BIBLIOGRAPHY OF DE MAGNETE. (continued 2)

[83] Page 27, line 21. Page 27, line 17. venas ... venis.—It is impossible to give in English this play on words between veins of ore and veins of the animal body.

[84] Page 28, line 23. Page 28, line 20. quem nos verticitatem dicimus.—See the notes on Gilbert's glossary, ante. The word verticity remained in the language. On p. 140 of Joseph Glanvill's Vanity of Dogmatizing (Lond., 1661) we read: "We believe the verticity of the Needle, without a Certificate from the dayes of old."

[85] Page 29, line 15. Page 29, line 16. Nos verò diligentiùs omnia experientes.—The method of carefully trying everything, instead of accepting statements on authority, is characteristic of Gilbert's work. The large asterisks affixed to Chapters IX. X. XI. XII. and XIII. of Book I. indicate that Gilbert considered them to announce important original magnetical discoveries. The electrical discoveries of Book II., Chapter II., are similarly distinguished. A rich crop of new magnetical experiments, marked with marginal asterisks, large and small, is to be found in Book II., from Chapter XV. to Chapter XXXIV.; while a third series of experimental magnetical discoveries extends throughout Book III.

[86] Page 31, line 30. Page 31, line 25. verticem.—The context and the heading of the Chapter appear to require verticitatem. All editions, however, read verticem.

[87] Page 32, line 12. Page 32, line 9. Gartias ab horto.—The passage from Gartias ab Horto runs as follows in the Italian edition of 1616, Dell' Historia dei Semplici Aromati.... di Don Garzia dall' Horto, Medico Portughese, ... Venezia mdcxvi., p. 208.

"Nè meno è questa pietra velenosa, si come molti hanno tenuto; imperoche le genti di queste bande dicono che la Calamita presa per bocca, però in poca quantità, conserva la gioventù. La onde si racconta, che il Re di Zeilan il vecchio' s'haveva fatto fare tutti i vasi, dove si cocevano le vivãde per lui, di Calamita. Et questo lo disse à me colui proprio, che fu à questo officio destinato."

[88] Page 32, line 29. Page 32, line 29. Plutarchus & C. Ptolemæus.—The garlick myth has already been referred to in the note to p. 1. The originals are Plutarch, Quæstiones Platonicæ, lib. vii., cap. 7, § 1; C. Ptolemæus, Opus Quadripartitum, bk. i., cap. 3. The English translation of the latter, by Whalley (London, 1701), p. 10, runs: "For if the Loadstone be Rubbed with Garlick, the Iron will not be drawn by it."

[89] Page 32, line 32. Page 32, line 33. Medici nonnulli.—This is apparently a reference to the followers of Rhazes and Paracelsus. The argument of Gilbert as to the inefficacy of powdered loadstones is reproduced more fully by William Barlowe in his Magneticall Aduertisements (1616, p. 7), as follows:

"It is the goodnesse of the Loadstone ioyned with a fit forme that will shew great force. For as a very good forme with base substance can doe but very litle, so the substance of the Loadstone bee it neuer so excellent, except it haue some conuenient forme, is not auaileable. For example, an excellent loadstone of a pound waight and of a good fashion, being vsed artificially, may take vp foure pounds of Iron; beate it into small pouder, and it shall bee of no force to take vp one ounce of Iron; yea I am very well assured that halfe an ounce of a Loadstone of good fashion, and of like vertue will take vp more then that pound will doe being beaten into powder. Whence (to adde this by the way) it appeareth manifestly, that it is a great error of those Physitions and Surgeons, which to remedy ruptures, doe prescribe vnto their Patients to take the pouder of a Loadstone inwardly, and the small filing of iron mingled in some plaister outwardly: supposing that herein the magneticall drawing should doe great wonders."

[90] Page 33, line 11. Page 33, line 8. Nicolaus in emplastrum divinum....—Nicolaus Myrepsus is also known as Præpositas. In his Liber de compositione medicamentorum (Ingoldstat, 1541, 4to) are numerous recipes containing loadstone: for example, Recipe No. 246, called "esdra magna," is a medicine given for inflammation of the stomach and for strangury, compounded of some forty materials including "litho demonis" and "lapis magnetis." The emplastrum divinum does not, however, appear to contain loadstone. In the English tractate, Præpositas his Practise, a worke ... for the better preservation of the Health of Man. Wherein are ... approved Medicines, Receiptes and Ointmentes. Translated out of Latin in to English by L. M. (London, 1588, 4to), we read on p. 35, "An Emplaister of D. N. [Doctor Nicolaus] which the Pothecaries call Divinum." This contains litharge, bdellium, and "green brasse," but no loadstone.

Luis de Oviedo in his treatise Methodo de la Coleccion y reposicion de las Medicinas simples, edited by Gregorio Gonçalez, Boticario (Madrid, 1622), gives (p. 502) the following: "Emplasto de la madre. Recibe: Nuezes moscadas, clauos, cinamono, artemisia, piedraimon. De cada uno dos onças.... Entre otras differencias que ay de piedraiman se hallan dos. Vna que por la parte que mira al Septentrion, atrae el hierro, por lo quel se llama magnes ferrugineus. Y otra que atrae la carne, a la qual llaman magnes creaginus."

An "Emplastrum sticticum" containing amber, mummy, loadstone, hæmatite, and twenty other ingredients, and declared to be "vulnerum ulcerumque telo inflictorum sticticum emplastrum præstantissimum," is described on p. 267 of the Basilica chimica of Oswaldus Crollius (Frankfurt, 1612).

[91] Page 33, line 12. Page 33, line 9. Augustani ... in emplastrum nigrum....—Amongst the physicians of the Augsburg school the most celebrated were Adolphus Occo, Ambrosio Jung, and Gereone Seyler. This particular reference is to the Pharmacopœia Augustana ... a Collegio Medico recognita, published at Augsburg, and which ran through many editions. The recipe for the "emplastrum nigrum vulgo Stichpflaster" will be found on p. 182 of the seventh edition (1621-2). The recipe begins with oil of roses, colophony, wax, and includes some twenty-two ingredients, amongst them mummy, dried earthworms, and two ounces lapidis magnetis præparati. The recipe concludes: "Fiat Emplastrum secundùm artem. Perquàm efficax ad recentia vulnera et puncturas, vndè denominationem habet." The volume is a handsome folio not unlike Gilbert's own book, and bears at the end of the prefatory address ad Lectorem identically the same cul de lampe as is found on p. 44 of De Magnete.

The contradictions as to the alleged medicinal virtues of loadstone are well illustrated by Galen, who in his De facultatibus says that loadstone is like hæmatite, which is astringent, while in his De simplici medicina he says it is purgative.

[92] Page 33, line 14. Page 33, line 12. Paracelsus in fodicationum emplastrum.—Paracelsus's recipe for a plaster against stab-wounds is to be found in Wundt vund Leibartznei ... D. Theoph. Paracelsus (Frankf., 1555, pp. 63-67).

[93] Page 33, line 17. Page 33, line 15. Ferri vis medicinalis.—This chapter on the medicinal virtues of iron is a summary of the views held down to that time. Those curious to pursue the subject should consult Waring's Bibliotheca Therapeutica (London, 1878). Nor should they miss the rare black-letter quarto by Dr. Nicholas Monardus, of Seville, Joyfull Newes out of the New-found Worlde, translated by John Frampton (London, 1596), in which are recited the opinions of Galen, Rhazes, Avicenna, and others, on the medicinal properties of iron. In addition to the views of the Arabic authors, against whom his arguments are directed, Gilbert discusses those of Joannes Manardus, Curtius, and Fallopius. The treatise of Manardus, Epistolarum medicinalium libri viginti (Basil., 1549), is a résumé of the works of Galen and the Arabic physicians, but gives little respecting iron. Curtius (Nicolaus) was the author of a book, Libellus de medicamentis præparatibus et purgantibus (Giessæ Cattorum, 1614). The works of Fallopius are De Simplicibus Medicamentis purgentibus tractatus (Venet., 1566, 4to), and Tractatus de Compositione Medicamentorum (Venet., 1570, 4to).

[94] Page 34, line 7. Page 34, line 3. quorundã Arabum opiniones.—The Arabian authorities referred to here or elsewhere by Gilbert are:

Albategnius (otherwise known as Machometes Aractensis), Muhammad Ibn Jābir, Al-Battānī.

Avicenna (otherwise Abohali). Abou-’Ali al-’Hoséin ben-’Abd-Allah Ibn-Sinâ, or, shortly, Ibn Sîna.

Averroes. Muhammad Ibn Ahmed Ibn-Roschd, Abou Al-Walíd.

Geber. Abū Mūsā Jābir Ibn Haiyān, Al-Tarsūsi.

Hali Abas. ’Alí Ibn Al-’Abbás, Al Majúsi.

Rhazes, or Rasis. Muhammad Ibn Zakarīyā.

Serapio. Yuhanná Ibn Sarapion.

Thebit Ben-Kora (otherwise Thabit Ibn Corrah). Abū Thabit Ibn Kurrah, Al Harrani.

[95] Page 34, line 38.: Page 34, line 40. electuarium de scoria ferri descriptum à Raze.—Rhazes or Rasis, whose Arabic name was Muhammad Ibn Zakarīyā, wrote De Simplicibus, ad Almansorem. In Chap. 63 of this work he gives a recipe for a stomachic, which includes fennel, anise, origanum, black pepper, cinammon, ginger, and iron slag. In the splendid folio work of Rhazes publisht at Venice in 1542, with the title Habes candide lector Continẽtem Rasis, Libri ultimi, cap. 295, under the heading De Ferro, are set forth the virtues of iron slag: "Virtus scorie est sicut virtus scorie [a]eris sed debilior in purgãdo: et erugo ferri est stiptica: et cũ superpositur retinet fluxus menstruorũ.... Ait Paulus: aqua in qua extinguitur ferrũ calens.... Dico: certificatus sum experientia q˜ valet contra emorryodas diabetem et fluxum menstruorum."

[96] Page 35, line 16.: Page 35, line 13. Paulus.—This is not Fra Paolo Sarpi, nor Marco Polo, nor Paulus Jovius the historian, nor Paulus Nicolettus Venetus, but Paulus Aeginæ.

[97] Page 35, line 29.: Page 35, line 28. Sed malè Avicenna.—The advice of Avicenna to administer a draught containing powdered loadstone, reads as follows in the Giunta edition (Venice, 1608):

Lib. ii., cap. 470, p. 356. "Magnes quid est? Est lapis qui attrahit ferrum, quum ergo aduritur, fit hæmatites, & virtus ejus est sicut virtus illius.... Datur in potu [ad bibitionem limaturæ ferri, quum retinetur in ventre scoria ferri. Ipse enim extrahit] ipsam, & associatur ei apud exitum. Et dicitur, quando in potu sumuntur ex eo tres anulusat cum mellicrato, educit solutione humorem grossum malum."

The passage is identical with that in the Venetian edition of 1486, in both of which the liquid prescribed is mellicratus—mead. Gilbert says that the iron is to be given in juice of mercurialis. Here he only follows Matthiolus, who, in his Commentaries on Dioscorides, says (p. 998 of the Basil. edition of 1598): "Sed (vt idem Auicenna scribit) proprium hujusce ferrei pharmaci antidotum, est lapis magnes drachmæ pondere potus, ex mercurialis, vel betæ succo."

Serapio, in his De Simplicibus Medicinis (Brunfels' edition, Argentorati, 1531), p. 264, refers to Galen's prescription of iron scoriæ, and under the article de lapide magnetis, p. 260, quotes Dioscorides as follows: "Et uirtus huius lapidis est, ut quãdo dantur in potu duo onolosat ex eo cũ melicrato, laxat humores grossos."

The original passage in Dioscorides, De Materia Medica, ch. 147 (Spengel's edition of 1829) runs: "Τοῦ δὲ μαγνήτου λίθου ἄριστός ἐστιν ὁ τὸν σίδηρον εὐχερῶς ἕλκων, καὶ τὴν χρόαν κυανίζων, πυκνός τε κὰι οὐκ ἄγαν βαρύς. Δύναμιν δὲ ἔχει πάχους ἀγωγὸν διδόμενος μετὰ μελικράτου τριωβόλου βάρος· ἔνιοι δὲ τοῦτον καίοντες ἀντὶ αἱματίτου πιπράσκουσιν.."

In the Frankfurt edition of Dioscorides, translated by Ruellius (1543), the passage is:

"Magnes lapis optimus est, qui ferrum facile trahit, colore ad cœruleum uergente, densus, nec admodum gravis. Datur cum aqua mulsa, trium obolorum pondere, ut crassos humores eliciat. Sunt qui magnetem crematū pro hæmatite vendant...."

In the Scholia of Joannes Lonicerus upon Dioscorides In Dioscoridæ Anazarbei de re medica libros a Virgilio Marcello versos, Scholia nova, Ioanne Lonicero autore (Marburgi, 1543, p. 77), occurs the following:

"De recremento ferri. Cap. XLIX.

"Σκωρία σιδήρου. scoria vel recrementum ferri. Quæ per ignem à ferro et cupro sordes separantur ac reijciuntur, et ab aliis metallis σκωρία uocantur. Omnis scoria, maxime uero ferri exiccat. Acerrimo aceto macerauit Galenus ferri scoriam, ac deinde excocto, pharmacum efficax confecit ad purulentas quæ multo tempore uexatæ erant, aures, admirando spectantium effectu. Ardenti scoria uel recrementum ἕλκυσμα, inquit Galenus."

See also the Enarrationes eruditissimæ of Amatus Lusitanus (Venet., 1597), pp. 482 and 507, upon iron and the loadstone.

[98] Page 36, line 27. Page 36, line 29. eijcitur for ejicitur.

[99] Page 37, line 18. Page 37, line 22. ut Cardanus philosophatur.—Cardan's nonsense about the magnet feeding on iron is to be found in De Subtilitate, lib. vii. (Basil., 1611, p. 381).

[100] Page 38, line 4. Page 38, line 7. ferramenta ... in usum navigantium.—Compare Marke Ridley's A Short Treatise of Magneticall Bodies and Motions (Lond., 1613), p. a2 in the Preface Magneticall, where he speaks of the "iron-workes" used in building ships. The phraseology of Marke Ridley throws much light on the Latin terms used by Gilbert.

[101] Page 38, line 36. Page 38, line 42. vruntur; changed in ink to vrantur in the folio of 1600; but uruntur appears in the editions of 1628 and 1633.

[102] Page 39, line 12. Page 39, line 12. virumque; altered in ink to virunque in all copies of the folio edition of 1600.

[103] Page 40, line 32. Page 40, line 33. ad tantos labores exantlandos.—Pumping, as it was in mining before the invention of the steam engine, may best be realized by examining the woodcuts in the De re metallica of Georgius Agricola (Basil., Froben, 1556).

[104] Page 40, line 34. Page 40, line 36. quingentas orgyas.—Gilbert probably had in his mind the works of the Rorerbühel, in the district of Kitzbühl, which in the sixteenth century had reached the depth of 3,107 feet. See Humboldt's Cosmos (Lond., 1860, vol. i., p. 149).

[105] Page 43, line 34. Page 43, line 33. glis.—This word, here translated grit, does not appear to be classical Latin; it may mean ooze or slime.

[106] Page 45, line 25. Page 45, line 26. Motus igitur ... quinque. The five kinds of magnetic motions correspond in fact to the remaining sections of the book; as follows: Coitio, Book II.; Directio, Book III.; Variatio, Book IV.; Declinatio, Book V.; and Revolutio, Book VI.

[107] Page 46, line 7. Page 46, line 8. Jofrancus Offusius.—The reference is to the treatise De divina astrorum faculitate of Johannes Franciscus Offusius (Paris, 1570).

[108] Page 47, line 15. Page 47, line 18. Græci vocant ἠλεκτρον, quia ad se paleas trahit. In this discussion of the names given to amber, Gilbert apparently conceives ἠλεκτρον to be derived from the verb ἑλκεῖν; which is manifestly a doubtful etymology. There has been much discussion amongst philologists as to the derivation of ἠλέκτρον or ἤλεκτρον, and its possible connection with the word ἠλέκτωρ. This discussion has been somewhat obscured by the circumstance that the Greek authors unquestionably used ἤλεκτρον (and the Latins their word electrum) in two different significations, some of them using these words to mean amber, others to mean a shining metal, apparently of having qualities between those of gold and silver, and probably some sort of alloy. Schweigger, Ueber das Elektron der Alten (Greifswald, 1848), has argued that this metal was indeed no other than platinum: but his argument partakes too much of special pleading. Those who desire to follow the question of the derivation of ἤλεκτρον may consult the following authorities: J. M. Gessner, De Electro Veterum (Commentt. Soc. Reg. Scientt. Goetting., vol. iii., p. 67, 1753); Delaunay, Mineralogie der Alten, Part II., p. 125; Buttmann, Mythologus (Appendix I., Ueber das Elektron), Vol. II., p. 355, in which he adopts Gilbert's derivation from ἕλκειν; Beckmann, Ursprung und Bedeutung des Bernsteinnamens Elektron (Braunsberg, 1859); Th. Henri Martin, Du Succin, de ses noms divers et de ses variétés suivant les anciens (Mémoires de l'Académie des Inscriptions et Belles-lettres, Tome VI., 1^re série, 1^re partie, 1860); Martinus Scheins, De Electro Veterum Metallico (Inaugural dissertation, Berlin, 1871); F. A. Paley, Gold Worship in relation to Sun Worship (Contemporary Review, August, 1884). See also Curtius, Grundzüge der griechischen Etymologie, pp. 656-659. The net result of the disputations of scholars appears to be that ἠλέκτωρ (he who shines) is a masculine form to which there corresponds the neuter form ἤλεκτρον (that which shines). Stephanus admits the accentuation used by Gilbert, ἠλέκτρον, to be justified from the Timæus of Plato; see Note to p. 61.

[109] Page 47, line 16. Page 47, line 19. ἅρπαξ dicitur, & χρυσοφόρον.—With respect to the other names given to amber, M. Th. Henri Martin has written (see previous note) so admirable an account of them that it is impossible to better it. It is therefore given here entire, as follows:

"Le succin a reçu chez les anciens des noms très-divers. Sans parler du nom de λυγκούριον, lyncurium, qui peut-être ne lui appartient pas, comme nous le montrerons plus loin, il s'est nommé chez les Grecs le plus souvent ἤλεκτρον au neutre,¹ mais aussi ἤλεκτρος au masculin² et même au féminin,³ χρυσήλεκτρος,⁴ χρυσόφορος⁵ et peut-être, comme nous l'avons vu, χαλκολίθανον; plus tard σούχιον⁶ ou σουχίνος⁷, et ἠλεκτριανὸς λίθος;⁸ plus tard encore βερενίκη, βερονίκη ou βερνίκη;⁹ il s'est nommé ἅρπαξ chez les Grecs établis en Syrie;¹⁰ chez les Latins succinum, electrum, et deux variétés, chryselectrum et sualiternicum ou subalternicum;¹¹ chez les Germains, Gless;¹² chez les Scythes, sacrium;¹³ chez les Egyptiens, sacal;¹⁴ chez les Arabes, karabé¹⁵ ou kahraba;¹⁶ en persan, káruba.¹⁷ Ce mot, qui appartient bien à la langue persane, y signifie attirant la paille, et par conséquent exprime l'attraction électrique, de même que le mot ἅρπαξ des Grecs de Syrie. En outre, le nom de haur roumi (peuplier romain) était donné par les Arabes, non-seulement à l'arbre dont ils croyaient que le succin était la gomme, mais au succin lui-même. Haur roumi, transformé en aurum par les traducteurs latins des auteurs arabes, et consondu mal à propos avec ambar ou ambrum, nom arabe latinisé de l'ambre gris, a produit le nom moderne d'ambre, nom commun à l'ambre jaune ou succin, qui est une résine fossile, et à l'ambre gris, concrétion odorante qui se forme dans les intestines des cachalots. On ne peut dire avec certitude si le nom de basse grécité βερνίκη est la source ou le dérivé de Bern, radical du nom allemand du succin (Bernstein). Quoi qu'il en soit, le mot βερνίκη a produit vernix, nom d'une gomme dans la basse latinité, d'où nous avons fait vernis.¹⁸"

¹ Voyez Hérodote, III., 115; Platon, Timée, p. 80 c; Aristote, Météor., IV., 10; Théophraste, Hist. des plantes, IX., 18 (19), § 2; Des pierres, § 28 et 29; Diodore de Sic., V., 23; Strabon, IV., 6, n^o 2, p. 202 (Casaubon); Dioscoride, Mat. méd., I., 110; Plutarque, Questions de table, II., 7, § 1; Questions platoniques, VII., 1 et 7; Lucien, Du succin et des cygnes; le même, De Pastrologie, § 19; S. Clément, Strom. II., p. 370 (Paris, 1641, in-fol.); Alexandre d'Aphr., Quest. phys. et mor., II., 23; Olympiodore, Météor., I., 8, fol. 16, t. I., p. 197 (Ideler) et l'abréviateur d'Etienne de Byzance au mot Ηλεκτρίδες.

² Voyez Sophocle, Antigone, v. 1038, et dans Eustathe, sur l'Iliade, II., 865; Elien, Nat. des animaux, IV. 46; Quintus de Smyrne, V., 623; Eustathe, sur la Périégèse de Denys, p. 142 (Bernhardy), et sur l'Odyssée, IV., 73; et Suidas au mot ὑάλη.

³ Voyez Alexandre, Problèmes, sect. 1, proœm., p. 4 (Ideler); Eustathe, sur l'Odyssée, IV., 73, et Tzetzès, Chiliade VI., 650.

⁴ Voyez Psellus, Des pierres, p. 36 (Bernard et Maussac).

⁵ Voyez Dioscoride, Mat. méd., I., 110.

⁶ Voyez S. Clément, Strom., II., p. 370 (Paris, 1641, in-fol.). Il paraît distinguer l'un de l'autre τὸ σούχιον et τὸ ἤλεκτρον, probablement parce qu'il attribue à tort au métal ἤλεκτρον la propriété attractive du succin.

⁷ Voyez le faux Zoroastre, dans les Géoponiques, XV., 1, § 29.

⁸ Voyez le faux Zoroastre, au même endroit.

⁹ Voyez Eustathe, sur l'Odyssée, IV., 73; Tzetzès, Chil. VI., 650; Nicolas Myrepse, Antidotes, ch. 327, et l'Etymol. Gud. au mot ἤλεκτρον. Comparez Saumaise, Exert. plin., p. 778.

¹⁰ Voyez Pline, XXXVII., 2, s. 11, n^o 37.

¹¹ Voyez Pline, XXXVII., 2, s. 11-13, et Tacite, Germanie, ch. 45. La forme sualiternicum, dans Pline (s. 11, n^o 33), est donnée par le manuscrit de Bamberg et par M. Sillig (t. V., p. 390), au lieu de la forme subalternicum des éditions antérieures.

¹² Voyez Tacite et Pline, ll. cc.

¹³ Voyez Pline, XXXVII., 2, s. 11, n^o 40, Comp. J. Grimm, Gesch. der deutsch. Sprache, Kap. x., p. 233 (Leipzig, 1848, in-8).

¹⁴ Pline, l. c.

¹⁵ Voyez Saumaise, De homon. hyles iatricæ, c. 101, p. 162 (1689, in-fol.).

¹⁶ Voyez Sprengel, sur Dioscoride, t. II., pp. 390-391.

¹⁷ Voyez M. de Sacy, cité par Buttmann, Mythologus, t. II., pp. 362-363.

¹⁸ Voyez Saumaise, Ex. plin., p. 778. Il n'est pas probable que le mot βερνίκη ou βερενίκη nom du succin dans la grécité du moyen âge, soit lié étymologiquement avec le nom propre βερενίκη, qui vient de l'adjectif macédonien βερένικος pour φερένικος.

[110] Page 47, line 17. Page 47, line 20. Mauri vero Carabem appellant, quià solebant in sacrificijs, & deorum cultu ipsum libare. Carab enim significat offerre Arabicè; ita Carabe, res oblata; aut rapiens paleas, vt Scaliger ex Abohali citat, ex linguâ Arabicâ, vel Persicâ.—The printed text, line 18, has "Non rapiens paleas," but in all copies of the folio of 1600, the "Non" has been altered in ink into "aut," possibly by Gilbert's own hand. Nevertheless the editions of 1628 and 1633 both read "Non." There appears to be no doubt that the origin of the word Carabe, or Karabe, as assigned by Scaliger, is substantially correct. As shown in the preceding note, Martin adopted this view. If any doubt should remain it will be removed by the following notes which are due to Mr. A. Houtum Schindler (member of the Institution of Electrical Engineers), of Terahan.

Reference is made to the magnetic and electric properties of stones in three early Persian lapidaries. There are three stones only mentioned, amber, loadstone, and garnet. The electric property of the diamond is not mentioned. The following extracts are from the Tansûk nâmah, by Nasîr ed dîn Tûsi, A.D. 1260. The two other treatises give the first extracts in the same words.

"Kâhrubâ, also Kahrabâ [Amber],

"Is yellow and transparent, and has its name from the property, which it possesses, of attracting small, dry pieces of straw or grass, after it has been rubbed with cloth and become warm. [Note. In Persian, Kâh = straw; rubâ = the robber, hence Kâhrubâ = the straw-robber.] Some consider it a mineral, and say that it is found in the Mediterranean and Caspian seas, floating on the surface, but this is not correct. The truth is that Kâhrubâ is the gum of a tree, called jôz i rûmî [i.e., roman nut; walnut?], and that most of it is brought from Rûm [here the Eastern Rome] and from the confines of Sclavonia and Russia. On account of its bright colour and transparency it is made into beads, rings, belt-buckles, &c. ... &c.

"The properties of attraction and repulsion are possessed by other substances than loadstone, for instance, by amber and bîjâdah,¹ which attract straws, feathers, etc., and of many other bodies, it can be said that they possess the power of attraction. There is also a stone which attracts gold; it has a pure yellow colour. There is also a stone which attracts silver from distances of three or two yards. There are also the stone which attracts tin, very hard, and smelling like asafœtida, the stone attracting hair, the stone attracting meat, etc., but, latterly, no one has seen these stones: no proof, however, that they do not exist."

Avicenna (Ibn Sinâ) gives the following under the heading of Karabe (see Canona Medicinæ, Giunta edition, Venet., 1608, lib. ii., cap. 371, p. 336):

"Karabe quid est? Gumma sicut sandaraca, tendens ad citrinitatem, & albedinem, & peruietatem, & quandoque declinat ad rubedinem, quæ attrahit paleas, & [fracturas] plantarum ad se, & propter hoc nominatur Karabe, scilicet rapiens paleas, persicè.... Karabe confert tremori cordis, quum bibitur ex eo medietas aurei cum aqua frigida, & prohibet sputum sanguinis valde.... Retinet vomitum, & prohibet materias malas a stomacho, & cum mastiche confortat stomachum.... Retinet fluxum sanguinis ex matrice, & ano, & fluxum ventris, & confert tenasmoni."

Scaliger in De Subtilitate, Exercitatio ciii., § 12, the passage referred to by Gilbert says: "Succinum apud Arabas uocatur, Carabe: quod princeps Aboali, rapiens paleas, interpretatur" (p. 163 bis, editio Lutetiæ, 1557).

¹ Bîjâdah is classified by Muhammad B. Mansûr (A.D. 1470) and by Ibn al Mubârak (A.D. 1520) under "stones resembling ruby"; the Tansûk nâmah describes it in a separate chapter. From the description it can be identified with the almandine garnet, and the method of cutting this stone en cabochon, with hollow back in order to display its colour better is specially mentioned. The Tansûk nâmah only incidentally refers to the electric property of the bîjâdah in the chapter on loadstone, but the other two treatises specially refer to it in their description of the stone. The one has: "Bîjâdah if rubbed until warm, attracts straws and other light bodies just as amber does"; the other: "Bîjâdah, if rubbed on the hair of the head, or on the beard, attracts straws." Surûri, the lexicographer, who compiled a dictionary in 1599, considers the bîjâdah "a red ruby which possesses the property of attraction." Other dictionaries do not mention the attractive property, but some authors confound the stone with amber, calling it Kâbrubâ, the straw-robber. The bîjâdah is not rubellite (red tourmaline) for it is described in the lapidaries as common, whereas rubellite (from Ceylon) has always been rare, and was unknown in Persia in the thirteenth century.

[111] Page 47, line 21. Page 47, line 25. Succinum seu succum.—Dioscorides regarded amber as the inspissated juice of the poplar tree. From the Frankfurt edition of 1543 (De Medicinali materia, etc.) edited by Ruellius, we have, liber i., p. 53:

Populus. Cap. XCIII.

"... Lachrymam populorum commemorant quæ in Padum amnem defluat, durari, ac coire in succinum, quod electrum vocant, alii chrysophorum. id attritu jucundum odorem spirat, et aurum colore imitatur. tritum potumque stomachi ventrisque fluxiones sistit."

To this Ruellius adds the commentary:

"Succinum seu succina gutta à succo dicta, Græcis ἤλεκτρομ [sic], esse lachryma populi albæ, vel etiam nigræ quibusdam videtur, ab ejusdem arboris resina. Dioscoridi et Galeno dicta differens et πτερυγοφόρος, id est paleas trahens, quoque vocatur, quantum ei quoque Galenus tribuit li. 37, ca. 9. Succinum scribit à quibusdam pinei generis arboribus, ut gummi à cerasis excidere autumno, et largum mitti ex Germania septentrionali, et insulis maris Germanici. quod hodie nobis est compertissimum: ad hæc liquata igni valentiore, quia à frigido intensiore concrevit. pineam aperte olet, calidum primo gradu, siccum secundo, stomachum roborat, vomitum, nauseam arcet. cordis palpitationi prodest. pravorem humorum generationem prohibet.

"Germani weiss und gelbaugstein et brenstein.

"Galli ambra vocant: vulgo in corollis precariis frequens."

In the scholia of Johann Lonicer in his edition of Dioscorides, we find, lib. i., cap. xcviii., De nigra Populo:

"ἄιγειρος, populus nigra ... idem electrum vel succinum αἱγείρου lachrymam esse adseverat [Paulus], cui præter vires quæ ab Dioscoride recensentur, tribuit etiam vim sistendi sanguinis, si tusum in potu sumatur. Avicennæ Charabe, ut colligitur ex Joanne Jacobo Manlio, est electrum hoc Dioscoridis, attestatur Brunfelsius. Lucianus planè nullum electrum apud Eridanum seu Padum inveniri tradit, quandoquidem ne populus quidem illa ab nautis ei demonstrari potuerit. Plinius rusticas transpadanas ex electro monilia gestare adfirmat, quum à Venetis primum agnoscere didicissent adversus nimirum vitia gutturis et tonsillarum. Num sit purgamentum maris, vel lachryma populi, vel pinus, vel ex radiis occidentis solis nascatur, vel ex montibus Sudinorum profluat, incertum etiam Erasmus Stella relinquit. Sudinas tamen Borussiorum opes esse constat."

Matthiolus (in P. A. Mattioli ... Opera quæ extant omnia, hoc est Commentarii in vi libros P. Dioscoridis de materia medica, Frankfurt, 1596, p. 133) comments on the suggestion of Galen that amber came from the Populus alba, and also comments on the Arabic, Greek, and Latin names of amber.

The poplar-myth is commemorated by Addison (in Italy) in the lines:

Amber is, however, assuredly not derived from any poplar tree: it comes from a species of pine long ago extinct, called by Göppert the pinites succinifer.

Gilbert does not go into the medicinal uses, real or fancied, that have been ascribed to amber in almost as great variety as to loadstone. Pliny mentions some of these in his Natural Historie (English version of 1601, p. 609):

"He [Callistratus] saith of this yellow Amber, that if it be worne about the necke in a collar, it cureth feavers, and healeth the diseases of the mouth, throat, and jawes: reduced into pouder and tempered with honey and oile of roses, it is soveraigne for the infirmities of the eares. Stamped together with the best Atticke honey, it maketh a singular eyesalve for to help a dim sight: pulverized, and the pouder thereof taken simply alone, or else drunke in water with Masticke, is soveraigne for the maladies of the stomacke."

Nicolaus Myrepsus (Recipe 951, op. citat.) gives a prescription for dysentery and diabetes confiding chiefly of "Electri vel succi Nili (Nili succum appellant Arabes Karabem)."

[112] Page 47, line 22. Page 47, line 26. Sudauienses seu Sudini.—Cardan in De Rerum Varietate, lib. iii., cap. xv. (Editio Basil., 1556, p. 152), says of amber:

"Colligitur in quadam penè insula Sudinorum, qui nunc uocātur Brusci, in Prussia, nunc Borussia, juxta Veneticum sinum, & sunt orientaliores ostiis Vistulæ fluuii: ubi triginta pagi huic muneri destinati sunt," etc. He rejects the theory that it consists of hardened gum.

There exists an enormous literature concerning Amber and the Prussian amber industry. Amongst the earliest works (after Theophrastus and Pliny) are those of Aurifaber (Bericht über Agtstein oder Börnstein, Königsberg, 1551); Goebel (De Succino, Libri duo, authore Severino Gœbelio, Medico Doctore, Regiomont., 1558); and Wigand (Vera historia de Succino Borussico, Jena, 1590). Later on Hartmann, P. J. (Succini Prussici Physica et civilis Historia, Francofurti, 1677); and the splendid folio of Nathaniel Sendel (Historia Succinorum corpora aliena involventium, Lipsiæ, 1742), with its wealth of plates illustrating amber specimens, with the various included fossil fauna and flora. Georgius Agricola (De natura Fossilium, liber iv.), and Aldrovandi (Musæeum Metallicum, pp. 411-412) must also be mentioned. Bibliographies of the earlier literature are to be found in Hartmann (op. citat.), and in Daniel Gralath, Elektrische Bibliothek (Versuche und Abhandlungen der Naturforschenden Gesellschaft in Danzig, Zweiter Theil, pp. 537-539, Danzig and Leipzig, 1754). See also Karl Müllenhoff, Deutsche Altertumskunde, vol. i., Zweites Buch, pp. 211-224, Zinn und Bernsteinhandel (Berlin, 1870), and Humboldt's Cosmos (Bohn's edition, London, 1860, vol. ii., p. 493).

The ancient Greek myth according to which amber was the tears of the Heliades, shed on the banks of the river Eridanus over Phaethon, is not alluded to by Gilbert. It is narrated in well-known passages in Ovid and in Hyginus. Those interested in the modern handling of the myth should refer to Müllenhoff (op. citat., pp. 217-223, der Bernsteinmythus), or to that delightful work The Tears of the Heliades, by W. Arnold Buffum (London, 1896).

[113] Page 47, line 30. Page 47, line 36. quare & muscos ... in frustulis quibusdam comprehensos retinet.—The occurrence of flies in amber was well known to the ancients. Pliny thus speaks of it, book xxxvii., chap. iii. (p. 608 of P. Holland's translation of 1601):

"That it doth destill and drop at the first very clear and liquid, it is evident by this argument, for that a man may see diverse things within, to wit, Pismires, Gnats, and Lizards, which no doubt were entangled and stucke within it when it was greene and fresh, and so remain enclosed within as it waxed harder."

A locust embedded in amber is mentioned in the Musæum Septalianum of Terzagus (Dertonæ, 1664).

Martial's epigram (Epigrammata, liber vi., 15) is well known:

See also Hermann (Daniel), De rana et lacerta Succino Borussiaco insitis (Cracov., 1580; a later edition, Rigæ, 1600). The great work on inclusa in amber is, however, that of Nathaniel Sendel. See the previous note.

Sir Thomas Browne must not be forgotten in this connexion. The Pseudodoxia (p. 64 of the second edition, 1650) says:

"Lastly, we will not omit what Bellabonus upon his own experiment writ from Dantzich unto Mellichius, as he hath left recorded in his chapter De Succino, that the bodies of Flies, Pismires and the like, which are said oft times to be included in Amber, are not reall but representative, as he discovered in severall pieces broke for that purpose. If so, the two famous Epigrams hereof in Martiall are but poeticall, the Pismire of Brassavolus Imaginary, and Cardans Mousoleum for a flie, a meer phancy. But hereunto we know not how to assent, as having met with some whose reals made good their representments." See also Pope's Epistle to Dr. Arbuthnot, line 169.

[114] Page 47, line 34. Page 47, line 40. Commemorant antiqui quod succinum festucas et paleas attrahit.—Pliny (book xxxvii., chap. ii., p. 606 of the English edition of 1601) thus narrates the point:

"Hee [Niceas] writeth also, that in Aegypt it [amber] is engendered.... Semblably in Syria, the women (saith hee) make wherves of it for their spindles, where they use to call it Harpax, because it will catch up leaves, straws, and fringes hanging to cloaths."

p. 608. "To come to the properties that Amber hath, If it bee well rubbed and chaufed betweene the fingers, the potentiall facultie that lieth within, is set on work, and brought into actual operation, whereby you shall see it to drawe chaffe strawes, drie leaves, yea, and thin rinds of the Linden or Tillet tree, after the same sort as loadstone draweth yron."

[115] Page 47, line 36. Page 47, line 42. Quod etiam facit Gagates lapis.—The properties of Jet were well known to the mediæval writers. Julius Solinus writes in De Mirabilibus, chapter xxxiv., Of Britaine (English version of 1587 by A. Golding):

"Moreover to the intent to passe the large aboundance of sundry mettals (whereof Britaine hath many rich mynes on all sides), Here is store of the stone called Geate, and y^e best kind of it. If ye demaund y^e beautie of it, it is a black Jewell: if the qualitie, it is of no weight: if the nature, it burneth in water, and goeth out in Oyle; if the power, rubbe it till it be warme, and it holdeth such things as are laide to it; as Amber doth. The Realme is partlie inhabited of barbarous people, who even frõ theyr childhoode haue shapes of divers beastes cunninglye impressed and incorporate in theyr bodyes, so that beeing engraued as it were in theyr bowels, as the man groweth, so growe the marks painted vpon him...."

Pliny describes it as follows (p. 589, English edition of 1601):

"The Geat, which otherwise we call Gagates, carrieth the name of a toune and river both in Lycia, called Gages: it is said also, that the sea casteth it up at a full tide or high water into the Island Leucola, where it is gathered within the space of twelve stadia, and no where else: blacke it is, plaine and even, of a hollow substance in manner of the pumish stone, not much differing from the nature of wood; light, brittle, and if it bee rubbed or bruised, of a strong flavour." (Book xxxvi., chap. xviii.)

In the Commentary of Joannes Ruellius upon Dioscorides, Pedanii Dioscoridis Anazarbei de medicinali materia libri sex, Ioanne Ruellio Suessionensi interprete ... (Frankfurt, 1543, fol., liber quintus, cap. xcii.) is the following description:

"In Gagatarum lapidum genere, præferendus qui celeriter accenditur, et odorem bituminis reddit. niger est plerunque, et squalidus, crustosus, per quam levis. Vis ei molliendi, et discutiendi. deprehendit sonticum morbum suffitus, recreatque uuluæ strangulationes. fugat serpentes nidore. podagricis medicaminibus, et a copis additur. In Cilicia nasci solet, qua influens amnis in mare effunditur, proxime oppidum quod Plagiopolis dicitur. vocatur autem et locus et amnis Gagas, in cujus faucibus ii lapides inveniuntur.

"Gagates lapis colore atro, Germanis Schwartzer augstein, voce parum depravata, dicitur. odore dum uritur bituminis, siccat, glutinat, digerit admotus, in corollis precariis et salinis frequens."

And in the Scholia upon Dioscorides of Joannes Lonicer (Marpurgi, 1643, cap. xcvii., p. 80) is the following:

"De Gagate Lapide. Ab natali solo, urbe nimirum Gagae Lyciae nomen habet. Galenus se flumen isthuc et lapidem non invenisse, etiamsi naui parua totam Lyciam perlustravit: ait, se autem in caua Syria multos nigros lapides invenisse glebosos, qui igni impositi, exiguam flammam gignerent. Meminit hujus Nicander in Theriacis nempe suffitum hujus abigere venenata."

There is also a good account of Gagates (and of Succinum) by Langius, Epistola LXXV., p. 454, of the work Epistolarum medicinalium volumen tripartitum (Francofurti, 1589).

[116] Page 47, line 39. Page 47, line 45. Multi sunt authores moderni.—The modern authors who raised Gilbert's wrath by ignorantly copying out all the old tales about amber, jet, and loadstone, instead of investigating the facts, were, as he says at the beginning of the chapter, some theologians, and some physicians. He seems to have taken a special dislike to Albertus Magnus, to Puteanus (Du Puys), and to Levinus Lemnius.

[117] Page 47, line 39. Page 47, line 46. & gagate.—The editions of 1628 and 1633 both read ex gagate.

[118] Page 48, line 14. Page 48, line 16. Nam non solum succinum, & gagates (vt illi putant) allectant corpuscula.—The list of bodies known to become electrical by friction was not quite so restricted as would appear from this passage. Five, if not six, other minerals had been named in addition to amber and jet.

(1.) Lyncurium. This stone, about which there has been more obscurity and confusion than about any other gem, is supposed by some writers to be the tourmaline, by others a jacinth, and by others a belemnite. The ancients supposed it to be produced from the urine of the lynx. The following is the account of Theophrastus, Theophrastus's History of Stones. With an English Version ..., by "Sir" John Hill, London, 1774, p. 123, ch. xlix.-l. "There is some Workmanship required to bring the Emerald to its Lustre, for originally it is not so bright. It is, however, excellent in its Virtues, as is also the Lapis Lyncurius, which is likewise used for engraving Seals on, and is of a very solid Texture, as Stones are; it has also an attractive Power, like that of Amber, and is said to attract not only Straws and small pieces of Sticks, but even Copper and Iron, if they are beaten to thin pieces. This Diocles affirms. The Lapis Lyncurius is pellucid, and of a fire Colour." See also W. Watson in Philos. Trans., 1759, L. i., p. 394, Observations concerning the Lyncurium of the ancients.

(2.) Ruby.

(3.) Garnet. The authority for both these is Pliny, Nat. Hist., book xxxvii., chap. vii. (p. 617 of English edition of 1601).

"Over and besides, I find other sorts of Rubies different from those above-named;... which being chaufed in the Sun, or otherwise set in a heat by rubbing with the fingers, will draw unto them chaffe, strawes, shreads, and leaves of paper. The common Grenat also of Carchedon or Carthage, is said to doe as much, although it be inferiour in price to the former."

(4.) Jasper. Affaytatus is the authority, in Fortunii Affaitati Physici atque Theologi ... Physicæ & Astronomicæ cōsiderationes (Venet., 1549), where, on p. 20, he speaks of the magnet turning to the pole, likening it to the turning of a "palea ab Ambro vel Iaspide et hujuscemodi lapillis lucidis."

(5.) Lychnis. Pliny and St. Isidore speak of a certain stone lychnis, of a scarlet or flame colour, which, when warmed by the sun or between the fingers, attracts straws or leaves of papyrus. Pliny puts this stone amongst carbuncles, but it is much more probably rubellite, that is to say, red tourmaline.

(6.) Diamond. In spite of the confusion already noted, à propos of adamas (Note to p. 47), between loadstone and diamond, there seems to be one distinct record of an attractive effect having been observed with a rubbed diamond. This was recorded by Fracastorio, De sympathia et antipathia rerum (Giunta edition, Venice, MDLXXIIII, chap. v., p. 60 verso), "cujus rei & illud esse signum potest, cum confricata quædã vt Succinum, & Adamas fortius furculos trahunt." And (on p. 62 recto); "nam si per similitudine (vt supra diximus) fit hæc attractio, cur magnes non potius magnetem trahit, q˜ ferrum, & ferrum non potius ad ferrum movetur, quàm ad magnetem? quæ nam affinitas est pilorum, & furculorum cum Electro, & Adamante? præsertim q˜ si cum Electro affines sunt, quomodo & cum Adamante affinitatem habebunt, qui dissimilis Electro est?" An incontestable case of the observation of the electrification of the diamond occurs in Gartias ab Horto. The first edition of his Historia dei Semplici Aromati was publisht at Goa in India in 1563. In chapter xlviii. on the Diamond, occur these words (p. 200 of the Venetian edition of 1616): "Questo si bene ho sperimentato io più volte, che due Diamanti perfetti fregati insieme, si vniscono di modo insieme, che non di leggiero li potrai separare. Et ho parimente veduto il Diamante dopo di esser ben riscaldato, tirare à se le festuche, non men, che si faccia l'elettro." See also Aldrovandi, Musæum Metallicum (Bonon., 1648, p. 947).

Levinus Lemnius also mentions the Diamond along with amber. See his Occulta naturæ miracula (English edition, London, 1658, p. 199).

[119] Page 48, line 16. Page 48, line 18. Iris gemma.—The name iris was given, there can be little doubt, to clear six sided prisms of rock-crystal (quartz), which, when held in the sun's beams, cast a crude spectrum of the colours of the rainbow. The following is the account of it given in Pliny, book xxxvii., chap. vii. (p. 623 of the English version of 1601):

"... there is a stone in name called Iris: digged out of the ground it is in a certaine Island of the red sea, distant from the city Berenice three score miles. For the most part it resembleth Crystall: which is the reason that some hath tearmed it the root of Crystall. But the cause why they call it Iris, is, That if the beames of the Sunne strike upon it directly within house, it doth send from it against the walls that bee neare, the very resemblance both in forme and also in colour of a rainebow; and eftsoones it will chaunge the same in much varietie, to the great admiration of them that behold it. For certain it is knowne, that six angles it hath in manner of the Crystall: but they say that some of them have their sides rugged, and the same unequally angled: which if they be laid abroad against the Sunne in the open aire, do scatter the beames of the Sunne, which light upon them too and fro: also that others doe yeeld a brightnes from themselves, and thereby illuminat all that is about them. As for the diverse colours which they cast forth, it never happeneth but in a darke or shaddowie place: whereby a man may know, that the varietie of colours is not in the stone Iris, but commeth by the reverberation of the wals. But the best Iris is that which representeth the greatest circles upon the wall, and those which bee likest unto rainebowes indeed."

In the English translation of Solinus's De Mirabilibus (The excellent and pleasant worke of Julius Solinus containing the noble actions of humaine creatures, the secretes and providence of nature, the descriptions of countries ... tr. by A. Golding, gent., Lond., 1587), chapter xv. on Arabia has the following:

"Hee findeth likewise the Iris in the Red sea, sixe cornered as the Crystall: which beeing touched with the Sunnebeames, casteth out of him a bryght reflexion of the ayre like the Raynebowe."

Iris is also mentioned by Albertus Magnus (De mineralibus, Venet., 1542, p. 189), by Marbodeus Gallus (De lapidibus, Par. 1531, p. 78), who describes it as "crystallo simulem sexangulam," by Lomatius (Artes of curious Paintinge, Haydocke's translation, Lond., 1598, p. 157), who says, "... the Sunne, which casting his beames vpon the stone Iris, causeth the raine-bowe to appeare therein ...," and by "Sir" John Hill (A General Natural History, Lond., 1748, p. 179).

Figures of the Iris given by Aldrovandi in the Musæum Metallicum clearly depict crystals of quartz.

[120] Page 48, line 16. Page 48, line 18. Vincentina, & Bristolla (Anglica gemma siue fluor). This is doubtless the same substance as the Gemma Vincentij rupis mentioned on p. 54, line 16 (p. 54, line 18, of English Version), and is nothing else than the so-called "Bristol diamond," a variety of dark quartz crystallized in small brilliant crystals upon a basis of hæmatite. To the work by Dr. Thomas Venner (Lond., 1650), entitled Via Recta or the Bathes of Bathe, there is added an appendix, A Censure concerning the water of Saint Vincents Rocks neer Bristol (Urbs pulchra et Emporium celebre), in which, at p. 376, occurs this passage: "This Water of Saint Vincents Rock is of a very pure, cleare, crystalline substance, answering to those crystalline Diamonds and transparent stones that are plentifully found in those Clifts."

In the Fossils Arranged of "Sir" John Hill (Lond., 1771), p. 123, is the following entry: "Black crystal. Small very hard heavy glossy. Perfectly black, opake. Bristol (grottos, glass)" referring to its use.

The name Vincentina is not known as occurring in any mineralogical book. Prof. H. A. Miers, F.R.S., writes concerning the passage: "Anglica gemma sive fluor seems to be a synonym for Bristolla, or possibly for Vincentina et Bristolla. Both quartz and fluor are found at Clifton. In that case Vincentina and Bristolla refer to these two minerals, and if so one would expect Bristolla to be the Bristol Diamond, and Vincentina to be the comparatively rare Fluor spar from that locality."

At the end of the edition of 1653 of Sir Hugh Plat's Jewel House of Art and Nature, is appended A rare and excellent Discourse of Minerals, Stones, Gums, and Rosins; with the vertues and use thereof, By D. B. Gent. Here, p. 218, we read:

"We have in England a stone or mineral called a Bristol stone (because many are found thereabouts) which much resembles the Adamant or Diamond, which is brought out of Arabia and Cyprus; but as it is wanting of the same hardnesse, so falls it short of the like vertues."

[121] Page 48, line 18. Page 48, line 19. Crystallus.—Rock-crystal. Quartz. Pliny's account of it (Philemon Holland's version of 1601, p. 604) in book xxxvii., chap, ii., is:

"As touching Crystall, it proceedeth of a contrarie cause, namely of cold; for a liquor it is congealed by extreame frost in manner of yce; and for proofe hereof, you shall find crystall in no place els but where the winter snow is frozen hard: so as we may boldly say, it is verie yce and nothing else, whereupon the Greeks have give it the right name Crystallos, i. Yce.... Thus much I dare my selfe avouch, that crystall groweth within certaine rockes upon the Alps, and these so steepe and inaccessible, that for the most part they are constrained to hang by ropes that shall get it forth."

[122] Page 48, line 18. Page 48, line 20. Similes etiam attrahendi vires habere videntur vitrum ... sulphur, mastix, & cera dura sigillaris. If, as shown above, the electric powers of diamond and ruby had already been observed, yet Gilbert was the first beyond question to extend the list of electrics beyond the class of precious stones, and his discovery that glass, sulphur, and sealing-wax acted, when rubbed, like amber, was of capital importance. Though he did not pursue the discovery into mechanical contrivances, he left the means of that extension to his followers. To Otto von Guericke we owe the application of sulphur to make the first electrical machine out of a revolving globe; to Sir Isaac Newton the suggestion of glass as affording a more mechanical construction.

Electrical attraction by natural products other than amber after they have been rubbed must have been observed by the primitive races of mankind. Indeed Humboldt in his Cosmos (Lond., 1860, vol. i., p. 182) records a striking instance:

"I observed with astonishment, on the woody banks of the Orinoco, in the sports of the natives, that the excitement of electricity by friction was known to these savage races, who occupy the very lowest place in the scale of humanity. Children may be seen to rub the dry, flat and shining seeds or husks of a trailing plant (probably a Negretia) until they are able to attract threads of cotton and pieces of bamboo cane."

[123] Page 48, line 23. Page 48, line 25. arsenicum.—This is orpiment. See the Dictionary of metallick words at the end of Pettus's Fleta Minor.

[124] Page 48, line 23. Page 48, line 26. in convenienti cœlo sicco.—The observation that only in a dry climate do rock-salt, mica, and rock-alum act as electrics is also of capital importance. Compare page 56.

[125] Page 48, line 27. Page 48, line 31. Alliciunt hæc omnia non festucas modo & paleas.—Gilbert himself marks the importance of this discovery by the large asterisk in the margin. The logical consequence was his invention of the first electroscope, the versorium non magneticum, made of any metal, figured on p. 49.

[126] Page 48, line 34. Page 48, line 36. quod tantum siccas attrahat paleas, nec folia ocimi.—This silly tale that basil leaves were not attracted by amber arose in the Quæstiones Convivales of Plutarch. It is repeated by Marbodeus and was quoted by Levinus Lemnius as true. Gilbert denounced it as nonsense. Cardan (De Subtilitate, Norimb., 1550, p. 132) had already contradicted the fable. "Trahit enim," he says, "omnia levia, paleas, festucas, ramenta tenuia metallorum, & ocimi folia, perperam contradicente Theophrasto." Sir Thomas Browne specifically refuted it. "For if," he says, "the leaves thereof or dried stalks be stripped into small strawes, they arise unto Amber, Wax, and other Electricks, no otherwise then those of Wheat or Rye."

[127] Page 48, line 34. Page 48, line 38. Sed vt poteris manifestè experiri....

Gilbert's experimental discoveries in electricity may be summarized as follows:

[128] Page 48, line 35. Page 48, line 39. quæ sunt illæ materiæ.—Gilbert's list of electrics should be compared with those given subsequently by Cabeus (1629), by Sir Thomas Browne (1646), and by Bacon. The last-named list occurs in his Physiological Remains, published posthumously in 1679; it contains nothing new. Sir Thomas Browne's list is given in the following passage, which is interesting as using for the first time in the English language the noun Electricities:

"Many stones also both precious and vulgar, although terse and smooth, have not this power attractive; as Emeralds, Pearle, Jaspis, Corneleans, Agathe, Heliotropes, Marble, Alablaster, Touchstone, Flint and Bezoar. Glasse attracts but weakely though cleere, some slick stones and thick glasses indifferently: Arsenic but weakely, so likewise glasse of Antimony, but Crocus Metallorum not at all. Saltes generally but weakely, as Sal Gemma, Alum, and also Talke, nor very discoverably by any frication: but if gently warmed at the fire, and wiped with a dry cloth, they will better discover their Electricities." (Pseudodoxia Epidemica, p. 79.)

In the Philosophical Transactions, vol. xx., p. 384, is A Catalogue of Electrical Bodies by the late Dr. Rob. Plot. It begins "Non solum succinum," and ends "alumen rupeum," being identical with Gilbert's list except that he calls "Vincentina & Bristolla" by the name "Pseudoadamas Bristoliensis."

[129] Page 49, line 25. Page 49, line 30. non dissimili modo.—The modus operandi of the electrical attractions was a subject of much discussion; see Cardan, op. citat.

[130] Page 51, line 2. Page 51, line 1. appellunt.—This appears to be a misprint for appelluntur.

[131] Page 51, line 22. Page 51, line 23. smyris.—Emery. This substance is mentioned on p. 22 as a magnetic body.

[132] Page 52, line 1. Page 51, line 46. gemmæ ... vt Crystallus, quæ ex limpidâ concreuit. See the note to p. 48.

[133] Page 52, line 30. Page 52, line 32. ammoniacum.—Ammoniacum, or Gutta Ammoniaca, is described by Dioscorides as being the juice of a ferula grown in Africa, resembling galbanum, and used for incense.

"Ammoniack is a kind of Gum like Frankincense; it grows in Lybia, where Ammon's Temple was." Sir Hugh Plat's Jewel House of Art and Nature (Ed. 1653, p. 223).

[134] Page 52, line 38. Page 52, line 41. duæ propositæ sunt causæ ... materia & forma.—Gilbert had imbibed the schoolmen's ideas as to the relations of matter and form. He had discovered and noted that in the magnetic attractions there was always a verticity, and that in the electrical attractions the rubbed electrical body had no verticity. To account for these differences he drew the inference that since (as he had satisfied himself) the magnetic actions were due to form, that is to say to something immaterial—to an "imponderable" as in the subsequent age it was called—the electrical actions must necessarily be due to matter. He therefore put forward his idea that a substance to be an electric must necessarily consist of a concreted humour which is partially resolved into an effluvium by attrition. His discoveries that electric actions would not pass through flame, whilst magnetic actions would, and that electric actions could be screened off by interposing the thinnest layer of fabric such as sarcenet, whilst magnetic actions would penetrate thick slabs of every material except iron only, doubtless confirmed him in attributing the electric forces to the presence of these effluvia. See also p. 65. There arose a fashion, which lasted over a century, for ascribing to "humours," or "fluids," or "effluvia," physical effects which could not otherwise be accounted for. Boyle's tracts of the years 1673 and 1674 on "effluviums," their "determinate nature," their "strange subtilty," and their "great efficacy," are examples.

[135] Page 53, line 9. Page 53, line 11. Magnes vero....—This passage from line 9 to line 24 states very clearly the differences to be observed between the magnetical and the electrical attractions.

[136] Page 53, line 36. Page 53, line 41. succino calefacto.—Ed. 1633 reads succinum in error.

[137] Page 54, line 9. Page 54, line 11. Plutarchus ... in quæstionibus Platonicis.—The following Latin version of the paragraph in Quæstio sexta is taken from the bilingual edition publisht at Venice in 1552, p. 17 verso, liber vii., cap. 7 (or, Quæstio Septima in Ed. Didot, p. 1230).

"Electrum uero quæ apposita sunt, nequaquàm trahit, quem admodum nec lapis ille, qui sideritis nuncupatur, nec quicquā à seipso ad ea quæ in propinquo sunt, extrinsecus assilit. Verum lapis magnes effluxiones quasdam tum graves, tum etiam spiritales emittit, quibus aer continuatus & iunctus repellitur. Is deinceps alium sibi proximum impellit, qui in orbem circum actus, atque ad inanem locum rediens, ui ferrum fecum rapit & trahit. At Electrum uim quandam flammæ similem & spiritalem continet, quam quidem tritu summæ partis, quo aperiuntur meatus, foras eijcit. Nam leuissima corpuscula & aridissima quæ propè sunt, sua tenuitate atque imbecillitate ad seipsum ducit & rapit, cum non sit adeo ualens, nec tantum habeat ponderis & momenti ad expellendam aeris copiam, ut maiora corpora more Magnetis superare possit & uincere."

[138] Page 54, line 16. Page 54, line 18. Gemma Vincentij rupis.—See the note to p. 48 supra, where the name Vincentina occurs.

[139] Page 54, line 30. Page 54, line 35. orobi.—The editions of 1628 and 1633 read oribi.

[140] Page 55, line 34. Page 55, line 42. in euacuati.—The editions of 1628 and 1633 read inevacuati.

[141] Page 58, line 21. Page 58, line 25. assurgentem vndam ... declinat ab F.—These words are wanting in the Stettin editions.

[142] Page 59, line 9. Page 59, line 9. fluore.—This word is conjectured to be a misprint for fluxu but it stands in all editions.

[143] Page 59, line 22. Page 59, line 25. Ruunt ad electria.—This appears to be a slip for electrica, which is the reading of the editions of 1628 and 1633.

[144] Page 60, line 7. Page 60, line 9. tanq materiales radij.—The suggestion here of material rays as the modus operandi of electric forces seems to foreshadow the notion of electric lines of force.

[145] Page 60, line 10. Page 60, line 12. Differentia inter magnetica & electrica.—Though Gilbert was the first systematically to explore the differences that exist between the magnetic attraction of iron and the electric attraction of all light substances, the point had not passed unheeded, for we find St. Augustine, in the De Civitate Dei, liber xxi., cap. 6, raising the question why the loadstone which attracts iron should refuse to move straws. The many analogies between electric and magnetic phenomena had led many experimenters to speculate on the possibility of some connexion between electricity and magnetism. See, for example, Tiberius Cavallo, A Treatise on Magnetism, London, 1787, p. 126. Also the three volumes of J. H. van Swinden, Receuil de Mémoires sur l'Analogie de Electricité et du Magnétisme, La Haye, 1784. Aepinus wrote a treatise on the subject, entitled De Similitudine vis electricæ et magneticæ (Petropolis, 1758). This was, of course, long prior to the discovery, by Oersted, in 1820, of the real connexion between magnetism and the electric current.

[146] Page 60, line 25. Page 60, line 31. Coitionem dicimus, non attractionem.—See the remarks, at the outset of these Notes, on Gilbert's definitions of words.

[147] Page 60, line 33. Page 61, line 1. Orpheus in suis carminibus.—This passage is in the chapter Λιθικά of Orpheus, verses 301 to 327. See Note to p. 11, line 19.

[148] Page 61, line 15. Page 61, line 19. Platonis in Timæo opinio.—The passage runs (edition Didot, vol. ii., p. 240, or Stephanus, p. 80, C.):

Καὶ δὴ καὶ τὰ τῶν ὑδάτων πάντα ῥεύματα ἔτι δὲ τὰ τῶν κεραυνῶν πτώματα καὶ τὰ θαυμαζόμενα ἠλέκτρων περὶ τῆς ἕλξεως καὶ τῶν Ἡρακλείων λίθων, πάντων τούτων ὁλκὴ μὲν οὐκ ἔστιν οὐδένι ποτε, τὸ δὲ κενὸν εἶναι μηδεν περιωθεῖν τε αὑτὰ ταῦτα εἰς ἄλληλα, τό τε διακρινόμενα καὶ συγκρινόμενα πρὸς τήν αὑτῶν διαμειβόμενα ἕδραν ἕκαστα ἰέναι πάντα, τούτοις τοῖς παθήμασι πρὸς ἄλληλα συμπλεχθεῖσι τεθαυματουργημένα τῷ κατὰ τρόπον ζητοῦντι φανήσεται.

[149] Page 61, Line 30. Page 61, line 38. The English version of the lines of Lucretius is from Busby's translation.

[150] Page 62, line 5. Page 62, line 7. Iohannes Costæus Laudensis.—Joannes Costa, of Lodi, edited Galen and Avicenna. He also wrote a De universali stirpium Natura (Aug. Taurin., 1578).

[151] Page 63, line 3. Page 63, line 4. Cornelius Gemma 10. Cosmocrit.—This refers to the work De Naturæ Divinis Characterismis ... Libri ii. Avctore D. Corn. Gemma (Antv., 1575, lib. i., cap. vii., p. 123).

"Certè vt à magnete insensiles radij ferrum ad se attrahunt, ab echineide paruo pisciculo sistuntur plena nauigia, à catoblepa spiritu non homines solùm, sed & alta serpentum genera interimuntur, & saxa dehiscunt."

See also Kircher's Magneticum Naturæ Regnum (Amsterodami, 1667, p. 172), Sectio iv., cap. iii., De Magnete Navium, quæ Remora seu Echeneis dicitur. See the note to p. 7, line 21.

[152] Page 63, line 6. Page 63, line 7. Guilielmus Puteanus.—Puteanus (Du Puys) wrote a work De Medicamentorum quomodocunque Purgantium Facultatibus, Libri ii. (Lugd., 1552), in which he talks vaguely about the substantial "form" of the magnet, and quotes Aristotle and Galen.

[153] Page 63, line 21. Page 63, line 25. Baptistæ Portæ.—The passage in the translation is quoted from the English version of 1658, pp. 191, 192.

[154] Page 64, line 4. Page 64, line 9. Eruditè magis Scaliger.—Gilbert pokes fun at Scaliger, whose "erudite" guess (that the motion of iron to the magnet was that of the offspring toward the parent) is to be found in his book De Subtilitate, ad Cardanum, Exercitatio CII. (Lutetiæ, 1557, p. 156 bis).

[155] Page 64, line 7. Page 64, line 11. Diuus Thomas.—On p. 3 Gilbert had already spoken of St. Thomas Aquinas as a man of intellect who would have added more about the magnet had he been more conversant with experiments. The passage here quoted is from the middle of Liber vii. of his commentaries on the de Physica of Aristotle, Expositio Diui Thome Aquinatis Doctoris Angelici super octo libros Physicorum Aristotelis, etc. (Venice, Giunta edition, 1539, p. 96 verso, col. 2).

[156] Page 64, line 16. Page 64, line 24. Cardinalis etiam Cusanus.—Cardinal de Cusa (Nicolas Khrypffs) wrote a set of dialogues on Statics, Nicolai Cusani de staticis experimentis dialogus (1550), of which an English version appeared in London in 1650 with the title, The Idiot in four books; the first and second of wisdom, the third of the minde, the fourth of statick experiments. By the famous and learned C. Cusanus. In the fourth book of statick Experiments, Or experiments of the Ballance, occurs (p. 186) the following:

"Orat. Tell me, if thou hast any device whereby the vertues of stones may be weighed.

"Id. I thinke the vertue of the Load-stone might be weighed, if putting some Iron in one scale, and a Load-stone in the other, untill the ballance were even, then taking away the Load-stone, and some other thing of the same weight being put into the scale, the Load-stone were holden over the Iron, so that that scale wou'd begin to rise; by reason of the Load-stones attraction of the Iron, then take out some of the weight of the other scale, untill the scale wherein the iron is, doe sinke againe to the æquilibrium, or equality still holding the Load-stone unmovable as it was; I beleeve that by weight of what was taken out of the contrary scale, one might come proportionably to the weight of the vertue or power of the Load-stone. And in like manner, the vertue of a Diamond, might be found hereby, because they say it hinders the Load-stone from drawing of Iron; and so other vertues of other stones, consideration, being alwayes had of the greatnesse of the bodyes, because in a greater body, there is a greater power and vertue."

In the 1588 edition of Baptista Porta's Magiæ Naturalis Libri xx., in lib. vii., cap. xviii., occurs the description of the use of the balance to which Gilbert refers.

[157] Page 67, line 21. Page 67, line 22. aëris rigore.—All editions read thus, but the sense seems to require frigore.

[158] Page 67, line 27. Page 67, line 31. Fracastorius.—See his De Sympathia, lib. i., cap. 5 (Giunta edition, 1574, p. 60).

[159] Page 68, line 5. Page 68, line 6. Thaletis Milesij.—See the note to p. 11, line 26.

[160] Page 68, line 30. Page 68, line 35. Ità coitio magnetica actus est magnetis, & ferri, non actio vnius.—See the introductory remarks to these notes. There is a passage in Scaliger's De Subtilitate ad Cardanum (Exercitat. CII., cap. 5, p. 156 op. citat.) which may be compared with Gilbert's for its use of Greek terms: "Nã cùm uita dicatur actus animæ, acceptus est abs te actus pro actione. Sed actus ille est ἐντελέχεια, nõ autem ἔργον. At Magnetis attractio est ἔργον, non autẽ ἐντελέχεια." To which Gilbert retorts: "non actio unius, utriusque ἐντελέχεια; non ἔργον, συνεντελέχεια et conactus potius quam sympathia." He returns on p. 70 to the attack on Scaliger's metaphysical notions. There is a parallel passage in the Epitome Naturalis Scientiæ of Daniel Sennert (Oxoniæ, 1664), in the chapter De Motu.

[161] Page 71, line 4. Page 71, line 8. vt in 8. physicorum Themistius existimat.—See Omnia Themistii Opera (Aldine edition, 1533, p. 63), Book 8 of his Paraphrase on Aristotle's Physica.

[162] Page 71, line 9. Page 71, line 14. Quod verò Fracastorius.—Op. citat., lib. i., cap. 7, p. 62 verso.

[163] Page 73, line 2. Page 73, line 2. si A borealis.—The editions of 1628 and 1633 omit the twelve words next following.

[164] Page 73, line 9. Page 73, line 11. ex minera.—Minera is not a recognized word, even in late Latin. It occurs again, p. 97, line 12.

[165] Page 77, line 2. Page 77, line 2. multo magis.—This is an à fortiori argument. It is interesting to find Gilbert comparing the velocity of propagation of magnetic forces in space with the velocity of light. The parallel is completed in line 13 by the consideration that as the rays of light require to fall upon an object in order that they may become visible, so the magnetic forces require a magnetic object in order to render their presence sensible.

[166] Page 78, line 14. Page 78, line 16. Orbem terrarum distinguunt.—The editions of 1628 and 1633 here add a figure of a globe marked with meridians and parallels of latitude, but with an erroneous versorium pointing to the south. These editions also both read existentiam for the word existentium in line 20.

[167] Page 83, line 5. Page 83, line 5. magnes longior maiora pondera ferri attollit.—Gilbert discovered the advantage, for an equal mass of loadstone, of an elongated shape. It is now well known that the specific amount of magnetism retained by elongated forms exceeds that in a short piece of the same material subjected to equal magnetizing forces.

[168] Page 83, line 24. Page 83, line 28. Non obstant crassa tabulata.—Gilbert has several times referred (e.g., on p. 77) to the way in which magnetic forces penetrate solid bodies. The experimental investigation in this chapter is the more interesting because it shows that Gilbert clearly perceived the shielding action of iron to be due to iron conducting aside or diverting the magnetic forces.

[169] Page 85, line 26. Page 85, line 31. non conveniant.—The editions of 1628 and 1633 both read et conveniant.

[170] Page 86, line 3. Page 86, line 3. illud quod exhalat.—Literally, that which exhales, in the sense of that which escapes: but in modern English the verb exhale in the active voice is now not used of the substance that escapes, but is used of the thing which emits it. It must therefore be rendered that which is exhaled (i.e., breathed out).

[171] Page 86, line 13. Page 86, line 15. Ita tota interposita moles terrestris.—Gilbert's notion that the gravitational force of the moon in producing the tides acts through the substance of the earth may seem curiously expressed. But the underlying contention is essentially true to-day. The force of gravity is not cut off or screened off by the interposition of other masses. A recent investigation by Professor Poynting, F.R.S., has shown that so far as all evidence goes all bodies, even the densest, are transparent with respect to gravitational forces.

[172] Page 86, line 18. Page 86, line 20. Sed de æstus ratione aliàs.—There is no further discussion of the tides in De Magnete. But a short account is to be found in Gilbert's posthumous work De Mundo nostro Sublunari Philosophia nova (Amsterdam, Elzevir, 1651), in Lib. v., the part which in the manuscript was left in English, and was turned into Latin by his brother. It comprises about fifteen quarto pages, from Cap. X. to Cap. XIX. inclusive, beginning with a characteristic diatribe against Taisnier, Levinus Lemnius, and Scaliger. But in assigning causes he himself goes wide of the mark. Proceeding by a process of elimination he first shows that the moon's light cannot be the cause that impels the tides. "Luna," he says, "non radio, non lumine, maria impellit. quomodo igitur? Sane corporum conspiratione, acque (ut similitudine rem exponam) Magnetica attractione." This cryptic utterance he proceeds to explain by a diagram, and adds: "Quare Luna non tam attrahit mare, quàm humorem & spiritum subterraneum; nec plus resistit interposita terra, quàm mensa, aut quicquam aliud densum, aut crassum, magnetis viribus."

[173] Page 87, line 7. Page 87, line 9. armatura.—Here this means the cap or snout of iron with which the loadstone was armed. This is apparently the first use of the term in this sense.

In the Dialogues of Galileo (p. 369 of Salusbury's Mathematical Collections, Dialogue iii.), Sagredus and Salviatus discuss the arming of the loadstone, and the increased lifting power conferred by adding an iron cap. Salviatus mentions a loadstone in the Florentine Academy which, unarmed, weighed six ounces, lifting only two ounces, but which when armed took up 160 ounces. Whereupon Galileo makes Salviatus say: "I extreamly praise, admire, and envy this Authour, for that a conceit so stupendious should come into his minde. ... I think him [i.e., Gilbert] moreover worthy of extraordinary applause for the many new and true Observations that he made, to the disgrace of so many fabulous Authours, that write not only what they do not know, but whatever they hear spoken by the foolish vulgar, never seeking to assure themselves of the same by experience, perhaps, because they are unwilling to diminish the bulk of their Books."

[174] Page 87, line 12. Page 87, line 15. The reference to lib. 3 is a misprint for lib. 2. It is corrected in the edition of 1633, but not in that of 1628.

[175] Page 87, line 17. Page 87, line 21. conactu.—The editions of 1628 and 1633 read conatu.

[176] Page 88, line 2. Page 88, line 3. Coitio verò non fortior.—This heading to chap. xix., taken with the seven lines that follow, and the contrast drawn between unitio and coitio, throw much light on the fundamental sense attached by Gilbert to the term coitio. It is here clearly used in the sense of mutual tendency toward union. Note also the contrasted use in chap. xx. of the verbs cohære and adhære. Adhærence connotes a one-sided force (an impossibility in physics), cohærence a mutual force.

[177] Page 90, line 9. Page 90, line 9. nempè vt alter polus maius pondus arripiat.—This acute observation is even now not as well known as it ought to be. Only so recently as 1861 Siemens patented the device of fastening a mass of iron to one end of an electromagnet in order to increase the power of the other end. The fact, so far as it relates to permanent magnets was known to Servington Savery. See Philos. Transactions, 1729, p. 295.

[178] Page 92, line 3. Page 92, line 4. Suspendit in aëre ferrum Baptista Porta.—Porta's experiment is thus described (Natural Magick, London, 1658, p. 204): "Petrus Pellegrinus saith, he shewed in another work how that might be done: but that work is not to be found. Why I think it extream hard, I shall say afterwards. But I say it may be done, because I have now done it, to hold it fast by an invisible band, to hang in the air; onely so, that it be bound with a small thread beneath, that it may not rise higher: and then striving to catch hold of the stone above, it will hang in the air, and tremble and wag itself."

[179] Page 97, line 29. Page 97, line 33. Sed quæri potest ...—The question here raised by Gilbert is whether the lifting-power of magnets of equal quality is proportional to their weight. If a stone weighing a drachm will lift a drachm, would a stone that weighs an ounce lift an ounce? Gilbert erroneously answers that this is so, and that the lifting-power of a loadstone, whether armed or unarmed, is proportional to its mass.

The true law of the tractive force or lifting-power of magnets was first given in 1729 by James Hamilton (afterwards Earl of Abercorn) in a work entitled Calculations and Tables Relating to the Attractive Virtue of Loadstones ... Printed [at London?] in the Year 1729. (See also a paper in the Philos. Transactions, 1729-30, vol. xxxvi., p. 245). This work begins thus:

"The Principle upon which these Tables are formed, is this: That if Two Loadstones are perfectly Homogeneous, that is, if their Matter be of the same Specifick Gravity, and of the same Virtue in all Parts of one Stone, as in the other; and that Like Parts of their Surfaces are Cap'd or Arm'd with Iron; then the Weights they sustain will be as the Squares of the Cube Roots of the Weights of the Loadstones; that is, as their Surfaces."

Upon lifting-power see also D. Bernoulli, Acta Helvetica, iii., p. 223, 1758; P. W. Haecker, Zur Theorie des Magnetismus, Nürnberg, 1856; Van der Willigen, Arch. du Musée Teyler, vol. iv., Haarlem, 1878 ; S. P. Thompson, Philos. Magazine, July, 1888.

In the book of James Hamilton, p. 5, he mentions a small terrella weighing 139 English grains, which would sustain no less than 23,760 grains, and was valued at £21 13s. 10¾d.

In the Musæum Septalianum of Terzagus (Dertonæ, 1664, p. 42) is mentioned a loadstone weighing twelve ounces which would lift sixty pounds of iron.

Sir Isaac Newton had a loadstone weighing 3 grains, which he wore in a ring. It would lift 746 grains.

Thomson's British Annual, 1837, p. 354, gives the following reference: "In the Records of General Science, vol. iii., p. 272, there is an interesting description of a very powerful magnet which was sent from Virginia in 1776 by the celebrated Dr. Franklin to Professor Anderson, of Glasgow. It is now in the possession of Mr. Crichton. It weighs 2½ grains, and is capable of supporting a load of 783 grains, which is equivalent to 313 times its own weight."

[180] Page 99, line 10. Page 99, line 11. Manifestum est.—In this, as in many other passages, Gilbert uses this expression in the sense that it is demonstrable rather than meaning that it is obvious: for the fact here described is one that is not at all self-evident, but one which would become plain when the experiment had been tried. For other instances of this use of manifestum see pages 144, line 20; 158, line 19; 162, line 10.

[181] Page 100, line 20. Page 100, line 24. si per impedimēta ... pervenire possunt.—All editions agree in this reading, but the sense undoubtedly requires non possint. Compare p. 91, line 21.

[182] Page 102, line 4. Page 102, line 4. capite 4.—This is a misprint for capite 40, and is retained in the later editions. In the quotation from Baptista Porta, where the English version of 1658 is adhæred to, the words "& deturbat eam" have been omitted by the translator.

[183] Page 107, line 16. Page 107, line 18. Cardanus scribit.—The alleged perpetual motion machine is mentioned in De rerum varietate, lib. 9, cap. xlviii. (Basil., 1581, p. 641). See also the Note to p. 223. For Peregrinus and for Taisnier, see the note to p. 5, lines 8 and 12.

[184] Page 107, line 19. Page 107, line 21. Antonij de Fantis.—His work is: Tabula generalis scotice subtilitatis octo Sectionibus vniuersam Doctoris Subtilis Peritiā cōplectēs: ab excellentissimo doctore Antonio de Fātis taruisino edita ... Lugd., 1530.

[185] Page 108, line 26. Page 108, line 31. Cusani in staticis.—See the note to p. 64, line 16.

[186] Page 108, line 33. Page 108, line 41. Languidi ... tardiùs acquiescunt.—The editions of 1628 and 1633 omit these seven words.

[187] Page 109, line 11. Page 109, line 13. halinitro.—Either native carbonate of soda or native carbonate of potash might be meant, but not saltpetre. Scaliger, in his De Subtilitate ad Cardanum (Lutet., 1557, p. 164), Exercitatio CIII., 15, under the title, Nitrum non est Salpetræ, says: "More tuo te, tuaque confundis. Salpetræ inter salis fossilis ponis hîc. Mox Halinitrum inter salis, & nitri naturam, speciem obtinere."

"Sal nitrum is salt which is boiled out of the earth, especially fat earth, as in stables, or any place of excrements." (A Chymicall Dictionary explaining Hard Places and Words met withall in the Writings of Paracelsus ..., Lond., 1650.)

[188] Page 109, line 20. Page 109, line 23. arte ioculatoriâ.—Edition 1628, joculatoriâ; edition 1633, jaculatoriâ.

[189] Page 110, line 11. Page 110, line 12. qualis fuit Antonij denarius.—The Elizabethan version of Pliny (book xxxiii., ch. ix., p. 479) runs thus: "To come now unto those that counterfeit money. Antonius whiles hee was one of the three usurping Triumvirs, mixed yron with the Romane silver denier. He tempered it also with the brasen coine, and so sent abroad false and counterfeit money."

Georgius Agricola (De Natura Fossilium, p. 646) says:

"Sed ea fraus capitalis est, non aliter ac eorum qui adulterinas monetas cudunt, argento miscentes multam plumbi candidi portionem, aut etiam ferri, qualis fuit Antonii denarius, ut Plinius memoriæ tradidit. Nunc dicam de candido plumbo, nam majoris pretii est quàm aes. In quod plumbum album, inquit Plinius, addita aeris tertia portione candidi adulteratur stannum."

[190] Page 111, line 3. Page 111, line 3. Meminerunt Chatochitis lapis Plinius, atque Iulius Solinus.—The passage in Pliny (English version of 1601, book xxxvii., ch. x., p. 625) runs:

"Catochitis is a stone proper unto the Island Corsica: in bignesse it exceedeth ordinarie pretious stones: a wonderfull stone, if all be true that is reported thereof, and namely, That if a man lay his hand thereon, it will hold it fast in manner of a glewie gum."

[191] Page 111, line 7. Page 111, line 7. Sagda vel Sagdo.—Albertus Magnus in De Mineralibus (Venet., 1542, p. 202) says:

"Sarda quem alij dicunt Sardo lapis est qui se habet ad tabulas ligni sicut magnes ad ferrū, et ideo adhæret ita fortiter tabulis nauium quòd euelli nō possit, nisi abscindatur cum ipso ea pars tabulæ cui inhæserit, est autē in colore purissimus nitens."

And Pliny (op. citat., p. 629):

"Sagda is a stone, which the Chaldeans find sticking to ships, and they say it is greene as Porrets or Leekes."

[192] Page 111, line 8. Page 111, line 8. Euace.—Evax, king of the Arabs, is said to have written to Nero a treatise on the names, colours, and properties of stones. See the note on Marbodæus, p. 7, line 20.

[193] Page 113, line 14. Page 113, line 19. repulsus sit. The words read thus in all editions, but the sense requires repulsa sint.

[194] Page 113, line 23. Page 113, line 29. Electrica omnia alliciunt cuncta, nihil omninò fugant vnquam, aut propellunt. This denial of electrical repulsion probably arose from the smallness of the pieces of electric material with which Gilbert worked. He could hardly have failed to notice it had he used large pieces of amber or of sealing-wax. Electrical repulsion was first observed by Nicolas Cabeus, Philosophia Magnetica, Ferrara, 1629; but first systematically announced by Otto von Guericke in his treatise Experimenta Nova (ut vocantur) Magdeburgica, de Vacuo Spatio (Amstel., 1672).

[195] Page 113, line 29. Page 113, line 37. cùm de calore quid sit disputabimus.—The discussion of the nature of heat is to be found in Gilbert's De Mundo nostro Sublunari (Amstel., 1651), lib. i., cap. xxvi., pp. 77-88.

[196] Page 115, line 23. Page 115, line 23. trium vel quatuor digitorum.—Here as in all other places in Gilbert, digitus means a finger's breadth, so that three or four digits means a length of two or three inches, or from six to eight centimetres.

[197] Page 117, line 26. Page 117, line 25. ille Thebit Bencoræ trepidationis motus.

"Trepidation in the ancient Astronomy denotes a motion which in the Ptolemaic system was attributed to the firmament, in order to account for several changes and motions observed in the axis of the world, and for which they could not account on any other principle." (Barlow's Mathematical Dictionary.)

[198] Page 118, line 10. Page 118, line 8. cuspis is aut lilium.—Gilbert uses cuspis or lilium always of the North-pointing end of the needle. Sir Thomas Browne speaks of "the lilly or northern point"; but he differs from Gilbert in saying "the cuspis or Southern point" (Pseudodoxia Epidemica, 1650, p. 46). Only in one place (p. 101, line 5) does Gilbert speak of cuspis meridionalis. Everywhere else the south-pointing end is called the crux.

[199] Page 118, line 15. Page 118, line 13. nam æquè potens est.—Later observation showed this view to be incorrect. The horizontal component of the earth's magnetic field is not equally strong all over the globe, and the sluggishness of the needle's return to its position of rest is not due to the supporting pin becoming blunt with wear. The value of the horizontal component is zero at the north magnetic pole, and increases toward the magnetic equator. It is greatest near Singapore and in Borneo, being there more than twice as great as it is at London. (See Captain Creak in Report of Voyage of H.M.S. Challenger, Physics and Chemistry, vol. ii., part vi., 1889.)

[200] Page 119, line 5. Page 119, line 2. lapis.—Both Stettin editions read lapidis.

[201] Page 119, lines 9-11. Page 119, lines 7-9. The gist of the whole book is summarized in these lines. They furnish a cardinal example of that inductive reasoning which was practist by Gilbert, and of which Bacon subsequently posed as the apostle. Compare pages 41 and 211.

[202] Page 120, line 8. Page 120, line 5. dicturi sumus.—Change of verticity is treated of in book iii., chap. x., pp. 137 to 140.

[203] Page 125, line 24. Page 125, line 29. appositam.—All editions give this word, though the sense requires appositum.

[204] Page 128, line 9. Page 128, line 11. non nimis longum.—The editions of 1628 and 1633 read (wrongly) minus instead of nimis.

[205] Page 130, line 12. Page 130, line 14. The word hunc in the folio of 1600 is corrected in ink to tunc, and the Stettin editions both read tunc.

[206] Page 132, line 9. Page 132, line 10. minimus & nullius ponderis.—The editions of 1628 and 1633 both wrongly read est for &.

[207] Page 132, line 28. Page 133, line 1. nutat.—The editions of 1628 and 1633 both wrongly read mutat.

[208] Page 134, line 22. Page 134, line 25. in rectâ sphærâ.—The meaning of the terms a right or direct sphere, an oblique sphere and a parallel sphere are explained by Moxon on pages 29 to 31 of his book A Tutor to Astronomy and Geography (Lond., 1686):

"A Direct Sphere hath both the Poles of the World in the Horizon ... It is called a Direct Sphere, because all the Celestial Bodies, as Sun, Moon, and Stars, &c. By the Diurnal Motion of the Primum Mobile, ascend directly Above, and descend directly Below the Horizon. They that Inhabit under the Equator have the Sphere thus posited."

"An Oblique Sphere hath the Axis of the World neither Direct nor Parallel to the Horizon, but lies aslope from it."

"A Parallel Sphere hath one Pole of the World in the Zenith, the other in the Nadir, and the Equinoctial Line in the Horizon."

[209] Page 136, line 1. Page 136, line 1. præsenti.—The editions of 1628 and 1633 read sequenti, to suit the altered position of the figure.

[210] Page 137, line 24. Page 137, line 28. atque ille statim.—The Stettin editions both wrongly read illi.

[211] Page 139. There is a curious history to this picture of the blacksmith in his smithy striking the iron while it lies north and south, and so magnetizing it under the influence of the earth's magnetism. Woodcuts containing human figures are comparatively rare in English art of the sixteenth century; a notable exception being Foxe's Acts and Monuments with its many crude cuts of martyrdoms. The artist who prepared this cut of the smith took the design from an illustrated book of Fables by one Cornelius Kiliani or Cornelius van Kiel entitled Viridarium Moralis Philosophiæ, per Fabulas Animalibus brutis attributas traditæ, etc. (Coloniæ, 1594). This rare work, of which there is no copy in the British Museum, is illustrated by some 120 fine copper-plate etchings printed in the text. On p. 133 of this work is an etching to illustrate the fable Ferrarii fabri et canis, representing the smith smiting iron on the anvil, whilst his lazy dog sleeps beneath the bellows. The cut on p. 139 of Gilbert gives, as will be seen by a comparison of the pictures just the same general detail of forge and tools; but the position of the smith is reversed right for left, the dog is omitted, and the words Septrenio and Auster have been added.

In the Stettin edition of 1628 the picture has again been turned into a copper-plate etching separately printed, is reversed back again left for right, while a compass-card is introduced in the corner to mark the north-south direction.

In the Stettin edition of 1633 the artist has gone back to Kiliani's original plate, and has re-etched the design very carefully, but reversing it all right for left. As in the London version of 1600, the dog is omitted, and the words Septentrio and Auster are added. Some of the original details—for example, the vice and one pair of pincers—are left out, but other details, for instance, the cracks in the blocks that support the water-tub, and the dress of the blacksmith, are rendered with slavish fidelity.

It is perhaps needless to remark that the twelve copper-plate etchings in the edition of 1628, and the twelve completely different ones in that of 1633, replace certain of the woodcuts of the folio of 1600. For example, take the woodcut on p. 203 of the 1600 edition, which represents a simple dipping-needle made by thrusting a versorium through a bit of cork and floating it, immersed, in a goblet of water. In the 1633 edition this appears, slightly reduced, as a small inserted copper-plate, with nothing added; but in the 1628 edition it is elaborated into a full-page plate (No. xi.) representing the interior, with shelves of books, of a library on the floor of which stands the goblet—apparently three feet high—with a globe and an armillary sphere; while beside the goblet, with his back to the spectator, is seated an aged man, reading, in a carved armchair. This figure and the view of the library are unquestionably copied—reversed—from a well-known plate in the work Le Diverse & Artificiose Machine of Agostino Ramelli (Paris, 1558).

In the Emblems of Jacob Cats (Alle de Wercken, Amsterdam, 1665, p. 65) is given an engraved plate of a smith's forge, which is also copied—omitting the smith—from Kiliani's Viridarium.

[212] Page 140, line 2.. Page 140, line 2. præcedenti.—This is so spelled in all editions, though the sense requires præcedente.

[213] Page 141, line 21. Page 141, line 24. quod in epistolâ quâdam Italicâ scribitur.—The tale told by Filippo Costa of Mantua about the magnetism acquired by the iron rod on the tower of the church of St. Augustine in Rimini is historical. The church was dedicated to St. John, but in the custody of the Augustinian monks. The following is the account of it given by Aldrovandi, Musæum Metallicum (1648, p. 134), on which page also two figures of it are given:

"Aliquando etiam ferrum suam mutat substantiam, dum in magnetem conuertitur, & hoc experientia constat, nam Arimini supra turrim templi S. Ioannis erat Crux a baculo ferreo ponderis centum librarum sustentata, quod tractu temporis adeò naturam Magnetis est adeptum, vt, illivs instar, ferrum traheret: hinc magna admiratione multi tenentur, qua ratione ferrum, quod est metallum in Magnetem, qui est lapis transmutari possit; Animaduertendum est id à maxima familiaritate & sympathia ferri, & magnetis dimanare cum Aristoteles in habentibus symbolum facilem transitum semper admiserit. Hoc in loco damus imaginem frusti ferri in Magnetem transmutati, quod clarissimo viro Vlyssi Aldrouando Iulius Caesar Moderatus diligens rerum naturalium inquisitor communicauit; erat hoc frustum ferri colore nigro, & ferrugineo, crusta exteriori quodammodo albicante." And further on p. 557.

"Preterea id manifestissimum est; quoniam Arimini, in templo Sancti Ioannis, fuit Crux ferrea, quæ tractu temporis in magnetem conuersa est, & ab vno latere ferrum trahebat, & ab altero respuebat." See also Sir T. Browne's Pseudodoxia Epidemica (edition of 1650, p. 48), and Boyle's tract, Experiments and Notes about the Mechanical Production of Magnetism (London, 1676, p. 12).

Another case is mentioned in Dr. Martin Lister's A Journey to Paris (Lond., 1699, p. 83). "He [Mr. Butterfield] shewed us a Loadstone sawed off that piece of the Iron Bar which held the Stones together at the very top of the Steeple of Chartres. This was a thick Crust of Rust, part of which was turned into a strong Loadstone, and had all the properties of a Stone dug out of the Mine. Mons. de la Hire has Printed a Memoir of it; also Mons. de Vallemont a Treatise. The very outward Rust had no Magnetic Virtue, but the inward had a strong one, as to take up a third part more than its weight unshod." Gassendi and Grimaldi have given other cases.

Other examples of iron acquiring strong permanent magnetism from the earth are not wanting. The following is from Sir W. Snow Harris's Rudimentary Magnetism (London, 1872, p. 10).

"In the Memoirs of the Academy of Sciences for 1731, we find an account of a large bell at Marseilles having an axis of iron: this axis rested on stone blocks, and threw off from time to time great quantities of rust, which, mixing with the particles of stone and the oil used to facilitate the motion, became conglomerated into a hardened mass: this mass had all the properties of the native magnet. The bell is supposed to have been in the same position for 400 years."

[214] Page 142, line 13. Page 142, line 15. tunc planetæ & corpora cœlestia.—Gilbert's extraordinary detachment from all metaphysical and ultra-physical explanations of physical facts, and his continual appeal to the test of experimental evidence, enabled him to lift the science of the magnet out of the slough of the dark ages. This passage, however, reveals that he still gave credence to the nativities of judicial Astrology, and to the supposed influence of the planets on human destiny.

[215] Page 144, line 14. Page 144, line 14. ijdem.—The editions of 1628 and 1633 erroneously read iisdem.

[216] Page 147, line 27. Page 147, line 29. ex optimo aciario.—Gilbert recommended that the compass-needle should be of the best steel. Though the distinction between iron and steel was not at this time well established, there is no reason to doubt that by aciarium was meant edge-steel as used for blades. Barlowe, in his Magneticall Advertisements (Lond., 1616), p. 66, gives minute instructions for the fashioning of the compass-needle. He gives the preference to a pointed oval form, and describes how the steel must be hardened by heating to whiteness and quenching in water, so that it is "brickle in a manner as glass it selfe," and then be tempered by reheating it over a bar of red hot iron until it is let down to a blue tint. Savery (Philos. Trans., 1729) appears to have been the first to make a systematic examination of the magnetic differences between hard steel and soft iron.

Instructions for touching the needle are given in the Arte de Nauegar of Pedro de Medina (Valladolid, 1545, lib. vi., cap. 1).

[217] Page 149, line 8. Page 149, line 9. per multa sæcula.—Compare Porta's assertion (p. 208, English edition) "iron once rubbed will hold the vertue a hundred years." Clearly not a matter within the actual experience of either Porta or Gilbert.

[218] Page 153, line 2. Page 153, line 2. Cardani ab ortu stellæ in cauda vrsæ.—What Cardan said (De Subtilitate, Edit. citat., p. 187) was: "ortum stellæ in cauda ursæ minoris, quæ quinque partibus orientalior est polo mundi, respicit."

[219] Page 153, line 21. Page 153, line 26. sequitur quod versus terram magnam, siue continentem ... à vero polo inclinatio magnetica fiat.—Gilbert goes on to point out how, at that date, all the way up the west European coast from Morocco to Norway, the compass is deflected eastward, or toward the elevated land. He argued that this was a universal law.

In Purchas his Pilgrimes (Lond., 1625), in the Narrative, in vol. iii., of Bylot and Baffin's Voyage of 1616, there is mentioned an island between Whale-Sound and Smith's Sound, where there had been observed a larger variation than in any other part of the world. Purchas, in a marginal note, comments on this as follows: "Variation of the Compass 56° to the West, which may make questionable D. Gilbert's rule, tom. 1., l. 2, c. 1, that where more Earth is more attraction of the Compass happeneth by variation towards it. Now the known Continents of Asia, &c., must be unspeakably more than here there can be, & yet here is more variation then about Jepan, Brasil, or Peru, &c."

Gilbert's view was in truth founded on an incomplete set of facts. At that time, as he tells us, the variation of the compass at London was 11⅓ degrees eastward. But he did not know of the secular change which would in about fifty-seven years reduce that variation to zero. Still less did he imagine that there would then begin a westward variation which in the year 1816 should reach 24° 30', and which should then steadily diminish so that in the year 1900 it should stand at 16° 16' westward. For an early discussion of the changes of the variation see vol. i. of the Philosophical Transactions (Abridged), p. 188. Still earlier is the classical volume of Henry Gellibrand, A Discovrse Mathematical on the Variation of the Magneticall Needle (Lond., 1635). Gilbert heads chapter iii. of book iiii. (p. 159) with the assertion Variatio uniuscuiusque loci constans est, declaring that to change it would require the upheaval of a continent. Gellibrand combats this on p. 7 of the work mentioned. He says:

"Thus hitherto (according to the Tenents of all our Magneticall Philosophers) we have supposed the variations of all particular places to continue one and the same. So that when a Seaman shall happly returne to a place where formerly he found the same variation, he may hence conclude he is in the same former Longitude. For it is the Assertion of Mr. Dr. Gilberts. Variatio vnicuiusq; Loci constans est, that is to say, the same place doth alwayes retaine the same variation. Neither hath this Assertion (for ought I ever heard) been questioned by any man. But most diligent magneticall observations have plainely offred violence to the same, and proved the contrary, namely that the variation is accompanied with a variation."