[27] PAGE 5, LINE 32. Page 5, line 40. _Franciscus Maurolycus_.--The work to which the myth of the magnetic mountains is thus credited is, _D.

Francisci Abbatis Messanensis Opuscula Mathematica_, etc. (Venet, MDLXXV, p. 122a). "Sed cur sagitta, vel obelus a vero Septentrione, quandoque ad dextram, {12} quandoque ad sinistram declinat? An quia sagitta, sicut magnes (cuius est simia) non verum Septentrionem, sed insulam quandam (quam Olaus Magnus Gothus in sua geographia vocat insulam magnetum) semper ex natura inspicere cogitur?"

[28] PAGE 5, LINE 35. Page 5, line 43. _Olaus Magnus_.--The famous Archbishop of Upsala, who wrote the history of the northern nations (_Historia de Gentibus Septentrionalibus_), of which the best edition, illustrated with many woodcuts, appeared in Rome in 1555. An English edition entitled _A Compendious History of the Goths, Swedes, and Vandals, and Other Northern Nations_ was printed in London in 1658; but it is much abbreviated and has none of the quaint woodcuts. The reference on p. 5 appears to be to the following passage on p. 409 (ed. 1555). "Demum in suppolaribus insulis magnetum montes reperiuntur, quorum fragmentis ligna fagina certo tempore applicata, in saxeam duritiem, et vim attractivam convertuntur," or the following on p. 89: "Magnetes enim in extremo Septentrionis veluti montes, unde nautica directio constat, reperiuntur: quorum etiam magnetum tam vehemens est operatio, ut certis lignis fagineis conjuncti, ea vertunt in sui duritiem, & naturam attractivam." On p. 343 is a woodcut depicting the penalties inflicted by the naval laws upon any one who should maliciously tamper with the compass or the loadstone, "qui malitiose nauticum gnomonem, aut compassum, & praecipue portionem magnetis, unde omnium directio dependet, falsaverit." He was to be pinned to the mast by a dagger thrust through his hand. It will be noted that the ships carried both a compass, and a piece of loadstone wherewith to stroke the needle.

There is in the Basel edition of this work, 1567, a note _ad lectorem_, on the margin of Carta 16a, as follows:

"Insula 30 milliarium in longitud. & latitud. Polo arctico subjecta.

"Vltra quam directorium nauticum bossolo dic[~u] uires amittit: propterea qud ilia insula plena est magnetum."

This myth of the magnetic mountains, probably originating with Nicander, appears, possibly from an independent source, in the East, in China, and in the tales of the Arabian Nights.

Ptolemy gives the following account in his _Geographia_ (lib. vii., cap.

2):

[Greek: Pherontai de kai allai sunecheis deka nesoi kaloumenai Maniolai en ais phasi ta siderous echonta helous ploia katechesthai, mepote tes Herikleias lithou peri autas genomenes, kai dia touto epiourois naupegeisthai.] Some editions omit the name of the Manioles from the passage.

No two authorities agree as to the place of these alleged magnetic mountains. Some place them in the Red Sea. Fracastorio, _De Sympathia et Antipathia_, cap. 7 (_Opera omnia_, Giunta edition, 1574, p. 63), gives the following reason for the variation of the compass:

"Nos igitur diligentius rem considertes dicimus causam, [~q] perpendiculum illud ad polum vertatur, esse montes ferri, & magnetis, qui sub polo sunt, vt negociatores affirmant, quorum species per incredibilem distantiam vsque ad maria nostra propagata ad perpendiculum vsq;, vbi est magnes, consuetam attractionem facit: propter distantiam autem quum debilis sit, non moueret quidem magnetem, nisi esset in perpendiculo: quare & si non trahit vsq; ac.

principium, vnde effluxit, at mouet tam[~e], & propinquiorem facit, quo potest. Quod si naues sorte vllae propinquiores sint illis montibus, ferrum omne ear[~u] cuellitur, propter quod nauigijs incolae vtuntur clauis ligneis astrictis."

In the last chapter of his _De Sympathia_, Fracastorio returns to the subject {13} in consequence of some doubts expressed by Giambattista Rhamnusio, seeing that the loadstones in the Island of Elba do not sensibly deflect the magnet. Fracastorio replies thus (p. 76, _op. citat._):

"Primum igitur vtrum sub Polo sint. Magnetis mtes, nec ne, sub ambiguo relinquamus, scimus enim esse, qui scribt planas magis esse eas regiones, de quo Paulus Iouius E[~p]us Nucerinus Lucul[~e]tus historiar[~u] nostri t[~e]poris scriptor, circa e Sarmatiae partem, quae Moscouia n[~u]c dicitur, diligent[~e] inquisitionem ab incolis fecit, qui ne eos eti inueniri montes retulere, qui Rhyphei ab antiquis dicti sunt: meminimus tam[~e] nos quasdam chartas vidisse earum, quas mundi mappas appellt, in quibus sub polo montes notati erant (qui Magnetis montes inscripti fuerant). Siue igitur sint, siue non sint ij montes, nihil ad nos in praesentiarum attinet, quando per montes polo subiectos cathenam illam montium intelligimus, qui ad septentrionem spectant tanti, & tam vasti, ac Ferri & Magnetis feraces: qui, & si magis distant a nostro mari, [~q] Iluae insulae montes, potentiores tamen sunt ad mouendum perpendiculum propter abundantiam & copi Ferri, & Magnetis. Fortasse autem, & qui in Ilua est Magnes, non multae actionis est in ea minera: multi enim d[~u] in minera sunt, minus valent, [~q] extracti, [~q] spirituales species sua habeant impedimenta: signum autem parum valere in sua minera Iluae insulae Magnetem, [~q] tam propinquus quum sit nauigijs illac praetereuntibus, perpendiculum tamen non ad se cuertit."

Aldrovandi in the _Musaeum Metallicum_ (Bonon., 1648, p. 554) gives another version of the fable:

"Nonnulli, animadversa hac Magnetis natura, scripserunt naves, quibus in Calecutanam regionem navigatur, clavis ferreis non figi, ob magneticorum frequentiam scopulorum, quoniam facile dissolverentur. Sed Garzias in Historia Aromatum id fabulosum esse tradidit: quandoquidem plures naues Calecutanae regionis, & illius tractus, ferreis clauis iunctas obseruauit: imm addidit naues in insulis Maldiuis ligneis quidem clauis copulari, non quia a Magnete sibi metuant, sed quoniam ferri inopia laborant."

According to Aldrovandi (p. 563, _op. citat._) the magnetic mountains are stated by Sir John Mandeville to be in the region of Pontus.

Lipenius in his _Navigatio Salomonis Ophritica illustrata_ (Witteb., 1660), which is a mine of curious learning, in discussing the magnetic mountains quotes the reply of Socrates to the inquirer who asked him as to what went on in the infernal regions, saying that he had never been there nor had he ever met any one who had returned thence.

The loadstone rock figures in several early charts. In Nordenskiold's _Facsimile Atlas_ (Stockholm, 1889) is given a copy of the Map of Johan Ruysch from an edition of Ptolemy, publisht in Rome in 1508, which shows four islands within the ice-bound Arctic regions. South of these islands and at the east of the coast of Greenland is the inscription: _Hic compassus navium non tenet, nec naves quae ferrum tenent revertere valent._ To which (on p. 63) Nordenskiold adds the comment: _Sagan on magnetberg, som skulle draga till sig fartyg forande jern, ar gamal._ And he recalls the reference of Ptolemy to the magnetic rocks in the Manioles. A second inscription is added to Ruysch's map in the ornamental margin that borders the Arctic islands. _Legere est in libro de inventione fortunati sub polo arctico rupem esse excelsam ex lapide magnete 33 miliarium germanorum ambitu._ This refers to a matter recorded in Hakluyt's _Principall Navigations_ (Lond., 1589, p. 249), namely: "A Testimonie of the learned Mathematician, maister John Dee, {14} touching the foresaid voyage of Nicholas de Linna. Anno 1360 a frier of Oxford, being a good Astronomer, went in companie with others to the most Northren islands of the world, and there leaving his company together, he travelled alone, and purposely described all the Northern islands, with the indrawing seas: and the record thereof at his return he delivered to the king of England. The name of which booke is _Inventio Fortunata_ (_aliter fortunae_) _qui liber incipit a gradu 54 usq. ad polum_."

The situation of the alleged loadstone rock is thus described by T.

Blundevile in his _Exercises_ in the chapter entitled _A plaine and full description of Peter Plancius his vniuersall Map, seruing both for sea and land, and by him lately put foorth in the yeare of our Lord, 1592_....

Written in our mother tongue by M. Blundeuill, Anno Domini 1594. The passage is quoted from p. 253 of the third edition (1606):

"Now betwixt the 72. and 86. degrees of North latitude he setteth downe two long Ilands extending from the West towardes the East somewhat beyond the first Meridian, and from the saide Meridian more Eastward he setteth downe other two long Ilandes ... and hee saith further that right under the North pole there is a certaine blacke and most high rocke which hath in circuite thirtie and three leagues, which is nintie and nine miles, and that the long Iland next to the Pole on the West is the best and most healthfull of all the North parts. Next to the foresaide Ilandes more Southward hee setteth downe the Ilandes of Crocklande and Groynelande, making them to haue a farre longer and more slender shape then all other mappes doe....

Moreouer at the East end of the last Ilande somewhat to the Southwarde, he placeth the Pole of the Lodestone which is called in Latine Magnes, euen as Mercator doth in his Mappe who supposing the first Meridian to passe through Saint Marie or Saint Michael, which are two of the outermost Ilandes of the Azores Eastwarde, placeth the Pole of the stone in the seuentie fiue degree of Latitude, but supposing the first Meridian to passe through the Ile Coruo, which is the furthest Ile of the Azores Westwarde, he placeth the Pole of the Lodestone in the seuentie seuen degree of Latitude."

Further, in the chapter on _The Arte of Nauigation_ in the same work (p.

332, _ed. citat._), Blundevile says:

"But whereas Mercator affirmeth that there should bee a mine or great rocke of Adamant, wherunto all other lesser rockes or Needles touched with the Lodestone doe incline as to their chiefe fountaine, that opinion seemeth to mee verie straunge, for truely I rather beleeue with Robert Norman that the properties of the Stone, as well in drawing steele, as in shewing the North Pole, are secret vertues given of GOD to that stone for mans necessarie vse and behoofe, of which secrete vertues no man is able to shewe the true cause."

The following is one of the inscriptions in the compartments of the great Chart of Mercator entitled _Ad Usum Navigantium_, published in 1569:

"Testatur Franciscus Diepanus peritissimus nauarchus volubiles libellas, magnetis virtute infectas recta mundi polum respicere in insulis C.

Viridis, Solis, Bonauista, et Maio, cui proxime astipulantur qui in Tercera, aut S. Maria (insulae sunt inter Acores) id fieri dicunt, pauci in earundem occidentalissima Corvi nomine id contingere opinantur. Quia vero locorum longitudinis a communi magnetis et mundi meridiano iustis de causis initium sumere oportet, plurium testimonium sequutus primum meridianum per dictas C. Viridis insulas protraxi, et quum alibi plus minusque a polo deuiante {15} magnete polum aliquum peculiarem esse oporteat quo magnetes ex omni mundi parte despiciant, euum hoc quo assignaui loco existere adhibita declinatione magnetis Ratisbonae obseruata didici. Supputaui autem eius poli situm etiam respectu insulae Corui, ut iuxta extremo primi meridiani positus extremi etiam termini, intra quos polum hunc inueniri necesse est, conspicui fierent, donec certius aliquod nauclerorum obseruatio attulerit."

Not all the map-makers were as frank as Paulus Merula, the author of a _Cosmographia Generalis_, printed by Plantin in 1605, at Leyden. For in the description of his _tabula universalis_ (_op. citat._ lib. iii., cap. 9) he says that he does not believe in the magnetic islands; but that he has put them into his chart lest unskilful folk should think that he had been so careless as to leave them out!

In the well-known myth of Ogier the Dane, immortalized by William Morris in the _Earthly Paradise_ (London, 1869, vol. i., p. 625), the loadstone rock is an island in the far North. But this story is not one of the Scandinavian sagas, and belongs to the Carlovingian cycle of heroic poems, of which the chief is the _Chanson de Roland_; and Ogier le Danois is really not a Dane but an _Ardennois_.

In the Middle-High German epic of Kudrun, the adventures of the fleet of Queen Hilda when attracted by the loadstone mountain at Givers, in the North Sea, are narrated at some length. (See _Kudrun, herausgegeben und erklart von Ernst Martin_. Halle, 1872.) One stanza will serve as a sample:

1126. Ze Givers vor dem berge lac daz Hilden her.

swie guot ir anker waeren, an daz vinster mer.

magneten die steine heten si gezogen.

ir guote segelboume stuonden alle gebogen.

which may be rendered:

1126. At Givers before the mountain lay Hilda's ships by.

Though good their anchors were, upon the murky sea.

Magnets the stones were had drawn them thither.

Their good sailing masts stood all bent together.

Recent magnetic research has shown that while there are no magnetic mountains that would account for the declination of the compass in general, yet there are minor local variations that can only be accounted for by the presence of magnetic reefs or rocks. The reader is referred to the account of the magnetic survey of Great Britain in the _Philosophical Transactions_ (1890) by Professors Rucker and Thorpe. The well-known rocky peak the Riffelhorn above Zermatt, in Switzerland, produces distinct perturbations in the direction of the compass within half a mile of its base. Such local perturbations are regularly used in Sweden for tracing out the position of underground lodes of iron ore. See Thalen, _Sur la Recherche des Mines de Fer a l'aide de Mesures magnetiques_ (Soc. Royale des Sciences d'Upsal, 1877); or B. R. Brough, _The Use of the Magnetic Needle in exploring for Iron Ore_ (_Scientific American_, Suppl. No. 608, p. 9708, Aug. 27, 1887).

Quite recently Dr. Henry Wilde, F.R.S., has endeavoured to elucidate the deviations of the compass as the result of the configurations of land and sea on the globe, by means of a model globe in which the ocean areas are covered with thin sheet iron. This apparatus Dr. Wilde calls a _Magnetarium_. See _Proc. Roy. Soc._, June, 1890, Jan., 1891, and June, 1891. {16} An actual magnetic rock exists in Scandinavia, the following account of it being given in the _Electrical Review_ of New York, May 3, 1899:

"The island of Bornholm in the Baltic, which consists of a mass of magnetic iron ore, is much feared by mariners. On being sighted they discontinue steering by compass, and go instead by lighthouses. Between Bornholm and the mainland there is also a dangerous bank of rock under water. It is said that the magnetic influence of this ore bank is so powerful that a balanced magnetic needle suspended freely in a boat over the bank will take a vertical position."

[29] PAGE 5, LINE 35. Page 5, line 43. _Josephus Costa._--This is unquestionably a misprint for _Acosta_ (Joseph de), the Jesuit, whose work _Historia natural y moral de las Indias_ was publisht at Seville in 1590.

An Italian edition appeared at Venice in 1596. The English edition, translated by E. Grimestone, _The Naturall and Morall Historie of the East and West Indies_, was publisht in London in 1604 and 1878. There are in Gilbert's book references to two writers of the name of Costa or Costaeus, Joannes Costa of Lodi, who edited Galen and Avicenna (see pp. 3 and 62), and Filippo Costa of Mantua, who wrote on antidotes and medicaments (see p.

141). The passage to which Gilbert refers is in Acosta's _Historia_ (ed.

1590, p. 64).

"Deziame a mi vn piloto muy diestro Portugues [~q] eran quatro puntos en todo el orbe, donde se afixaua el aguja con el Norte, y contaualas por sus nombres, de que no me acuerdo bien. Vno destos es el paraje de la Isla del Cueruo, en las Terceras, o Islas de Acores, como es cosa y a muy sabida.

Passando di alli a mas altura, Noruestea, que es dezir, [~q] declina al Poniente ... que me dig la causa desta efecto?... Porque vn poco de hierro de fregarse c la piedra Iman ...

"Mejor es, como dize Gregorio Theologo, que a la Fe se sujete la razon, pues aun en su casa no sabe bien entenderse...."

[30] PAGE 5, LINE 36. Page 5, line 45. _Livius Sanutus._--Livio Sanuto publisht at Venice in 1588 a folio work, _Geografia distinta in xii Libri; ne' quali, oltre l'esplicatione di nostri luoghi di Tolomeo, della Bussola e dell' Aguglia, si dichiarono le provincie ... dell' Africa_. In this work all Liber i. (pages 1-13) deals with observations of the compass, mentioning Sebastian Cabot, and other navigators. He gives a map of Africa, showing the central lakes out of which flow the _Zaires fluvius_ and the _Zanberes fluvius_.

[31] PAGE 6, LINE 2. Page 6, line 5. _Fortunius Affaitatus._--The work of Affaytatus, _Physicae ac astronomiae considerationes_, was publisht in Venice in 1549.

[32] PAGE 6, LINE 3. Page 6, line 6. _Baptista Porta._--The reference is to his celebrated _Magia naturalis_, the first edition of which came out in 1558 at Naples. An English edition, _Natural Magick by John Baptista Porta, a Neapolitaine_, was printed in London, 1658. Book seven of this volume treats "Of the wonders of the Load-stone." In the proem to this book Porta says: "I knew at Venice R. M. Paulus, the Venetian, that was busied in the same study: he was Provincial of the Order of servants, but now a most worthy Advocate, from whom I not only confess, that I gained something, but I glory in it, because of all the men I ever saw, I never saw any man more learned, or more ingenious, having obtained the whole body of learning; and is not only the Splendor and Ornament of Venice or Italy, but of the whole world." The reference is to Fra Paolo Sarpi, better known as the historian of the Council of Trent. Sarpi was himself known to Gilbert. {17}

His relations with Gilbert are set forth in the memoir prefixt to the edition of his works, _Opere di Fra Paolo Sarpi, Servita_ ... in Helmstat, MDCCLXI, p. 83. "Fino a questi giorni continuava il Sarpi a raccorre osservazioni sulla declinazione dell' Ago Calamitato; e poi ch' egli, atteso il variare di tal declinazione, assurdita alcuna non trovava riguardo al pensamento dell' Inglese Guglielmo Gilberto, cioe, che l'interno del nostro Globo fosse gran Calamita...." Here follows a quotation from a letter of Sarpi to Lescasserio:

"... Unde cuspidem trahi a tanta mole terrena, quae supereminet non absurde putavit Gullielmus Gilbertus, et in eo meridiano respicere recta polum, cave putes observatorem errasse. Est Vir accuratissimus, et interfuit omnibus observationibus, quas plures olim fecimus, et aliquas in sui gratiam, et cum arcubus vertici cupreo innitentibus, et cum innatantibus aquae, et cum brevibus, et cum longis, quibus modis omnibus et Hierapoli usus suit."

Sarpi had correspondence with Gilbert, Bacon, Grotius, and Casaubon. He also wrote on magnetism and other topics _in materia di Fisica_, but these writings have perisht. He appears to have been the first to recognize that fire destroyed the magnetic properties. (See _Fra Paolo Sarpi, the greatest of the Venetians_ by the Rev. Alexander Robertson, London, 1894; see also the notice of Sarpi in Park Benjamin's _Intellectual Rise in Electricity_.)