mutant tc rtstrtngrrt. Abcrtus, Ilr .\Jitrwa/ih, Book 2. Tractate 2, chapter I; in O//era Onwia, vol. 5, 30; IVyckoff, 70. ‘~‘IIc original reads: Adamas autcm, sicut fccimus mentionem, lapis est duri~simus, parum crystallo obscurior, coloris tamen lucidi fulgentis, adco solidus UI ncquc ignc ncquc fcrro mollwat vcl volvatur. Solvitur tamcn et mollcscit sanguine ct carni hirci. Later on in lhc text, Albcrttts cotttinttcs to claim that goat’s blood softens the adamas: ‘ad talcs rnim exarationrs opcrtct habrrc instrutncnta drccntrr aptata; quad non potrst essc in partibus adamantis, nisi mollircntur sanguine hircino’. (‘For cttgraving demands instruments properly adapted [for cutting gems]; attd this cannot br IIW cast- with l’ragmcnts of adamant, unless they should first be sofiened with goat’s blood.‘) I~ront Albtwus, Dr ~\linern/i6us, Book 2, ‘I’ractatc 3, chapter 2; in O//era Omia, 5, 50; Wyckoq I39 ... “,I, Nbrrttts, Jk .\Jbwrali/~rrs, Book 2, ‘I’ractatr 2, chapter I in Opra Owtia, vol. 5, 30, \VyckolT, 70 7 I. ‘I’hr original wads: Solvitur ctiam lapis iste, quod mirabilius vidctur, plumbo proptcr multum ;tr_gcntttttt vivum qttod cst in ipso. Hit autcm lapis pcnctrat f&-rum ct cactcras gctnmas nmttcs, ~;;:ttwr cl~:~lybrm in quo rclittrtur. ,\lbrrtus, I% .\Jimnlil,~~.~, Book 2, ‘I’ractatc 2, chapter I; in Opra Ow~ia, vol. 5, 3 I; \Vyckoll; 7 I. ‘l’hc original rcitds: ,\lajor autcm quantitas istitts lapidis adhttc invcttta csl magnitudo avcllanac. Nitscitttr ittttctn in Arabia ct Cypro sccundutn plurimutn.

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supcrius’

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59

disputes and quarrels, and against poisons and attach of phantasms and nightmares. call the stone diamant, and some untruthfully say that it attracts iron.“‘5

Some people

Albertus considers the magnes or lodestone under chapter 11. Hc describes its origin in the Indian Ocean, and repeats the story of its sinking ships by drawing their metal nails out. Then he mentions his own experience with the lodestone:

I

myself have seen one Found in the part of Teutonia called the province of Franconia, which was of large size and vety powertiul; and it was extremely black, as if it were iron rusted and burnt with pitch. It has a wonderful power of attracting iron, so that the power is transferred to the iron and then that too attmcts; and sometimes many needles are sew, thus suspended one from anothcr.z’“1

After telling the story of garlic destroying the magnet, 20’ hc thcr. notes its unequal attraction: ‘In our own time a magnet has been found that attracted iron from one corner and repelled it from another. And Aristotle says that is another kind of magnet. One of our order, a careful observer, has told me he had seen a mdgnct belonging to the Emperor Frederick, which did not attract iron, but on the contrary, the iron attracted the stonc.‘20R Albertus continues by reporting the pseudo-Aristotle tale of a magnet attracting human flesh, and details its power to cure dropsy. 209 Finally, he concludes with two more talcs; the magnet that betrayed the unfaithful wife by forcing her out of bed, and the magnet that thieves used to drive occupants out of houses, so they could break in. Both magnets worked by alarming their victims with nightmarcs.2’0 In Tractate 3, Albertus finally applies this considcrablc discussion of the adamas

;

n,i

Nbertus, Dz dfirrptnlibrcs, Book 2, Tractatc 2, chapter I in O/wrn O~wrin, vol. 5, 3 I; \Vyckof& 71. The original reads: hit lapis quando magnrti supcrponitur, ligat magnetem et non permittit ipsum f&rum trahere. Major autcm virtus ejus est in auro vcl argcnto vrl rhalybc. Dicuntque magi, quod lacerto sinistro alligatus, valet contra hostcs et insaniam ct indomitas best& et fcros hominrs et contra jurgia et rixas et contra venena et incursus phantasmatum ct incuborum. Hunt autcm lazidem diamantem ctiam quidam vacant, etiam quidam fcrrum attrahcrc mcntiuntur. Book 2, Tractatr 2, chapter I I; in O/wrn O,,rrin, vol. 5, 40; \\‘yckoli; 103. The original reads: Ego \;di invcniri in partibus Tcutoniac in ca prolincia quite Franria Orientalis vocantur, unum magnae quantitatis ct maxime clTicaciac, et liuit valdc niger, ac si cssrt ferrum rubiginosum et combustum cum picc. Virtus autem cjus cst mirabilis in attractionr f&i, ita quod virtutcm cjus transmittat in fcrrum, ut illud etiam attmhat; et aliquando multac acus hoc ~~odo suspensae ad se invicem videntur. \Vyckom, 104, note 3, suggests this story comes from Claudius Ptolrmy’s Tetrabiblios (vol. I, 3, l3), but May, (1979), 231 234, has shown the belief was simply dur to a misunderstanding of Pliny, and was continually repeated by Plutarch, Ptolemy, Solinus, Marbode and many others. .‘,“I Nbertus, /A Afincmlibrcs, Book 2, Tractatr 2, chaptrr I I; in Opera Omin, vol. 5, 40; \Vyckor, 104. The original reads: lnventus autcm cst nostris tcmporibus magncs, qui ab uno angttlo traxit fcrrutn, ct ab alio fitgavit: et hunt hristotelcs ponit aliud genus essc maguctis. Narravit mihi unus cx nostris sociis curiosus expcrimentator, quod vidit Fredericum Impcratorem habcrc magnctcm, ui non traxit Crrum, sed ferrum vice versa traxit lapidem. %I Albertus, De Afhterdih, Book 2, Tractate 2, chapter I in O/,rm Otwrin, vol. 5. 40; \Vyckoiofl;

’

Nbcr~us, DrMnerdi6us,

101.

2118

Albcrtus. \Vycko& 104.

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Lie A finrralibus. Book 2.

‘I’lXCtiltC

2. chapter

I I; in Opt-m Onmia, vol. 5, 40 41;

and magnet to the mariner’s compass. Again, he borrows from the lapidary of pseudo-Aristotle, applying the same Hebrew wordszl* to the North and South poles of the needle as Vincent of Beauvais (see above): The corner or a certain kind of magnet has the power of attracting iron towards zoron, that is, the North: and mariners make use ofthis. But another corner of this magnet attracts in the opposite direction, towards aphron, that is, the south pole. And if you bring iron near to the north corner of the magnet, the iron becomes North, and if you bring it near to the opposite corner, it immediately becomes South.“‘z

Albertus goes on to describe more of the usual magnetic myths; ‘that neither iron nor any stone can overcome the adamas’,*r3 and that ‘if two or more magnets of equal power are placed above or below, and a body of baret, that is, iron, is placed between, it will hang suspended in the air. ‘*I4 He concludes by describing magnets that attract other things besides iron, such as gold, silver, lead, bones, hair, water, and even human flesh .*I5 Some of these ‘magnets’ are probably medical or chemical compounds; yet in Albertus, as in other writers of this period, there was a tendency to ‘assimilate into one description a number of different things which have “some effect on” hair, water, fish, etc ‘.*I6 This ‘assimilation’ is very prominent in the pseudo-Albertus Ihe Bookof SecTets’7. The author of this work is unknown, but he is believed to have been a contemporary of Albcrtus, possibly a disciple; at any event, the earliest manuscripts firmly date this text in the late thirteenth century. st* As in the De Mineralibus,there are two chapters dealing with the lodestone, one considering the ma.es and the other the adarnas.The magncs rcvcals whcthcr a wife is chaste, and, as before, causes

?,I

~lottelay, 35, considers these words Arabic. Albertus, Dr ,\finern/Gus, Book 2, Tractate 3, chapter 6; in O/wa Omtia, vol. 5, 56; \Vycr;of& 148. The original reads: Anhwlus magnctis cujusdam est, cujus virtus apprehendi ferrum est ad zoron, hoc cst, septcntrionalem: et hoc utuntur nautae: angulus vero alius magnetis illi oppositus trahit ad aphron, id est, polum meridionalem: et si approximes rerrum versus angulum zoron, convertit se l&rum ad moron: et si ad oppositum angulum approximes, convertit se directr ad aphron. F$trlay, 35, has an incomplelc translation d this passage. Albertus, IIF Afiwdihr, Book 2, Tractate 3, chapter 6; in O,!wrnOtrwin, vol. 5, 56; \VyckoK, 148. The original rcdds: quad adamas tierrum et kdpides omnes non constringit. 211 Albertus, 11~~\limwdihrs, Book 2, Tractatc 3, chapter 6; in O/wn On,nia, vol. 5, 5% \VyckolT, 148. Tlw original reads: ouod si magnetcs duo vel plures subtus ct supra coaequatis virtutibus ~~dinentur, ct cotpus in baret, hoc cst, ferro quad cst in medio dispon&n~, pen&bit in acre. Alhcrtus, Ilr A/imwdihro, Book 2, Traetate 3, chapter 6; in O/wrr Onlttm, vol. .5, 56; \VyekoK 149. 211, Wyckolt; 149, note 18. 117 There arc many editions. For a modern version, SW 1,lichacl R. Best, and Frank H. Brightman, 771~bart/~~f.!ecw/s $Jlhrr/rts Afngtltts (Oxford, 1973). For a facsimile reprint, see Alh~~tus f,pgw,\ 77~ II& sf ~prre/.~ (London, 1560; reprinted Amsterdam, 1969). Best and Brtghtman, xiv xv; Lynn Thorndike, ‘Further constderation of the Er~wi~t~rc~ln, Spe&rt~ .h/rmtominr and De Sccre/it Aldientm ascribed to Albert us Magnus,’ Specrrlwrt,30 955), 413 433. 112

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sleepers to flee a house, allowing thieves to break in.*lg Meanwhile, the diamond permits its bearer to overcome his enemies, and it is good against madness, wild and vencmous beasts, fighting, poisons, and fantasies.‘20 The Book of Secrets also claims the lodestone will cause an epileptic to fall dead to the ground.**’ Despite the credulity of the author, he does promote the importance of checking the truth of such stories by experience; as he says, For although we know not a manifest reason why the Loadstone draw& it to iron, notwithstanding cxpcrirnce doth manifest it so, that no man may deny it. And like as this is marvcllous, which only experience doth certiry, should a man supposc in other things. And hc should not deny any matwllous thing although he hath no rrason, but he ought to prove by expctiencc; for the cause of marvcllous things are hid, and of so diverse causes going before; that man’s understanding, afirr Plato, may not apprehend them. ‘l‘hercforc the Loadstow drawcrh iron to it, and a certain other stone draweth glass.?‘? A far more careful disciple of Albertus was St. Thomas Aquinas (circa 1225--l 274). Aquinas cntercd the Dominican order about 1243, where hc worked under Albertus. Hc taught at Cologne (1248-l 252), and later at Paris (1252-l 259, 1269- 1272). Between 1259 and 1268 hc was a theological advisor and a lecturer to the Papal Curia; after his teaching at Paris, he directed Dominican studies at the University of Naples (12721274). Aq uinas is the central figure of scholastic philosophy, integrating Aristotelian naturalism and scientific rationalism with the Christian faith; his works included the Summa Conh Genhles (1259-l 264) and the Summa 77leolog& (1265-1273). He also wrote many commcntarics on Aristotle and religious works. His opinions on the magnet arc found in the Summa ?heologicn and his Commentay on At&ode’s Pi,,;,,.22s Aquinas’ comments on the magnet are valuable for two reasons; his works wcrc among the most influential of the entire medieval period, and they were favourably reviewed by Gilbert. The Summa nleologiae contains a considerable discussion of demonic forces and occult qualities. In discussing the propriety of invoking thcsc mysterious effects, Aquinas writes: ‘It is legitimate to make USCof the natural forces of bodies in order to produce their proper clliicts. Yet thcsc have hidden powers which man is not yet capable of explaining, for cxamplc, why a magnet attracts

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Best and Brightman, 26; also 93 94. Best and Brightman, 3 Best and Brightman, 53. .‘.‘L Brst and Brightman, 82. z.‘* For more on Aquinas, SW I:.C. Coplrston, Aqrriw~ (Harmnndsworth, Middlcsrx, 1955); Jamrs A. Wrishcipl, Aicr> nlum~r D>lpino: Ifi> /ifi I/UJI~$I nrd work (Garden City, N.Y., Doublrday and Company, 1974); and \Villiam Wallace, ‘Aquinas, St. Thomas’, in D.S.B., vol. I, 196 200.

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iron; Augustine cites many other examples. ‘224 The exact date of this passage is uncertain; however, it is known that the second part of the Summa was largely written during the second period of Aquinas’ Paris teaching, which fell between 1269-1272.225 Aquinas discussed the magnet in somewhat more detail in his eighth book Commentariade Physic Auditu Sive PhysicoorumAristotelis(Commentaryon A&t&z’s Physks). This work was composed during 1268- 1269, probably as part of a lecture course. In explaining the causes of motion, Aquinas invokes the magnet, suggesting that it draws iron by imparting some attractive ‘quality’ to it. In his words,

to.pull

in this way a magnet is said iron. For just as a generator moves heavy and light things insofar as he gives them a form through which they are moved to a place, so also a magnet imparts some quality to iron through which the iron is moved to the magnet. And that this is true is evident from three things. First a magnet does not pull iron from any distance, but only from nearby. But if iron were moved to a magnet only as to an end, it would tend towards it from any distance. Secondly, if a magnet is greased with other things, it cannot attract iron. It is as if these other things either impede the alterative force of the iron or else change it to its contrary. Thirdly, in order for a magnet to attract iron, the iron must first be rubbed with the magnet, especially if the magnet is small. It is as if the iron receives some power from the magnet in order to be moved by it. Thus a magnet attracts iron not only as an end, but also as a mover and its alterer.‘?‘j

Here we see a very competent effort to understand how the magnet attracts; Aquinas seems to believe that it emanates a force which, when it strikes the iron, causes it to changed into another magnetic object, which is then pulled back to the frst magnet. Aquinas also realizes that the magnet’s force decreases with distance; howcvcr, he still believes that rubbing magnets with materials (probably goat’s blood or the other materials we have encountered) can cause them to lose

221

St. Thomas Aquinas, Summa ?71eologiae,2A, 2AE, question 96, Article 2 (New York, 1968), vol. 40, 74-75. The original reads: Licitum cnim cst uti naturalibus virtutibus corporum ad proprios clhcctus induccndos. Res autem naturales habent quasdam virtutes occultas, quarum ratio ab homine assianari non potest: sicut quad adamas trahit ferrum. et multa alia quac Augustinus enumerat. /$hras is rcf&ing to Au&tine’s De 7rinilnle, vol. III, 8, 9. Weisheipl, (1974), 216-222. 221, Thomas Aauinas. In OCIOLibras. De Rhsicv Auditu sive Phwicancm Aristvtelis Commentaria (Naples, D’Auria Pontifciu;, l953), 395; Cvtnhwkuy on Ati.Me’s ffyks, Book 7, Lecture 3, translated by Richard J, Blackwell, Richard J. Spath and W. Edmund Thirkel (New York, 1963), 433. The original passage reads: ct hoc modo magnes dicitur traherc ferrum. Sicut enim gcnerans movet gravia et l&a inquantum dat cis formam per quam moventur ad locum, ita et magnes dat aliquam qualitatem ferro per quam movctur ad ipsum. Et quod hoc sit verum patet ex tribus. Prima quidem, quia magnes non trahit f&rum ex quacumque disttdncia sed cx propinquo; si autem &rum moverctur ad magnctem solum sicut ad fnem sicut grave ad suum locum, ex qualibet distantia tenderct ad ipsum. !&undo, quia si magncs aliis perungatur, ferrum attraherc non potest, quasi aliis vim altcrativam ipsius impedicntibus aut etiam in contrarium alterantibus. Tertio, quia ad hoc quod magncs attrahat ferrum, oportct prius ferrum liniri cum magnetc, maxime si magttes sit parvus, quasi cx magnete aliquam virtutem fcrrum accipiat ut ad cum movcatur. Sic igitur magnes attrahit ferrum non solum sicut Bnis, scd ctiam slcut movcns et altcrans.

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their power. What is important here is Aquinas’ explanation of this assumed effect, which is quite plausible; that some materials can ‘screen’ magnetic force. About the same time as Aquinas, Florentine notary, magistrate and politician Brunetto Latini (circa 1220-1294) described the magnet in his Li l&es dou trkor, a three-book compilation of the sciences, history, philosophy, religion, rhetoric and politics. This was designed to be essentially a summary of the principal teachings of past authorities, especially the Bible, Pliny, Solinus, Isidore, Aristotle, and Cicero.227 Latini was a member of the ill-fated Florentine Guelph party, whose military defeat by the Ghibellines of Farinata degli Uberti (died 1264) during the 1260 battle of Montaperti caused him to seek exile in France (1260-l266). During this time he practised law, and wrote (in the Oil dialect of Northern France) the T&or (circa 1265). In 1267 be returned to Florence, holding public offices and later the chancellorship of Florence (1273). He spent his later years translating Cicero, and writing oratorical and political works such as the Favarello(1 282).‘28 The T&or basically considers the lodestone as a guide to sailors. It is not concerned with the underlying causes of magnetism, although Latini seems to hint that the fixed stars at the poles are responsible: for sailingthe marinersstudy the stars that there are. and that they call the north star. And the men which arc in Europe and in parts around there sail to the north star, and the others sail to the south. And to verify this, they take a needle of the magnet, that is the lodestonr. You will find that it has two sides, one which bean to the north star, the other bears the other way, and each of the sides ally the needle towards that star which that face bears, and in this the mariners will find revealed what they have not taken watch for. ‘This is because these two stars do not move themselves, unlike the other stars which there are, some of which turn around in very little circles, and the others very wide circles.“” At this point, we must pause to unravel a very strange story. Latini is often quoted as ha;ring written that the compass, though useful, is avoided by sailors who do not want to be thought magicians. This claim goes back to a forged letter of Brunetto Latini in the Mont& Magazine of 1802, which claims that he derived

hlottelay, 43; Elio Costa, ‘Latini, Brunctto’, in: D.M.A., vol. 7, 382 383. Costa, 382-383. Brunctto Latini, in P. Chabaille, cd., Li liorps dorrhtwr par Bruneth Inhi (Paris, 1863), Book part 3, chapter i20, l47- 148: SW also Francis J. Carmody, cd., Li livres dorr /riser (Berkclcy/l_os Angeies, 1948; reprinted Geneva, 1975), !07 The oriinal reads: Por cc nagent Ii marinirr as cnscgncs dcs estoilcs ki i sont, k’il apelcnt tramontaines, et Ir gcns ki sont cn Europr rt en restc partie nagcnt a la tramontainc dc septcntrion ct Ii autre nagent a la tramontainc dc midi. Et kr cc soit vcrit&, prcnirs unc piere d’aimant: vous trouver& k’clc a .ii. faces, une ki gist vers la tramontaine de midi, ct l’autrc gist vcrs I’autrc. Et chascunc dcs .ii. faces alic la puintr dr I’aguillc vers celc tramontainc a qui cele face gisoit. Et por cc scroient Ii marcnicr sovcnt dcceu s’il ne s’en prcsisscnt garde. Et por cc que ccs.ii. estoiles ne se mcuvcnt, avient il kc lcs autres estoiles ki sont enki entour ont plus pctis cerclcs, et lcs autrcs grignoirs, sclonc cc quc lcs uncs i sont plus pr& et lcs autres plus loing. Klaproth, 45, has an incomplete version of this.

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his knowledge of the directive property of the compass from Roger Bacon (see below) during a trip to England: He [Bacon] further showed me a black ugly stone, called a magnet, which has the surprising property of drawing iron to it; and upon which if a needle be rubbed, and afterwards tastened to a straw, the needle will instantly turn towards the Pole-star: therefore, be the night ever so dark, so as neither moon or star be visible, yet shall the mariner be able, by the help of this needle, to steer his vessel aright. This discovery, which appears useful in so great a degree to all who travel by sea, must remain concealed until other times; because no master mariner dares to use it, lest he should fall under suspicion of being a magician; nor would even the sailors venture themselves out to sea under his command if he took with him such an instrument, which seems to be constructed under the influence of some infernal spiriLz3”

That this passage is forged should be evident to even the most casual reader. Virtually all of our previous sources have spoken of the compass needle’s great utility and value in navigation; this one alone says that mariners refuse to sail with it on board. Moreover, it claims this ‘surprising property’ must ‘remain concealed until other times’, despite the fact it had been widely publicized in encyclopaedias, histories, and poems for almost a century. Finally, there is no evidence that Latini ever visited Bacon in England, indeed, throughout much of this period Bacon was in fact in France.231 Even so, historians have continued ever since 1802 to quote this passage as genuine. Both Klaproth and Mottelay cited it, and implied that it was to be found in the T7is07!~~2 Mottclay compounded the error by later assigning a date of ‘prior to the year 1260’233 to this fictitious meeting of Latini and Bacon; and English university historian Robert Gunther was also fooled,234 along with Dante historian

2,11

ofa

‘Extracts from the Portfolio Man of betters’, 7Ae Mm/h/v Maguzitte or Rrihh Regiskr, vol. 13, prt. I (London, 1802), 447 450. This forgery even provides a’Frcnch original’ of part of this P;:ssage on the magnet, which appears on p. 449-450. SeeJrremiah Hackett, ‘Bacon, Roger’, in I>.AL4., vol. 2, 35 42. If one is still not satisfied, there is the embarrassed admission by the editor the following year: ‘Mr. Dupre, the gentleman from whom we received the communications rcspccting Brunetto Latini, which have appeared in several numbers of our Magazine, has tdrought proper, though not till after detection, to confess that he has been imposing upon us, and that, in the supposed Ictters of that person, he only meant to give a picture of English literature and manners, as they existed at that period, in imitation of the Fcnch Anacharsis. WC so little approve of impositions of any kind, that we think it necessary to ask pardon of our readcm Tar having led them into a tcmporaty error”. (Mont/& Magazine or g/it/~ &i.s/er, 14 (1803) part 2, 391.) Nas, the error was far from temporary! Klaproth, 46; Mottclay, 43. ‘?S Mottclay, 59. 211 R.T. Gunther, fkr!ll .hw in O.$rd (Oxford, printrd for the author, l920-, vol. I, 298.

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M.A. 0rrz3j and cartography historian Lloyd Brown (as late as 1949).236 Mitchell, though he was well aware of the forgery, analyzed the Trlsor and came to the surprising conclusion that Latini’s discussion ‘of the polar property of the magnet anticipates the letter of Petrus Peregrinus by about nine years. This is frequently forgotten by commentators’.237 Leaving aside the date of the TY&OY (circa 1265), knowledge of the polar property, as we have seen above, is far older than Latini. We shall return to Roger Bacon’s true contribution to the magnet shortly. Before we leave Latini, though, we should very briefly consider the work of one of his most famous pupils, Dante Alighieri (1265-1321), who briefly mentioned the magnet in his La Diuina Commedia.238 In Canto 12 of the Paradise, Dante likens his attraction towards the voice of Italian scholastic philosopher St. (Giovanni) Bonaventura (1221-1274) to that of a compass needle for the north: ‘from the heart of one among the new lights moved a voice, that made me go to it as the magnetic needle does to the north star, in turning to is whereabouts.23g The Paradbo was probably written between 13 14- 132 1,240and so of course occurs long after the work of Peregrinus; it is mentioned here primarily because most magnetic writers do not bother to either date, cite or translate it properly.*“’ English Franciscan philosopher and scientist Roger Bacon (circa 12 13-circa 1292) is the last figure we shall examine before Peregrinus. Bacon, who was one of the principal medieval advocates of experimentation, was born at Ilchester, Somerset, and studied at Oxford. Hc received his degree before 1239, and became regent master of the Arts facult) at Paris; he was there at the same time as both Albertus Magnus and William of Auvergne (see above). He lectured on Aristotle (then forbidden) until at least 1247, and taught mathematics, philosophy and perspective at the studium of the Paris Franciscans between about 1257-1266.

MA. Orr, (Mrs. John Evctshed), Dnnc and tie varlya.r/rononrers (London, 1913), 292. Orr, however, includes a magnetic rcfcrcnce almost completely &torcd by others (cxccpt Schuck, (I 9 I5), 30), that of Ristoro d’Arczzo (128!!), who wrote in his Conr@i;iotcp CI Mondo, vol. 7, prt. 4, chapter 2, L’angola, the guidi Ii marinari, cht per la virtu dcl cielo + tratta c rivolta alla stella la qualc 6 chiamata tramontana. (‘l’he needle which guides marks, for by the virtue of the heavens it i:,attractcd and turned towards that star which is called thr North star’.) Brown, 127. 217 Mitchell, 145. ?I” Par more biographical information, see Holmes Dns/e. 21’8 Dante, Lo Diuina Commrdia,‘Paradise’, Canto 12, linrs 28 30; in: CA. Scartaxzini, cd., la DivinaCommcdiadi Dante diiglticn’(Milan, l893), 724; and GA. Scartaezini, G. Vandclli, and L. Polacco, Dcnte Alighicri Lo Dizka Commrdia(Milan, 1920), 759; translated by Hcmy Francis Gary, in: 7% Divine Cotwr?r 332. I’hc original reads: Del cuor dcll’una dcllc luci nuovc/Si mossc vow, $c l’ago alla stclla/Parcr mi fccc in volgcrmi al sue dove. Holmes, 44. 211 Klaproth has no citation; Mottelay, 43 44, gives the English of vv. 28 -30 but thr Italian of only v. 29; and iMitchell, 126, just rckrs to v. 26 but gives ncither English nor Italian. Mottelay, besides placing Dante between Latini (1260) and ‘l’orfarus (12GG) on account of his l2G5 birth, also ktlsely claims @. 43) that this is ‘the first poem written in the Italian language’.

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As he was almost certainly in France during part (if not all) of Latini’s exile there, it is possible the two met, but as we have seen above, the often-quoted story of Bacon giving Latini knowledge of the magnet is incorrect. Between 1266-1268, he wrote his opus Maius, Opus Minus and opus Trtium, under the orders of Pope Clement IV (died 1268). This was followed by the Compendium Studii Philosophiae (127 l-l 272), in which he harshly attacked various classes of society, particularly the Franciscans and Dominicans. Between 1277-l 279 his views were condemned by Franciscan master Jerome of Aeroli, later Pope Nicholas IV (1227-1292); he may also have been imprisoned. He wrote the Compendium Studii nleologiiae in 1292, but beyond that, little more is known of his lifc.z”2 Bacon discussed the maeet in his Opus Minus.243 Here, he described experiments in which hc had held a lodestone above and below a floating piece of magnetized iron. \Vhrrein if the iron is placed in a vessel full of water, and the hand is placed under the vessel, the touched part plunges into the water in the direction of the magnet. And if our outside magnet is carried down on all sides, the touched part of the iron above runs upright in the direction of thr placr where the magnet is brought down. And if part of the magnet is thrown in the way of part oT the touched iron, it llccs away Tram it, just as if it were an enemy; just as a sheep from a wolf. And when rhc magnet is rcmovcd the touched part proceeds in a straight line to the place in the hravrns similar to the part of the magnct.“t4

Thcsc cxpcrimcnts led him to conclude that it was not the Pole Star that attracted the magnetic nccdlc, but rather all four cardinal points of the heavens. ~lost of the philosophers arc ignorant of belirvrd until now that the star Nautira rathrr thr parts of the heavens. And so attttally thr south, tllr cast, tllr wrst, just

Ha&It,

35 42 AC:. Crombir.

thr cause of cmnmon rxpcriencc in these parts, and they [thr pole star] caused it. But this star does not cause it, it oprratrs well towards thrw other parts of the world, as to tlw north. Similarly they do not consider that four

and.1.D.

North, ‘BXOII, Roger’, in: D.S.B., vol. I, 377-385;

(Lolldun, 1863), 393 384. Mutklay dates tl& work 1254; I\larws, I9 has it right. later on in this ~prk, Bacon briclly discussrs the adamant as WCII (Brewer, 537). Bacon. O/m Minor, in: Brcwcr, 383 384. ‘I’hc original wads: Qtod si krrum ponatur in VBSPplrno aquas, VI mailus ponatur sub vasr, tacta pars dcmergit sc in aqua in directurn magnetis. RI si drkwtur undiquc- magnrs extra IIOS, i&rum super partcm tactam rrcctam curtit in dircctum cujuslihrt loci, ad qucm dckrtur magnrs. Et si ima pars magnetis objiciatur parti ferri tactac Rtgarct cam sicut inimiram; sirut agnus IU~NIIIL Et alhto magnetc pars tacta dirigit SC ad locum cocli similcm parti magnctis.

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parts of the world are distinguished in the magnet. But so many assign to one part, that with the star Nautica they come together in their narural properties.Y4S

Basing his argument on this passage, geophysicist Ronald Merrill has ar,gucd that Bacon was the first to question the northsouth directivity of the ma.gnetic ncedle;2J6 however, we have seen many prior examples, Neckam and (possibly) John of St. Amand being the most obvious. In addition, this passage is, like that ofJohn of St. Amand, another interesting anticipation of Gilbert’s 1600 idea of the world being a large magnet.2J7 Yet some scholars have gone further, and suggested that Bacon had further knowlcdgc, specifically concerning magnetic variation. This, however, is unlikely. Bacon does not notice that the needle varies in one direction (variation); rather, he says it can be attracted in all directions. Had he actually observed variation, hc would certainly have singled out the particular direction required. D.H. Tarling’s geomagnetic data suggest a variation of about 8 degrees east during this period, which is quite small, and likely to bc overlooked even if one were aware of it.24H Bacon is also important to our story because of his comments on Peter Percgrinus (fl. 1261-1269), whom he praised in the Opus Tohum. ‘There are but two perfect mathematicians,’ Bacon says, ‘John of London and Petrus de Maharne-Curia, a Picard.’ Further on, he described Peter in greater detail, calling him a great doctor, alchemist, cxperimentalist and technician: I know of only one pcnou who descrvcs to havr p&c li>r his work on rxpcrimcntal philosophy, for hc does not care f’nr the discoursrs of mm and thrir wordy w&arc, hut quietly and diligently pursues the works ol’ wisdom. ‘l‘hcrcforc, what others gropr aftrr blindly, as bats in the cwning twilight, this man contcmplatcs in all thr light of the sun ~CC;WSC hc is a master of cxperimcnt. Hcncc, he knows all natural scicncc whcthcr pertaining to mrdiciw and alchemy, or to matters cclcstial and tcrrcstrial. lnderd he is shamed if any layman. or grandma, or soldier, or country bumpkin knows anything hc himself does not know. Hc has worked diligcntiy in the smelting of metals, gold, silwr. and other metals hcsidrs; its also in thr working ol’ minerals; hr is thoroughly acquainted with all sorts of arms and implcmcnts used in milital) smirc and in hunting, bcsidrs which hr is skilled in agriculture and the mcasurcment ol’ ktnds. Hr has ronsidrwd carcliully the rxpcriments, dwiccs and incantations ofwitrhrs itnd magicians, und likwisc thr illusions and tricks of all jugglcn; SO that nothing is hiddrn from him whirl1 hr ought to know, and Itr knows hm\

II-3

Bacon, @KS ,\/inor, in: Brww, 384. ‘I’hr original reads: Vulgus philosophantium n&t causam cxpcticntiac wlgatac in hnc partc, VI credit quad stclla Nautira Ctrit ad hoc. Srd strlla non facit ad hoc srd pars cocli. Et ita hcnr opcrantur trcs aliar mundi partrs; scilirrt mrridics, orirns. et occidcns, sirut septrntrio. Similitcr non considrrant quad quutour imur partcs mundi distinguuantur in magnctc. Scd tot attrihutn~t uni parti. quar cum stt4lit conwnit Natttiru in naturali ~,f+!tiltC.

’

Mcnill, 3. ?,i Gilbert suggcstcd, in hct, that Pcrchtinus got his idcas 011 thr m;tgnrt directly f’rum Bacon: ‘Of date two htmdtwd ycttrS or more carlicr than F’rarastorio, is a stnitll work ittttihtttrd to one Pcttus Pcrcgrinus, a pretty eruditr bunk considering thr timr: many bclicvc it nwcs its origin to the opinions oT Roger Bacon, Englishman of &ford’ SW Gilhcrt’s /k Al~_~wfe,vol. I, &tptcr I,

R”:;I”.Tarling. 68

59.

to throw out all things false and magical. And so without him it is impossible that philosophy could bc completed, or be treated usetirlly or with certainty. BUI just as he cannot be valued with respect IO price, so he does not rstimatc his own worth. For should he wish to stand well with kings and princes, hc would find those who would honour and enrich him.““’

Apart from Bacon’s high praises of him, almost nothing else is known about Peter Peregrinus (fl. 1261- 1269). We do know that he was a member of the army of Sicilian king Charles I of Anjou (1226-l 285), who in 1269 was leading an assault on the city of Luccra; on 8 August of that year, he completed his Epistola2joand signed it ‘Petri Peregrini de Maricourt’, leading scholars to suggest that he was probably a native of the town of Meharicourt in Picardy.25t Peregrinus is also generally credited with a treatise on the construction of the astrolabe (1261).252 However, it is for the EpistolaPetri Markourt ad Sygerumde FoucacourtMilitetn,de

.‘I’,

Baco~l, O//U.\ ‘@%/litct~, in: Brew-r, 35, 46 47. lncompletcly translated by ‘Brother Potamain’ in Llcrtcns. Joseph Charles (‘Brother Arnold’), 77~ letter of FWt7c.rI’ercgritttrs on //beAlegne/ AD. 12G9 (NW York, 1904), xii-xiii. ‘I‘hc original passage reads: Non cnim cognosco nisi unum, qui laudcm potcs~ habcrc in opcribus hujus scientiac; nam ipsc non curat dc scrmonibus et pugnis vcrborum, srd pcrscquitur opera sapicntiac, ct in illis quiescit. Et idro quod alii caccutientcs nituntur viderc, UI vcspcrtilio luccm solir in rrcpusculo, ipsc in plcno fulgorc contcmplatur, propter hoc quod CSI dominus cxpcrimcntorum; ct idro scit naturalia per mpcrientiam, CI mcdicinalia, CI alkimistica, CI omnia tam coclcstia quam inlicriora; immo vrrccundatur si aliquis laicnr. vel vetula, vcl miles, vrl rusticus dr rurr sciat quac ipsc ignorat. Unde omnia opera fundcntium mctalla, CI quac oprrantur aura, rt argcnto, CI cartcris mctallis, CI omnibus mineralibus, ipse rimatus est; ct omnia qua’ ad militrm, cl ad arma, C’I ad venationcs ipsc novit; omnia quac ad agriculturam, et ad mcnsuras tcrrarum cl opera rusticorum, examinavit; ctiam cxpcrimcnta vctularum et sortilcgia, cl carmina carum CI omnium maaicorum considcravit: cl similitcr omnium ”ioculatorum illusioncs ct ingcnia; ut nihil quod sriri dcbeat lateat ipsum, L’Iquatcnus omnia fhlsa CI magica S&I rcprobarc. Et idro sine co impossihlc WI quod complcatur philosophia, net tractetur utilitcr ncc ccrtitidinalitcr. Scd hit, sicut non C*SIdignus prctio, sic ncc pretium acstirnat sui. Nam si vellct cum rcgibus c-1 principihus start-, bcnc invcnirct qui cum honorarct cl ditaret. Marginal glosses in IWO locations $tttify this ligurr as Prrcgrintts; dnc says ‘it should br noted this is about ‘Peterof Maharncuria.’ It scrms incrcdiblr, but .Liitcbell, 125, dates this work at l209! One would like to bclicw that this is just a typo, 1~111 if so, why place it bctwccn ‘Guyor’ (dated 1204 1206) and ‘Cardinal $tf Viny (l219)? For more on Pcrcerinus. SW Hainc Golden Robison. ‘Pctcr Pcrcrrrinus of Maricourt,’ in: D.M.A., vol. 9, 520 521;‘Rdward Grant, ‘Pctcr Pcrcgrinus’, in: D.S.B.,‘;ol. 10, 532 -540. 251 Guiscppc Boliito, and Camillo lMclei d’l+Xl, ///rnf/nlo de// ‘as/rolabia di fieka feregri~o diMarimr/ (I 927).

<.

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Mrgnete,2S3that Peter is most famous. The Epistola is divided into two parts. The first section, of ten short chapters, deals primarily with magnetic experiments and theories; the second, of three chapters, describes magnetic instruments. Peregrinus’ ‘wet’ compass appears in the first part, and his ‘dry’ compass in the second. The treatise begins (part 1, chapters l-2) by warning its readers that only those well trained in physics and astronomy will be able to follow his treatment of magnetism. Then Peregrinus gives (chapter 3) the four principal characteristics of superior lodestones: they have an untarnished iron color, are homogeneous, heavy, and have a ‘strong attraction for iron’.234 Hc then defines the north and south points of the stone (chapter 4), using for the first time his rounded lodestone (lapide rotundatoo). 253 With this, he tells (chapter 5) how to construct a Guyot type of ‘wet’ mariner’s compass. In his words, Placr a vessel containing thr lodestone in another large vessel fillrd with water, so that, in the first vessel, the stow may lx like a sailor in a ship. 1x1 the fir~ vcsscl have plenty of room in the second, just like a hoar lloating in the river, and I insist on plenty of room so that the free motion of the stone may not bc impeded by the contact of the smtll vessel ag&st the side OCthe larger veswl. For the stone, thus placed, will turn its small vessel about until its north point will stand in thr direction of thr northern point of the heavens.‘“”

Here we have a description of an unusual mariner’s compass, similar to the Guyot ‘wet’ model in principle, but using an entire lodestone instead of a needle, floated in a large cup. This, of course WChave already seen in the work of Roger Bacon. Pcregrinus clearly knows the traditional form of ‘wet’ compress as well, for he rcfcrs

‘I’herearc many editions. M;~~wscripts of thr 4;~tola exist in many I~urnpean lilxtrirs, incluling the Bodleian, Vatican, Trinity College (Dublin), Bihliothcqtte Nationalc, Lcidm, Grnrva and Turin cAlrctions. ‘l‘hc Rrst ptintrd rdition was that of Lindau physician Achillrs Cassrr (Augshurg, 1588); this was rcptintcd as the ‘Epistola Petri Pcrcgrini dc Xlsricourt ad Sygcrum dc Foucaucourt Militcm de Magttctc’ in: C. Hellmamt, cd., Rara Mgm~icn (Brrlin, 1898; 27 41. ‘I’hcrr arc xevcral English translations, including that of Sylvanus P. ‘I’homson (I~nndon, I902), Joseph Chat& hIcrterts or ‘Brother Arnold (NW York, 1904), and H. D. Harrandon, ‘Some carly contributions to thr history of gcomagnrtism-I’, Temttial Magneh and A/nw/&eric I~leeltici!r, 48, (I) (1943), 3 17. Other usrful editions arc ‘I’imoteo Bertrlli’s ‘Sulla Rpistola di Pirtro Pcrcgrino di Xlaticourt ct sopra alcuni truvati c troric mqnctiche drl secolo XIII’, BaNeffirto i hih/ioga$n e di skwi~ C//t Anze malemzfiche ejikhr, (Romr. 1868). vol. I, 70 89; and P. Radclrt-dc Gravr and D. Spciscr, ‘1~ De .\fqttc/e dr Picrrc dr Maticourt’, Rme d’Hihire de\ Scirtm el leun a/$lrmtion r, 28 (1975). 193 234. ‘5 Pctrtts Pcrcgrintts, Rara Alqne/ira. 30. ‘l‘hc original passagc wads: per furtctn licrri ct magni pondctis attractioncm. Pcrqrinus dots ttot givr all tltr diflicrcttt types or lodrstottr or magnet, as ti the cncyclopaedists (especially Vincent). Pctrus Pcrcgtinus, Rara Alagtetica, 3 I. Pctrus Pcrcgtinus, Rara Muye/ira, 3 I 32. ‘l’hr original passagr wads: ponc in alio tnagno vase plcno aquc, ut sit lapis in pti*mo vast sicut ttauta in navi; vas autrtn pritnum sit in srcuttdo spatiosc, sicut navis in fhtminr fhtctuans; CI dice, spatiusc, nr per cnntacttmt ipsius ad litnbium magtti vasis, naturalis mntus lapidis impcdiatur. Hit rnitn lapis, sir positus, vulvrt suttnt panuin vas quouque polus scptcmtrionalis Iapidis, in dirccto, scptemtrionali ccli. ‘3

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>‘It,

70

to placing a magnetic needle on a bit of wood or straw and placing it on water; then ‘one end will turn towards the star they call the nautical star.‘257 Pere.enus uses his ‘wet’ model compass to p&form some attraction experiments with lodestones, and proves the fundamental law of the ma.~let (chapier 7): like poles repel, and unlike poles attract. In his words, ‘as a r&, the ndrthei part in a stone attracts the southern part in another stone.258 This idea had already been implied by Albertus and Bacon. He also demonstrates the repulsion of like poles (chapter S-9), invoking a variation of the common Medieval agent-patient relationship to explain both phenomena; one pole is the agent, and the other the patient, and when the agent meets the patient there is attraction, but when agent meets agent, you get repulsion. *XI 0; course Peregrinus was not the first to try and explain magnetic force; notable examples we have seen include Neckam, Guido della Colone, Aquinas, Bacon, and John of St. Amand. Peregrinus then deals with the vexing question of the origin of magnetic force (chapter 10). He rejects the idea of the magnet being attracted to a mine of lodestones near the north pole (as we saw in Guinicelli); instead, he believes that ‘from the poles of the world the poles of the magnet receive their virtue. From this it is clearly apparent that the magnetic needle does not point to the nautical star, since the meridian circles do not intersect there but in the poles.260 Peregrinus is basically saying that the magnet points to the geographical or celestial pole instead of Polaris, and clearly realizes the latter is not exactly at the pole, but rather dcscrLcs d small circle around it. This is apparent from an earlier passage, in which he says the magnetic needle ‘does not point towards the star but rather towards the pol~‘.*~~ Possible prior candidates for this idea include John of St. Amand, Albertus, and Bacon. Percgrinus clearly sees the magnetic needle as pointing precisely north, and has no concept of magnetic variation. Some authors have attributed this to him,*‘j* based upon a gloss in one of the surviving manuscipts of the Epistola(Leyden Q 27), which claims that ‘the part [of the magnet] that looks towards the North sometimes inclines to the East. The exact quantity of this declination I have 237 Pctrus Pcregrinus, Rura Mqne/icu, 33. The original passage reads: una pars movetibur ad 5$+un, quam nauticam vacant. _ Petrus Peregrinus, Rara Mqnehca, 31-32. The original passage reads: pro rcgula, quod pars wptemtrionalis, in‘iapide, partemmeriodionalem attrahit in alio lapide. Pctrus Peregrmus, Rara Magnetica, 33-34. 2#,11 Pctrus Peregrinus, Rara Magneha, 35. The original passage reads: quare, a polis mundi, poli magnetis virtutem recipiunt. Et ex hoc apparet manifeste quod non ad stcliam nauticam movetur, T,yrn ibi non concurrant orbcs meridiani, sed in polis. _ Pctrus Peregrinus, Ram Mognelica, 33. The original passage reads: nam veritas est, quod non gjovetur ad stellam dictam, sed ad polum. MelchisSdek ThCvcnot, Receuil des vgwges (Paris, E. Michallet, 1681), 29. See also more recent writers, including Hutchinson, Advanced hh~k of eke&i& and magnehn (London, I9 I 7), vol. I, 4, and John Henry Poynting, Electricity and mgnefim (London, 1914), 169.

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observed, after numerous experiments, to bc five dcgrccs’. The gloss is a fifteenth century (and possibly later) addition to one of the compass figures in the manuscript, written in a different hand, and is certainly no cvidcncc for variation.263 The second part of the Episofa describes scvcral magnetic instruments. The first (part 2, chapter I) is a combined sighting tool and floating Guyot ‘wet’ compass: an oval magnet is sealed in a wooden cast and floated in a large round vessel of water. Around the vcsscl’s rim is a scale of 360 parts; a rule with sighting pins is then placed on the scaled magnet. This instrument could not only tell directions, but also celestial azimuths. As Percgrinus claims, it was a truly versatile device; with it, ‘you will know, morcovcr, by the azimuth, the hours, the ascendants, and ascensions, and all things ncccssary according to the science of the astrolabc’.‘“” It was a considerable improvcmcnt on the ‘wet compass then known, for the scale made, for the first time, prccisc mcasurcmcnt possible. The second instrument (chapter 2) was a pivoted ‘dry’ compass, like that of Neckam, but again with a scale attached. This time, a circular wooden vcsscl was covered with glass, and a pivot placed through its center, upon which was mounted a magnetized iron needle (which would point north-south) and, at right angles to it, an unmagnctizcd silver or brass nccdlc (which would point cast-west). The glass covering would have an inscribed scale, again with 360 parts. This ‘dry’ compass was clearly the one Pcrcgrinus rccommendcd for navigation: ‘Through this instrument you will be enabled to direct your cours’s(‘ towards states and islands, and any other place in the world, and whcrcsocvcr you may bc, on land or on sra, provided that their longitudes and latitudes arc known to you’.“‘” Dcspitc such claims, WC must rcmcmbcr that this dcvicc is not original; Percgrinus’ main innovation was an already-common ‘astrolabic’ scale, and it is simply false to claim that the Epirtola describes ‘the carlicst known pivoted compass’.“i” The third and final instrument (chapter 3) was intended to be a pcrpctual motion machine; it is basically a toothed wheel powcrcd by an oval magnet. Each tooth of the wheel is attracted by the magnet’s north pole, and, once it passes

Pctrus Pcrqrinus,

Rara Jfqdica.

39. ‘l’hr

orifiinal

reads: Per hoc instrumrnwnn dirigrs

grcssus IUOS ad civitatrs CI ins&s, c’t loca mundi quccumquc, VI ubicumquc fucris, in trrra \d kd nxni, dummodo longitudines rt latitudincs ipsorum sint tihi no~r. Mottelq, plz~tehcing p. 53: .\lrrrill, Ibid., 5, and Claire I.. Parkinson, Rr~ak//mu.g/~.~iti .h~ce

’

(London, Mansell Publishing,

198.5), 9, also inrorrccdy

aurihutr

the pivot IO Pcrcgrinus. Isear

Asimov, ‘Pcrcgrinus’ in: Arinrovi biographical dic/ioaap oj’.vitvm and /rd~ndogv (Garden City, N.Y ,, I St%), 48. inplics Ilic same.

72

the pole, it moves (by its momentum) to the south pole of the magnet, bringing up the next tooth. Each tooth is alternately attracted and repelled, yielding perpetual motion (at least in theory, but Peregrinus was of course unab!e to make a working modeQzG7 This idea seems to be a combination of seven4 sources. We have already inferred magnetically powered perpetual motion from Prester John and William of Auvergne, 268but an actual picture and description of a mechanical perpetual motion machine occurs in the sketchbook of French architect Villard de Honnecourt (circa 1225-1250).*@ Peregrinus’ treatise is one of the most important scientific textbooks and works of experimental physics of the thirteenth century.270 It exerted an enormous influence, not only in its time (there are at least thirty-one manuscript versions of it), but also upto the time of Gilbert. Despite this, however, we must not bc prejudiced by the exaggerated and incautious claims of many historians of science, who say that the Epistola is ‘the dawn of the scientific investigation of magnetism’.27’ Our study of Peregrinus’ predecessors has clearly shown that this view is not correct. Nor can we attribute to Percgrinus the invention of the terella,272 or the ‘carlicst suggestions relative to tcrrcstrial and cosmic magnetism’.27s Finally, he is not ‘the first to assign a dcfinitc position to the poles of a lodestone, and to give directions for determining which is north and which south’;‘74 this had been done earlier by Vincent, Albertus, Bacon and possibly John. A ‘middle ground’ is evidently necdcd in evaluating these extreme positions. Although the trcatisc of Percgrinus is very important for its breadth and clarity, our analysis shows that there is little in it that is entirely new. Both types of compasses, the ‘wet’ and the ‘dry’, had already been described, by Neckam, Guyot and others. The classification of magnets and lodestones had already become highly dcvelopcd in the lapidaries; and the various basic laws of magnetism had been described by many earlier authors. Their theories of the cause of magnetism

?l>i

Pcrcgrinus. Ruus, Rara Mqvc/ica, 39 40. m11 Asimov, 48, also claims Pcrcgrinus has ‘rhe first suggestion that magnetism might be ~grvcrtcd to kin& energy.’ Gimpcl, 127 130. Gilbert, vol. 2, chapter 35, 166, also believes that Pcqrinus ‘got the idea horn others’. Pcrcgrinus himself (p.39) claims that the many others had tried before him, but ;rtnc had used thr lodestone. Win, I, incorrectly says that Gilbert’s book is ‘the first cvcr scientific textbook’ and ignores Pcregrinus and others altogether. 27 Kramer, 191. 112 Mottclay, 47, says that ‘To Peregrinus is due the first inception of the terella’. We have $cady seen such a device in John of St. Amand (possibly earlier) and Bacon (certainly earlier). Sarton? vol. 2, 24. 27, Potamlan, xiv. Most of Potamian’s claims for the Epislolu, xiv-xv, are debatable. Brown, 128, makes the same errors.

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range from the simple to the complex, but they are clearly widely disseminated before 1269. Peregrinus may not have written ‘the first scientific treatise ever’;275 but he did collect, summarize, experiment upon, and extend the considerable knowledge of magnetism available in 1269. It is in this that his importance lies.